Seborrheic Keratoses

Seborrheic keratoses are common lesions, usually appearing around the fourth decade of life.¹ They can be single or multiple and can occur anywhere on the body, with the exception of the palms and soles. Clinically, they are sharply demarcated and slightly raised, appearing as if they were stuck on the skin’s surface (Fig. 20-1). Many have a verrucous surface with a soft, friable consistency; however, others may have a smooth surface. Characteristically, all seborrheic keratoses show keratotic plugs on careful surface inspection. Their color is usually brownish to brown-black, although color can vary from flesh color to deep black. The color within the individual lesion is usually uniform. Lesions can measure from a few millimeters to several centimeters. When subjected to trauma, they can become irritated, thereby causing an inflammatory base and occasional bleeding. Occasionally, seborrheic keratoses are pedunculate, especially on the neck.

Figure 20-1. Seborrheic keratoses.

The etiology of seborrheic keratoses is unknown, although they may be dominantly inherited. They are benign with no malignant potential, although the appearance of hundreds in rapid “showers” may be a sign of internal malignancy; this is the much-debated Leser-Trélat sign.² The most common tumor seen with this association is colonic adenocarcinoma. In the head and neck, the most common mistaken diagnosis is melanoma; therefore the pathologist sometimes receives a widely excised seborrheic keratosis that has been mistaken for melanoma. If the diagnosis is in doubt, a biopsy before definitive treatment should be performed.

Treatment of these lesions varies. Because these lesions are so superficial, they often can be excised flush with the skin, using any of the shaving techniques described later. These lesions also are amenable to light liquid nitrogen freezing, which creates a subepidermal blister and allows for removal of the keratosis with the blister. Because these are truly benign lesions, the best treatment is often no treatment, unless the lesions are cosmetically disfiguring.

Dermatosis Papulosa Nigra

Dermatosis papulosa nigra is a condition found in approximately 35% of black adults; its onset often occurs during adolescence. The lesions are located predominantly on the face, especially in the malar region, but they may also occur infrequently on the neck and upper trunk. They consist of small (1 to 3 mm), smooth, pigmented, stuck-on appearing, hyperkeratotic papules. Although they have the histologic appearance of a fibroma, many clinicians consider these papules to be a variant of seborrheic keratoses. The treatment of dermatosis papulosa nigra is difficult because of pigmentary problems that occur with the treatment of black skin. Options that have been tried include fine-needle electrosurgery followed by use of a small curette, shave excision, light freezing with liquid nitrogen, and dermabrasion. If the lesions are few, we prefer the first two methods. Cryosurgery can produce spotted hypopigmentation in blacks and should be avoided unless other treatment modalities are not available. Dermabrasion can be of two types: using either a 2-mm wheel or a small cone or pear diamond fraise, the lesions can be removed singly, very quickly, and easily. Dermabrasion can also result in mottled pigmentation after healing, which usually will fade with time. If the lesions are multiple and confluent, total regional dermabrasion may be the treatment of choice for the best cosmetic blend. Judicious use of ablative and pigment-specific lasers can be used to treat these lesions focally; however, meticulous technique is required to avoid pigmentary changes common to this patient population.³

Warts (Verruca Vulgaris)

Warts are common lesions caused by the human papillomavirus (HPV), which is a deoxyribonucleic acid (DNA) virus. Warts are traditionally classified by clinical appearance and location: verruca vulgaris (or common wart), deep hyperkeratotic palmar-plantar; superficial mosaic-type palmar-plantar; verruca plana; epidermodysplasia verruciform; and condyloma acuminatum. Classification may also be based on the genotype of papilloma virus. Hundreds of DNA genotypes have been identified, each with a distinct type-specific antigen, some of which correlate with various benign and malignant conditions.⁴ The most common facial warts include common warts (including filiform) and flat warts which are most commonly associated with the antigenic serotypes HPV-2 and HPV-3. Clinically, these lesions are hyperkeratotic. The filiform wart is often a pedunculate lesion occurring in isolation on the cheek, nasal tip or columella, or eyelid (Fig. 20-2). Common warts can occur anywhere on the face. Flat warts usually occur in younger patients or on the legs of women who regularly use a razor for shaving; they are small (1 to 2 mm), flat-topped, hyperkeratotic lesions, which can coalesce (Fig. 20-3).

Figure 20-2. Filiform warts.

Figure 20-3. Flat warts.

Because the virus survives within cells at the base of the hyperplastic epithelium and within the adjacent normal-appearing skin, eradication of warts can be difficult and recurrences are common. Most common treatments involve destruction of the infected tissue. The filiform wart can be anesthetized at its base and excised with scissors, with the base being lightly curetted and fulgurated under low current; this approach affords the best chance for cure. Filiform warts often are too verrucous and hyperkeratotic to be effectively treated with cryosurgery. Common warts that are thinner can be treated effectively with liquid nitrogen cryotherapy, although several treatments are usually needed. Flat warts present a difficult problem. At times, they can be effectively treated with liquid nitrogen. Perhaps the best method is to individually scrape each small wart off of the skin with a small curette, treating, when possible, all of the flat warts in an area at one time. In young children who do not tolerate surgical therapy well, one may use topical tretinoin at a concentration sufficient to produce erythema and irritation in an attempt to stimulate the body’s own immunity against the wart virus. In healthy children, avoiding treatment is often best, because the vast majority of warts spontaneously involute once the patient’s immune system recognizes the virus.⁵

Related to the poxvirus family is a group of viruses known as the molluscum contagiosum virus family (EM-2). An infection with one of these viruses appears clinically as a variable number of small, discrete, waxy, skin-colored, dome-shaped papillomas, 2 to 4 mm in diameter, with umbilicated centers (Fig. 20-4). Like all viral lesions, they ultimately will involute spontaneously. Histologically, they have a classic appearance of cytoplasmic inclusion bodies, which are the so-called molluscum bodies. The best treatment is usually superficial cryotherapy or curettage, as is the case with common warts. Topical therapies, including imiquimod cream, liquid podophyllin, cantharidin, and more recently, injectable candidal antigens, have been successfully used for the treatment of warts and mollusca.

Figure 20-4. Molluscum contagiosum.

Actinic Keratoses

Actinic keratoses, also called solar keratoses, are precancerous lesions.⁶ Studies indicate that squamous cell carcinoma will develop in one or more lesions in 5% to 20% of persons with solar keratoses.^7–10 They are seen on sun-exposed areas of the skin, usually in persons after the fourth decade of life. They are seen most commonly in fair-skinned individuals who get sunburned frequently. Clinically, these lesions are usually erythematous with adherent scale and show little or no infiltration (i.e., they are very superficial) (Fig. 20-5A). Often, the patient can feel the rough, adherent scale before the lesion is clinically visible. Solar keratoses can also be flesh colored or pigmented. They often do not have a sharp demarcation from surrounding skin and can spread peripherally. Occasionally these lesions develop marked hyperkeratosis, giving a clinical appearance of a cutaneous horn. On the vermillion lip, actinic keratoses are known as solar or actinic cheilitis.

Figure 20-5. A, Actinic keratoses. B, Keratoacanthoma. C, Noduloulcerative basal cell carcinoma. D, Nodular basal cell carcinoma. E, Pigmented basal cell carcinoma. F, Morpheaform basal cell carcinoma.

Actinic keratoses lesions are best removed and not watched. The most commonly used method for removing discrete lesions is cryosurgery. Shave excision can also be performed, but it would lead to extensive scarring in areas with numerous lesions. In persons with severe sun damage to the face or with diffuse actinic keratoses, regional treatment with topical 5-fluorouracil, imiquimod, or retinoid creams are effective therapies for an entire region of the body such as the arms, hands, scalp, or face.^11,12 Because proper use results in severe irritation, sound patient understanding and education, and physician reassurance are necessary to ensure adequate compliance. Photodynamic therapy, laser resurfacing, dermabrasion, and chemical peels are also effective field therapies.^13–16

Basal Cell Carcinoma

Basal cell carcinoma is the most common malignancy in humans,^17,18 accounting for 75% to 80% of new cancers in the United States each year. Depending on the study cited, approximately 86% of lesions occur initially in the head and neck, with 25% of all primary lesions occurring on the nose. Approximately 96% of recurrences are in the head and neck, with 38% being on the nose. Emmett reported that 75.5% of previously untreated basal cell carcinoma found in Australia occurred in the head and neck, 8.4% on the chest and back, and 16% on the arms and legs.¹⁹ When looking at recurrent tumors, 91% occurred on the head and neck, 7.5% on the chest and back, and 1.5% on the arms and legs. Similarly, the primary tumor of metastatic basal cell carcinomas is usually found on the head and neck. However, metastasis of basal cell carcinoma is rare, with reports estimating rates of 0.0028% to 0.1%.^20–22 In this discussion, we outline the epidemiology and clinical and histologic variations of basal cell carcinoma. Management of head and neck basal cell and squamous cell carcinomas are addressed in Chapter 82.

