International Journal of Clinical Science and Medical Research

Malignant anorectalmelanoma is a malignant tumour that developsfrom the pigmentary system. It is a rare tumour,accounting for less than 1% of anorectal cancers and 0.3% of malignant melanomas. Its prognosis is poor due to the early onset of metastases. We report a case.

A 78-year-old female patient with hypertension was admitted for rectal bleeding that had been ongoing for two months, with no other associated symptoms but a deterioration in her general condition. A proctological examination revealed a polypoid tumour with a blackish appearance located 3 cm from the anal margin. Abdominal examination revealed hepatomegaly with a hepatic splenic flexure at 14 cm. Colonoscopy revealed a polyploid mass 2 cm in diameterextending 3 cm in a hemicircular pattern, with a blackish appearance, and scattered nevi on the rectosigmoid mucosa.

Pathological examination of the biopsiesconcluded that the diagnosis was anorectal melanoma, with the presence of anti-PS100 and anti-HMB45 antibodies on immunohistochemistry. Staging investigations revealed liver metastases.

Rectal bleeding; Anorectal melanoma; Liver metastases

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