关键词: 病理学, 免疫组织化学

Abstract: Objective To explore the histopathological and immunohistochemical features of gastrointestinal stromal tumor（GIST）. Methods Histopathological and immunohistochemical detections were peformed in 22 cases of primary GIST with CD₁₁₇, CD₃₄, Desmin,SMA, S-100 protein by SP methods. Results The primary cell morphology consisted of spindle shaped cells and epithelioid cells. Cystification, mucification， hemorrhage or necrosis presented at the same time. The mitotic count was higher than 5/50HPF in 5 cases in which the diameters of tumor were above or equal to 5 cm. Cystification, hemorrage or necrosis were found in 4 cases and mucification in 1 case. The mitotic count was 2-5/50HPF in 2 cases which were epithelioid cell and tumor diameter were 2-4 cm with mucification in 1 case. CD₁₁₇ and CD₃₄ showed diffuse strong expression with immunohistochemical staining, the posit ive rates were 95.5% and 68.2%, respectively. Desmin almost never presented, S-100 protein and SMA focally presented or were absent. Conclusion The morphology of GIST consist of various kinds of cell types and different arrangements. Immunohistochemical staining is positive for CD₁₁₇ and CD₃₄, negative for desmin, focally positive or absent for S-100 protein and SMA. The tumor′s diameters are above or equalto 5 cm, mitotic count is over 5/50HPF, hemorrhage or necrosis might be helpful to identify tumors with malignant potential.

Key words: pathology, immunohistochemistry