skin tumours

skin tumours

See SKIN DISORDERS.

skin tumours

benign or malignant hyperplasia of cells at dermoepidermal junction (see Table 1, Table 2 and Table 3)
Table 1: Clarke's levels, denoting the level of invasion of a skin tumour
LevelFeature
ILesion confined to epidermis (i.e. in situ)
IIEpidermal lesion has just invaded into upper dermis
IIIEpidermal lesion has significantly invaded upper dermis
IVEpidermal lesion has invaded as far as deeper reticular dermis
VEpidermal lesion has invaded through dermis into subcuticular tissues

The greater the depth of lesion penetration, the more liable it is to undergo metastasis.

Table 2: Classification of skin tumours
Tumour typeDegree of malignancyExamples
Epidermal tumours (see Table 4)Benign
Premalignant
Malignant
Seborrhoeic keratoses
Bowen's disease
Basal cell carcinoma
Squamous cell carcinoma
Pigmented skin lesionsBenignFreckle
Lentigo
Pigmented and potentially metastatic skin tumoursBenignCongenital naevus
Acquired naevus
Speckled/lentiginous naevus
Becker's naevus
Spitz naevus
PremalignantDysplastic naevus
Melanoma
MalignantSubungual melanoma
Vascular tumoursBenignPyogenic granuloma
Glomus tumour
MalignantKaposi's sarcoma
Fibrous tumoursBenignAcquired fibrokeratoma
Dermatofibroma
MalignantDermatofibrosarcoma
Adnexal tumoursBenignEccrine poroma
OthersBenignLeiomyoma (smooth muscle)
Subungual exostosis (bone)
Myxoid cyst (joint lining herniation)
Ganglion (joint fluid)
Bursitis (joint inflammation)
Piezogenic pedal papule (fat herniation)
Neurofibromatosis (nerve)
Table 3: Epidermal tumours that tend to malignancy
TumourFeatures
Seborrhoeic keratoses (senile or seborrhoeic wart; basal cell papilloma)Incidence increases with advancing age
Location: trunk, but also affect leg and foot
Aetiology: unknown
Cellular involvement: epidermal cells
Progression: start as small lesions which increase in size and degree of pigmentation over time
Edge: distinct edge which may overhang surrounding skin
Pigmentation: variable colour; homogeneous pigmentation
Surface: warty; horny cysts
Differential diagnosis: verrucae; hyperkeratosis
Treatment: liquid nitrogen; curettage
Bowen's disease (intraepidermal carcinoma in situ)Location: sun-exposed skin - face, neck, legs, dorsum of foot
Progression: slowly enlarging reddish, scaly patch; 1:20 lesions may progress to a squamous cell carcinoma
Cellular involvement: the entire epidermis is replaced by abnormal cells (atypical nuclei and mitosis patterns) but the basement membrane is normal
Edge: irregular, clearly demarcated margin
Surface: scaly or crusted
Differential diagnosis: psoriasis
Treatment: early stages: 5-fluorouracil; late stages: liquid nitrogen or curettage
Basal cell carcinoma (BCC) (rodent ulcer; basal cell epithelioma)Commonest skin tumour in Caucasians; incidence increases with advancing age; rarely metastatic
Location: sun-exposed skin: commonest on the face; rare on the foot
Progression: initially small lesion which gradually extends over months to years; it may crust over and appear to heal, but crust comes away to reveal the underlying lesion
Cellular involvement: basal-layer epidermal cells bud downwards toward the dermis to form dermal palisades
Edge: raised/rolled nodular (pearly) border
Surface: domed ± central eroding and extending ulcer
Differential diagnosis: Bowen's disease, squamous cell carcinoma, melanoma, vascular lesions
Treatment: excision and biopsy; liquid nitrogen, radiation therapy
Squamous cell carcinoma (SCC) (cutaneous cell carcinoma)Second most common cell tumour; locally destructive and may metastasize via the lymphatics
Aetiology: immune-suppressed patients; albinos; impaired DNA repair mechanisms; skin contaminants (soot, tar, mineral oils, hydrocarbons); as the end development of Bowen's disease or actinic keratoses; chronic irritation (such as in a long-standing leg ulcer); repeated exposure to radiation (ultraviolet, X-rays; radiant heat)
Location: any area of skin, but rare on the foot (a variant, verrucous carcinoma, is only found on the foot - see below)
Progression: begins as a reddish plaque mimicking dermatitis or eczema, becoming indurated
Edges: irregular and raised
Surface: nodular and/or irregular, ragged, sloughy, ulcer; oozing
Treatment: wide excision and biopsy; lymphadenectomy and radiation therapy if there is associated lymphatic spread
Verrucous carcinoma of the foot (epithelioma; carcinoma cingulatum)Location: at any skin site; predilection for plantar skin
Progression: initially resembles verruca plantaris; slowly progressive to form a nodular lesion and later a soggy, foul-smelling ulcer with sinuses somewhat remote from the main lesion
Cellular involvement: obviously malignant epidermal cells invade the dermis
Treatment: as for SCC
Table 4: Clinical features of presentations of malignant skin lesions
LesionClinical features
Lentigo malignant melanomaSlow-growing flat lesion, often affecting facial skin in the elderly
Irregular border, slowly extending
Variegated colour
May develop nodular centre, ulcerate and spread aggressively
Superficial spreading melanomaMay affect any skin area, especially in Caucasians (male back, female leg)
Irregular raised border, slowly extending
Central area may become pale and appear to 'resolve' (which designates that the lesion is invading underlying tissues)
Nodular melanomaMay affect any skin, but especially the lower limbs and trunk
Many lesions are amelanotic ± pigmented collar
Grows rapidly and bleeds easily
May be misdiagnosed as a vascular lesion
Acral lentiginous melanomaTends to present in black and oriental skin
Presents initially as a flat freckle-like lesion that extends and becomes nodular
Often underdiagnosed
Subungual melanomaMelanoma involving the nail unit
May be difficult to distinguish from benign melonychia or subungual haematoma
Tends to affect proximal nail area and eponychium, and spreads distally
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