[Malignant melanoma of the anorectal mucosa]

A 62-year-old man was admitted to hospital because of rectal bleeding of unknown cause.

Coloscopy showed a rectal tumour as cause of the bleeding and concomitant hypochromic microcytic anaemia. Histological examination established the diagnosis of anorectal malignant melanoma. Further staging examinations did not reveal metastatic disease.

An radical abdominoperineal rectal resection amputation was performed. The postsurgical course was uneventful. However, multiple lung metastases were detected 6 weeks later.

Anorectal malignant melanoma is a rare cause in the differential diagnosis of anorectal tumours. Surgery remains the therapy of choice. Chemotherapy and immunotherapy are principally used in a palliative setting. Despite advances in therapy, the prognosis of this tumour entity remains unfavourable.