Abstract:Objective:To investigate the clinicopathologic characteristics, diagnosis and treatment of gastrointestinal stromal tumor (GIST).
Methods :Clinical data of 218 patients with GIST who underwent surgical en bloc resection were analyzed retrospectively. Light microscopy was used to study the morphologic characteristics, and the expression of CD117, CD34, S-100, Vimentin (VIM), and smooth muscle actin (SMA) was detected by S-P immunohistochemical method.
Results:The primary sites of GIST were in stomach in 69.7%(n=152), in small intestine 12.4%(n=27), in colorectum 13.8%(n=30), and in esophagus 4.1%(n=9). Among them, malignant tumors accounted for 53.2% (n=116). Most of GIST patients initially presented with an abdominal mass and alimentary tract hemorrhage. In addition, the diagnosis was confirmed by histopathology and immuno-histochemistry in all the patients. CD117 showed diffuse strong expression, CD34 and VIM often showed diffuse strong expression, and SMA and S-100 occasionally showed focal expression, and the positive rates were 100%, 76.2%, 38.1%, 4.8%, and 4.8%, respectively. There was no significant difference in the expression of CD117, CD34, S-100, VIM, and SMA protein in benign versus malignant GIST (P＞0.05). Fifty-eight GIST patients who were treated surgically were followed up from six months to three years. Nineteen patients had recurrent malignant disease, and 5 of them were managed with further surgery.
Conclusions:CD117 is a sensitive and specific marker for the diagnosis of GIST, but immunophenotype is not a predictor of the malignancy of GIST. Surgical resection, including en bloc resection of the tumors, is the only curative treatment.