S3013 The Two Challenges in Management of Gastric Glomus Tumors

Abstract

INTRODUCTION: Gastric glomus tumors (GGTs) are rare gastrointestinal lesions originating from the neuromuscular arterial canal or vascular lumen which share many overlapping features with other stromal lesions. Even though most cases of GGTs are benign, there is lack of reliable histological features predictive of tumor behavior. CASE DESCRIPTION/METHODS: A 42-year-old male with hypertension and gastroesophageal reflux disease presented with a history of intermittent left upper quadrant pain and non-bloody, non-bilious emesis. He was afebrile and had a soft, non-distended abdomen. Labs were notable only for mild iron deficiency anemia. Contrast-enhanced computed tomography (CT) of the abdomen showed a 3.2 × 2.7 × 3.1 cm soft tissue mass with central calcification and vascularity along the lesser curvature of the stomach. Esophagogastroduodenoscopy (EGD) demonstrated a 3 cm submucosal ulcerated mass at the incisura (Figure 1). Endoscopic ultrasonography (EUS) showed a well-defined hypoechoic lesion arising from the muscularis propria, with maximum diameter of 3.3 cm (Figure 2). Further investigation with fine needle aspiration (FNA) of the lesion demonstrated – small, round and uniform cells intermixed with capillary-sized vessels along with in-tumor-calcification, mild pleomorphism, and sparse Ki67 staining, but no evidence of mitotic activity (Figure 3A) which demonstrated positivity for smooth muscle actin and synaptophysin and weak stained for placental alkaline phosphatase suggestive of a glomus tumor (Figure 3B). The tumor cells lacked markers more indicative of an epithelioid gastrointestinal stromal tumor including: CD117, CD34, Desmin, S-100, and DOG1. After discussing surveillance versus endoscopic/surgical resection options with the patient, surgical wedge resection of the tumor was performed for definitive management. Pathology of excision specimen was consistent with a benign gastric glomus tumor. DISCUSSION: GGTs pose two challenges: 1) differentiation from more common stromal/mesenchymal tumors and 2) prediction of tumor behavior. In our patient, although EUS and FNA showed small benign cells, given the patient’s young age, symptomatic presentation, ulcerated lesion appearance and neovascularity, we proceeded with resection after shared decision making. Given the rarity of GGTs, this case highlights the importance of establishing an accurate diagnosis and the various factors that must be taken into consideration to best determine malignant potential.Figure 1.: A) EGD of pre-pyloric stomach showing multiple, small non-bleeding erosions near the antrum (yellow arrows). B) EGD showing a large, submucosal mass with no bleeding and no stigmata of recent bleeding was found at the incisura (yellow arrows).Figure 2.: EUS showing a hypoechoic mass in the stomach incisura angularis (yellow arrows).Figure 3.: A) Hematoxylin and Eosin (H& E) staining of FNA (30x magnification). B) Smooth muscle actin (SMA) stain on FNA specimen which is characteristically positive in glomus tumors (16x magnification).