Clinical And Pathological Study Of Gastrointestinal Stromal Tumors And Leiomyomas

Background: Traditionally, the gastrointestinal mesenchymal tumors (GIMTs) have been almost uniformly classified as gastrointestinal smooth muscle tumors (GISMTs). However, recent evidence indicates that most mesenchymal tumors of the gastrointestinal (GI) tract are referred to as gastrointestinal stromal tumors (GISTs). Differentiating between GISTs and GISMTs is important clinically because GISTs frequently have malignant potential.Objectives: To study the clinicopathological and immunohistochemical features of GISTs and leiomyomas (LMs), and explore the value of the immunohistochemical stain in the diagnosis.Methods: Forty-nine patients with gastrointestinal mysenchymal tumors were reclassified. Their clinical data were reviewed, and their morphologic characteristics were studied by endoscopy, endoscopic ultrasonography and light microscopy. The expressions of GDI 17, CD34, SMA, h-caldesmon (HCD) and Ki-67 were detected by immunohistochemical method.Results: Among 27 cases of GISTs, there were 14, 4 and 9 cases in the stomach, intestine and esophagus, respectively. Their ages ranged from 19 to 80 years (median 58 years). Microscopically, the tumors showed two basic cell compositions with spindle cells and epithelioid cells. GISTs tended to have a higher degree of cellularity and a lesser degree of cytoplasmic eosinophilia man observed in leiomyomas. Immunohistochemically, most GISTs were diffusely positive for GD117 (24 of 27) and for CD34 (20 of 27). However, among 22 cases of LMs, there were 20 and 2 cases in the esophagus and stomach, respectively. Their ages ranged from 28 to 71 years (median 42 years). Immunohistochemically,all cases were strongly positive for SMA, and were negative for CD117 and CD34. The expression of Ki-67 in GISTs was significantly higher than that in LMs (PX).05).Conclusions: The most common gastrointestinal mesenchymal tumors are GISTs, whereas leiomyomas are more common in the esophagus. GISTs and leiomyomas have clinicopathologic differences. Immunohistochemical markers (particularly CD117 and CD34) are useful to differentiate GISTs and leiomyomas. The cell proliferation activity in GISTs was higher than that in LMs.