Clinical & Medical Case Reports

Anal canal melanoma is a rare tumor, constituting 0.5-2% of all the anorectal malignancies and less than 2% of all melanomas. We present a case of a 38 year old male, who presented with mass descending per-rectum for duration of three months, with occasional bleeding Per-rectum while straining for stools. He consulted in various hospitals, which diagnosed him to have hemorrhoids and advised for conservative management. On examination, he had a 4x4 centimeters bluish black mass descending per rectum which became prominent on bearing down, with no active bleeding and no lymphadenopathy. Computed tomography (CT) abdomen revealed anal canal thickening, extending to the distal rectum with peritoneal deposits. Colonoscopy revealed a growth arising from the anal verge, extending 10 centimetres upwards. Guided biopsy confirmed it to be mucosal melanoma, following the application of S-100 and HMB 45 stains. Considering the advance nature of the condition, he received chemotherapy (dacarbazine and cisplatin).Anal canal melanomas are the third most common, following cutaneous and ocular varieties. They frequently present with non-specific symptoms: rectal bleeding, tenesmus, anorectal mass, change in bowel habits and hemorrhoids. It most commonly metastasizes to inguinal lymph nodes, mesenteric lymph nodes, hypogastric lymph nodes, para –aortic lymph nodes, liver, lung, skin and brain. Surgery (WLE/APR) may be an option when presented early without distal organ involvement. Palliative chemo/radiotherapy for advanced diseases. High index of clinical suspicion, especially when the symptoms are incongruent with clinical findings is of utmost importance in diagnosing and managing aggressive conditions like this.