Primary anorectal malignant melanoma.

A case of primary anorectal malignant melanoma seen in a 46 year old woman is presented herein. Her most marked symptoms were bloody stools and anal pain. Endoscopic examination indicated a tumor with ulceration but without pigmentation in the anorectal region. Histologic examination of the biopsied specimens showed spindle-shaped cells with atypia proliferating in a bandlike arrangement, as in leiomyosarcoma. An abdominoperineal resection was done and detailed histological examination of the tumor confirmed the nature of the tumor to be malignant melanoma. The postoperative immunochemotherapy consisted of Dimetyl-Triazeno-Imidasole-Carboxamide (DTIC), Amino-Methyl-Pyrimidinyl-Methyl-Chlorethyl-Nitrosourea-Hydrochlori de (ACNU), Vincristine (VCR) and OK-432. The patient has been well without recurrence for fifteen months following her operation through the continuous administration of these agents.