Metastatic malignant melanoma from anorectum presenting as an isolated breast tumor: A case report and literature review.

Rationale: Anorectal malignant melanoma regularly exhibits a biological aggressive behavior which is metastasizing to lung, bone, brain or other organs and tissues early in the course of the disease. Compared with melanoma in the other parts of the body, anorectal malignant melanoma is relatively rare. Metastatic to the breast tissue from anorectal malignant melanoma or from other extra-mammary tumors are very rare.