Unsuspected gastric glomus tumour.

Gastric glomus tumours (GGTs) are rare predominantly benign, mesenchymal neoplasms that commonly arise from the muscularis or submucosa of the gastric antrum and account for <1% of gastrointestinal soft-tissue tumours. Historically, GGT has been difficult to diagnose preoperatively due to the lack of unique clinical, endoscopic and CT features. We present a case of an incidentally identified GGT in an asymptomatic man that was initially considered a neuroendocrine tumour (NET) by preoperative fine-needle aspiration biopsy with focal synaptophysin reactivity. An elective robotic distal gastrectomy and regional lymphadenectomy were performed. Postoperative review by pathology confirmed the diagnosis of GGT. GGTs should be considered by morphology as a differential diagnosis of gastric NET on cytology biopsy, especially if there is focal synaptophysin reactivity. Additional staining for SMA and BRAF, if atypical/malignant, can help with this distinction. Providers should be aware of the biological behaviour and treatment of GGTs.