Primary rectal malignant melanoma-case report.

INTRODUCTION: Primary malignant melanoma that arises from the true anatomic rectal mucosa is extremely rare. CASE REPORT: An endoscopic investigation of a 79-year-old woman with long history of tenesmus and rectal bleeding revealed posterior fleshy mass 4.5 cm from the anal verge. Biopsies demonstrated malignant melanoma. She underwent abdominoperineal resection and is doing well one year after the operation.
CONCLUSION: Owing to its rarity and histologic variability, misdiagnosis as lymphoma, carcinoma or sarcoma is common.