Metastatic Gastrointestinal Stromal Tumor to the Omentum and Endometrium: A Case Report

Gastrointestinal Stromal Tumor (GIST) is an uncommon stromal malignancy of Gastrointestinal (GI) tract. GISTs have been increasingly reported in sites other than GI tract. Currently, GISTs are considered metastatic when they occur outside GI tract; however, there is a possibility of a primary stromal tumor of omentum and/or gynecologic tract with similar mutation profile and histopathology but different prognosis and clinical behavior. Here, we report a case of 52-year-old female with widespread lesions in her abdomen and pelvis, which turned out to be a GIST; however, no lesions were identified in the GI tract which raises the possibility of omental or ovarian primary stromal tumor. Since GISTs are mutation derived tumors, it is highly likely that the stroma of other locations can undergo similar tumorigenesis due to mutations in c-KIT and/or PDGFRA genes and present similarly to primary GI tract GISTs. More studies are required to look for other possible primary sites and difference in clinical behavior and prognosis to appropriately stage the patient before treatment, as GISTs that occur outside GI tract tends to behave aggressively and are usually resistant to imatinib therapy. Keywords: Gastrointestinal stromal tumor; Omentum; Endometrium; Metastasis; Epithelioid; Carcinomatosis