An Unusual Case of Gastric Submucosal Tumor: Glomus Tumor

A 36-year-old woman presented with a 10-day history of epigastric pain that was exacerbated by hunger and at night. Laboratory tests showed mild anemia. Gastroscopy revealed a 2.5-cm crater-like lesion on the posterior wall of the greater curvature of the antrum, with a central ulceration measuring 1.2 x 1.0 cm, suspected to be a gastric submucosal tumor (SMT). Endoscopic ultrasonography identified a mixed echogenic mass measuring 3.0 x 2.7 cm, originating from the muscularis propria and submucosa, initially thought to be a heterotopic pancreas. Endoscopic submucosal excavation was performed for removal. Histopathological analysis showed the tumor was composed of glomus cells, with round, centrally located nuclei and indistinct cell borders, arranged around dilated blood vessels. Immunohistochemical staining was positive for SYN, SMA, and H-caldesmon, but negative for CK, CgA, DOG-1, S100, and desmin. A diagnosis of glomus tumor was confirmed. Follow-up gastroscopy over the next 3 years showed no recurrence.