Basal cell carcinoma, which is more common in men than in women, is seen most frequently in individuals between 40 and 60 years of age. With the aging of the sunbathing generation, however, basal cell carcinomas are occurring with increasing frequency in younger people. Scandinavians and people of Celtic extraction (particularly Irish), who frequently have Fitzpatrick skin type I or type II (sunburn easily), appear to be more prone to basal cell carcinoma than those with more darkly pigmented skin. Although uncommon in blacks, predilection for occurrence on the head and neck is the same as in whites.²³ Exposure to sunlight—primarily to the rays in the ultraviolet B spectrum—is the primary risk factor for basal cell carcinoma; this has been shown experimentally and reproduced clinically. The tumor is more common as one approaches the equator and at high altitudes. Basal cell carcinomas occur most commonly on the head and neck areas, with the nasal tip and the nasal ala being the most common; the cheeks and the forehead are the next most common. The left side of the body is more common than on the right, perhaps because of selective sun exposure in individuals whose occupation preferentially exposes the left side (i.e., driving).

Although sun exposure is the primary etiologic agent of basal cell carcinoma, other risk factors include genetics, occupation,²⁴ immunosuppression, ionizing radiation, and the presence of scars. Farmers, sailors, and fishermen, because of their heavy occupationally actinic exposure, have a higher than average incidence of skin cancer. The most common genetic syndromes include nevoid basal cell carcinoma syndrome and xeroderma pigmentosum.²⁵ The former is an autosomal dominant condition in which basal cell carcinomas arise on any area of the body, with the predilection being toward sun-exposed sites, beginning at an early age and continuing throughout life. These patients also have skeletal abnormalities, including bifid ribs, jaw cysts, frontal bossing, and calcified falx cerebri. Xeroderma pigmentosum is an autosomal recessive disease caused by a defect in DNA repair that leads to the development of basal cell carcinoma and other cutaneous malignancies in response to sun exposure and other carcinogens in childhood and early adulthood.

Immunosuppression (iatrogenic or associated with leukemias or lymphomas) has been shown to increase the incidence and aggressiveness of basal cell carcinomas. Chemical carcinogens—notably arsenic—play a tumorigenic role. Arsenic usually comes from well water that has been contaminated with arsenic, but patients with asthma, hay fever, or psoriasis may ingest arsenic in medicinal Fowler’s solution. Arsenic-induced basal cell carcinomas tend to be primarily on the trunk and are accompanied by keratoses of the palms and soles, pigmentary changes, and nail changes (Mees’ lines). Exposure to ionizing radiation is also an important etiologic factor; tumors can arise in areas of radiation damage, often many years after superficial radiotherapy for acne or tinea capitis, or as a depilatory at an early age. Basal cell carcinoma can arise within a scar or area of trauma. The injury may act as a cofactor, adding to the effect of already existing risk factors, such as sunlight and genetic susceptibility. Smallpox vaccinations and burn scars have been associated with basal cell carcinoma.

To the trained and observant eye, the clinical recognition of basal cell carcinoma is not difficult. Typically, lesions are nodular with a smooth, raised, translucent or “pearly” border with prominent telangiectasia (see Fig. 20-5D).²⁶ In addition, they may ulcerate and form a crust (see Fig. 20-5C). A typical history involves a pimple-like lesion that bleeds and does not heal. Pruritus is a common early symptom. Basal cell carcinoma may be pigmented (see Fig. 20-5E) yet maintain the clinical features of pearly, translucent borders and telangiectasia. Superficial multicentric basal cell carcinomas are flat and pink with differing, intercommunicating extensions of tumor that may be either scaly or with raised borders.

Other forms of basal cell carcinoma are clinically more subtle, histologically more aggressive, and more difficult to treat. Approximately 20% of primary basal cell carcinomas demonstrate infiltrative growth patterns with significant subclinical disease and high rates of recurrence.^27–29 Importantly, many primary tumors demonstrate histologic heterogeneity with subclinical extension.³⁰ Morpheaform basal cell carcinomas (see Fig. 20-5F) present as yellowish plaques, which develop telangiectasia, may ulcerate, and may have a sclerotic or scarlike appearance. The margins are often indistinct. Histologically, this tumor extends subclinical, finger-like projections intradermally, which make complete excision difficult. This tumor has a scarlike, stromal matrix that gives it a fibrous, sclerotic appearance and nature.

Recurrent basal cell carcinomas (Fig. 20-6A) present with varying clinical appearance, depending on the type of initial treatment. It may appear at the edge of a skin graft, within a scar created by electrosurgery, under a scar created by cryosurgery, or as a nodule developing within a suture line. Recurrent basal cell carcinomas are often nodular and accompanied by a morpheaform or sclerotic histologic picture in the deeper portions of the tumor. This picture may represent an aggressive histologic de-differentiation of the tumor, a factor that may partially account for its clinically aggressive behavior and resistance to treatment. The majority of recurrent basal cell carcinomas demonstrate infiltrative patterns in the original tumor; aggressive behavior may be predicted by careful evaluation of histologic features.³¹

Figure 20-6. A, Recurrent basal cell carcinoma. B, Chondrodermatitis nodularis helicis. C, Squamous cell carcinoma. D, Pigmented squamous cell carcinoma. E, Superficial spreading melanoma. F, Irregular border of superficial spreading carcinoma.

The typical basal cell carcinoma that occurs in the head and neck of the middle-aged or older fair-skinned person is not difficult to diagnose. One must be aware, however, that this tumor has a variety of clinical appearances, can appear in young people, and can occur in areas other than the head and neck. Any suspicious, nonhealing, pruritic, scaly lesion—especially one that occurs in a sun-exposed area of the fair-skinned individual—should be investigated with a biopsy. Biopsy techniques for basal cell carcinoma are simple. It has been well documented that implantation metastases from basal cell carcinoma do not occur, because the tumor needs a stroma to provide an environment in which to grow. The most appropriate technique is a medium-depth shave biopsy. The depth of the biopsy ideally should be mid-dermis; this depth gives a dermal collagen network that is amenable to any form of therapy. If a morpheaform basal cell carcinoma is suspected, the biopsy specimen often must extend deeper, perhaps through a punch or incisional biopsy. In cases of recurrent or superficial multicentric lesions or large clinical lesions, biopsy specimens should be obtained from multiple sites to assess the true clinical nature and size of the tumor. Biopsies of recurrent deep nodular lesions should be performed in an appropriate fashion to ensure an adequately deep specimen from the dermal nodule; this maneuver can be accomplished by means of an incisional biopsy or a deep-punch biopsy. As a rule of thumb, if the biopsy does not confirm the clinical opinion of basal cell carcinoma and the lesion remains suspicious, an additional biopsy of the lesion is indicated.

Chondrodermatitis nodularis helicis (see Fig. 20-6B) is an inflammatory disease of underlying helical cartilage that can mimic and be mistaken for basal cell carcinoma. The condition usually results from chronic trauma on the most protuberant portion of the ear. Surgery is the treatment of choice.

Squamous Cell Carcinoma

Squamous cell carcinoma is the second most common skin cancer and accounts for 10% to 20% of all cutaneous malignancies. Because of their tendency to recur and metastasize, squamous cell carcinomas carry the highest mortality of nonmelanoma skin cancers and account for the majority of deaths due to skin cancer in adults older than 85 years.³² The development of squamous cell carcinoma is multifactorial and involves both environmental and genetic factors. Risk factors for the development of squamous cell carcinoma include fair skin; chronic cumulative sun exposure; history of previous skin cancer; age older than 50 years; smoking; chronic inflammatory, infectious, or scarring skin lesions; chemical carcinogens; PUVA; HPV infection; and various genodermatoses. Similar to basal cell carcinomas, the most important factor is ultraviolet radiation. Fair-skinned individuals with longstanding chronic sun exposure, especially those close to the equator and at high altitudes, are at greatest risk. Men are affected two to three times more than women, and multiple cutaneous carcinomas are common.

