Gastric Glomus Tumor: A Rare Gastric Tumor Featuring Small Round Blue Cell; Diagnostic Pitfall for Carcinoid Tumor. (21st September 2018)

• Record Type: Journal Article
• Authors: Dhorajiya, Poojaben; Samuel, Julian; Mahabir, Roshan; Sharabi, Abdelsalam
• Is Part Of: American journal of clinical pathology. Volume 150(2018)Supplement 1
• Page Start: S29
• Page End: S29
• Publication Date: 2018-09-21
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqy090.072
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: The gastric glomus tumor is an extremely rare mesenchymal tumor. Majority of glomus tumors occur in the fingers and the extremities. They are believed to be derived from modified smooth muscle cells of a neuromyoarterial origin known as the glomus body. The stomach has been described as a rare site for glomus tumors. They are usually considered benign and comprise 0.1% to 1% of all gastrointestinal soft tissue tumors. Gastric glomus tumors are submucosal and lack specific clinical and endoscopic characteristics, making preoperative diagnosis often difficult. We present a 73-year-old male who presented with gastroesophageal reflux disease. Endoscopy revealed submucosal gastric antral mass. The gastric mass was locally resected. Gross examination revealed a white well-circumscribed firm mass measuring 1.5 cm in the greatest dimension. Microscopic evaluation demonstrated nests of small round blue cells within the submucosa. The preliminary diagnosis entertained was that of a low-grade neuroendocrine neoplasm (carcinoid tumor). Immunohistochemical stains were positive for synaptophysin but negative for CK7, CK20, DOG-1, C-KIT, S100, pancytokeratin (AE1/AE3), and chromogranin. Further ancillary studies showed that the tumor was positive for smooth muscle actin (SMA) and calponin. As a result, the diagnosis of glomus tumor was made. Synaptophysin has been shown to be positive in 20% of cases of gastric glomus tumors, which may possibly result in these tumors being diagnosed as carcinoid tumors. Gastric glomus tumors have good prognosis, but there have been rare cases of metastases to distant sites such as the liver, lungs, and brain. Thus, careful and close monitoring is required for follow-up. In conclusion, we present a rare case of a gastric glomus tumor exhibiting that careful histologic and immunohistochemical interpretation is vital to make an accurate diagnosis. Gastric glomus tumors are unusual and should be considered a differential diagnosis for a submucosal gastric mass.