Anal malignant melanoma

Abstract

This tumor generally arises as a small polypoid mass which is invariably protuberant. The tumor was ulcerative and was taken for an anal fissure initially. When protuberant it may suggest the diagnosis of a thrombosed internal hemorrhoid, since the tumor spreads upward into the lower rectum. Its true nature may only be revealed when the specimen is submitted to histologic examination. This tumor has a high metastasizing potential and is considered the most malignant form of intestinal cancer. Lymphatic spread may occur in 3 directions: upward to involve the inferior mesenteric glands, along the middle hemorrhoidal vessels to the internal iliac glands and to the inguinal lymph nodes. In this patient the left inguinal glands were enlarged, but not hard or fixed. The preferred form of treatment is abdominoperineal resection with bilateral groin dissection and deep pelvic node dissection. Radiotherapy and chemotherapy are of no value.