Anal canal melanoma misdiagnosed and treated as prolapsed hemorrhoids in a male patient

• Published in: Formosan journal of surgery : the official publication of the Surgical Association ... [et al.] Vol. 47; no. 2; pp. 74 - 77
• Main Authors: Mala, T.A., Gupta, R., Ahmad, S.R., Malla, S.A., Gupta, V.B., Shah, I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2014
• Subjects: anal canal melanoma; melanoma antigen HMB-45; protein S-100; thrombosed hemorrhoids; anal canal melanoma; thrombosed hemorrhoids; protein S-100; melanoma antigen HMB-45
• ISSN: 1682-606X
• DOI: 10.1016/j.fjs.2013.11.002

Malignant melanoma of the anal canal is a rare, but aggressive, tumor with a poor prognosis. It represents less than 1% of all melanomas and 4% of anorectal tumors. We are reporting this case because of its rarity in men and because, in this instance, the tumor was misdiagnosed as prolapsed thrombosed hemorrhoids and excised. Examination showed a visible exophytic irreducible growth measuring about 3 × 3 cm and protruding outside the anal verge and involving the anterior two-thirds of the circumference of the anal canal. A biopsy sample showed round to oval cells with prominent nucleoli and marked intracytoplasmic pigmentation. A magnetic resonance imaging scan showed a tumor with nearly complete luminal obstruction and liver metastasis. The patient received chemotherapy and radiotherapy, but the response was very poor and he died 2 months later.