POSTTRAUMATIC SQUAMOUS-CELL CARCINOMA

Between January 1, 1976, and January 1, 1986, we treated sixty-three patients who had histologically proved squamous-cell carcinoma that originated in a pre-existing scar or sinus of an extremity. In 49 per cent of the patients, metastases to regional lymph nodes either were present when the patient was first seen or subsequently developed. The age and sex of the patient, the etiology of the original scar, and the duration of illness bore no relationship to the result. The most significant factor in predicting the outcome was the grade of the tumour: for grade-I (low-grade) lesions, the incidence of metastasis was 10 per cent; for grade-II (moderately well differentiated) lesions, 59 per cent; and for grade-III (poorly differentiated) lesions, 86 per cent. Eleven patients had wide local excision of the lesion, which resulted in local recurrence in four patients and metastasis in three. Thirty patients had therapeutic amputation: one patient had recurrent disease and five patients had metastasis. Radical resection of lymph nodes after metastasis was uniformly unsuccessful in preventing additional metastasis. Ten patients who had a grade-II or grade-III tumor had prophylactic irradiation of the regional lymph nodes after the definitive operative treatment. At an average of thirty-seven months of follow-up, only one of them had metastasis. We recommend that well differentiated squamous-cell carcinoma be considered a low-grade tumor, according to the staging system for musculoskeletal neoplasms, and that more poorly differentiated squamous-cell carcinoma (grades II and III) be considered a high-grade lesion. Local excision should be reserved for a patient who has a low-grade lesion that can be radically excised and who can be closely followed. In a patient who has a higher-grade tumor, local excision is often difficult due to distortion of anatomy and tissue planes by previous trauma or burns, and amputation should be considered.