Pigmented Polypoid Lesion in a 24-Year-Old Woman With Hematochezia

Anorectal melanoma presenting as a polypoid lesion

“…Anorectal melanoma (ARM) is an extremely rare malignancy, which accounts for only 0.5%–4.6% of all malignant anorectal neoplasms and 1.4% of all melanomas 1 2 . ARM is usually polypoid and often melanotic 3 4 .…”

“…Amelanotic ARMs may be misdiagnosed as polyps or adenocarcinomas, which may contribute to their poor prognosis because of their highly aggressive potential. The overall median survival of ARM is reported to be 8–18.6 months 1 . This case highlights the importance of raising awareness of ARM, as having a high level of clinical suspicion could avoid misdiagnosis or delayed diagnosis, thereby improving prognosis.…”