Gastrointestinal Stromal Tumor of the Lesser Omentum: Report of a Case

Mitsuaki Morimoto¹⁾, Yoshiaki Tsuji¹⁾, Yasushi Hara¹⁾, Atsuhiko Koga¹⁾, Masataka Ushijima¹⁾, Jun Taguchi²⁾ and Fumihiro Yoshimura³⁾

Fukuoka Prefectural Hepato-gastroenterological Center Asakura Hospital, Department of Surgery¹⁾
Fukuoka Prefectural Hepato-gastroenterological Center Asakura Hospital, Department of Pathology²⁾
Saiseikai Hita Hospital, Department of Surgery³⁾

A 68-year-old woman admitted for an abdominal mass in the lateroabdomen was found on palpation to have an elastic hard mass 15 cm in diameter. Computed tomography showed a well-defined mass about 11.5× 9.0 cm adjacent to the anterior wall of the stomach. Laparotomy showed a mass of approximately 15 cm from the lesser omentum and slightly adherent to the stomach wall. We resected the mass completely, including the part of the stomach wall. The tumor was 13.5× 10.0× 9.0 cm and showed irregular nodularity. Most of it was composed of a multilocalated cyst filled with clotted blood and necrotic tissue. Histopathology shows the tumor was composed of spindle-shaped cells with high cellularity. Immunohistochemically, the tumor was negative for desmin and S-100 protein, but stained positive for KIT (CD 117), CD 34, and vimentin. We diagnosed this case as GIST. The patient remained free of recurrence when last seen about 1 year after her surgery.

Key words
gastrointestinal stromal tumor (GIST), lesser omentum

Reprint requests
Mitsuaki Morimoto Department of Surgery, Fukuoka Prefectural Hepatogastroenterological Center Asakura Hospital
422 Raiharu, Amagi, 838-0069 JAPAN

Accepted
September 22, 2004

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