Gastric epithelioid gastrointestinal stromal tumor with signet ring-like cell features: A case report

A gastrointestinal stromal tumor (GIST) with signet ring cell features is a rare variant of epithelioid GIST. The current case demonstrates a 35-year-old woman with a 22.0 cm stomach mass. Tomography-guided core biopsy of the mass showed an undifferentiated tumor with abundant signet ring cells in a myxoid background. A preliminary diagnosis of adenocarcinoma was considered based on histomorphologic features; however, by immunohistochemistry studies the tumor cells were negative for cytokeratins and intensely positive for CD117/c-kit and CD34. Therefore a diagnosis of GIST with signet ring-like cells features was rendered. Making a diagnosis in a small biopsy specimen is always challenging, due to the variable histomorphological features of these tumors.