1 Onset and duration

It is important always to ask the patient’s opinion of the cause of the lesion or of any incident associated with its onset. The patient may relate the lesion to an occupation, a drug or an injury. The length of history gives some idea of prognostic significance. The onset of skin lesions may be related by the patient to a triggering factor such as an insect bite. A previous history of repeated trauma may be important in pyogenic granuloma and in implantation dermoid cyst. A sudden change in the characteristics of a pre-existing mole suggests melanoma. Other skin lesions may be induced by local or systemic drug treatment.

2 Change and progression

The rate of progression helps to distinguish between benign and malignant conditions (Table 1.1). A skin lesion that progresses to a significant lump within a few days suggests infection (e.g. pyogenic granuloma); in a few weeks, hyperplasia (e.g. keratoacanthoma); or over several months, malignancy (e.g. basal and squamous cell carcinoma, melanoma). A pigmented skin lump that has not changed over several years suggests a benign mole. Most subcutaneous lumps are benign and very slowly progressive. ‘Sebaceous’ or epidermoid cysts are prone to infection, partial resolution and recurrence. Sometimes a ganglion may rupture after trauma and disappear, to return later. Abdominal wall hernias may appear suddenly after a strain and slowly progress; they are usually reducible and reappear on standing. Basal cell carcinomas may appear to heal in part of their circumference but are usually inexorably progressive.

Table 1.1 Growth pattern of some common skin nodules

3 Other symptoms

Pain is not a common symptom of subcutaneous lumps. When present it suggests inflammation or lesions such as neurofibromas and implantation dermoid cysts. Glomus tumours contain numerous nerve endings; they are classically associated with severe pain. Severe pain in an ulcer suggests an ischaemic cause.

Ulceration and bleeding suggest malignant change. Catching of the lesion on clothing suggests the possibility of malignant change in a pigmented naevus but is also a feature of any verrucous lesion.

Itch is common in basal cell carcinoma, melanoma and leukaemic skin nodules.

4 Multiplicity

The presence of other lumps or ulcers is often a guide to pathology. Lipomas and neurofibromas are sometimes multiple and symmetrical. ‘Sebaceous’ cysts are often multiple, particularly when on the scalp or scrotum. Many benign skin lesions tend to be multiple, particularly in older patients (cherry angiomas, seborrhoeic keratoses, senile purpura, liver spots). The appearance of satellite nodules suggests that a mole is malignant.

The history should be completed by a general systems review and the family, social, occupational and allergic history. This is particularly important for skin ulcers where systemic diseases such as alcoholism, rheumatoid arthritis and diabetes are important factors to consider, both in aetiology and in treatment. Diabetes mellitus is frequently a factor in delayed healing of ulcers. Some conditions have a particular geographical predisposition such as the ‘Bairnsdale ulcer’ for which the aetiology is an atypical mycobacterium of limited geographical range.

1 Situation and depth

If you can accurately describe the anatomical position of a lump and know the range of pathology possible at that site you will more easily make a clinical diagnosis.

Situation is described regionally in relation to the body surface. Depth is assessed in relation to the skin and deeper layers. The region occupied by the lesion is defined. The relationship of the lesion to surface landmarks, including distance of the lump from prominent bony points, is recorded. Many lumps are characteristic of specific regions: ‘sebaceous’ cysts occur in the scalp and scrotum, implantation dermoid cysts occur mainly in the hand. Lipomas are most often found in the subcutaneous tissues of the trunk or limbs. Ganglia, tendon sheath swellings and bursae occur at defined points near joints, bony prominences and tendons. Lymph node swellings occur in defined anatomical areas.

The site of ulcers is often also suggestive of their diagnosis. Ischaemic ulcers are at the tips of digits or over points of pressure necrosis — the latter often suggesting neuropathy. The ulcers of venous insufficiency are usually situated around the ankle and lower leg.

The depth of the lesion in relation to the skin must always be noted. A lump is ‘layered’ in the correct anatomical plane; an ulcer’s floor, base and edge are assessed. A lump in a limb will be arising primarily from or involving skin, subcutaneous tissue, muscle layers or the underlying bone. On the trunk it will be important to determine if a lump is within the body cavity or the parieties. Assessment of depth should be ordered and precise and demands accurate sectional anatomical knowledge of the region. Lumps in the subcutaneous fat plane that are attached to the fascia investing deeper muscles will have their mobility impaired when the muscles are tensed. A lump below the fascial plane will be obscured, as well as becoming less mobile, when the muscles are tense. Bony lumps are fixed and immobile.

The edge of an ulcer may be protuberant and elevated above the skin surface, suggesting malignancy. A healing ulcer has pink healthy granulation tissue in the floor and the edge is made less distinct by a thin overlying layer of regenerating epithelium that may appear bluish. A sloughing floor, with induration extending around the base and sharply outlined edges, suggests chronicity. Deep chronic indolent ulcers with little granulation tissue are often ischaemic.

2 Size

The lesion should be measured in centimetres. Estimation of size is unreliable and it is useful to be aware of the span of one’s own digits and hand as a graduated ruler is not always available. The size of a lump or ulcer is usually measurable with precision in two dimensions; diameter in depth should be estimated as accurately as possible.

3 Shape and surroundings

The lump’s shape and physical characteristics are defined in the subsequent steps of examination. Following a practised sequence ensures that no important details, such as the presence of pulsation within the lump, are omitted.

The shape of a lump or ulcer can be regular or irregular. Regular shapes are spheres, circles and ovals.

A smoothly regular spherical lump strongly suggests a cyst. Most solid lumps have slight or prominent irregularities of shape, even when generally spherical or oval. To describe a lump’s shape as spherical implies that it has been assessed totally in three dimensions. This is only possible with very mobile lumps or when an adjunct to examination such as an ultrasound is available. More often only a portion of the circumference of the lump can be felt and its roundness implied from this assessment. Cystic liquid collections are common in skin and subcutaneous tissues and include ‘sebaceous’ cysts and bursae.

Solid lumps such as lipomas, neurofibromas and lymph nodes are usually irregularly round or oval in shape. Lipomas have another very characteristic feature: they are lobular, mirroring their origin from lobulated fat. They thus form mobile soft lobulated subcutaneous lesions with an indistinct ‘slipping’ edge, unlike ‘sebaceous’ cysts that are spherical and firmer, are attached to the skin and have distinct margins. Lymph nodes also have discrete margins and, when multiple, present as lobulated or bosselated swellings with a defined edge.

