Glomus Tumor of the Stomach

A sixty-four-year old male patient presented to the emergency room with massive upper gastrointestinal tract bleeding. During distal gastrectomy, a submucosal, well demarcated mass with a diameter of 2.4 cm was palpable in the antral region of the lesser curvature. Histopathological examination of the mass revealed uniform tumor cells with clear cytoplasms and round nuclei, forming nests, strands and sheets between dense, irregularly branching, thin-walled vessels. Immunohistochemistry was positive for vimentin and SMA and negative for cytokeratin, CD34, synaptophysin, chromogranin A, NSE, CD117 (C-kit) and S-100 protein. Electron microscopy demonstrated tumor cells with clear cytoplasms and round nuclei with coarsely dispersed chromatin, forming groups around vascular structures. Clinical findings, gross appearance, tumor pattern, immunohistochemical findings and electronmicroscopic findings were all consistent with a glomus tumor.