[Primary anorectal malignant melanomas. 2 cases].

Two cases of primary ano-rectal melanoma are reported. Primary melanoma of the anorectum is an uncommon and highly malignant disease (the survival rate is about 7 to 12 percent at 5 years). The tumour may be difficult to diagnose when it is not pigmented (16 to 53 percent of the cases). At histological examination the diagnosis is impossible in 30 percent of the cases. It is facilitated after local excision by immune markers (vimentin, PS 100, HMB 45 immunostaining). Radical abdominal perineal resection may cure patients with less than 2 mm wide lesions. The few cases of long term survival have resulted from radical surgery. For larger lesions staged IV or V by Breslow's method conservative local approach by excision achieves local palliation. Radiation is a palliative therapy in extensive tumours. Combined chemotherapy with fotemustine and dacarbazine may be attempted in case of metastatic spread.