Lumps arising from the skin may be nodular, flattened, dome-like or polypoidal in shape; polyps may be sessile or pedunculated. Neurofibromas of the skin form soft, domed lumps (molluscum fibrosum). Subcutaneous neurofibromas form firm, fusiform subcutaneous swellings at the site of nerves.

Many anatomical structures have such a characteristic shape and such constancy of position that a swelling of the whole organ can often be identified virtually on sight: thyroid and parotid glands, kidney, liver and spleen. Tubular or dumb-bell-shaped subcutaneous lesions suggest enlargements of tendon sheaths.

Ulcers can be regular or irregular in shape and their edges can also be described as serpiginous, sloping, everted, rolled, overhanging or punched-out (Fig 1.2). Brown pigmentation, a desquamative rash and induration of skin and subcutaneous tissues around an ulcer suggest venous insufficiency. Redness, heat, oedema and cellulitis indicate active spreading infection.

The lump’s relationship to its surroundings is assessed. Impaired mobility, with attachment to surrounding structures, is an important diagnostic sign. Relationships must be assessed in all dimensions. Attachments to overlying skin and deeper layers are noted, as well as any effects on key local structures such as nerves, tendons or tubes such as blood and lymph vessels and viscera. Nerve function proximal and distal to the lesion is noted, as are the effects of tendon and joint movements. Evidence of arterial or venous insufficiency, of lymphatic enlargement or obstruction, or of visceral obstruction or fistulation, is sought.

4 Colour

Variations in skin reaction and colour occur over lumps and skin lesions and at the edge and floor of ulcers. A skin nodule featuring a waxy or pearly nodular edge with fine cutaneous telangiectasis is likely to be a basal cell carcinoma. Pigmented skin lesions are common. Deep black suggests melanoma or skin necrosis with gangrene. Variegated colour intensity and halo depigmentation can also be features of melanoma. Brown lesions include benign and malignant moles, seborrhoeic keratoses, dermato-fibromas and some basal cell carcinomas. Vascular lesions can be red or brownish. Senile angiomas and pyogenic granulomas are usually bright red, as are strawberry naevi and spider naevi. Port wine stains are a deeper red colour. Seborrhoeic keratoses are characteristically brown, greasy and rough to the touch — like a blob of sealing wax on the skin. Yellow discolouration seen through the skin may indicate pus, xanthoma or gouty tophus. A grey or tan verrucous appearance is common with a number of benign nodules. Cutaneous lymphoedema varies in appearance but may be tan or pinkish with a characteristic orange peel appearance where the skin pouts between the pores. Erythema and heat suggest superadded infection.

5 Contour

The surface contour of a lesion is allied to its shape and can also be described as regular (smooth, round) or irregular. An irregular contour can be:

6 Consistency

The consistency of the lesion is often very helpful in diagnosis. The simplest classification of consistency of lumps is:

Apart from these four grades, familiar analogies can help to describe size and consistency (e.g. golf ball or tennis ball size and feel). A diagnostic description (solid or cystic lump) combines the clinical features of shape, contour, consistency and other aspects.

A cyst is a localised collection of fluid: cysts in body tissues mostly contain liquid, a few contain gas (lung cyst, pneumatosis coli). Cysts usually have an epithelial lining. The term pseudo-cyst is often applied to pancreatic and peripancreatic liquid collections without an epithelial lining.

Associated physical features that should be considered along with consistency are compressibility, cough impulse, reducibility and pulsation.

Compressibility is the sign of emptying on pressure. This sign is found with venous lakes and cavernous haemangiomas (compressible, but not pulsatile, vascular lesions); with hernias (compressible and reducible lesions); and with some bursae and ganglia that communicate freely with adjacent joints. After emptying on pressure, lesions may refill when the pressure is released. Hernias may not recur and refill unless the patient stands or is made to cough.

Vascular blushing on compression is an allied important sign, which occurs when some pigmented vascular lesions are compressed with a transparent slide. Cavernous haemangiomas, telangiectasis and spider naevi show this sign; in the case of spider naevi it occurs when the central arteriole is compressed. Port wine stains (capillary haemangiomas) and senile angiomas, where the colour is not due only to easily displaced intraluminal blood, do not show the sign, nor do purpuric or petechial spots.

Cough impulse: on coughing an expansile impulse is felt over a hernia. Hernias share this sign with venous swellings associated with valvular incompetence and with meningoceles.

Reducibility is a term usually applied to hernias. Venous swellings, pharyngeal diverticula and some ganglia communicating with joints can also be reduced by recumbency and pressure.

Pulsation may be apparent on inspection. It should be confirmed by palpation and checked to be synchronous with the pulse. Venous pulsation is usually visible but impalpable; arterial pulsation is visible and palpable. Pulsation may be truly expansile due to an aneurysm or a very vascular solid lump such as a toxic goitre or vascular neoplasm. Pulsation may, however, be transmitted to the lump by a nearby blood vessel. Differentiation between the two forms of pulsation can be very difficult, particularly with deeply situated lumps such as para-aortic lymphadenopathy versus an abdominal aortic aneurysm. Help can sometimes be given by the two finger test: a finger is placed on either side of the swelling — movement of the fingers in the same direction occurs with transmitted pulsation and centrifugally divergent movement occurs with expansile pulsation. The test is often difficult to interpret.

If pulsation is detected it is essential to also test for a thrill on palpation and a bruit on auscultation. These findings suggest arterial stenosis, aneurysm or arteriovenous shunting.

7 Temperature

Increased warmth on palpation indicates inflammation or increased vascularity from some other cause. Vascular tumours are often warm to palpation. The temperature is best assessed by applying the drier, thinner and cooler dorsal surface of the fingers to the skin over the swelling and comparing it to a similarly exposed area. Increased warmth may accompany a focal infected lesion such as a furuncle or a diffuse inflammation such as cellulitis. Heat, a localised cord-like swelling and tenderness suggest thrombophlebitis when found along the anatomical position of a superficial vein, or acute lymphangitis when along the course of lymphatic drainage to tender lymph nodes. Warmth in focal lesions such as bursae, cysts or tendon sheaths suggests inflammation or infection. Unilateral coldness of a limb indicates the presence of ischaemic vascular disease.

