Objective: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that express type 3 tyrosine kinase receptors and are thought to develop from the neoplastic transformation of the interstitial Cajal cells. The present study was performed to morphologically and immunohistologically evaluate GISTs, to compare their qualities using a GIST risk categorization system, and to identify the diagnostic and prognostic parameters of GISTs.
Material and methods: A total of 27 patients with GISTs underwent treatment and were followed up at the Gaziosmanpaşa Taksim Training and Research Hospital. Descriptive statistics was used to calculate the mean and median values. Survival analysis was performed by the Kaplan-Meier method. The analyses were performed using the SPSS version 22.0 software.
Results: The mean follow-up time was 3.5 (5 months to 13 years) years. The mean age was 60.4 (29-82) years. The tumors were localized in the stomach (62.9%), extraintestinal areas (14.8%), intestine (7.4%), esophagus (7.4%), and rectum (7.4%). Twenty-four patients were classified according to the Fletcher system. Of these patients, 7 (25.9%) were classified as very low risk, 8 (29.6%) as low risk, 7 (25.9%) as intermediate risk, and 2 (7.4%) as high risk. Twenty-four patients underwent surgery. Of the 3 patients who did not undergo surgery, 1 had metastatic disease at the time of diagnosis, and 2 had mini- or micro-GISTs in the stomach. On endoscopic surveillance, all tumors remained stable. Three out of the 27 patients were lost to follow-up. Two patients developed recurrence, and 1 patient died of GIST.
Conclusion: We analyzed the clinical and pathological characteristics of GIST. The most common site of tumor origin was the stomach. The size, mitotic index, and Ki-67 values were to be found high in intermediate- and high-risk groups and metastatic diseases.