Whereas the majority of squamous cell carcinomas may be cured if diagnosed and treated early, some behave aggressively with high rates of metastasis. Risk factors associated with high rates of recurrence and metastasis include chronically sun exposed skin, scarred areas in non–sun-exposed skin, tumors greater than 2.0 cm in diameter, recurrent tumors, chronic immunosuppression, poor histologic differentiation, depth of invasion, and perineural involvement.^33,34 The true risk of recurrence or metastasis for each variable is unknown; however, associations are clearly established. Clinically, squamous cell carcinomas can be separated into actinically induced and those that arise de novo on non–sun-exposed skin. The former are the more common and are associated with a low incidence of metastasis (<1% in most series). Some studies suggest that de novo lesions have a higher metastatic potential; approximately 2% to 6%. The mucosal variant of the squamous cell carcinoma, seen clinically as carcinoma of the lip, has a metastatic potential of up to 13.7%; therefore these distinctions are important in prognosis.³⁵ The worst prognostic indicator is perineural invasion, which has been shown to metastasize in 47.3% of cases.

Squamous cell carcinoma may present clinically in several ways.³⁶ Thick, scaling, hyperkeratotic plaques may present on the exposed surface of the body, in particular the ear, lip, or nose (see Fig. 20-6C). Lesions may change slowly over a period of time. If the crust is removed, the base is often ulcerated and has a rolled margin. Lesions may also present as a persistent ulcer, particularly in an old scar, or as a superficial multifocal change in generally sun-damaged skin. The latter is often the most difficult lesion to diagnose, requiring several biopsies at different points. Occasionally, a squamous cell carcinoma will become a vegetative nodular lesion; this lesion often has a cystic feel and can ulcerate and progressively enlarge. Often these exophytic lesions have not invaded deeply. They all have a tendency to ulcerate and become more erosive in appearance than a basal cell carcinoma. As with basal cell carcinoma, they can become pigmented (see Fig. 20-6D) and often appear similar clinically to keratoacanthomas, especially when the latter are in the growth phase. However, these lesions usually grow more slowly than keratoacanthomas, thereby allowing for distinction on clinical as well as histologic grounds. When this occurs, biopsy is always indicated. The treatment of cutaneous squamous cell carcinoma is discussed in depth in another chapter.

Bowen’s disease refers to an intraepithelial squamous cell carcinoma or carcinoma in situ. Clinically it presents as a well-demarcated, erythematous, scaling thin plaque that may be easily misdiagnosed as psoriasis, eczema, or tinea. Bowen’s disease on sun-exposed skin behaves less aggressively than non–sun-exposed such as the genitalia; if left unrecognized and untreated, it may progress to invasion. Bowen’s disease associated with arsenic exposure may be associated with internal malignancies. In the absence of arsenic exposure, however, this association is not well supported.

Keratoacanthoma is a rapidly growing tumor that presents as an exophytic dome-shaped nodule with central keratin on sun-damaged skin (see Fig. 20-5B). The categorization of keratoacanthoma has been controversial, but it is now thought to be a variant of squamous cell carcinoma. There are some unique features that distinguish it clinically from the common type of squamous cell carcinoma. Keratoacanthomas are characterized by a rapid proliferative phase followed by plateau, then involution. Not all keratoacanthomas, however, involute, and predicting which ones will is difficult. The involution phase can sometimes take up to 1 year. Two rare clinical forms of keratoacanthomas deserve mention. The giant keratoacanthoma can reach 5 cm or more and can cause the destruction of underlying tissues. Eruptive keratoacanthomas often present as many hundreds of characteristic papules that measure 2 to 3 mm in diameter. Metastatic keratoacanthomas have been reported, however, and may represent typical squamous cell carcinoma. Keratoacanthomas can be difficult to treat. Surgical excision is the treatment of choice for most keratoacanthomas, with Mohs micrographic surgery reserved for facial lesions. Because of the involution potential of keratoacanthomas, cytotoxic agents can be used to induce involution. We favor methotrexate at a dose of 12.5 to 25 mg/mL, with approximately 0.5 to 1 mL injected into the lesion at 3- to 4-week intervals. Although complete involution may not occur, it may allow for easier surgical management by reducing the size of the tumor.

Nevocellular Nevus

Nevocellular nevi, commonly known as moles, are common benign skin neoplasms that appear shortly after birth to late in life. Acquired nevocellular nevi are classified according to their location and stage of development within the skin.

Junctional Nevus

Junctional nevi are tan to brownish macules (flat lesions) of uniform color and smooth border (Fig. 20-7B). Dots of black pigment may be present, but, unlike with melanoma, the normal skin markings are preserved. Lesions vary from a few millimeters to a centimeter or more in diameter. The melanocytes or nevus cells are located at the junction of the epidermis and the dermis (dermoepidermal junction). The lesion can occur anywhere on the body and is the nevus most commonly mistaken for melanoma. When in doubt, one should perform a biopsy of the lesion. Junctional nevi occur anytime after birth and are the common moles found in children before puberty. Their importance lies in their ability to develop into malignant melanoma, although this rarely occurs before puberty. Most junctional nevi remain benign throughout life and can evolve over time into either compound or intradermal nevi. Treatment of these nevi is often dictated by suspicion of melanoma or cosmetic reasons, and usually includes a shave in noncosmetic areas or a fusiform excision with closure in cosmetically important areas. Melanocytes are cold sensitive, and strictly junctional nevi can be removed with deep cryotherapy.

Figure 20-7. A, Lentigo maligna melanoma. B, Junctional nevus. C, Intradermal nevus. D, Blue nevus. E, Halo nevus. F, Nevus sebaceus.

Intradermal Nevus

Intradermal nevi are common mature moles of adults, occurring anywhere on the body but rarely on the palms and soles. It is most common on the scalp or face in adults, varying in size from a few millimeters to several centimeters. It may be flat and smooth or raised and warty, pigmented or nonpigmented, sessile or pedunculate (see Fig. 20-7C). It often contains coarse hairs, reflecting the depth within the dermis of the nevus cells. It is benign and rarely becomes malignant. By definition, all of the nevus cells occur within the dermis. This mole is best treated by shave excision when it is pedunculate and hairless. When it is on the head or neck and contains hair, it is necessary to excise this mole using either the punch excision technique or routine excision to remove the complete depth of the hair follicles within the nevus.

Compound Nevus

Compound nevi, which are a combination of junctional and intradermal elements, are found most commonly in adults. They are brown to black moles, usually less than 1 cm in diameter. A brown macular ring is frequently around the periphery of the lesion. It can contain hair and is often clinically indistinguishable from an intradermal nevus. Although the compound nevus, like any mole, can develop into a malignant melanoma, it usually remains benign and matures into an intradermal nevus. Treatment usually consists of shave or excision and closure. As with intradermal nevi, the choice of treatment depends on location and on the presence or absence of hair.

Blue Nevus

Blue nevi present as dark blue or black hairless flat or raised lesions that are usually less than 0.5 cm in diameter, indurated, and palpable. The overlying epidermis is remarkably smooth and the outline regular (see Fig. 20-7D). Blue nevi most commonly occur on the head and neck, the dorsa of the hands and feet, and the buttocks. They are more common in women than men and usually undergo very little change after their initial presentation. The treatment of these lesions is excision or observation. The excision must be deep, because the pigment often extends deep into the subcutaneous fat, thereby resulting in the deep blue color of the lesion. Malignant transformation of blue nevi is rare; however, tumors demonstrate highly aggressive behavior, thus these lesions must be carefully evaluated histologically.^38,39

Halo Nevus

The halo nevus is a phenomenon usually associated with a junctional nevus in children or adolescents. Most commonly found on the back, it is often a benign-looking brown papular lesion in the center of a well-circumscribed pale white circle of depigmented skin (see Fig. 20-7E). This appearance reflects the body’s rejection of the nevus cells, because an inflammatory response ensues in which the melanocytes of the nevus and those of the immediately surrounding epidermis are destroyed.⁴⁰ Often, when left alone, these nevi disappear.

Spitz Nevus

Spitz nevus is also known as a juvenile melanoma or a compound melanocytoma. These rapidly growing pigmented lesions occur principally in children, although they can occur in adults. They are usually less than 1 cm in size and are pink or red, or occasionally brown or black. A Spitz nevus may be soft or hard, but is usually dome-shaped and can be either sessile or pedunculated. It can occur anywhere on the body and is often difficult to diagnose clinically. Its main importance is its histologic resemblance to melanoma, with even experienced pathologists having difficulty distinguishing between the two.⁴¹ Very few of these nevi, however, progress to malignancy. Treatment of a Spitz nevus is the same as that for an intradermal or compound nevus.

Congenital Nevi

Congenital nevi are malformations of neuroectoderm comprised of melanocytes, affecting 1% to 6% of the population. There is great heterogeneity in their appearance, size, and location. Lesions may be light brown to black, are variously shaped, usually have sharp borders, are flat to mammillated on the surface, and often contain hair. When large or in conspicuous locations such as the face, they may be associated with significant psychosocial impact on affected individuals and their families.

Congenital nevi are usually present at birth; however, in some lesions pigmentation may occur gradually over the first few years of life. In addition to being aesthetically disfiguring, congenital nevi may be associated with a risk of melanoma, neurocutaneous melanocytosis, or malignant tumor, such as rhabdomyosarcoma, among others. Whether this malignant potential is due to the increased number of melanocytes or to some inherited premalignant tendency in the cells themselves is not clear. Congenital nevi are classified according to size with those less than 1.5 cm being small, 1.5 to 20 cm being medium, greater than 20 cm being large, and greater than 50 cm being giant. The precise risk for development of melanoma associated with congenital nevi is difficult to establish; however, risk clearly correlates with size, with the greatest risk being associated with giant congenital nevi. The risk of cutaneous or extracutaneous melanoma associated with small congenital nevi is estimated at 0% to 4.9% and generally occurs at or after puberty. The risk is 4.5% to 10% in large congenital nevi and usually occurs before puberty in this group.^42,43 Histologic evaluation of changes within congenital nevi should be evaluated by a dermatopathologist experienced in the evaluation of pigmented lesions. Individuals with large congenital nevi are also at risk for development of neurocutaneous melanosis in which proliferation of leptomeningeal melanocytes may be associated with neurologic disease, structural malformations, and malignant degeneration. Giant axial lesions and those with greater than 20 satellite lesions are at greatest risk.⁴⁴ The prognosis for patients with symptomatic neurologic disease is poor. Approximately half of patients with neurocutaneous melanosis develop central nervous system melanoma.⁴⁵

The management of congenital nevi should be individualized based upon nevus size, thickness, location, risk for development of melanoma and other associated conditions, psychological impact, and effects of therapy on the patient and family. Treatment options include surgical excision, dermabrasion, chemical peels, laser therapy, and observation. The timing and choice of therapy should take into consideration the medical, cosmetic, and psychological factors.^46,47

Dysplastic Nevus

Dysplastic nevus syndrome, described by Clark and colleagues, is also known as the B-K mole syndrome.⁴⁸ It consists of the association of familial malignant melanoma, which often occurs in multiple lesions, with “dysplastic nevi” in both the melanoma patient and many of his or her relatives. Dysplastic nevi are usually larger than ordinary melanocytic nevi, ranging from 5 to 15 mm; they present with an irregular border and a haphazard mixture of colors: tan, brown, black, and pink. Centrally, there is often a small, palpable component (Fig. 20-8A). Dysplastic nevi are located on either exposed or nonexposed skin and form throughout adult life, unlike typical nevi that form in earlier years and tend to fade in later years. The idea that a dysplastic nevus may transform itself into a malignant melanoma remains controversial.⁴⁹

Figure 20-8. A, Dysplastic nevus. B, Venous lakes. C, Dermatofibroma. D, Fibrous papule. E, Cylindroma. F, Sebaceous hyperplasia.

Solar Lentigo

Solar lentigo, also known as actinic lentigo, are keratinocytic pigmented macules that commonly present on the sun-exposed skin of the head and neck.⁵⁰ They commonly occur as multiple lesions and have been referred to as lentigo senilis. The lesions rarely occur before the fifth decade of life, they slowly increase in size and number, and they form in more than 90% of whites who are older than 70 years old, most commonly on the dorsa of the hands and on the face. They are not infiltrative, and they possess a uniform dark brown color and an irregular outline. Varying in size from minute to greater than 2 cm, they may coalesce to form larger lesions. Malignant degeneration does not occur. These lesions may resemble seborrheic keratoses in clinical appearance, and both conditions are referred to in lay terms as “liver spots.” Solar lentigo, however, are less hyperkeratotic than seborrheic keratoses and have no areas of follicular prominence. It is important to distinguish solar lentigo from melanoma in situ, which may also present as dark brown macules on sun-damaged skin of the head and neck. Solar lentigo can be easily treated with pigment-specific lasers, intense pulsed light devices, cryotherapy, topical retinoids, or chemical peels such as trichloroacetic acid.

Nevus Sebaceus

Nevus sebaceus of Jadassohn is a common benign congenital lesion that presents as a pebbly, flesh-colored, hairless, well-demarcated lesion of the scalp (see Fig. 20-7F) and other areas of the head and neck. The size varies from 0.5 cm to several centimeters. Off the scalp, the lesion can be linear, closely resembling a linear epidermal nevus. Histologically, these tumors evolve in three discrete stages of growth. In the first few months of life, the sebaceous glands in the lesion are well developed. Thereafter, through childhood, the sebaceous glands are underdeveloped and therefore greatly reduced in size and number; in this phase, the diagnosis may be missed. At puberty, the lesions assume a diagnostic appearance, which is histologically characterized by the presence of large numbers of mature or nearly mature sebaceous glands and by papillomatous hyperplasia of the epidermis. During puberty, various benign and malignant epidermal and adenexal tumors develop in nevus sebaceous. Ten percent to 30% of lesions develop neoplasms during adulthood, usually between the fourth and seventh decades. The most common benign neoplasms include trichoblastoma and syringocystadenoma papilliferum. Of primary importance is the occurrence of basal cell carcinoma in 5% to 7% of sebaceous nevi; numerous other malignant neoplasms have been reported, including squamous cell carcinoma, sebaceous carcinoma, ductal carcinoma, and leiomyosarcoma.^51–55 Treatment of nevus sebaceus is complete surgical excision. Complete excision before puberty as a preventive measure had been previously advocated; however, more recently this recommendation has been called into question due to the low incidence of malignant lesions and the ability to identify such changes clinically.^56,57 Others have proposed observation with excision of selected lesions, however many prefer excision for aesthetic reasons.⁵⁸

Epidermoid Cysts

Epidermoid cysts are true cysts. Their lining resembles that of the normal epidermis. This lining produces fully matured, keratinized cellular debris, which fills the cavity of the cyst. Epidermoid cysts are thought to originate from the follicular infundibulum of hair shafts and may arise either spontaneously or as a result of inflammation or trauma to the area. Injection of surface epidermal material to deeper dermal or subcutaneous layers as a result of penetrating trauma or the use of needles has also been postulated. These cysts are rarely found before puberty, but they have been found in all age groups after this period. If these cysts appear before puberty or in large numbers, they may be an indication of Gardner’s syndrome, which is an autosomal dominant condition that predisposes the patient to intestinal cancer. Although malignant degeneration is uncommon, epidermoid cysts can present a cosmetic problem, and, if they rupture or become infected, they may cause severe pain and scarring. Although some of these lesions occasionally respond to intracystic injections of triamcinolone, surgical excision is the most effective treatment. It is necessary to carefully dissect and remove the entire cyst wall, because retained segments may lead to recurrent growth of the cyst.

