/Wang Cuizhong(王翠众，Dept Gen Surg，Zhongshan Hosp Fudan Univ，Shanghai 200032)…∥Chin J Gastrointest Surg.-2011，14(8).-599～602

ObjectiveTo investigate the clinicopathological and molecular genetic characteristics of gastrointestinal stromal tumor(GISTs)with significant cystic changes，and to assess their biological behavior.MethodsClinicopathological features of 7 patients with cystic GISTs treated at the Zhongshan Hospital of Fudan University from February 2005 to January 2010 were summarized retrospectively.The mutations status of c-kit and PDGFR-α were analyzed.ResultsThere were 2 males and 5 females aged from 46 to 76 years old.Primary site of GISTs included stomach(n=4)，duodenum(n=1)，and small intestinal(n=2).Tumor size ranged from 6 to 16 cm with obviously cystic changes.Tumor cells were found in the solid components under microscope，of which epithelioid cell type were found in 4 case and spindle cell type in 3 cases.The mitotic figures were no more than 3/50 HPF in all the patients.According to the NIH criteria，4 were high-risk and 3 were low-risk.Based on morphological characteristics，3 cases were as borderline tumor，3 moderate-risk，and 1 moderate-risk.Gene mutation of exon 11 of c-kit were identified in 3 cases.During the follow up ranging from 9 to 80 months，all the 7 patients had cancer-free survival.ConclusionThe biological behavior of cystic GIST is indolent with a low risk of malignancy and favorable prognosis.10 refs，5 figs，1 tab.