Incidentally Detected Microscopic Gastrointestinal Stromal Tumor: Clinicopathological and Immunohistochemical Evaluation of 11 Cases

Abstract

Aim: Gastrointestinal stromal tumor (GIST) originating from interstitial Cajal cells is the most common mesenchymal tumor of the gastrointestinal tract, often located in the stomach, but can be seen anywhere in the gastrointestinal tract. In this study, microGISTs, a preclinical form of GIST; retrospective evaluation was aimed with clinical, histopathological and immunohistochemical findings. Materials and Methods: This study included 11 cases who underwent surgery in our hospital between 2005 and 2017, were diagnosed as microGIST. Results: Three of the cases included in the study were male (27%), eight were female (73%), and the mean age was 59 years. The average lesion diameter was 0,7 cm. All lesions are asymptomatic and detected during surgeries for other reasons. In eight of 11 cases, the lesion was located in the stomach (73%) and three of them in the small intestine (27%). Mitotic activity was observed in only two cases. Spindle cell morphology was detected in all of them. While five of the cases were determined as dedifferentiated (45%), four of them were differentiated by muscle (36%), two of them were differentiated by nerve (19%). There was no risk of progressive disease in any case. In all cases, tumor cells were diffuse positive with CD117 and DOG1 in the immunohistochemical study. Conclusion: MicroGISTs are clinically different and have a pathologically significant low proliferative capacity than other similar tumors. These tumors with benign behavior potential should be kept in mind in the differential diagnosis of spindle cell mesenchymal lesions in the gastrointestinal tract.