8 Tenderness

Tenderness on palpation usually coexists with erythema and increased warmth in inflammatory lesions. Most noninflamed lumps are not tender; although, neurofibromas, plantar warts, implantation dermoid cysts and areas of fat necrosis are examples of lumps that can be tender. The glomus tumour, a benign vascular hamartoma affecting the limbs and fingers and presenting as a subcutaneous or subungual small brown swelling, is exquisitely tender and sensitive to the lightest pressure.

9 Transillumination

Transillumination is the most important physical sign characterising a thin-walled cyst containing clear fluid. The sign can be difficult to elicit in very small or deeply placed lesions and should always be tested while the lump and its ambience are well shaded, preferably in a dark room.

Bursae, hydroceles and epididymal cysts are common transilluminable lumps. Ganglia involving tendon sheaths usually transilluminate. Firmer, deeper ganglia near joints usually do not. ‘Sebaceous’ cysts do not transilluminate because of their pultaceous contents and thick walls. Lipomas are not usually transilluminable and never brilliantly so. Transillumination of a focal lump must be differentiated from the normal luminescence of subcutaneous tissue around the beam of a torch.

10 Fluctuation and percussion

Fluctuation is tested (preferably in two planes at right angles to each other) with a compressing and a testing finger. The lump must be fixed to ensure that it has not been itself moved by the compressing finger. The transmitted impulse of fluid is appreciated by the second, testing finger (Fig 1.3). A variation of this test is the demonstration of a fluid thrill in ascites. With some lumps, three fingers can be used conveniently. Two fingers of one hand on opposite sides of the lump control it and both test for transmission of an impulse when the index finger of the other hand compresses the lump, or both compress the lump while the index finger of the other hand tests for fluctuation.

Figure 1.3 Testing fluctuation

Two watching fingers detect transmitted impulse (A) while the displacing finger applies compression (B).

Fluctuation is present in liquid or gaseous lumps with deformable walls and also in some soft, solid swellings. Fluctuation is thus found in hydroceles, sebaceous cysts, bursae, ganglia (if soft and superficial) and in lipomas.

Percussion determines whether a swelling is resonant or dull. Percussing a swelling after confirming it is fluctuant can help distinguish between gas-containing and liquid-containing swellings. An inguinoscrotal hernia with contained bowel will be tympanitic, as contrasted with the dullness of a liquid-containing hydrocele.

11 Fixity

Skin attachment to a lump is demonstrated by skin retraction and dimpling on inspection or by decreased skin mobility on palpation, with inability to pinch or push the skin away from the lump. A dimple forms when the skin over the lump remains fixed to it. If the skin over a lump is tightly stretched the sign is more difficult to elicit.

Swellings should also be tested for their attachment to deeper structures. Free mobility in all directions is found with benign skin lumps and lumps in the subcutaneous fat without deep attachment. Limited mobility over the underlying muscle suggests deep fascial or muscle attachment. The sign is positive with neoplastic or inflammatory fibrosis around a lump and with subfascial or intermuscular lumps.

Transverse mobility across the line of an artery or nerve suggests a lesion of one of these structures. No mobility at all is found with lumps arising from or fixed to bone, periosteum or joint capsule.

Mobility on swallowing is an important sign for neck swellings: structures normally related to the trachea or larynx exhibit this sign, which is characteristic of a goitre (Ch 2.15). Movement on inspiration occurs when intraperitoneal lumps are related to the under surface of the diaphragm (liver, spleen).

12 Fields

Examining the draining lymphatic nodes as potential sites of distant spread of a lesion is a routine part of physical examination and is particularly important in inflammatory and neoplastic lesions.

After finishing the regional examination, a general physical examination and systems review may detect associated abnormalities essential for completion of the diagnosis (metastatic malignancy, other lymph nodes involved and lesions at many sites).

Common causes of benign skin lesions

Clinical features, diagnostic and treatment plans

Diagnosis in most instances can be made on clinical assessment including dermoscopy. Most lesions will need no treatment other than reassurance. Many are specifically age-related.

Children

Port-wine stain (capillary haemangioma)

This is the most common vascular developmental lesion and is a hamartoma of endothelial origin. It is present at birth, most often on the face or neck as a dark macular stain. These lesions do not regress and can become darker and develop nodular eruptions late in life. Treatment may be required for cosmetic reasons and utilises laser photocoagulation and, less commonly, surgery.

Strawberry naevus (cavernous haemangioma)

This is a bright red, raised tumour of the face or neck that usually appears in the first few weeks of life, partially blanches on pressure, grows rapidly over the next year or so and then gradually regresses with thrombosis. Most regress completely by the age of 10 years; treatment is usually not required.

Benign mole

A few longstanding benign pigmented brown moles will be found on practically every person. In Australia the risk of malignancy with multiple naevi does not increase until an individual has 200 lesions. There is a recognised genetic predisposition to multiple naevi. There are several varieties containing melanocytes (naevus cells).

Intradermal, junctional and compound naevus

Intradermal naevus is the most common benign mole, deriving its name from the fact that the pigment cells lie entirely within the dermis (Fig 1.5). The macroscopic appearance varies considerably: from a soft flattened pale brown or flesh-coloured nodule or macule, to a deep brown warty excrescence. The edge is usually well defined. Many contain hair, which is a helpful diagnostic point — hairy moles are virtually always intradermal and benign. Intradermal naevi occur all over the body skin and are usually present from birth but are rare on the palms or finger-tips. They vary in size from a few millimetres to large lesions several centimetres across. They are biologically conservative, wholly benign lesions, throughout life.

Figure 1.5 The histology of benign pigmented moles

A: junctional naevus showing melanocytes at the epidermal–dermal junction; B: intradermal naevus with pigmented cells in the dermis. The histological combination of A and B is known as a compound naevus.

Junctional naevus. As its name implies, this lesion contains pigment cells at the junction of epidermis and dermis. Macroscopically these are flatter, often macular lesions, of varying depth of pigmentation. They vary in size from a few millimetres to several centimetres. They may be present at birth or appear later. The edge is sometimes less well defined than that of an intradermal naevus.

Compound naevus contains both junctional and intradermal components. In almost all moles the radical youthful potential of the immature junctional melanocyte progresses to a maturely conservative intradermal adulthood. Occasionally a junctional or compound naevus develops malignant change in adulthood.

