Gastric hibernoma: a novel location and presentation of a rare tumor

We present a case of gastric hibernoma, an unusual tumor with a location novel to the literature. A 39-year-old female presented with one year of upper gastrointestinal bleeding and dysphagia. Gastroenterology performed an esophagogastroduodenoscopy with ultrasound and identified a 6 cm mass within the muscularis propria of the antrum. Computed tomography demonstrated a 9.7 × 7.8 × 4.8 cm(3) heterogeneous antral mass with internal septa. A distal gastrectomy with Bilroth I gastroduodenostomy was performed with 4 cm proximal and 2 cm distal margins. Excision was appropriate to make the diagnosis, exclude malignancy, and remove a symptomatic mass. Hibernoma was confirmed by histopathology. These are rare tumors of brown fat named for their resemblance to the thermogenic tissue found in hibernating animals. They typically present as a slowly enlarging mass of the thigh or shoulder. To our knowledge, this is the first presentation of a hibernoma as a submucosal gastric mass.