Integument problems

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Chapter 1 Integument problems

Jane Fox, David Speakman

1.1 Introduction

Many lesions of skin or subcutaneous tissue are easily recognised and a diagnosis can be made virtually on inspection alone. Lipomas, ‘sebaceous’ cysts and ganglia are very common and usually have classic diagnostic features. Subcutaneous swellings are thus commonly benign — malignancies are rare but important to recognise. Many focal surface lesions are also benign and easily diagnosed; however, skin cancers are also common and any hint of malignancy requires biopsy for a certain diagnosis.

Dermatological conditions are more extensive secondary skin reactions representing a more general abnormality of the skin and subcutaneous tissues. There are many causes of dermatitis and most are not considered here except for a brief outline of common dermatological terms. Skin lesions are often associated with a secondary skin reaction.

An ability to accurately describe skin changes facilitates clinical communication and record keeping.

Focal skin lesions are divided morphologically into four main types: macules; papules or nodules; vesicles or pustules and wheals (Fig 1.1).

A macule is a localised surface change in skin colour without bulk or substance. It is important to note whether the colour change is permanent or blanches on compression. A lightly pigmented brown or tan macule is called a lentigo or freckle. A papule is a small solid projection above the skin surface; a larger papule is called a nodule. A flattened nodule is described as a plaque. Vesicles are elevated fluid-containing lesions: When large they are called bullae or blisters and when they contain pus, pustules. Acne (Greek — a facial eruption) comprises multiple small pustules, which if embedded are described as comedoform. Milia are tiny embedded cutaneous plaques due to keratinous retention foci; they are most common on the facial skin. Wheals are white, raised lesions of localised dermal oedema without blistering. Widespread wheals are often called urticaria, an atopic (allergic) reaction. If the skin is broken the lesion is an ulcer. Distinct morphological types of ulcer are also described (Fig 1.2).

image

Figure 1.2 Types of epithelial ulceration

Sources: Squamous cell carcinoma: From Rakel 2007; Basal cell carcinoma: From Rakel 2007; Venous ulcer: From Bolognia et al 2007; Neuropathic ulcer: From Bolognia et al 2007; Peptic ulcer: Courtesy of Robin Foss, University of Florida; Anal fissure: Courtesy of Gershon Effron, Sinai Hospital of Baltimore; Keratoacanthoma: From Habif 2003.

Secondary skin reactions result from scratching or from the effects of the primary lesion itself. In a dry lesion the flaky or powdery shedding of the stratum corneum, the horny layer of the skin, is known as a desquamative or psoriatic reaction. In many superficial ulcers, vesicles, pustules or bullae, desquamated epidermal cells form a scab: a crust of dried exudate. An eschar is a patch of necrotic skin, typically caused by a deep burn; slough is the dead or devitalised tissue in the base of an ulcer. Lichenification is leathery thickening of the skin around a lesion, usually due to chronic inflammatory fibrosis, which often also produces subcutaneous induration around an ulcer. Induration can also be due to malignant infiltration. Diffuse skin pigmentation is often seen around ulcers, especially venous ulcers of the lower limb — the pigment is brown haemosiderin.

Haemorrhages into the skin occur in various forms. Purpura is a haemorrhagic disorder in which spontaneous bleeding occurs into the dermis and epidermis of skin or into mucous membranes, causing a red or purple macular lesion. Minute (1 mm or less) punctate spots of epidermal bleeding are called petechiae. Larger, less sharply defined areas, often with subcutaneous swelling, are known as ecchymoses or bruises. Haematomas are focal areas of subcutaneous haemorrhage that elevate the skin. Purpura may follow drug reactions, sepsis or haemopoietic malignancies and occurs spontaneously in the old, particularly on the hands and forearms (senile purpura). Purpura is commonly associated with vascular fragility; petechiae are more characteristic of a coagulation disorder such as thrombocytopenia.

Cutaneous haemangiomas are of various types (congenital, hamartomatous, degenerative and neoplastic). Telangiectasis are small focal collections of dilated blood vessels in the skin or mucous membranes. Spider naevi are bright red arteriolar spots with radiating surrounding capillary vessels, located mainly over the upper trunk and face.

Skin pathologies such as haemangiomas or epithelial neoplasms can vary widely in their morphological appearance, despite a common cause. Basal cell carcinoma may appear as: a nodule or plaque; a comedo-like lesion; a cystic lesion; a small area of scaly psoriatiform skin; a pigmented skin lesion; a healing ulcer; or an area of subcutaneous induration and sclerosis. The burrowing ulceration with extensive tissue destruction of the classic ‘rodent’ ulcer is a further late and too-long neglected manifestation.