Few pigmented moles in children will need treatment. Malignant change does not occur until puberty but skin malignancy is seen in teenagers, albeit rarely. Surgical removal may be required for cosmetic reasons or because of an inconvenient site.

Blue naevus (Mongolian spot)

This lesion is uncommon and is an intradermal lesion of a different type from other pigment-cell naevi. It presents as a characteristically bluish-grey, flat or slightly elevated nodule on the face or limbs. It is always benign. Surgical removal may be required for cosmetic reasons or because of an inconvenient site.

Freckles (ephelides)

These light tan, small pigmented macules are influenced by solar exposure in sensitive individuals with fair skin (sun spots) and may disappear with time.

Infective warts

The common infective wart (verruca vulgaris) is a localised hyperkeratotic skin overgrowth due to stimulation by the human papilloma virus. Warts occur commonly in children and young adults and can persist unchanged for years or regress and disappear spontaneously. They are most common on the hands, often affecting adjacent fingers and form greyish nodules with a classic roughened surface showing a mosaic, finely tessellated appearance. Untreated warts of the hand and fingers are often exophytic in their growth and cauliflower-like in appearance. Warts of the soles are also common in children and adolescents; these tend to become trodden into the foot with a flattened horny surface (endophytic) and often become painful. Differentiation of a plantar wart (‘papilloma’) from a simple callosity is aided by paring down the horny epidermal surface of the lesion to expose the characteristic mosaic appearance with punctate spots — as distinct from the horny featureless plug of keratin exposed by paring a callosity. The procedure is painless and gives symptomatic relief for both conditions as well as aiding diagnosis. The pavemented surface of the wart and its clearly defined margin with a potential cleft separating it from normal skin are other diagnostic aids. Both warts and callosities occur over pressure points such as metatarsal heads or the calcaneum.

Pyogenic granuloma

These can cause exuberant vascular lesions of mucocutaneous surfaces in children and may need diagnostic excision.

Causes of ‘suspicious’ skin lesions

Clinical features and diagnosis

1 Basal cell carcinoma (BCC)

These commonly occur on the face but may present at less typical sites. Basal cell tumours are locally malignant but do not metastasise to lymph nodes or via the bloodstream. They can present in various ways (Box 1.4). The usual presentation is as a raised pink nodule with a characteristically translucent pearly sheen and with fine telangiectasis visible through the stretched skin surface. Later the nodule proceeds to central shallow ulceration with a rolled edge. The lesions grow slowly but irrevocably and neglected ones can cause gross local infiltration and destruction of tissue — the ‘rodent’ ulcer. Occasionally, multiple BCC occur with a familial and inherited pattern.

Box 1.4

Clinical forms of BCC

Familial

Nodular

Ulcerative

Cystic

Psoriatic

Comedoform

Sclerosing

Pigmented

Other macroscopic presentations are common. Cystic, psoriatic and comedoform varieties can cause confusion with benign sebaceous (epidermoid) cysts, psoriasis and acne. Pigmented BCC can resemble melanoma. A diffusely sclerosing or cicatrising form (‘brush-fire’ BCC) tends to grow slowly at the periphery and heal in the centre so that its extent can be very difficult to determine without frozen section histology at operation. Histology shows a locally invasive cancer of the basal cells of the epidermis.

5 Malignant melanoma

This is the most malignant of all skin tumours. It occurs throughout adult life. Melanomas are particularly prevalent in fair-skinned populations in tropical climates. They are more common in females than in males and their geographical frequency varies widely. Melanomas are rare in black races, except in depigmented areas of skin. Any brown or black mole that shows increase in size, irritation, bleeding, nodularity or ulceration should arouse suspicion and should be excised (Fig 1.6).

Figure 1.6 The ABCDE assessment aids in the identification of skin lesions suspicious of melanoma

A: Asymmetry — one half unlike the other; B: Border — irregular edge; C: Colour — variable pigmentation; D: Diameter — usually larger than 6 mm; E: Evolving — change in the lesion including increasing elevation.

From Townsend et al, 2007

An important subgroup (amelanotic melanoma) are not pigmented and will be difficult to tell macroscopically from SCC or BCC or infective lesions. Common sites for melanoma are the face, limbs and trunk. Poor prognostic factors relate to increasing depth of the lesion, ulceration, mitotic count, satellite or transit nodules and lymph node spread. Spread to regional nodes is common and considerably worsens prognosis. Blood-borne metastases may occur at any site. Several clinically distinct macroscopic types can be recognised and have progressively worsening prognoses.

Hutchinson’s melanotic freckle (lentigo maligna melanoma). This presents initially as a dark brown macular stain on the face of older patients, particularly elderly women. Histology shows junctional activity without invasion and the lesions can remain stationary for years. Spreading growth continues laterally in an irregular fashion, giving a distinct but irregular edge and a typically variegated pigmented appearance of the surface. The lesion will invariably progress ultimately to malignant change and the edge of the malignancy can be difficult to define.

Superficial spreading melanoma. This is the most common type of melanoma. It has a short pre-invasive stage in which spread is lateral, giving a brownish-black papule with an indistinct macular edge, proceeding to invasive spread.

Nodular melanoma. This type has the worst prognosis and spreads laterally and invasively from an early stage; malignant deep invasion is also seen early.

Treatment plans

Focal lesions that are suspicious of malignancy require surgical excision. An ulcerated lesion automatically induces suspicion. Lesions can usually be sorted clinically into those in which the diagnosis of BCC, SCC, keratoacanthoma or melanoma is fairly clear-cut and those in which the diagnosis is equivocal. Many diagnostic mimics exist (Table 1.2). Surgical excision provides a tissue diagnosis and for most lesions is curative with one procedure. Massive and cosmetically disfiguring excisions should not be performed.

Table 1.2 Malignancies and their mimics

5 Melanoma

Treatment of all suspicious lesions (Box 1.5) is by surgical excision and confirmation of diagnosis by histology. Excision should be adequate in width and depth. It is difficult to define precisely the requirements for adequate excision; for benign skin lesions 1–2 mm is adequate. Recommended margins relate to the depth of the tumour. Where adequate excision and primary closure is not cosmetically acceptable, plastic and reconstructive options should be considered in surgical planning.

Box 1.5

Suspicious pigmented lesions

Malignant melanoma

Melanotic freckle

Intradermal and subungual haematoma

Rapidly growing benign naevi–junctional, compound

Pigmented BCC

Rapidly growing or ulcerated dermatofibroma

Rapidly growing or ulcerated seborrhoeic keratosis

Kaposi sarcoma

The management of melanoma and the prognosis depends on the thickness of the primary tumour, its size and the extent of local and distant spread. If regional nodes are affected they should be removed. Sentinel node biopsy is an important staging procedure.

Melanomas are relatively resistant to most forms of adjuvant treatment: irradiation, chemotherapy and immune therapy have all been employed and further treatment is best considered within a multidisciplinary clinic.

The most reliable prognostic local indicator after putatively curative excision is the depth of the lesion. This can be staged either by:

• extension progressively from epidermis to papillary dermis, to reticular dermis and to subcutaneous fat (Clark) or

• simple measurement of the tumour depth (Breslow) in millimetres (Fig 1.7).

Figure 1.7 Prognosis in malignant melanoma is measured in two ways: depth of invasion (Clark’s levels I–V) or simple measurement of tumour depth in millimetres. Comparison of the two methods is shown. Level I: an in situ lesion above the basement membrane of the basal layer of the epidermis, less than 0.75 mm in depth. Level II: the lesion is invading into the papillary dermis, equivalent to a depth 0.75–1.5 mm. Level III: the lesion fills the papillary dermis down to its junction with the reticular dermis, a depth of 1.5–2.25 mm. Level IV: the lesion extends into the reticular dermis, a depth of 2.25–3.0 mm. Level V: well into the subcutaneous tissue, a depth greater than 3.0 mm

Lymph node involvement considerably worsens prognosis at any stage. The natural history of recurrences or metastasis is very variable. Late metastases — 10 years or more after the initial presentation — are quite common, so follow-up should be prolonged and meticulous, looking for locoregional and distant metastatic disease and new primary lesions. Therapy for recurrent melanoma may include excision of metastatic disease (Table 1.3).

Table 1.3 Tumour depth in melanoma influences management and prognosis

Diagnostic and therapeutic plans

All pigmented naevi in children are benign, although their growth pattern may not suggest this. Many spontaneously remit. Excision is indicated only on cosmetic grounds or for future prophylaxis.

Many adult lesions will be longstanding and also clearly benign. Different types of benign pigmented moles are summarised in Table 1.4.

Indications for excision of pigmented skin lesions are outlined in Box 1.6. Ultimate diagnosis rests on histological examination of the excised specimen. Biopsy is usually best done by total excision rather than incision. Frozen section diagnosis can be helpful in planning the extent of operative excision for equivocal lesions. About 50% of malignant melanomas arise in a pre-existing dysplastic naevus.

Box 1.6

Pigmented skin lesions — indications for excision

Suspicion of malignant melanoma

Prophylactic excision of premalignant lesions

melanotic freckle

‘dysplastic’ naevus: particularly large junctional and compound naevi and those on certain sites (palms, genitals, soles)

Repeated trauma to benign lesions (intradermal naevus in beard area)

Cosmetic

Other suspicious pigmented lesions

pigmented basal cell carcinoma

dermatofibroma

seborrhoeic keratosis

Kaposi’s haemangiosarcoma in high-risk individuals (AIDS organ transplant)

1 Lipoma

The most common of all subcutaneous lumps is a benign tumour of adipocytes: lipoma. Lipomas are usually found on the limbs and trunk but can occur anywhere there is fat. Lipomas in less common sites (e.g. breast, parotid gland, subfascial or intramuscular) can cause diagnostic difficulty with other common lumps at these sites (breast cancer, salivary mixed tumour, muscle sarcoma) and the classic physical signs of lipoma can be distorted by the overlying gland capsule or deep fascia. Subfascial lipomas, for example, have their mobility decreased or might even disappear on contraction of the muscle. Lipomas in subcutaneous fat are virtually always benign. Although they can become very large, they always exhibit simple expansile growth — never invading surrounding tissues, just displacing them. If adequately excised, they will not recur. In contrast, lesions in the retroperitoneum are frequently malignant: liposarcoma. These will invade locally and frequently recur after excision.

Subcutaneous lipomas present as very slow-growing, soft, painless, subcutaneous swellings. The surface contour is classically lobulated. In areas of lax skin they are freely mobile in the subcutaneous layer and consequently tend to slip from beneath the palpating finger (Fig 1.8). Mobility and freedom from attachment to the skin, although classic and helpful signs, are not invariable. In regions such as the back of the neck, where the skin is thick and the underlying subcutaneous fat is closely attached to it, a large lipoma just beneath the skin tends to be firmer and flatter. The lipoma then cannot be moved independently of the surface skin nor can the skin be pinched or pushed away from the lump without skin dimpling. Differentiation from sebaceous cyst becomes more difficult in these circumstances but the irregular shape and lobulated contour of the lipoma, as distinct from the spherical shape and smooth surface of the cyst, usually are unequivocal contrasts. In areas of very lax skin, lipomas can become pedunculated but this more commonly occurs with cutaneous neurofibromas. Lipomas are often fluctuant. Firmer or deeper ones and those beneath thick overlying skin are not fluctuant. Lipomas do not usually transilluminate.

Figure 1.8 Lipoma and sebaceous cyst

A: the surface contour of a lipoma is classically lobulated; B: when a lipoma is pressed, it tends to slip from beneath the finger; C: these features are not seen in sebaceous cyst, which is fixed to the skin, has a spherical shape and a smooth contour

Patients often have more than one lipoma. More striking (and quite common) is the condition of multiple, symmetrical, painless subcutaneous lipomas of limbs and trunk, which is sometimes familial. These patients do not have the cutaneous and other manifestations of Von Recklinghausen’s disease (multiple neurofibromatosis) and differentiation between the two conditions is usually obvious.

Occasionally lipomas may show degenerative fat necrosis, particularly after repetitive trauma, and become painful. A quite different and less common condition is painfully indurated lipomatous thickening of the legs, often with vasomotor symptoms, occurring in middle-aged females — painful adipodystrophy or Dercum’s disease. These patients do not have discrete lesions and local surgery has no place in treatment. Sympathectomy may be helpful.

