Malignant melanoma, [s8]uncommon

In a black patient, malignant melanomas arise only from non- pigmented parts of his skin[md]the soles of his feet (most commonly), the palms of his hands, his nail beds, and his mucosae. In a white patient, a melanoma can arise anywhere, usually in a pre-existing mole, especially after long exposure to sunlight, commonly on a man's trunk or a woman's legs, or, rarely, from the choroid plexus of the eye. In both black and white races malignant melanomas only occur after puberty; most are pigmented, but a few are amelanotic. They spread: (1) By local infiltration, usually horizontally at first, but later vertically into the deeper tissues. (2) To the regional lymph nodes; deposits may also grow in lymphatic channels on the way there. (3) Through the bloodstream.

Treatment is surgical; there is no effective radiotherapy or chemotherapy. Radical surgery (amputation) is no better than wide local excision.

Fig. 32-7 MALIGNANT MELANOMAS. A, if a melanoma presents as late as this, remember that amputation has no immediate advantage over local excision and grafting. Amputation is only indicated if satisfactory removal is impossible without it. B, Clark's levels of invasion. Level I does not penetrate the basement membrane. Level II extends into the papillary dermis. Level III extends to the reticular interface. Level IV invades the reticular dermis. Level V penetrates the subcutaneous fat. C, excise a melanoma with a margin of at least 2 cm of normal skin round it. D, amputate a subungual melanoma. D, and E, if a melanoma of the ]]sole presents sufficiently early, excise it and graft the wound. B, after Grabb WC, and Smith JW, (ed.) ''Plastic Surgery: A Concise Guide to Clinical Practice'. Little Brown, with kind permission. C, to E, after Hilliard F. Seigler, in Rob C, and Smith R, ''Operative Surgery', p.221. (Butterworth) With kind permission.

MALIGNANT MELANOMA PREVENTION. (1) Any elevated mole (pigmented lesion) more than 0.5 cm in diameter which shows any sign of growth should be excised. (2) White skins, including those of children, should be exposed to as little sunlight as possible.

THE DIAGNOSIS differs in black patients and white ones.

Suspect that a black patient has a melanoma if he has: (1) Any growing dark lesion on the soles of his feet, on the palms of his hands, or in his nail beds, particularly in his big toe. The commonest site is at the junction of the deeply and lightly pigmented areas on the borders of his hands and feet. (2) A deeply pigmented lesion on the sole of his foot, more than 2 cm in diameter, whether or not it is ulcerated. (3) An ulcerated lymph node in his groin, with dark areas showing through the skin, or in the base of the node.

Suspect that a white patient has a melanoma if: (1) A previously existing pigmented mole does anything unusual[md]if it enlarges, weeps, scabs, bleeds, itches, ulcerates, becomes darker, or produces a dark surrounding halo. (2) Any pigmented lesion grows progressively. Be especially suspicious if it is larger than 10 mm, with an irregular border, surface, or pigmentation. (3) He has a rapidly growing fleshy ulcerated skin tumour, even if it is pale (it may be amelanotic).

THE DIFFERENTIAL DIAGNOSIS includes a benign naevus (28.10), a pigmented seborrhoeic wart, a squamous cell papilloma or carcinoma (32.19), a capillary cavernous haemangioma (28.10), and Kaposi's sarcoma (32.21). Histologically, the diagnosis can be difficult.

STAGING [s7]MALIGNANT MELANOMA This is the prognosis for cases treated by wide local excision.

Stage One. There is local infiltration only, not extending more than 5 mm from the primary lesion. Overall, there is a 70% 5 year survival

Stage Two. A local lesion, and clinical or histological evidence of spread to the nodes. 20% 5 year survival.

Stage Three. Disseminated disease, sometimes there is no sign of a primary lesion. No 5 year survivals.

A more accurate prognosis can be obtained in Stages One and Two by examining the depth of infiltration of the excised specimen macroscopically. Stage A [lt]0.75 cm. Stage B 0.75 to 1.5 mm. Stage C [mt]1.5 cm. Alternatively, Clark's levels (B, Fig. 32-7) can be used.

THE TREATMENT [s7]OF MALIGNANT MELANOMA Treatment is surgical, there is no effective radiotherapy or chemotherapy.

If you suspect that a lesion is a melanoma, but have not previously biopsied it (Stage One), excise it with a margin of at least 2 cm of normal tissue all round. Remove all the underlying subcutaneous tissue and deep fascia. If the bed that remains is suitable, graft it immediately. If not, take a graft, store it, and apply it 5 to 7 days later when granulations have formed (57.3). Take a split skin graft from the opposite limb, not the limb bearing the melanoma. Prophylactic block dissection of the regional nodes probably does not help. Follow him up regularly, so that if his regional nodes enlarge, you can do a block dissection or refer him for it.

If there is local infiltration, and spread to his regional nodes (Stage Two), refer him for a wide local excision, and a block dissection of his regional nodes (usually inguinal). If you cannot refer him, see Section 32.34 on block dissection. If there is growth in the intervening lymphatics (for example in the neck), excise these in continuity. It is doubtful if this improves survival, but it does remove deposits which may ulcerate.

If there is already widespread dissemination (Stage Three), there is nothing you can do, except provide terminal care (33.1).

If wide local excision is not possible without amputation, as for example under the big toe or a nail, amputate proximal to the lesion.

HISTOLOGY. If possible, send the whole specimen for examination. If this is impractical, cut it so as to make it possible to ascertain the depth of penetration, and the margins of normal tissue excised in the vertical and horizontal planes.

Fig. 32-8 ENDEMIC AFRICAN KAPOSI'S SARCOMA (KS). A, the lymphadenopathic form affects children and young adults. B, the infiltrating form. C, the typical nodules of the common indolent form are more often seen on the leg. D, the large cauliflower- like local lesions of the aggressive form.