Morphological terms also define dermatological conditions. Eczema is a blotchy, ill-defined, red macular rash that can progress to papule and pustule formation. Dermatitis can be either wet (usually because of its site e.g. intertrigo, nappy rash) or dry, where it can be associated with the features of hyperkeratosis (hypertrophy and hyperplasia of the stratum corneum), lichenification and pigmentation. When itch precedes the rash, the condition is called neurodermatitis; itchiness following the rash is more suggestive of contact dermatitis. Acanthosis is a hyperkeratotic reaction of prickle cell overgrowth. Acanthosis in association with pigmentation (acanthosis nigricans) is often secondary to a gastrointestinal or haematological malignancy.

A morbilliform rash is a large, red, blotchy, confluent ill-defined macular rash seen on the face, neck and trunk (measles) or on the limbs (drug sensitivity reactions). Psoriatiform lesions are flat, red papules with silvery scales, which can be associated with dry eczema or basal cell carcinoma; psoriasis is a primary skin condition occurring on the extensor surfaces of the limbs and around the nails. Impetiginous lesions are pustular nodules with crusts seen in eczema, herpes, staphylococcal and yeast infections of the skin. Acneiform lesions are small, pointed pustules that may be a primary condition or occur secondary to drug sensitivity. Acne rosacea with telangiectasis, when marked over the nose and associated with sebaceous gland overgrowth, is called rhinophyma. A pemphigoid lesion is a large bullous eruption of the skin.

Erythema nodosum is a condition in which flat red nodules are found on the lower limbs. They occur in association with tuberculosis, rheumatic fever, some drug reactions, sarcoidosis and inflammatory bowel disease. Vitiligo is a well-defined area of depigmentation found on exposed areas and usually is of little clinical significance and poorly understood but sometimes associated with endocrine abnormalities. Erythema ab igne is an area of mottled pigmentation seen on the front of the knees and shins from longstanding exposure to heat, particularly radiant heat such as from sitting in front of a radiator.

The clinical history of a lump or ulcer

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

  Length of history Clinical appearance
Basal cell carcinoma Months to years Pearly nodule
Central crusting and ulceration
Rolled or beaded, telangiectatic edge
Any site, especially head and neck
Squamous cell carcinoma Months Indurated, ulcerating, raised nodule, everted friable edge
Contact bleeding
Sun-exposed surfaces
Keratoacanthoma Weeks Rapidly growing
Dome shaped
Volcanic apical ulceration
Sun-exposed surfaces
Pyogenic granuloma Days or weeks Small, soft, cherry red lesions
Contact bleeding
Common on mucocutaneous surfaces

The physical examination of a lump or ulcer

The routine sequence of examination involves inspection, palpation, percussion, auscultation and movement.

An abnormality in a bilateral structure should be compared and contrasted with its normal side. Assessment of a lump traditionally follows a sequential analysis of its characteristics (Box 1.1). Although not all the features are applicable to all lumps, it is essential to follow an ordered sequence when characterising any lump. The most important features are the site (which should be defined anatomically in all dimensions) and the physical characteristics, including relationships of the lump to its surroundings.

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.

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.

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.

1.2 Focal skin lesions

Most focal skin lesions will be manifestly benign longstanding lesions of congenital or acquired origin that have caused the patient no problem and require no treatment. Benign skin lesions include a large number of congenital blemishes, moles, malformations and hamartomas. Benign neoplasms, localised infections and miscellaneous causes are also common (Fig 1.4). An important group of lesions are dysplastic and premalignant. Accurate diagnosis of this latter group is extremely important, as early surgical treatment of suspicious skin lesions is curative for most forms of skin malignancy. Screening programs and self-examination in high-risk populations have been employed but vary in effectively diagnosing early lesions. Repeated practice at assessing common skin lesions rapidly improves diagnostic skills. Accurate diagnosis relies first on a careful history and examination.

Focal skin disorders can be assessed on clinical grounds into:

Pigmented lesions (naevi) form a distinct category within each of these two groups.

Clearly benign lesions

Benign skin lesions will usually have been present from birth or for many years without change. In children and adolescents, congenital moles and vascular malformations are common, as are freckles and infective warts; skin malignancies are rarely seen (Box 1.2). In adulthood, degenerative and other specific lesions occur with increasing frequency in patients over the age of 40 years (Box 1.3); differentiation of benign lesions from cancers becomes increasingly important. Lesions are defined as macules or nodules. Common macules are the port wine stain, café au lait spots (neurofibromatosis), some junctional naevi and freckles. Freckles are common in children and adolescents. In older patients senile freckling of the skin is common, as are spider naevi and senile purpura. Common benign nodules include pigmented moles and angiomas. Verrucous lesions are also common in children and adults. Benign skin tags and keratoses are seen with increasing frequency in older patients. Benign traumatised lesions may ulcerate. In adults this always invokes suspicion of malignancy; in children benign ulcerated or infective lesions are relatively common. Skin vesicles occur with herpetic infections, eczema and impetigo.

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

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.

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.