Treating lipomas often consists of just reassuring the patient of the benign nature of the lump. Removal, if required, is usually simple. Even large ones can be shelled out completely from within their soft capsules through quite small incisions (Fig 1.9). Recurrence does not occur after removal of the whole lesion. Incision is preferably along lines of skin cleavage (Langer’s lines).

Figure 1.9 Excision of a lipoma

A–C: Most lipomas can be shelled out after infiltration with a local anaesthetic and an incision directly over the lesion

2 ‘Sebaceous’ cyst

These are also very common and are usually easy to differentiate from lipomas, though the two are often confused by students. The histories are often similar — slow-growing painless subcutaneous lumps — although a history of recurring infection and discharge will sometimes immediately indicate that the lesion is a cutaneous cyst. Two points should be borne in mind during the examination:

(a) ‘Sebaceous’ cysts arise from the skin and its appendages and are thus primarily cutaneous swellings — they move with and not apart from the skin. They are thus always attached to the skin at their summit, even when very large and with the major part of their bulk expanded into the soft tissues beneath the skin. Even so, they remain ensheathed by a dermal layer (Fig 1.8). The presence of a punctum (not always present) makes their epidermal origin even more obvious — it is usually at the summit but may be eccentric and can be missed unless sought for with care.

(b) Cysts almost always assume a rounded form and a smooth regular contour during growth, which distinguishes them from lipomas.

Cysts are often multiple; most are found on the scalp. Other common sites are face, neck, back and scrotum, but they can occur within any area of hair-bearing skin. Usually they are painless, increasing slowly in size over months or years. Infection can cause more rapid and painful increase in size. Most ‘sebaceous’ cysts will present as dome-shaped or spherical lumps with a classically smooth and rounded contour that is tense and fluctuant. They may have an overlying yellow punctum at the site of major skin attachment. Like all superficial cysts, the ease of eliciting signs of liquid content varies with their size, the nature of the liquid within them and the thickness of the cyst wall. Because their contents are usually like toothpaste and their walls quite thick, most ‘sebaceous’ cysts are fluctuant but not transilluminable. Although commonly called ‘sebaceous’ cysts, a more appropriate term is keratinous or epidermoid cyst for they usually have a flattened squamous epithelial lining and contain desquamated keratinous debris, not sebum. The keratinous contents resemble toothpaste or cream cheese — often erroneously described as pus even when not infected. Two subtypes of cysts can be described from examination of this epithelial lining: epidermoid (the common type) and pilar or trichilemmal cysts (where the epithelium resembles that lining the hair follicle). The common disorder of sebaceous glands is acne, seen mainly in young adults.

Complications of keratinous cysts are common:

Infection and abscess formation have already been mentioned. Infected cysts can be very malodorous. Although spontaneous resolution with destruction of the cyst may occasionally occur, simple incision or spontaneous drainage of pus is more usually followed by recurrence of the lesion. Cure requires excision of the cyst, including its wall. A large infected sebaceous cyst of the scalp is known as Cock’s peculiar tumour. This can mimic a squamous cell carcinoma of skin (Ch 1.2) and highlights the importance of always confirming the diagnosis histologically. Another and more serious error is to mistake an underlying bony tumour of the calvarium for a sebaceous cyst. Cysts lie within the skin of the scalp above the epicranial aponeurosis and are always mobile over the underlying bone; however, the scalp is stretched quite tightly over the skull and this sign can be misinterpreted by the inexperienced or careless observer.

‘Seborrhoeic’ horn. Slow extrusion and accretion of keratin occasionally gives an elongated ‘seborrhoeic’ horn. These can result from any keratinising skin lesion, but most are benign. The most common cause is a benign squamous papilloma.

Plaque formation. Slow attrition of the overlying epidermis accompanied by desiccation of the cyst contents can result in a firm, grey cutaneous plaque beneath an ulcer. Calcification in the plaque and epithelial regrowth leads to the lesion known as ‘benign calcifying epithelioma of Malherbe’ (pilomatrixoma), seen most often on the scalp or forehead as a very hard intracutaneous and subcutaneous plaque. It is quite benign but can mimic a skin neoplasm and is usually best excised.

Treatment. Symptomatic ‘sebaceous’ cysts need to be excised in toto, which can be done under local anaesthesia. The simplest technique is to bisect the cyst cleanly and avulse each half from within using a haemostat (Fig 1.10). Bleeding is usually minimal. Complicated cysts need formal excision. Histological confirmation of the diagnosis is always mandatory.

Figure 1.10 Excision of a sebaceous cyst

Infiltration of local anaesthetic. A: bisection through the punctum and avulsion of each half using an artery forcep; B: formal excision using an elliptical incision. The cyst is freed from the subcutaneous tissue by blunt dissection.

3 Ganglion

Ganglia present as more deeply placed subcutaneous lumps around joints or tendon sheaths. They are seen very commonly throughout adult life; they may be precipitated by work involving repetitive movement or associated with degenerative arthritis of the underlying joint. Associated arthritis may be the cause of symptoms, and treatment of the more obvious ganglion will not then effect a cure. Common sites for ganglia are wrists, fingers and feet. Their consistency and size are variable and may change with movement of the corresponding joint or tendon.

They present either as small localised swellings or as diffuse tendon sheath enlargements.

Localised swellings. A tense focal lump due to herniation or cystic degeneration of the joint capsule or tendon sheath is the most common form of ganglion. A very common presentation is a small (1–2 cm), tense, firm or hard subcutaneous swelling on the dorsum of the wrist joint towards its radial side and made more prominent by hyperflexion of the joint (Fig 1.11). The lump is immobile, fixed to the deep tissues and not attached to skin. Most will be too firm to elicit fluctuation and are not usually transilluminable. These ganglia may be unilocular or multilocular and contain a clear glairy synovial-like fluid. The natural history varies considerably. Many or most are symptomless in themselves and grow very slowly or remain static. Spontaneous resolution sometimes occurs; this may be accelerated by local pressure causing apparent rupture and dissipation. Recurrence is frequent.

Figure 1.11 Ganglion on the dorsum of the wrist joint is made more prominent by hyperflexion of the joint

Other common sites are: the volar aspect of the wrist near the flexor carpi radialis tendon; the volar aspect of the metacarpophalangeal or interphalangeal joints; or the dorsal and medial aspects of the ankle or forefoot.

