title: [Imaging and pathological features of gastrointestinal stromal tumors].
abstract: OBJECTIVE
  To investigate the imaging features and pathological manifestations of gastrointestinal stromal tumors (GISTs).
  
  
  METHODS
  The imaging characteristics and pathological manifestations of 26 surgically treated patients with histologically confirmed GISTs were retrospectively analyzed.
  
  
  RESULTS
  The tumors were found to originate from the small bowel (n=10), stomach (n=8), colon (n=6), mesentery (n=1) and omentum (n=1). The imaging and pathological features of GISTs were (1) most of GISTs were well-defined and exophytic (n=19, 73.1% ), which usually compressed the adjacent tissues but no invasion. The tumor diameter ranged from 5.1 to 23.5 cm with a mean diameter of 11.6 +/- 5.9 cm, (2)most tumors had an inhomogenous density or signal intensity due to necrosis(n=21, 80.8%), hemorrhage (n=15, 57.7%) or calcification (n=3, 11.5%) within the tumor, (3) on the CT or MR images, heterogeneous enhancement pattern presented as peripheral or intra-tumor patchy enhancement was common (n=21, 80.8%). Furthermore, enhanced striped vessels were seen in 12 patients. However, homogenous enhancement pattern was rare (n=5, 19.2%), (4) the most common site where GIST metastasized to was the liver (n=7), followed by the peritoneum (n=4), but rarely to lymph nodes, (5) of these 26 patients, spindle-cell type was observed in 69.2% (n=18), epithelioid-cell type in 23.1% (n=6), and mixed cell type in 7.7% (n=2). Immunohistochemical studies showed positive CD117 expression in all of these 26 patients, but positive CD34 expression in only 22 patients.
  
  
  CONCLUSIONS
  Gastrointestinal stromal tumor usually presents as a exophytic, well-defined large tumor, with internal striped vessels, necrosis or hemorrhage within. It usually metastasizes to the liver or the peritoneum but rarely to lymph nodes. Pathologically, most of gastrointestinal stromal tumors consist of spindle-cells, while a small portion of the tumors are composed of epithelioid-cells or mixed ones. Both CT and MRI play an important role in the diagnosis of gastrointestinal stromal tumors.
authors: Department of Radiology, Third Hospital, Guangzhou Medical College, Guangzhou 510150, China. gzflair@163.com
authors: Ting
authors: T
authors: Song
authors: Jun
authors: J
authors: Shen
authors: Hao-chang
authors: HC
authors: Guo
authors: Bi-ling
authors: BL
authors: Liang
authors: Heng
authors: H
authors: Pan
authors: Kui-ming
authors: KM
authors: Jiang
authors: Jian-xing
authors: JX
authors: Xian
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000378:metabolism; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D018952:Antigens, CD34; D019009:Proto-Oncogene Proteins c-kit