Pilar Cysts

Pilar cysts, which are also known as trichilemmal cysts or wens, are also true cysts; they are clinically indistinguishable from epidermal cysts. The tendency to form such cysts appears to be inherited as an autosomal dominant trait. The lining of the cyst differentiates in a manner analogous to that of the outer root sheath of the hair follicle; this fact allows for its differentiation from epidermal cysts. Most pilar cysts occur on the scalp, and they are uncommon before puberty. Multiple cysts are often present. If a pilar cyst ruptures or becomes infected, considerable pain and scarring may result. As with epidermal cysts, the best treatment is complete surgical excision. Proliferating pilar tumors are uncommon tumors thought to originate from pilar cysts and have the potential for malignant transformation. Although these lesions are uncommon, they may be associated with significant morbidity and mortality and must be excised completely.^59,60

Dermoid Cysts

Dermoid cysts are rare tumors that are frequently present at birth. They may measure up to 4 cm in diameter, although they are generally less than 2 cm. They may occur anywhere, but they are most common on the face, particularly in the area of the lateral eyebrow, the orbit, and the nose. Dermoid cysts appear to result from the inclusion of embryonic epidermis within embryonal fusion planes. Histologically, these cysts are lined by an epithelium that resembles normal epidermis. They can be differentiated from epidermal cysts by their attachment to adnexal structures, which include hair, sebaceous glands, eccrine glands, and apocrine glands.⁶¹ Treatment is by surgical excision. If a dermoid cyst is located over the nasal root, however, care must be taken, because this tumor may be confused with a nasal glioma.⁶²

Steatocystoma Multiplex

Steatocystoma multiplex, an uncommon condition, is often familial, demonstrating an autosomal dominant mode of inheritance. Although lesions can be discovered at any age, they most commonly occur shortly after puberty. The condition presents as multiple 1- to 2-cm cysts, generally located intradermally. They are most commonly found on the anterior chest, but they are also found on the face, forehead, ears, eyelids, and scalp. When punctured, these lesions exude a yellowish, oily fluid and, occasionally, hairs. On histologic examination, these cysts contain a highly corrugated wall of epithelial cells. Embedded within the wall are multiple sebaceous gland lobules, which may be partially responsible for the contents of the cyst. The mode of keratinization of the epithelial lining appears to resemble that of the outer root sheath, and indeed invaginations are often present within the cyst wall that appear similar to hair follicles. Infection with pain and subsequent scarring is a major problem associated with this condition. Treatment is disappointing because of the large number of lesions present, although individual lesions can easily be excised. On the face, cosmetically acceptable improvement has been reported with excision, CO₂ laser, dermabrasion, and oral retinoids.^63–66

Milia

Milia are small (usually 1 to 2 mm) cysts that differ histologically from epidermal cysts only in their small size. Clinically, they are whitish, smooth globules, most commonly seen on the face. They may arise spontaneously, but they are also frequently present as a result of trauma such as dermabrasion or burns or as a result of bullous diseases. When they arise after trauma or disease as a result of the occlusion of the pilosebaceous unit, they represent a retention cyst. Treatment is the same whether milia arise spontaneously or secondarily and is necessary only for cosmetic reasons; the lesion can easily be shelled out with a hypodermic needle or a comedo extractor. Because they may occasionally number in the hundreds, this treatment can be a considerably tedious chore.⁶⁷

Mucous Cysts

Mucous cysts are pseudocysts, because no true lining is present; they are also called mucous retention cysts or mucoceles. These lesions are usually located on the mucous surface of the lower lip and are asymptomatic. They are generally less than 1 cm in diameter and, if superficial, may appear slightly bluish and translucent. They appear to be the result of traumatic rupture of the ducts of minor salivary glands. With leakage of the contents into the tissue, an inflammatory process ensues, with the resultant formation of granulation tissues surrounding the cystic space. Mucous cysts may resolve spontaneously or can otherwise be treated by the intralesional injection of low-dose triamcinolone (2.5 mg/mL), excision, or marsupialization.⁶⁸

Infantile Hemangiomas

Infantile hemangiomas are the most common benign soft tissue tumor of childhood, occurring in approximately 10% of children. The incidence is greater in females than males and is increased in premature infants. Infantile hemangiomas are uniquely characterized by rapid proliferation during the first months of life followed by slow involution over several years. While most are of little significance, some have the potential for serious complication. The pathogenesis is not known, although positive staining for GLUT-1 (erythrocyte-type glucose transporter protein), which is normally expressed in endothelial cells of placenta, has suggested origination or transplantation from placental cells, although this has not been proven.⁷²

Historically the term hemangioma has been used to describe a variety of vascular anomalies, which led to much diagnostic confusion. The recent identification of specific immunohistochemical markers that distinguish infantile hemangiomas from other vascular malformations has allowed for classification based on biologic markers. The term infantile hemangioma is used exclusively to describe lesions with this distinct presentation and clinical behavior; older terms such as cavernous hemangioma and strawberry angioma have been abandoned.⁷³

Hemangiomas most often occur on the head and neck, although any area may be affected. When first noted at or shortly after birth, they are generally macular pink or bluish lesions. During the first year of life, hemangiomas exhibit a rapid growth phase, and the lesions become raised, dome-shaped to polypoid, and bright red to deep purple. After the first year of life, they enter a quiescent phase that is followed by a period of spontaneous involution. Hemangiomas may be superficial, deep, or mixed, and thus may vary in appearance significantly depending on the location, size, depth, and stage of development. Superficial hemangiomas develop into bright red noncompressible, partially blanching plaques. Deep lesions become partially compressible dermal nodules with a blue hue, often with overlying telangiectasia. Mixed lesions occur in 25% to 30% of lesions. In addition, there is great variation in the degree and rate of growth and involution of hemangiomas. In general, rapid proliferation occurs in the first 6 months, slow growth in the second 6 months, and involution occurs at a rate of 10% per year, with the majority of lesions completely involuted by the age of 10 years. Following involution the affected skin may not appear normal and may have residual telangiectasia, atrophy, scarring, and fibrofatty masses.

Although most hemangiomas are small and innocuous, a minority may present serious medical and psychological complications and may be associated with structural anomalies and neurocutaneous syndromes. The visible presence of hemangiomas and concerns for permanent disfigurement can lead to significant psychosocial stress that can be life altering for the child and family. Nasal tip lesions may distort the nasal anatomy and lead to significant deformity. Hemangiomas in the periorbital area may obstruct the visual axis or compress the orbit, leading to amblyopia and permanent visual loss. Lesions on the oral mucosa and perineum have a propensity for ulceration and bleeding during the rapid growth phase. Hemangiomas in the “beard area” may be associated with airway compromise. A small number of hemangiomas involve a large area of segmental distribution within developmental subunits. Segmental hemangiomas may have associated structural abnormalities with a high risk of serious complications. PHACES syndrome is a constellation of structural anomalies, including posterior fossa malformation, hemangioma, arterial anomalies, coarctation of the aorta, eye abnormalities, and sternal defects that are associated with segmental hemangiomas.^74,75

The heterogeneity of presentation of infantile hemangiomas and the potential risk of serious complications introduces complexity to the management of these lesions.⁷⁶ The majority of hemangiomas involute spontaneously with little consequence, thus treatment is primarily that of “active nonintervention,” which involves close observation during the proliferative phase and familial education and support. Treatment with pulsed dye lasers may be helpful for ulcerated lesions, but has been less useful for deeper lesions. Recent advances in laser therapy using combinations of visible and near infrared wavelengths, however, may have additional benefits for the treatment of hemangiomas. Lesions that threaten to impinge upon important anatomic structures, especially the eye or the respiratory tract, require treatment with systemic corticosteroids. Recalcitrant, life-threatening hemangiomas that are resistant to steroid therapy may require interferon-α 2a or 2b or vincristine chemotherapy, which may have significant adverse side effects. Surgical excision with purse-string closure has been demonstrated to be a valuable intervention for many lesions, particularly those on the face, at all stages of hemangioma development.⁷⁷

Cherry Angiomas

Cherry angiomas are also called senile angiomas or De Morgan’s spots. They may occur anywhere on the body but are most commonly found on the trunk and usually appear during young adulthood. They are generally 1- to 3-mm, bright-red, slightly raised, dome-shaped lesions. The lesions consist of multiple dilated capillaries found in the upper dermis. Cherry hemangiomas are benign and unrelated to systemic or congenital disease. Treatment is not necessary but may be desired for cosmetic reasons; these angiomas respond to both superficial electrodesiccation and laser surgery.

Pyogenic Granuloma

Pyogenic granuloma are common acquired vascular lesions of the skin and mucous membranes. They are most common in children and young adults, or during pregnancy, but may occur at all ages. The pathogenesis is unknown. Pyogenic granuloma most commonly occur at sites of trauma on the distal extremities and the face, and occasionally gingival mucosa, but may present on any part of the body. Histologically, the appearance is that of a polypoid, lobulated mass of newly formed capillary blood vessels surrounded by an edematous stroma.⁷⁸ Clinically, pyogenic granuloma present as dark red pedunculated nodules often with a surrounding collarette of scale at the base. Pyogenic granuloma are prone to ulceration and bleeding, which often brings the patient to medical attention. Because of their rapid and exuberant growth, these lesions are sometimes mistaken for a malignancy. The differential diagnosis includes malignant melanoma, Kaposi’s sarcoma, metastatic carcinoma, bacillary angiomatosis, and angiolymphoid hyperplasia with eosinophilia. Occasionally, the lesion spontaneously resolves. Lesions associated with pregnancy frequently involute after delivery; most often, however, the lesion must be treated surgically. This treatment is easily accomplished by surgical excision or curettage with electrodesiccation.

