Anal melanoma: an aggressive malignancy masquerading as hemorrhoids.

Anal melanoma is a devastating malignancy easily confused with benign hemorrhoids. Physician unfamiliarity with this bleeding rectal lesion can lead to delays in diagnosis and therapy. Four cases of anal melanoma, all initially mistaken for hemorrhoids, have been documented in the past 4 years at our institution. Despite surgical intervention and chemoimmunotherapy, each patient succumbed to widely metastatic disease. Average survival was 15.2 months. The clinical, pathologic, surgical, and oncologic features of anal melanoma are reviewed to enhance physician recognition of this unusual anorectal disorder.