Anorectal Malignant Melanomas: Experience of Uludag University

Abstract

Anorectal melanomas represent a group of mucosal melanomas with unknown etiology and poor prognosis. The lesions can be misdiagnosed as hemorrhoids during clinical examination. We reviewed the morphological and clinical features of 14 anorectal melanomas, and discuss the treatment modalities of this entity. Fourteen patients who were diagnosed with anorectal malignant melanoma between 1997 and 2004 were evaluated with regard to age, sex, size, morphology, lymph node or distant metastasis, treatment modality and survival. Eight patients were female and six were male, and their mean age was 58 years. The size of melanoma ranged from 3 cm to 8 cm. Pathological evaluation revealed epithelioid and spindle cell type tumor in seven and two patients, respectively, whereas, in the remaining seven patients, the tumor was composed of both types. Pigmentation was apparent in all tumors. There was lymph node metastasis in 11 patients and distant metastasis in all patients. Eleven patients underwent abdominoperineal resection and three were treated by local excision. Mean survival was 8.7 months. Prognosis of anorectal melanoma remains poor. Awareness of the diverse clinicopathological features of these lesions, both on the part of the clinicians and pathologists, is crucial for their early detection and proper treatment.

Keywords

• anal tumor
• malignant melanoma
• rectal tumor