A Case of Malignant Rhabdoid Tumor of the Rectum

Malignant rhabdoid tumor, first described in the kidneys of infants and children, is very rare and its prognosis extremely poor. Tumors with a similar appearance have been reported in at different extrarenal sites. We report a case of a malignant rhabdoid tumor of the rectum. A 63-year-old man admitted for melena was found on colonoscopy to have a type 1 rectal tumor with bleeding at the Ra portion. Abdominal CT showed a rectal tumor 10cm in diameter with lymphnode metastases. Invasive rectal carcinoma was suspected and Hartmann's operation with lymphadenectomy was performed. Macroscopically, the 10.0×8.4cm type 1 tumor with invasion of serosa was located in the rectum. Pathological findings showed discohesive cells with prominent nucleoli and eosinophilic cytoplasmic inlusions. Immunohistochemically, tumor cells are positive for cytokeratin and vimentin, identifying the tumor as a MRT of the rectum.