title: Solitary fibrous tumor of the greater omentum, mimicking gastrointestinal stromal tumor of the small intestine: a case report.
abstract: Solitary fibrous tumor (SFT) is one of the mesenchymal tumors, which rarely arises in the abdominal space. We report a very rare case of abdominal SFT, mimicking another mesenchymal tumor. A 52-year-old Japanese man was referred to our hospital for further evaluation and treatment of gallbladder polyp. Contrast-enhanced computed tomography (CT) showed an enhanced nodule within the gallbladder, and incidentally, also showed a well-circumscribed mass adjacent to the small intestine. The mass was depicted as slightly high density in plain CT, and with contrast-enhancement, the mass was partially stained in early phase and the stained area spread heterogeneously in delayed phase. Magnetic resonance imaging showed that the abdominal mass was depicted as slightly high intensity on T2-weighted imaging and low intensity on T1-weighted imaging. With double-balloon endoscopy and capsule endoscopy, we did not find any tumor inside the small intestine. These visual findings lead us to diagnose it as gastrointestinal stromal tumor of the small intestine with extraluminal growth. We planned to resect both the gallbladder polyp and the intraperitoneal tumor at the same time for pathologic diagnosis and treatment. When the operation was performed, we found a milk-white lobulated tumor on the greater omentum and the tumor was entirely resected. Microscopically, the gallbladder polyp was diagnosed as tubular adenoma, and the omental tumor was diagnosed as SFT. It is important to bear in mind that omental SFTs sometimes mimic other mesenchymal tumors and should be included in the differential diagnosis of abdominal tumor not revealed by endoscopy.
authors.affiliation: 1 Department of Gastrointestinal Surgery, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Urabe
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Yamagata
authors.forename: Susumu
authors.initials: S
authors.lastname: Aikou
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Mori
authors.forename: Hiroharu
authors.initials: H
authors.lastname: Yamashita
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Nomura
authors.forename: Junji
authors.initials: J
authors.lastname: Shibahara
authors.forename: Masashi
authors.initials: M
authors.lastname: Fukayama
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Seto
mesh_terms: D003287:Contrast Media; D003937:Diagnosis, Differential; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009852:Omentum / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D054364:Solitary Fibrous Tumors / Q000175:diagnosis* / Q000601:surgery*; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media
keywords: Extrathoracic location; Mesothelial tumor