title: Exophytic pedunculated gastrointestinal stromal tumor with remarkable cystic change.
abstract: A 59-year-old man with bloody stools, and previously diagnosed with sigmoid colon carcinoma, visited our hospital. Preoperative abdominal ultrasonography (US) showed another tumor, with an uneven irregular surface, measuring about 9 x 5 cm, below the left hypochondrium. The tumor consisted of several cysts. Abdominal computed tomography (CT) showed a multicystic tumor attached to the stomach, and its septum and marginal region were intensely stained on contrast imaging. On magnetic resonance imaging (MRI), low and markedly high signals were revealed in the tumor on T1-weighted and T2-weighted sequences, respectively. Contrast imaging of the upper digestive tract showed extramural compression of the greater curvature of the antral stomach by the tumor. The tumor was partially imaged by endoscopic ultrasonography (EUS), but continuity to the stomach was not confirmed. On abdominal angiography, the tumor was slightly stained via the gastroepiploic arteries. Surgical treatment was performed to excise both the gastric tumor and the sigmoid colon carcinoma. The gastric tumor was removed with gastric wall tissue where the tumor was attached to a 2-cm pedicle. It was multicystic, contained watery fluid, and had a smooth outer surface. Histologically, the tumor consisted of multiple irregular cysts without epithelial lining, and solid epitheloid cell nests in between. The tumor cells had clear or eosinophilic cytoplasm and round nuclei. No mitotic figures were seen. The tumor cells in the pedicle were connected with the muscularis propriae of the stomach. Immunohistochemistry showed c-kit-positive, CD34-positive smooth muscle actin (SMA)-negative, and S-100-negative staining of tumor cells. The final diagnosis was gastrointestinal stromal tumor (GIST).
authors.affiliation: Department of Gastroenterology, Gifu Prefectural Tajimi Hospital, 5-161 Maehatacho, 507-8522 Tajimi, Japan.
authors.forename: Itaru
authors.initials: I
authors.lastname: Naitoh
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Okayama
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hirai
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kitajima
authors.forename: Kazuki
authors.initials: K
authors.lastname: Hayashi
authors.forename: Tetsu
authors.initials: T
authors.lastname: Okamoto
authors.forename: Shinji
authors.initials: S
authors.lastname: Akita
authors.forename: Kazuo
authors.initials: K
authors.lastname: Gotoh
authors.forename: Mutsue
authors.initials: M
authors.lastname: Mizusima
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sano
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ohara
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nomura
authors.forename: Takashi
authors.initials: T
authors.lastname: Joh
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Itoh
mesh_terms: D005770:Gastrointestinal Neoplasms / Q000473:pathology*; D006801:Humans; D018191:Lymphangioma, Cystic / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D017154:Stromal Cells / Q000473:pathology*