Squamous cell carcinoma [s8](epithelioma) fairly common

Squamous cell carcinomas are common on the exposed surfaces of white-skinned people living an outdoor life in the tropics, whether Caucasian, or albino Africans (in whom they are particularly common). They are rare in black skins, except as a complication of chronic ulcers (31.2) and burn scars. Ulcer- cancers may present late, after they have already infiltrated bone, and can cause a pathological fracture.

A typical squamous cell carcinoma of the skin presents as an ulcer with an irregular, raised, round, everted edge, and an indurated base, which soon becomes attached to deeper structures, and may erode the bone underneath. Squamous cell carcinomas develop in adult life, or, occasionally, earlier (especially in albinos). They are low-grade tumours, which spread to the regional nodes late, and rarely metastazise through the blood. In theory, prevention is simple[md]by covering exposed white skin, and treating chronic ulcers and burns to make sure they heal. Unfortunately, albinos from disadvantaged families face serious problems.

SQUAMOUS CELL CARCINOMA X-RAYS. If the lesion is over a bone, X-ray it. A translucent area, under the ulcer, shows that bone is being infiltrated. Thickening of the bony cortex and trabeculae indicate secondary chronic osteitis, caused by infection, which has entered through the chronic ulcer, that caused the carcinoma.

THE DIFFERENTIAL DIAGNOSIS includes: (1) A chronic ulcer (31.2) which is not malignant[md]the distinction can be difficult clinically and histologically. (2) A tuberculous ulcer. (3) Yaws. (4) Syphilis. (5) Granuloma pyogenicum (34.2). (6) Fungal lesions. (6) Kaposi's sarcoma (32.21).

CAUTION ! ALWAYS confirm the diagnosis histologically first, before starting treatment.

THE PRIMARY LESION [s7]IN A SQUAMOUS CELL CARCINOMA Try to excise a squamous cell carcinoma with all the microscopic infiltration around it. So remove at least a 2 cm margin of macroscopically normal skin around the lesion, and at least a 1 cm margin underneath it. Graft the defect (57.2).

If a squamous cell carcinoma is not infiltrating or attached to bone, give the patient a general anaesthetic, a subarachnoid (A 7.7), or an axillary block (A 6.18). Local infiltration (A 5.4) is suitable for small lesions.

If there is a satisfactory base, for example, muscle, excise any deep fascia and apply a split skin graft (57.3). Tie-over sutures (57.8) may be useful to keep the dressing in place.

If the base is not suitable for grafting (57.3), for example, if it is connective tissue, fat, or tendon, take a split skin graft, store it in a refrigerator (57.8), and apply it when granulations are satisfactory, usually in 5 to 7 days.

If bone is exposed chisel away the cortex until you reach a bleeding surface, wait 7 to 14 days for granulations to form, and then graft.

Occasionally, you can close the defect with a rotation, transposition (57.11) or, or if you are sufficiently skilled, a myocutaneous flap (not described here).

If a squamous cell carcinoma is infiltrating bone so much, that the bone would fracture, if you removed enough of it to excise the lesion properly, amputate at the first joint proximal to the lesion, for example, the knee. Or, less satisfactorily, saw through the bone at least 10 cm away from the lesion, as seen clinically or on X-ray.

LYMPH NODES [s7]INVOLVED BY A SQUAMOUS CELL CARCINOMA If the patient's lymph nodes are not involved clinically, leave them. Follow him up carefully, because he will need a block disection (32.34) later, if they show clinical evidence of malignancy. Don't do a block dissection prophylactically, because there is a 10% chance that he will develop lymphoedema (31.4) after it, and it will not improve his prognosis.

If his nodes are enlarged, and you think that this is caused by secondary infection, give him antibiotics, and wait two weeks. If they respond, good. If they don't, biopsy one, and follow him up carefully.

If you think that his nodes are involved clinically but are not fixed to deeper structures, or he has an advanced ulcer-cancer (most commonly in his groin), refer him for block dissection, and wide excision of the primary, at the same time. Both operations should be done on the same occasion, because he may not return to have a block dissection, if his nodes do not trouble him. Block dissection (32.34) is not an easy operation, so try to learn it from an expert, before you do it yourself[md]accidental injury to the femoral artery or vein may be difficult to repair (see also carcinoma of the penis 32.33). The prognosis following wide excision of the primary and block dissection is good.

CAUTION ! Explain to him carefully that he must return regularly to have his lymph nodes examined. Too often, he leaves them until they form a stinking, ulcerated, fungating mass.

If the glands in his groin are enlarged and fixed to his femoral vessels, leave them. They will fungate, but there is little you can do about this (33.1).

If his inguinal nodes become enlarged when they were normal previously, or increase in size after his amputation stump has healed completely, but are still mobile, a block dissection is indicated (32.34).

DIFFICULTIES [s7]WITH SQUAMOUS CELL CARCINOMAS If the patient is an ALBINO, he (or she) is particularly prone to multiple squamous cell carcinomas. Advise long skirts or trousers, long sleeved shirts, wide hats, tinted glasses, and the avoidance of unnecessary exposure to the sun, especially between 1100 and 1500 hours. The patient must report any new lumps or bumps immediately. When an albino presents with a squamous cell carcinoma, treat him in the same way as a normal person.