Treatment. Localised ganglia often need no treatment. Associated degenerative joint disease may need attention. Acutely painful symptomatic lumps are treated initially by immobilisation; persistently symptomatic lumps are best excised. Compression (banging with a bible) and sclerosant injections are not recommended. Excision needs a bloodless field and a meticulous technique, avoiding neighbouring vital structures (tendons, radial artery, nerves). The lesion is excised in toto, if possible without rupture and including a local segment of joint capsule or tendon sheath. Surgery is usually curative but recurrences can occur.

Synovial (mucous) cyst of the finger is another common type of localised ganglion. This lesion presents as a subcutaneous cystic nodule over the dorsum of the terminal phalanx just distal to the interphalangeal joint. The tense fluctuant subcutaneous cyst is in close proximity to the nail bed and often causes local deformity of nail growth. Treatment is initially conservative (many resolve spontaneously). Local excision is required for persisting lesions; aspiration and local steroid injection may be tried first.

A mucous cyst that is completely subungual can be confused with melanoma.

Diffuse tendon sheath enlargement. A less common type of ganglion presents as a diffuse and usually less tense enlargement of the complete synovial tendon sheath. Flexor and extensor tendons of the wrist are most frequently involved and repetitive occupational stress may sometimes be a precipitating factor. These present as compound palmar or dorsal ganglia affecting the common flexor or extensor tendon sheaths. A compound ganglion comprises a bilocular hourglass swelling proximal and distal to the flexor or extensor retinaculum, exhibiting fluctuation that can be transmitted from one component to the other, often with accompanying crepitus due to inclusion (‘melon seed’) bodies. These swellings are usually transilluminable.

Treatment is initially conservative and directed against any precipitating factors. Aspiration and local steroid injections are usually followed by recurrence. Surgical treatment is almost always curative and involves removal of the superficial parietal tendon sheath.

4 Bursa

Bursae normally comprise collapsed sacs with a smooth lining of flattened synovial epithelium sited where bones, joints, ligaments, aponeuroses, tendons and skin lie in close proximity. They facilitate smooth friction-free movement between gliding tissue planes in a similar manner to synovial tendon sheaths. They often communicate with or are extensions of nearby joints (subacromial bursa, suprapatellar bursa). They lie between the skin and underlying bony prominences (olecranon bursa, prepatellar bursa) or they separate tendons and ligaments (anserine bursa, semimembranosus bursa). Bursae also can develop de novo at any site of abnormal friction (adventitious bursae). Symptoms follow excessive wear and strain leading to acute or chronic bursitis with an effusion of mucoid synovial-like fluid. Clinical presentations accordingly are most common in adulthood after the prolonged and repetitive strains of occupation or sport and are aggravated by age-related arthritic and soft tissue degeneration. Naturally occurring bursae are symmetrical and at defined anatomical sites. Common presentations are student’s elbow (olecranon bursa), bunion (inflamed bursa over first metatarsal head), housemaid’s knee (prepatellar bursa), clergyman’s knee (infra-patellar bursa) and weaver’s bottom (ischial tuberosity bursa).

Bursae thus present as subcutaneous cystic lumps, often with crepitus on movement. The lining of the bursal sac is usually closely adjacent and relatively fixed to the gliding surfaces it separates so the lump may show attachment to both the underlying bone and to overlying skin and thus have limited mobility. Superficial bursae, such as a bunion or prepatellar bursa, will be fluctuant and usually transilluminable. The skin overlying a superficial bursa is often calloused. Associated joint disease and deformities are common. Pain, tenderness and accompanying signs of inflammation will be particularly severe if bacterial infection supervenes from a skin breach.

Treatment. Treatment comprises rest and, for acute bursitis, immobilisation. Antibiotics are given if signs of local or systemic sepsis exist; aspiration may be required to culture the fluid. Surgical excision is required for chronic symptomatic lumps. The incision must be carefully sited to avoid a contracture across a nearby joint; attachments of the lump to skin and to underlying bone or tendon make excision more difficult.

5 ‘Dermoid’ cysts

The terms ‘dermoid’ cyst and ‘epidermoid’ cyst can be confusing. There are simple epidermoid (keratinous, sebaceous) retention cysts and neoplastic or hamartomatous dermoid cysts of male and female gametes. Two additional subcutaneous ‘dermoid’ cysts need definition.

Developmental (inclusion) dermoid cyst. This is usually diagnosed in early childhood and is a subcutaneous cystic lesion in areas of congenital fusion of epithelial clefts. Common sites are the ventral midline of the floor of mouth and neck and the lateral angles of the eyes. The latter may also show an associated bony depression beneath the cyst. Inclusion dermoids present as subcutaneous round or spherical lumps that may be soft or tense and are usually fluctuant and transilluminable. They are treated by surgical excision. Those in the neck can be confused with thyroglossal cysts or submental lymph nodes.

Traumatic (implantation) dermoid cyst. This is a common lesion of the fingers or palm in adults. It is due to implantation of epithelial elements, usually from repeated occupational trauma (e.g. a seamstress or wire worker) or related to a surgical incision. It presents as a small (<1 cm) firm spherical nodule just beneath the skin surface and attached to it and is often painful and tender. Usually an overlying puncture wound or scar is apparent. Symptomatic lumps need surgical excision.

6 Neurofibromas

These benign tumours contain neural and fibrous elements. They usually present as firm, painless, fusiform or lobular subcutaneous solid swellings aligned in the long axis of the limb in relation to subcutaneous peripheral nerves. Their mobility is greatest across the axis of the involved nerve. A few are tender with associated paraesthesiae in the nerve distribution. Cutaneous neurofibromas cause elevated soft skin nodules (molluscum fibrosum) that can become pedunculated. Von Recklinghausen’s disease (congenital neurofibromatosis) is dominantly inherited and exhibits multiple cutaneous and subcutaneous neurofibromas and is also associated with pigmented lentiginous skin lesions (café au lait spots), acoustic nerve tumours and bony abnormalities.

Treatment of isolated neurofibromas may require exploration and biopsy to confirm the diagnosis — a benign tumour involving a major nerve (e.g. median) must never be resected.

