CLINICAL-DIAGNOSIS AND THERAPY OF CUTANEOUS MELANOMA IN-SITU

BACKGROUND. The frequency of in situ melanoma is increasing, and it is often diagnosed fortuitously by histology. METHODS. We retrospectivel y reviewed 121 melanomas in situ in 113 patients with the aim of ident ifying the clinical features of, and optimal surgical treatment for th is cutaneous malignancy. Treatment was limited surgery with 3 mm margi ns of excision in 69 cases (57%) and wider margins of excision (more t han 3 mm) in 52 cases (43%). The lesions had a median diameter of 1 cm (range, 2-35 mm) and were generally macular (92% of cases) and asymme tric (87%), with an irregular border (88%) and nonuniform pigmentation (98%), usually in shades of brown (41%) and black (48%). These featur es had permitted a clinical diagnosis of melanoma or suspected melanom a in 62% of cases and of doubtful nevus in an additional 18% of cases. RESULTS. At a median follow-up of 4 years, there were six local recur rences (three treated by limited surgery and three by wider excision), all in situ melanomas. CONCLUSIONS. The typical clinical features of melanoma in situ, which are similar to those of early invasive melanom a, are usually sufficiently distinctive to suggest the clinical diagno sis of melanoma or suspected melanoma. Except for large size and super ficially extended lesions (larger than 2 cm), adequate treatment is ex cision with 3 mm margins, although larger lesions (larger than 2 cm) m ay have an appreciable incidence of local recurrence. (C) 1996 America n Cancer Society.