A Case of Gastrointestinal Stromal Tumor with Cystic Change arising in the Small Intestine, diagnosed Preoperatively as an Ovarian Tumor

Hajime Morohashi¹⁾²⁾, Kyogo Yamada¹⁾, Osamu Matsuura¹⁾, Soichiro Yamazaki¹⁾ and Masahiro Fujita¹⁾

Department of Surgery, Mutsu General Hospital¹⁾
Department of Surgery, Hirosaki University School of Medicine²⁾

We report a case of gastrointestinal stromal tumor (GIST) with cystic change difficult to distinguish from ovarian tumor. A 39-year-old woman found in ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) to have a solid, cystic pelvic tumor suspected of being to have ovarian tumor was found in laparotomy to have a solid 8.7-cm cystic tumor apparently arising in the small intestine 230 cm rostral to the Treitz ligament, necessitating partial resection of the portion of small intestine containing the tumor. Histopathologically, fascicular spindle-shaped tumor cells were found in the submucosa that were immunohistochemically positive for c-kit, yielding a diagnosis of gastrointestinal stromal tumor of the small intestine. Indications by US, CT, or MRI of an intrapelvic tumor necessitate additional examination for possible GIST of the small intestine. Our case is the tenth reported in Japan to have been diagnosed preoperatively as an ovarian tumor, but shown postoperatively to be GIST of the small intestine.

Key words
GIST (gastrointestinal stromal tumor), ovarian tumor

Reprint requests
Hajime Morohashi Department of Surgery, Mutsu General Hospital
1-2-8 Kogawamachi, Mutsu, 035-8601 JAPAN

Accepted
March 25, 2009

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