Glomus tumor of the duodenum: a rare case report.

Background: Glomus tumors (GTs) are mesenchymal neoplastic lesions arising from the glomus bodies and generally occur in the fingers and toes. Gastrointestinal GTs are rare, and most of them originate from the stomach; however, GT arising from the duodenum is exceedingly rare.

Case Presentation: A 68-year-old man was admitted due to abdominal pain. Endoscopy showed a round, smooth, elevated mass in the second portion of the duodenum with central ulceration. Abdominal contrast computed tomography showed a hypervascular tumor measuring 26 mm in diameter in the second portion of the duodenum, and pancreatic invasion was suspected. Endoscopic ultrasonography of the lesion confirmed a hypoechoic mass arising from the fourth layer of the duodenal wall. A biopsy was performed for central ulceration, and immunochemical studies showed positive results for smooth muscle actin (SMA) and negative results for S100, C-Kit, and CD34. Leiomyoma or gastrointestinal stromal tumor was suspected and pancreatoduodenectomy was performed. The specimen exhibited a vascular-rich tumor, 24 × 24 × 19 mm in size, with deep ulceration in the duodenum. Histological examination showed uniform small round cells with central nuclei and a pale cytoplasm (glomus cell) with perivascular proliferation. Immunochemical studies showed that the tumor was positive for SMA and collagen type IV, and negative for C-Kit, CD34, desmin, and S100. We diagnosed the tumor as a GT of the duodenum.

Conclusion: GTs of the duodenum are exceedingly rare, but should be considered in the differential diagnoses of duodenal submucosal lesions.