AJR:182, June 2004 1463 Original Report OBJECTIVE. This study was undertaken to describe the CT features of primary gastrointesti- nal stromal tumors in the omentum and mesentery and to identify any pathologic correlation. CONCLUSION. On contrast-enhanced CT, primary gastrointestinal stromal tumors in the omentum and mesentery are usually well-defined, huge masses that contain large areas of low-attenuation necrosis and hemorrhage and that lack central gas. astrointestinal stromal tumors ac- count for most primary mesenchy- mal tumors of the gastrointestinal tract [1]. Older articles in the medical literature refer to these tumors as leiomyomas, leiomyo- blastomas, and leiomyosarcomas, because these tumors were believed to originate from the smooth-muscle layers of the gastrointesti- nal tract wall. Recently, immunoreactivity for KIT (CD117, a tyrosine kinase growth factor receptor) has allowed gastrointestinal stromal tumors to be distinguished from true leiomyo- mas, leiomyosarcomas, neurofibromas, and schwannomas [2]. Moreover, the recent avail- ability of the KIT tyrosine kinase inhibitor (STI-571, imatinib [Gleevec], Novartis) has revolutionized the treatment of gastrointestinal stromal tumors [3], which makes it important to know this disease entity. Gastrointestinal stromal tumors are most frequently found in the stomach (60–70%), followed by the small intestine (20–30%), col- orectum (10%), and esophagus (< 5%) [4]. Al- though stromal tumors in the gastrointestinal tract commonly metastasize to the omentum and mesentery, they may also occur as primary tumors outside the gastrointestinal tract, espe- cially in the omentum and the mesentery [5]. A number of studies of gastrointestinal stromal tumors have been published in the radiology literature [6–9]; however, few case reports are available on the imaging appearances of pri- mary gastrointestinal stromal tumors in the omentum and mesentery [10, 11]. The purpose of our study was to describe the CT findings of primary gastrointestinal stromal tumors in the omentum and mesentery and to identify any pathologic correlation. Materials and Methods From January 1999 to May 2003, eight primary gastrointestinal stromal tumors in the omentum and mesentery were registered at the pathology registry of our institution. None of these tumors involved the gas- tric or intestinal walls, and no patient had a previous history of gastrointestinal stromal tumors. Clinical data were reviewed for patient age, sex, and presenting symptoms. The institutional review board at our hospi- tal did not require approval or informed patient con- sent for the review of medical records and images. CT data were available on a PACS (picture ar- chiving and communications system, Marotech) in all patients. CT examinations were performed with a So- matom Plus-4 (Siemens Medical Solutions) or a Hi- Speed Advantage (General Electric Medical Systems) scanner. Each patient received 120 mL of nonionic contrast material ([iopromide] Ultravist 370, Scher- ing) through an 18-gauge angiographic catheter in- serted into a forearm vein. The contrast material was Hyo-Cheol Kim 1 Jeong M in Lee 1 Se Hyung Kim 1 Kyoung Won Kim 2 Minjin Lee 3 Young Jun Kim 1 Joon Koo Han 1 Byung Ihn Choi 1 Received September 26, 2003; accepted after revision November 20, 2003. Supported in part by a grant from the 2003 BK21 Project for Medicine, Dentistry, and Pharmacy. 1 Department of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, SNUMRC, and Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea. Address correspondence to J. M. Lee (leejm@radcom.snu.ac.kr). 2 Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. 3 Department of Pathology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea. AJR 2004;182:1463–1467 0361–803X/04/1826–1463 © American Roentgen Ray Society G Primary Gastrointestinal Stromal Tumors in the Omentum and Mesentery: CT Findings and Pathologic Correlations Downloaded from www.ajronline.org by 52.73.204.196 on 05/16/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved