We describe herein a case of amelanotic melanoma of the rectum. Macroscopic
ally, the tumor was lacking in pigmentation and microscopically, it was fou
nd to be deficient in melanin. Moreover, the tumor cells showed positive st
aining for HNB-45, the antimelanoma antibody, which led to a diagnosis of a
melanotic melanoma. The patient died of metastatic tumors in the liver and
bone 17 months after undergoing abdominoperineal resection of the rectum an
d dissection of the bilateral inguinal lymph nodes.