Histopathological And Immunohistochemical Characteristics Of Gastrointestinal Stromal Tumors And Risk Group Analysis

Aim: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract. GISTs are thought to originate from the precursors of interstitial Cajal cells which regulate gastrointestinal peristaltism. GISTs include a group of heterogeneous tumors with different morphology and biologic behavior so their epidemiology, clinico-pathological features and prognosis is distinct in different countries. The aim of this study is to analyze the histopathological, immunohistochemical characteristics and risk groups of 100 patients with GIST in the last 10 years in our depertment. Patients and Methods: Between 2006-2016, 100 patients with GIST diagnosed in our Pathology laboratory were examined retrospectively. Risk groups were determined according to diameter and mitotic rates of the cases. Histopathologic and immunohistochemical features excluding diameter and mitosis were analyzed and the relationship between risk groups was analyzed. A Chi-care- Fischer was used for descriptive statistical analysis. Results: In our cases, there is no relationship between age, gender and risk groups. Colorectal, extra gastrointestinal system (peritoneum, mesentery and retroperitoneum), small intestine and stomach GISTs are in high risk group respectively. Small intestine, colorectal and extra gastrointestinal system tumors are larger diameter than stomach tumors. There is no relationship between immunohistochemical CD-34, S-100, SMA, desmin and risk groups. Tumors expressing over 10% of Ki-67 are in high-risk group. Stomach and extra gastrointestinal tumors represent more CD-34 expression. Tumors with necrosis, haemorrhage and high cellularity are at higher risk group. There is no relationship between risk groups and ulceration, growth pattern and atypia. Conclusions: GISTs are rare tumors of the gastrointestinal tract and may occur in different regions, in different variations. Detailed histopathologic and immunohistochemical examination of the GİSTs