A Case of Poorly Differentiated Early Rectal Adenocarcinoma with Tubulo-Villous Adenoma

Toshio Iino, Katsuhito Suwa, Eiichirou Miura, Yoshiyuki Furukawa, Yoshihiko Takao, Sadao Anazawa, Yoji Yamazaki, Katsuhiko Yanaga, Hiroyuki Kato* and Akio Yanagisawa**

Department of Surgery and Department of Pathology*, The Jikei University School of Medicine
Department of Pathology, Kyoto Prefectural University of Medicine**

A 42-year-old man with bloody stool was found in barium enema and colonoscopy to have a polypoid lesion 20 mm with an irregular surface and fold convergence in the rectum. Biopsies were consistent with poorly differentiated adenocarcinoma. Given the patient's disability, we conducted Hartmann's operation. Histological examination showed poorly differentiated adenocarcinoma invading the submucosal layer with lymphnode metastasis. The poorly differentiated adenocarcinoma was encircled by tubulovillous adenoma. No point mutation of the K-ras gene was observed in the poorly differentiated adenocarcinoma or tubulovillous adenoma. Immunohistochemically, only the poorly differentiated adenocarcinoma showed diffuse positive staining for p53 protein. Based on the pathological figure and molecular biological analysis, this case was definitively diagnosed as poorly differentiated adenocarcinoma following a pathway included in the adenoma-carcinoma sequence.

Key words
poorly differentiated adenocarcinoma, tubulovillous adenoma, early colon cancer

Reprint requests
Toshio Iino Department of Surgery, The Jikei University School of Medicine
3-25-8 Nishi-shinbashi, Minato-ku, 105-8461 JAPAN

Accepted
February 23, 2005

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