A Case of Rectal Cancer with the Component of Micropapillary Carcinoma

Masashi Hirota, Katsuya Yamashita, Toru Ichihara and Etsuko Nakamura*

Department of Surgery and Department of Pathology*, National Hospital Organization Toyohashi Medical Center

A 73-year-old woman admitted for melena was found in colonoscopy to have a type 2 tumor in the rectosigmoid area, necessitating high anterior resection under a diagnosis of rectal cancer. Histologically, the tumor consisted of moderately differentiated adenocarcinoma, with small papillary neoplastic cell clusters floating in clear spaces resembling lymphatic channels. The tumor penetrated the serosa, with lymphatic invasion and metastasis in 6 regional lymph nodes. Immunohistochemically, MUC1 was expressed at the stroma-facing surface of cells. Morphological and immunohistochemical findings yielded a definitive diagnosis of rectal cancer with micropapillary carcinoma components. Micropapillary carcinoma has a dismal diagnosis with a high incidence of lymphatic invasion and lymph node metastasis. Although micropapillary carcinoma has rarely been reported in the colorectum, the presence of micropapillary carcinoma in colorectal cancer mandates the need for aggressive therapy.

Key words
micropapillary carcinoma, colorectum

Reprint requests
Masashi Hirota Department of Surgery, National Hospital Organization Toyohashi Medical Center
50 Hamamichigami, Imure-cho, Toyohashi, 440-8510 JAPAN

Accepted
March 26, 2008

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