General principles

Physical examination is the most reliable means of detecting the site of surgical infection. Some deep subcutaneous infections are difficult to localise; the presence of fever, tachycardia and leucocytosis emphasises the need for a continued search for a deep abscess or necrotic focus. Blood culture is an essential step in diagnosis of severe infections, especially when no pus is available for culture, but should not delay treatment with antibiotics, surgical excision or drainage. If pus is available for culture, the method of collection should ensure that both aerobic and anaerobic organisms will be detected. A general history and examination is essential, both to evaluate the severity of the systemic effects of infection and to detect concurrent illness in need of attention. Urinalysis to detect diabetes is part of the clinical examination.

General principles of treatment (Box 1.7) are determined by the three main aetiological factors:

Box 1.7

The general principles of the treatment of surgical infection

Local drainage and debridement; control of local risk factors (e.g. oedema)

Immobilisation and elevation of the part

Control of infectious agents with antibiotics; control of systemic sepsis by resuscitation, analgesics and antipyretics

General measures to improve host resistance; attention to nutrition and control of concurrent illness

1 The primary site of infection

A minor wound is a common initiating source of infection. Risks of wound infection are increased by poor initial wound management. Prevention of wound infection depends on sound surgical technique: major risk factors are inadequate debridement, clumsy tissue handling, undue tension, ischaemic and foreign tissue and haematoma formation. In the carelessly sutured wound, bacterial defences are impaired and infective organisms can multiply under protected conditions, particularly if the wound remains contaminated by bacteria in the presence of foreign bodies and dead or devitalised tissue. Polymorphs require oxygen to kill bacteria. The PO₂ of the dead space within unduly tense skin sutures is markedly reduced. Foreign bodies in tissues form a nidus for infection and bacteria are frequently carried in with the foreign body. Wounds of the lower limbs are often more susceptible to infection, particularly in older patients because of established peripheral vascular disease (arterial or venous) and chronic oedema.

The presence of tension and impending tissue necrosis is suggested by persistent throbbing pain and systemic toxicity, and is an indication for urgent surgical decompression — even in the absence of signs of pus. Fluctuation is frequently a late sign of abscess formation and drainage should not be delayed until this sign is present (Fig 1.12). Superficial infected ulcers or infected wounds are best dressed by adequate drainage and by moist porous dressings. After drainage, later secondary closure by suture or by skin grafting may be required to reduce the length of convalescence. The local region should initially be rested, immobilised and elevated to minimise oedema. Physiotherapy is commenced once there is evidence of resolution of the infection and is an important component in final rehabilitation.

Figure 1.12 Incision and drainage of subcutaneous infection

A: the central area of the abscess is infiltrated with local anaesthetic; B: the abscess is incised to allow free drainage; C: an appropriate dressing is used to allow the cavity to heal by secondary intention

Common types

Clinical features and treatment plan

5 Specific sites

Subcutaneous infections at specific sites often originate in a focus of established pathology and require special management. Under this heading may be included hand infections (Ch 6.8), perianal abscess (Ch 7.22), bursitis (Ch 6.11), fungal infections, cervical tuberculosis, infected rheumatoid nodules and Ludwig’s angina. Gout and occupational tenosynovitis are aseptic inflammatory lesions that can mimic cellulitis.

Pilonidal abscess is a subcutaneous infection in the natal cleft. Infection will recur unless the nidus of hairs and surrounding granuloma is dealt with. Patients present in an acute attack with severe pain and swelling between the buttocks associated with fever and malaise. The abscess can arise de novo or there may be a past history of abscesses or of a discharging pilonidal sinus. The initial treatment of pilonidal abscess is prompt and adequate drainage, preferably under general anaesthesia. Laying open of all sinus tracts and removal of all hair should be done in this operation. Antibiotics are given to complement surgical drainage only if surrounding cellulitis is extreme. Careful dressing after wide incision can reduce the incidence of subsequent chronic sinus formation. A polymer stent is helpful once the open wound edges are stiffened by granulation.

Chronic pilonidal sinus. For a chronic sinus, the aims of treatment are excising the sinus and contained hair, removing the midline sinus or pits and obliterating the natal cleft to prevent the entry of hair at new sites. Excision of the lesion in toto, with primary suture, is often performed as an elective procedure (Fig 1.13).

Figure 1.13 The Karydakis operation for chronic pilonidal sinus

A: one side of the incision is placed further from the midline; B: the sinus and surrounding fibrous tissue is excised down to the fascia over the sacrum, creating a flap on one side; C: closure brings the flap away from the midline, avoiding a central unstable scar and thus reducing the chance of recurrence

Localised lymph node swellings

Generalised lymph node swellings

Localised lymph node swellings

Examples of acute local inflammations are cellulitis of the leg with inguinal adenitis and tonsillitis with cervical adenitis; examples of chronic inflammations are cat-scratch fever with axillary adenitis and tuberculous cervical adenitis. In local neoplastic spread the primary carcinoma may be apparent (squamous cell carcinoma of skin, melanoma) or occult (thyroid or laryngeal carcinoma with cervical node metastases, anal carcinoma with groin metastases). Clinical assessment of a focal lymph node enlargement is therefore incomplete until the entire area drained by the nodes has been searched and re-searched for a malignant or infective primary focus. When the primary focus has been previously removed (e.g. a skin melanoma) the responsible scar may be unobtrusive and the event forgotten by the patient — thus both history and examination must be complete and scrupulous.

The focal nodal enlargement may be the initial manifestation of a generalised lymphoma or may be the expression of a distant source of primary carcinoma (e.g. Troisier’s sign: enlarged supraclavicular nodes signalling an intrathoracic, intra-abdominal or testicular or prostatic neoplasm).

Generalised lymph node swellings

In systemic infections, associated clinical manifestations will usually assist in diagnosis. Nodes are often soft and tender in acute infections, firmer and matted in chronic infections.

The nodes of Hodgkin’s lymphoma are usually discrete and rubbery; those of non-Hodgkin’s lymphoma are typically firmer, more fixed and adherent to one another. Metastatic carcinoma gives firm or hard nodes. In leukaemias, associated anaemia and fever, purpura, intercurrent infections and mouth ulceration, bony pain and tenderness and skin deposits may also occur. The liver and spleen should be carefully palpated for enlargements.

Generalised lymphadenopathy with hepatosplenomegaly occurs with systemic infections and with haemopoietic and other malignancies. In chronic myeloid leukaemia, the spleen is often enlarged to a much greater degree than the lymph node enlargement; in lymphatic leukaemia the reverse applies.