Gastric Glomus Tumor: Preoperative Diagnosis with EUS/FNA

Abstract

Purpose: Gastric Glomus tumors are rare benign submucosal neoplasms that may be difficult to differentiate, with available imaging modalities including EUS, from the other submucosal tumors of the stomach namely gastrointestinal stromal tumors (GIST), Leiomyomas, Schwannomas, neuroendocrine tumors, etc. The diagnosis, thus, rests on the histological examination and immunohistochemistry. Endoscopic ultrasound with fine needle aspiration appears to be an ideal tool for obtaining material for preoperative diagnosis. A search of literature, however, shows only 2 cases where FNA was successfully employed in obtaining tissue for these tests. We report a case of gastric glomus tumor that was diagnosed preoperatively by EUS/FNA, at our center. Methods: A 44 year old woman presented with vague epigastric pain, dyphagia and nausea. She had had an upper GI barium study at an outside facility showing a filling defect in distal antrum along the lesser curvature of the stomach. A CT scan of the abdomen was ordered and an EGD/EUS was scheduled. The CT scan showed an enhancing, submucosal lesion along the posterior/superior aspect of the gastric pylorus, measuring 3.1 × 2.4 × 2.4 cm with intact underlying gastric mucosa. EUS revealed a 3.5 cm heterogeneous, hypoechoechoic circumscribed mass originating in the 3rd layer, with Doppler evidence of blood flow. FNA was obtained without any complications. Results: The pathology was reported as showing neoplastic epithelioid proliferation with signet ring like features. Immunohistochemistry, however, clarified the diagnosis with demonstration of positivity with smooth muscle actin, muscle specific actin, vimentin and collagen type IV; and negative reactivity with CD117, CD34, S100, keratin, chromogranin and synaptophysin. This immunohistochemical profile supported the diagnosis of glomus tumor. As the tumor exceeded the 2 cm size limit for it to be considered low risk for malignancy, she went on to have surgery with stomach antrectomy. A tumor 3.5 cm in greatest dimension was thus resected. Pathology was consistent with the earlier preoperative diagnosis; and no evidence of malignancy was found. Conclusion: Although in the experience of other operators the FNA and pathology have not always been conclusive in the diagnosis of gastric glomus tumor, our limited experience has been otherwise. This case illustrates a rare neoplasm that was successfully diagnosed preoperatively with EUS/FNA.