Salmon Patch

The salmon patch nevus is the most common vascular malformation of infancy, occurring in 30% to 40% of newborns. Salmon patch nevi are thought to represent persistent fetal circulation and present as pink macular patches on the posterior neck, scalp, glabella, forehead, and upper eyelids. When located on the nape of the neck, it is referred to as a “stork bite”; when present on the eyelid or glabella, it is referred to as an “angel’s kiss.” Eyelid lesions generally resolve within the first year of life, and the glabellar lesions also spontaneously involute but take somewhat longer. The nuchal lesions may persist into adult life, although some spontaneously fade.

Port Wine Stain

Port wine stain, or nevus flammeus, is a congenital vascular malformation that presents in approximately 0.3% of newborns. Port wine stains show no tendency to fade and, in fact, generally darken and thicken with age, becoming deeply violaceous and nodular during adult life. These lesions are often unilateral and may follow a trigeminal distribution on the face. Extensive areas of facial skin, oral mucosa, and conjunctival membranes are often involved, although any area may be affected. Although port wine stains are usually limited to the skin, their psychosocial impact may be great. Lesions present initially as pink or pale red patches that, with time, progress through deepening shades of red to take on a deeply violaceous hue. With increasing age, the ectatic vessels become progressively more dilated and may become nodular and protuberant. Their prominent location on the face may have a significant psychosocial impact on developing children. Large nodular lesions may also tend to bleed and become crusted. The treatment of choice is the flashlamp-pumped pulsed dye laser. With repeated treatment sessions, significant fading can occur, although only a small percentage of these nevi resolve completely.

Port wine stains may indicate more serious underlying disease associated with several congenital syndromes.⁷¹ Sturge-Weber syndrome (leptomeningeal nevus flammeus) is a port wine stain located along the distribution of the trigeminal nerve and angiomas within the meninges, with progressive calcification in these areas. Abnormalities associated with this condition include intractable seizures, developmental delay, and ocular abnormalities such as glaucoma. Increased incidence of Sturge-Weber syndrome is associated with involvement in the distribution of the three branches of the trigeminal nerve, bilateral involvement, and upper and lower eyelid involvement. Klippel-Trénaunay-Parkes-Weber syndrome (osteohypertrophic nevus flammeus) is characterized by hypertrophy of the soft tissues and bones of the lower extremity accompanied by a venous varicosity and an overlying port wine stain.

Spider Angioma

Spider angioma, or nevus araneus, is a common type of telangiectasia often presenting on the face, upper body, and distal extremities. Spider angiomas may occur on mucous membranes, in which case the differentiation from hereditary hemorrhagic telangiectasia must be made. Clinically, lesions appear as a central, raised, small body that may be pulsatile with multiple legs fanning out from the center. They may be associated with liver disease, pregnancy, and estrogen therapy; however, spider angiomas are often idiopathic, presenting in 15% of healthy children and adults. Treatment is by obliteration of the central feeding arterial, which can be accomplished with electrocautery or photocoagulation.

Hereditary Hemorrhagic Telangiectasia (Rendu-Osler-Weber Syndrome)

Hereditary hemorrhagic telangiectasia is a dominantly inherited condition that affects blood vessels throughout the body.⁷⁹ It is characterized by ectatic vessels of the skin, mucous membranes, and viscera. Often the presenting symptom is spontaneous epistaxis, which may begin during early childhood but more likely appears at puberty or during adult life. Telangiectasia generally begin around and after puberty. The superficial telangiectasia assumes three morphologic forms; the most common lesions are punctate, but they may also be linear or spider-like. The mucous membranes are almost always involved, with lesions occurring on the lips, oral and nasal mucous membranes, nasopharynx, and throughout the gastrointestinal tract. The lesions may ulcerate and frequently bleed. The condition is associated with pulmonary, cerebral, and hepatic arteriovenous malformations. Bleeding may occur from any of the vascular lesions throughout the body and may be fatal. The diagnosis is generally made when the combination of frequent hemorrhagic episodes, vascular ectasias, and a family history is recognized. Genetic testing is available for prenatal diagnosis. Importantly, because catastrophic hemorrhage can occur in children with clinically silent disease, screening imaging for cerebral and pulmonary arteriomalformations is indicated in children who have a family history. Treatment is aimed at control of specific hemorrhages and of anemia, if it arises. Individual cutaneous lesions may be treated by electrocauterization and photocoagulation.

Venous Lake

Venous lakes present as deep blue, cutaneous nodules that occur most frequently on the face, lips, and ears of elderly patients (see Fig. 20-8B). Sometimes called senile angiomas, they are composed of dilated thick- and thin-walled, otherwise normal-appearing vessels. The lesions may thrombose and involute, but frequently they persist. They are of no significance other than a cosmetic nuisance and may be treated with vascular-specific lasers.

Acrochordon

Acrochordon (skin tag, fibroepithelial papilloma) are extremely common lesions, occurring most often during middle to late life. They are flesh-colored, pedunculate tumors that are generally up to about 2 mm in diameter. They are soft and most commonly occur in flexural regions such as the axillae, the sides of the neck, inframammary areas, and the upper eyelids. The lesions are composed of mostly loose fibrous tissue (similar to that of the superficial dermis), and they are covered by a thin epidermis. No adnexal structures are present. The lesions are easily removed by simple sharp-scissors excision or light electrodesiccation.⁷⁹

Keloids and Hypertrophic Scars

Keloids and hypertrophic scars are uncontrolled proliferative responses to trauma by the fibrous tissue of the dermis.⁸⁰ Hypertrophic scar is a thickened scar that does not extend beyond the margins of the original injury, whereas a keloid is an exuberant growth extending beyond the borders of the initial scar. Keloids are most commonly seen in blacks. The epithelium overlying the tumor is frequently thinned and shiny, and the tumor may be tender and pruritic. The areas of predilection for keloids include the sternal area, the shoulders, and the upper back; they are also frequently seen on the earlobes after ear piercing and on the face. These tumors may be flat or extremely protuberant, dome shaped, or bosselated. They are most common in the second and third decades of life, becoming less common with age. Histologically, they present with distinctive keloidal collagen. Hypertrophic scars usually occur on sites of increased skin movement and tension; there is no racial predilection. Treatment of keloid and hypertrophic scars is challenging. Excision of these tumors generally has resulted in regrowth. Some success has resulted from radiation therapy, pressure, cryotherapy, injection of high-potency corticosteroids, interferon and fluorouracil, topical silicone dressings, and pulsed-dye laser treatment. Simple surgical excision is usually followed by recurrence unless adjunct therapies are used.

Dermatofibrosarcoma Protuberans

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue sarcoma of low to intermediate malignancy with low metastatic risk, however with aggressive local behavior and high recurrence rates. All ages may be affected. It usually presents a pink to reddish protuberant mass on the trunk or extremities; however, approximately 15% occur on the head and neck. Metastasis occurs in 1% to 4% of lesions, although approximately 10% demonstrate a high grade of malignancy with high risk of metastasis. Ninety percent of DFSP demonstrate translocation of chromosomes 17 and 22, in which the platelet-derived growth factor (PDGFB) gene is fused with the collagen 1 alpha gene, leading to upregulation of PDGFB expression in the tumor. Histologically DFSP are characterized by monomorphous spindle cells arranged in a storiform pattern. Less common variants include the Bednar tumor (laden with melanin) and myxoid variants. Small lesions may clinically and histologically resemble benign fibrous histiocytomas (dermatofibroma). Positive staining with CD34 differentiates these two entities. Some tumors demonstrate fascicles of spindle-shaped tumor cells with atypia, high cellularity, and an increased mitotic rate; clinically these tumors exhibit a more aggressive course with a greater probability of recurrence and metastasis.

