Primary anorectal malignant melanoma: two case reports and review of the literature.

Anorectal melanoma is a very rare tumor with poor prognosis because of delay in diagnosis. It is often mistaken for benign conditions such as hemorrhoids or rectal polyps. Surgical treatment ranges from local excision to radical abdominoperinal resection. Herein, we report 2 cases of anorectal malignant melanoma and further review the diagnostic and therapeutic approaches in light of the pertinent literature.