[Gastrointestinal stromal tumors. Observations on the basis of 29 cases]

42 gastrointestinal mesenchymal tumors are analyzed by the authors with characterization of immunohistochemistry and DNA study. Out of 42 tumors, 29 GIST 3 leiomyoma, 4 leiomyosarcoma, 3 benign schwannoma, 1 soliter fibrous tumor, 1 inflammatory myofibroblastic tumor and 1 benign haemangiopericytoma were found. All 29 GIST but two could be characterized by c-kit (CD-117) and CD-34 positivity independently weather they displayed focal neurogenic and/or myogenic immunomarkers. In GIST group, 10 cases were benign, 6 borderline and 13 malignant. All benign cases were euploid by DNA study, the malignant tumours were highly aneuploid. Concerning the borderline GIST group by morphology, the aneuploid DNA content may speak for malignant biological behavior, and the diploid DNA content in low grade malignant GIST by morphology may speak for better outcome in the malignant group. There is a discussion about the nomenclature of this morphological group, about the role of the c-kit gene and the necessity of the immunohistochemistry and DNA content determination.