A Case of Juvenile Rectal Carcinoma without a Family History of Colorectal Cancer Accompanied with Mismatch Repair Gene Deficiency

Toru Yoshida¹⁾⁵⁾, Yuko Baba¹⁾, Osamu Shimooki¹⁾, Tadashi Abe¹⁾, Tamotsu Sugai²⁾, Wataru Habano²⁾, Noriyuki Uesugi²⁾, Shin-ichi Nakamura²⁾, Kazuyoshi Saito³⁾ and Hitoshi Nomizu⁴⁾⁵⁾

¹⁾Division of Surgery Iwate Prefectural Kuji Hospital
²⁾Division of Pathology, Central Clinical Laboratory, School of Medicine Iwate Medical University
³⁾Department of Surgery I, Iwate Medical University
⁴⁾Department of Surgery, Hoshi General Hospital
⁵⁾Tohoku Familial Tumor Association

A 28-year-old man admitted for diarrhea was found on palpation to have an elastic hard mass, 10 cm in diameter, was palpated in the lower abdomen. Computed tomography and magnetic resonance imaging showed a solid tumor occupying the pelvic cavity. The preoperative diagnosis was rectal cancer and Miles'operation was conducted. Histopathological diagnosis was well differentiated adenocarcinoma with mucin production (a1, ly1, v1, n0, ow-, aw-, ew-, stage II). High-frequency microsatellite instability (MSI-H) was identified in the rectal specimen using a microsatellite assay. Germline mutation in the h-MSH2 gene was also identified. We diagnosed this case as rectal cancer accompanied with mismatch repair gene deficiency.
Assessment of MSI status is important for determing high-risk colorectal carcinoma.

Key words
microsatellite instability (MSI), hereditary nonpolyposis colorectal carcinoma (HNPCC), h-MSH2

Reprint requests
Toru Yoshida Division of Surgery Iwate Prefectural Kuji Hospital 10-1 Asahi-machi, Kuji-shi, 028-8040 JAPAN

Accepted
October 30, 2002

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