Complete surgical resection of the tumor is the treatment of choice. Lower recurrence rates have been demonstrated by Mohs micrographic surgery with microscopic margin control, providing a distinct advantage over wide local excision.⁸¹ Head and neck lesions tend to have high recurrence rates, and may particularly benefit from the use of Mohs surgery techniques. Some success has been demonstrated with pretreatment of advanced and metastatic DFSP with imatinib mesylate, a selective inhibitor of PDGFB kinases, before Mohs surgery, suggesting it may have a primary role in the treatment of DFSP in future.⁸²

Atypical Fibroxanthoma

Atypical fibroxanthoma is a low-grade malignant spindle-cell tumor that most commonly occurs on the sun-exposed areas of the elderly. They are believed to be of fibrohistiocytic origin and to be a superficial variant of a malignant fibrous histiocytoma.⁸³ The lesion is a pink to translucent nodule, generally 1 to 2 cm in diameter. Ulceration is not uncommon. Clinically these tumors may be mistaken for several different types of malignancies, including basal cell carcinomas, squamous cell carcinomas, and melanomas. The risk of metastasis is low, although local and distant metastases have been reported. Histologically, these lesions have a bizarre appearance, with large and atypical epithelioid and spindle cells, and multinucleate giant cells. Surgical excision is the treatment of choice. Accumulating data suggest lower recurrence rates with Mohs micrographic surgery.

Neurofibromas

Neurofibromas are soft, dome-shaped, flesh-colored lesions that may be located anywhere on the body; they may vary greatly in size, from quite small to large pedunculate lesions. Neurofibromas are derived from the Schwann cells of cutaneous nerves.⁸⁴ On histologic examination, they present as nonencapsulated, loose, spindeloid tumors. Solitary lesions may be easily excised. These tumors may be indicative of the genetic neurofibromatosis syndrome, which may be associated with severe neurologic problems as well as a risk of malignant degeneration of the tumor. When a neurofibroma is found, a careful search for other manifestations, which include café-au-lait spots and axillary freckling as well as a family history, should be carried out to rule out the syndrome.

Angiofibroma

Angiofibroma (adenoma sebaceum) is present as part of the genetic syndrome tuberous sclerosis. The autosomal dominant syndrome has variable expressivity; the finding of even one angiofibroma requires genetic counseling, because the patient may pass on a much more severe form of the disease to offspring.⁸⁵ Angiofibromas present as small dome-shaped papules, 2 to 3 mm in diameter, that are flesh colored or reddish brown. They are most commonly present on the sides of the nose and the medial cheeks. The original name is a misnomer, because, on histologic examination, no sebaceous components are noted. The tumors are composed mostly of fibrous tissue and have an angioid component. Laser therapy with a 532-nm KTP laser has been shown to be effective treatment with long remission periods, although new lesions develop with time.

Fibrous Papule

The fibrous papule is a common lesion, generally occurring on the nose—especially the alae—in older persons (see Fig. 20-8D). However, it can also be seen on the medial cheeks. These lesions present as small, 0.5-cm, dome-shaped, flesh-colored papules. Although they are rather common, some confusion persists regarding their origin and histologic nature.⁸⁶ They have been regarded as perifollicular fibromas, involuting melanocytic nevi, angiofibromas, or simply the result of trauma, such as folliculitis or excoriating pimples. Histologically, the lesion presents as a papule that is composed of numerous spindle-shaped and stellate cells, with occasional multinucleate cells present. Once the lesions have grown, they are generally quite stable and may be present for years; they may be treated by excision or curettage and electrodesiccation. They are of no significance unless related to tuberous sclerosis.

Trichoepithelioma

A trichoepithelioma is an uncommon entity that most often presents as small rounded nodules on the cheeks, eyelids, and nose. It appears to be dominantly inherited; however, pedigrees indicate a greater preponderance of affected females. The lesions are skin-colored to slightly pink and gradually increase, with time, in both number and size. A few telangiectatic vessels may be present, and there may be a slightly translucent quality to the lesions, which may lead to confusion with basal cell carcinoma; however, the lesions rarely ulcerate. If ulceration does occur, basal cell carcinoma should be considered. The histologic appearance of these lesions also closely resembles basal cell carcinoma, and distinguishing between the two is often difficult.⁸⁷ There are basophilic cells similar to those seen in basal cell carcinoma. The cells are arranged in masses, which may have fully keratinized centers. Occasionally the presence of a solitary lesion makes differentiation from basal cell carcinoma somewhat more difficult, and, unless definite differentiation toward hairlike structures is present, the tumor should be treated as a carcinoma. When multiple lesions are present, treatment is difficult because of the large number of tumors. Some success has been obtained with dermabrasion or laser resurfacing of the entire affected area.

Cylindroma

Cylindromas are slow-growing appendageal tumors derived from follicular epithelium. They may assume apocrine phenotype and usually present as solitary pink to red dermal nodules on the head, neck, and scalp. They present predominantly in older women with a 9:1 female-to-male ratio. The presence of multiple cylindromas is associated with the Brooke-Spiegler syndrome,⁸⁸ in which an autosomal dominantly inherited mutation in the CYLD tumor suppressor gene leads to the development of multiple cylindromas, trichoepitheliomas, and spiradenomas primarily located on the head and neck.^89,90 Multiple cylindromas may literally cover the scalp, resulting in a syndrome called “turban tumors” (see Fig. 20-8E). Individual tumors can reach 2 to 3 cm in diameter. Histologically, these tumors are composed of nests of darkly staining epithelial cells surrounded by a narrow band of hyaline material. The solitary lesion must be differentiated from basal cell carcinoma. Surgical excision is the only treatment. When large areas of the scalp are involved, this may be quite difficult and may require grafting. Although usually benign, cylindromas may undergo malignant transformation with subsequent local invasion and metastatic disease.

Hidrocystoma

A hidrocystoma may be either eccrine or apocrine in origin.⁹¹ In either case, the tumor usually presents as a solitary lesion and is most frequently seen on the face, especially around the eyelids. The lesion consists of translucent nodules with a firm, cystic consistency. The eccrine hidrocystoma is generally from 1 to 3 mm in diameter, whereas the apocrine hidrocystoma may attain a diameter of 1 cm. Both may have a bluish hue. The two types are distinguishable by histologic criteria. Microscopic examination reveals differing cellular detail and secretion patterns for the two types. In either case, treatment is excision.

Syringoma

Syringomas are benign tumors that originate from the eccrine sweat gland duct; they appear more often in women than in men.⁹² Syringomas are most commonly located on the face, with the lower eyelids being the most common site. They generally occur in adolescence or early adulthood and may be eruptive or occur in crops. They present as small 1- to 5-mm papules that are usually flesh colored but may be slightly translucent or yellowish. They may resemble trichoepitheliomas, but their location and histology help differentiate them. Histologically, these tumors appear as small nests of cystic ductal structures or as solid epithelial strands, many of which may have a characteristic tail-like projection. They are not associated with underlying abnormality. They do not tend to involute, however, and may present a cosmetic problem when located on the face. They can be treated with a pulsed ablative laser (CO₂ or erbium) or with light electrocoagulation using a fine epilating needle.

Sebaceous Hyperplasia

Sebaceous hyperplasia occurs mainly on the face, particularly the forehead, and represents benign enlargement of the normal sebaceous gland (see Fig. 20-8F). It is frequently called senile sebaceous hyperplasia, because it is usually seen in older persons.⁹³ One or hundreds of lesions may be present. They may be from 2 to 5 mm in diameter, and there is usually a central umbilication. These lesions are soft and yellowish and must be differentiated from basal cell carcinoma. Histologically, they present as hyperplastic sebaceous lobules that are otherwise normal in appearance. They are only a cosmetic problem; solitary lesions can be easily treated with a shave excision, electrodesiccation and curettage, or cryosurgery. When the lesions are numerous, surgical excision is not warranted. Therapy with systemic 13-cis retinoic acid has also been described.

Xanthelasma

Xanthelasmas present on or close to the eyelids as soft, yellowish, irregular papules. They usually appear in middle age and can affect either sex, and they are not often associated with xanthomas elsewhere on the body. Frequently, they are an isolated finding and do not always signify elevated serum triglyceride levels, although each patient should be examined for the existence of such a systemic problem.⁹⁴ Histologically, these lesions present as an accumulation of xanthoma cells, which are lipid-laden histiocytes. Treatment is the application of 50% to 65% trichloroacetic acid, light cautery, or excision.

