An unusual occurrence of synchronous gastrointestinal stromal tumor and high-grade serous carcinoma of the endometrium - A rare combination

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal (GI) tract and comprise <2.2% of all GI tumors. The incidence of endometrial cancer in India is 1.2%. Among synchronous cancers, female genital tract tumors, mostly endometrioid/ovarian carcinomas, constitute 5% of GIST patients. We describe an unusual case with synchronous occurrence of GIST of the stomach with high-grade serous carcinoma (HGSC) of the endometrium, which was proven by histopathological examination and further confirmed by immunohistochemistry. This is the first case published so far of a patient with synchronous occurrence of low-risk GIST of the stomach with HGSC of the endometrium. The main objective of the study is to present a unique case because we have not found any reports for coexistence of the described neoplasm as in our patient, and we hope that it will be valuable in future investigations about the genesis, diagnosis, and treatment of these types of tumors.