Nonmelanoma skin cancers

Epidemiology

These cancers are the commonest malignancies in Western populations, occurring particularly in fair-skinned Caucasians exposed to ultraviolet radiation (e.g. farmers, fishermen). The causes are:

♦ Ultraviolet radiation

♦ Ionizing radiation

♦ Chronic inflammation

♦ Human papillomavirus

♦ Immunosuppression

♦ Hereditary conditions (Xeroderma pigmentosum, basal cell naevus syndrome)

As well as these primary lesions, metastases to skin are fairly common from carcinomas of the breast, lung, and GI tract.

Pathology

Basal cell carcinomas (75% of non-melanoma skin cancers) are lesions which arise on sun-exposed areas—face, neck, ears, scalp, and arms. They are normally confined to hair-bearing skin. They present as a slow-growing, pink papule with telangiectasia. Variant lesions include:

♦ Ulcerative

♦ Superficial

♦ Multicentric

Metastases are rare and they are usually curable by either surgical excision or radiotherapy. The latter is preferred around the eyelids, nose, lips, and ears. Other treatment strategies are cryosurgery and topical 5-fluorouracil.

Squamous cell carcinoma (20%): this malignant lesion also arises on sun-exposed sites, but appears as a faster-growing, red papule which may erupt on a background of actinic keratosis. Ulceration, bleeding, and metastases to regional nodes may occur. Treatment is either surgery or radiotherapy; chemotherapy has been used for disseminated disease (cisplatin, methotrexate, 5-fluorouracil, bleomycin are active agents).

Merkel cell carcinoma is a rare but highly malignant neuroendocrine tumour of the skin. It presents as a dermal nodule on the head or neck of an elderly patient, rarely ulcerates, but commonly spreads to adjacent skin and regional nodes. Treatment is surgical but palliative radiotherapy is useful in controlling metastatic disease. Less than 50% survive three years.

Apocrine and eccrine gland cancers: a variety of these are described but all are rare and most are only locally invasive. Other uncommon malignancies are:

♦ Cutaneous angiosarcoma

♦ Kaposi's sarcoma (HIV-associated or endemic)

♦ Other soft tissue malignancies

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