Lipoma

Lipomas are single or multiple benign tumors composed of adipose tissue. They are soft and may be lobulated or rounded and cystic in nature, and they are generally freely movable. Except in rare syndromes, lipomas are nontender. They generally occur on the trunk, but they may also occur on the neck or any other part of the body. Histologically, they present as proliferations of normal-appearing fat cells that may be surrounded by a thin connective-tissue capsule. Single lesions present only cosmetic problems, and they are generally easily excised. Despite attaining sizes of more than 1 inch in diameter, they may often be expressed through a small, 4-mm punch hole.⁹⁵

Excisional Surgery

The shave biopsy is one of the most commonly performed procedures for cutaneous lesions.^96,97 It is a rapid means of removing tissue either as part of therapy or to establish diagnoses. A shave can be performed using various techniques, with the depth of the shave depending on the angle of the blade as it enters the skin. Usually a No. 15 or No. 10 Bard-Parker blade is used. One should remember that the sharpest point of the No. 15 blade is the rounded tip, whereas the No. 10 has its sharpest edge along the belly of the blade. The shave should be performed using the sharpest portion of the blade. One of the sharpest blades is the Gillette Blue Blade; it is excellent for shaving lesions. A blade breaker or hemostat can break the Blue Blade into any size or shape desired. The blade can then be held between the thumb and forefinger and flexed, thereby allowing for the performance of a superficial shave in which the blade sculpts along the contour of the surface being excised (e.g., the ala of the nose or the helix of the ear). Hemostasis can then be achieved with aluminum chloride. Monsel’s solution (ferric subsulfate) should be avoided on the face or cosmetic areas because of the ability of macrophages to phagocytose the iron, thereby causing a tattoo.

The punch, a fixed-diameter surgical knife, is an extremely valuable tool to a dermatologist for excision or biopsy. It comes in various sizes, from 2 mm to 1 cm, with 0.5-mm increments. Punches can be purchased as disposable instruments (Baker) or as permanent, sterilizable instruments. The most common sizes used for biopsy are 3 mm and 4 mm; however, a 2-mm punch can provide a cosmetically elegant biopsy of sufficient size for the pathologist. Whenever possible, the 4-mm punch should be used. All punch-biopsy incisions should be closed. Some tricks help with the use of a punch. By putting tension on the skin perpendicular to the anticipated line of closure (skin tension lines), one can cause the circular punch to leave an oval or ellipse for easier closure. The incision is usually closed with sutures or the recently introduced single-shot staple. A valuable trick is to use a punch to excise intradermal nevi. By selecting a punch that just fits around the nevus, one can easily excise it to the depth necessary to remove the entire lesion. Another trick, which can be used when nevi occur in areas of neutral skin tension or where skin tension lines are not obvious (e.g., the chin), is to use the punch to help determine the best lines of closure. If the surgeon uses a punch excision with no tension placed on the skin, the resulting circle will usually form itself into an oval along lines of facial expression and help in the determination of skin closure lines. Often the skin closure lines can occur at an angle that is perpendicular to what one might expect.

The wedge excision or biopsy, which is a variation of the fusiform excision (ellipse), can be used to remove lesions cosmetically or to perform biopsies. As a biopsy technique, it is either incisional or excisional. Whenever possible—especially when dealing with pigmented lesions—the excisional biopsy is preferred to give the pathologist the best chance for an accurate diagnosis. When the wedge procedure is performed as an incisional biopsy of a large, nodular lesion, the narrowest possible wedge (greater than the classic 3:1 length-to-width ratio) is made at the edge of the lesion so that one end of the wedge is through normal skin; then one side of normal skin is available through which to pass suture. This is an especially important advantage if the other side of the wedge is within friable tissue.

Scissors excision is a valuable method of cosmetically removing benign skin tumors. In the experienced hand, scissors can be used to produce an often-elegant cosmetic result very quickly. Scissors are best used on raised, pedunculate skin lesions in which the pedicle can be easily and rapidly cut with scissors. Our preference is to use fine-tipped, curved Iris or Gradle scissors. Tricks similar to those used for the shave biopsy apply to scissors excisions. Raising a bleb of anesthesia under a pedunculate lesion allows for better access to the base. Scissors are an excellent tool around the eyelids. Often a small chalazion clamp can be placed around a lesion, thereby permitting easy excision with fine scissors. Filiform or pedunculate lesions on the eyelids can be lifted with fine forceps and then cut with curved scissors. This procedure produces a small ellipse upon release of the eyelid skin, which either heals by itself or with the placement of one small stitch. Scissors can also be used for biopsies of oral mucosa. Again, a chalazion clamp can be placed on the lip, or a stitch can be placed around the area of the biopsy. One can then pull up on the stitch, thus creating a tent of tissue that can be scissors excised at the base to obtain a biopsy specimen.

A curet is a valuable tool to the skin surgeon. One should have a variety of sizes of curets available; larger curets are used to debulk or remove larger tumors, and smaller curets are used to do the same for small tumors or to help track small extensions of cutaneous tumors, such as basal cell carcinoma. A curet is held like a pencil, with the ring or small finger placed on the skin to anchor and stabilize the hand. Normal skin has a “gritty” feel with the curet, whereas abnormal skin or tumor often feels mushy or soft. One way to remove multiple molluscum contagiosum lesions on the face, for example, is to individually curet each small lesion (a small curet is used). If anesthesia is required, one can use either the usual local anesthetic or one of the refrigerant anesthetics, which both induces some anesthesia in the skin and hardens the lesion; hardening allows the lesion to be easily flicked off with a curet. A curet is often used in conjunction with electrosurgery.

Electrosurgery

Electrosurgery is a useful way to remove small benign lesions, to assist the curet with the removal of malignant lesions, and to assist the surgeon with the obtaining of hemostasis. Most electrosurgery performed in the office requires nothing more than a hyfrecator-like unit. This versatile instrument is easy to use because the patient does not need to be grounded, and the electrodesiccation or fulguration is at a more superficial depth than the electrocoagulation or cutting seen when a patient is grounded. Most of these electrosurgical units have two current settings. The low current is best for light electrodesiccation of benign lesions. One can also purchase a fine steel tip or place a 30-gauge needle on the standard tip; this tip can then be threaded down adnexal structures to treat benign adnexal tumors or to coagulate arterial vessels that are feeding vascular lesions. The high current setting, which is a more destructive mode, is used to burn tumor and surrounding tissue, such as during electrodesiccation or fulguration of basal cell carcinomas. Bipolar units, with the patient grounded, can be used to help sculpt lesions, such as in the case of a rhinophymatous nose.

Cryosurgery

Cryosurgical removal is the treatment of choice for many lesions. Systems vary from elaborate cryospray and cryoprobe units to something as simple as a Styrofoam cup containing liquid nitrogen to be applied with a cotton-tipped applicator. The superficial use of cryosurgery destroys tumor tissue, often with excellent cosmetic results. Hypopigmentation and other sequelae can develop, however, which make the use of cryosurgery in darker skin more difficult.

Chemical or Abrasive Surgery

Many superficial cutaneous lesions of the head and neck can be removed with the application of a chemical or with the use of abrasion. The chemicals most commonly used as peeling agents are trichloroacetic acid and phenol. The concentration of trichloroacetic acid used varies from 35% to 70%. Phenol is usually used as a concentrated solution (88%) or mixed as Baker’s solution. These chemicals can be used to peel benign pigmented or melanotic lesions, with good success. The most common form of abrasion is spot dermabrasion. Our favorite tool is the Bell hand engine with the diamond fraise or wire brush. The fraise can be purchased in varying sizes and shapes; small, 2-mm wheel, cone, or cylindric fraises are excellent tools for removing multiple small epithelial tumors.

Laser Surgery

The use of lasers in surgery and medicine has rapidly advanced in recent decades and continues to play an important role in the treatment of many cutaneous neoplasms on the head and neck. Innovations in optical technology have allowed for improved therapeutic efficacy and safety and the ability to treat patients with an increasing number of medical and aesthetic indications. Advances in visible and near infrared lasers and broadband light sources, including the development of longer pulse durations, broader spectrums, and combined wavelengths, continue to improve the treatment of numerous benign vascular and pigmented lesions. Far infrared lasers including CO₂ and erbium:YAG lasers remain a useful tool for the safe and effective treatment of numerous benign epidermal lesions, and can be the treatment of choice for some premalignant epidermal lesions, including actinic keratoses and actinic chelitis.^98,99 They may have a role in the treatment of some in situ carcinomas, although they may be less suitable without the evaluation of tissue margins. The basic principles of laser surgery are discussed in detail in Chapter 3; specific use of lasers used to treat vascular lesions is discussed in Chapter 201.