Work

Primary anorectal melanotic melanoma: a case report

Year: 2026

Type: article

Abstract: BACKGROUND: Anorectal melanoma (AM) is a rare and aggressive malignancy that is often advanced at the time of diagnosis. This case demonstrates the importance of a prompt colonoscopic evaluation, especially in older patients presenting with new gastrointestinal symptoms, and underscores the need for further research establishing a standardized treatment protocol. CASE PRESENTATION: We report a case of a 71-year-old white male who was referred to gastroenterology after noticing increased frequency of bright red blood per rectum following bowel movements. A subsequent colonoscopy revealed a 1.5-cm darkly pigmented, irregular mass in the anorectal region. The lesion was excised and sent for microscopic evaluation which disclosed highly malignant spindle and epithelioid cells producing a large amount of brown pigment. A diagnosis of anorectal melanoma was confirmed with positive immunohistochemical staining for S-100, HMB45, and Melan-A. A computed tomography (CT) scan of the abdomen and pelvis showed no evidence of metastasis. The patient then underwent a transanal resection of the area where the tumor was found. No residual melanoma was seen in the resected specimen. Follow-up evaluations over about 2 years have shown no evidence of recurrence. CONCLUSIONS: The positive outcome of this case highlights the importance of timely recognition as well as the ongoing need to explore and refine effective treatment options for AM.

Source: Journal of Medical Case Reports

DOI: 10.1186/s13256-026-06224-3

Authors: Kaitlyn Brown, Sofia Sirocchi, William Frank Willett

Institutions: Philadelphia College of Osteopathic Medicine, Emory Healthcare

Language: English

Topic: Cutaneous Melanoma Detection and Management

Subfield: Oncology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,890