S6111 Unmasking a Duodenal Lipoma: When Benign Looks Malignant

Introduction: Ulcerated duodenal lesions are uncommon and often raise concern for malignancy, particularly when they appear to be fungating or ulcerative during endoscopy. Benign lesions, such as lipomas, can mimic this appearance. Endoscopic ultrasound (EUS) plays a critical role in characterizing such lesions and guiding appropriate therapy. Case Description/Methods: A 79-year-old man was referred for an esophagogastroduodenoscopy (EGD) for evaluation of melena. EGD demonstrated a fungating, infiltrative mass with an ulcerated base in the second part of the duodenum (D2) opposite the ampulla. The ulcer base was clear without a visible vessel. The mass was biopsied and sent to pathology. Based on the ulcerated appearance of the mass, the likelihood of malignancy was presumed to be high. Therefore, computed tomography abdomen and pelvis was obtained which revealed a 2.3 cm well-circumscribed fatty lesion within the duodenal wall likely representing a lipoma. Pathology revealed duodenal mucosal fragments and fibrofatty tissue with inflammation and reactive changes. Given the atypical, ulcerated appearance, a liposarcoma component could not be excluded, hence, we decided to perform a repeat esophagogastroduodenoscopy with endoscopic ultrasound (EUS). EUS revealed a 20 × 35 mm hyperechoic mass arising from the submucosal layer with well-defined borders. Since EUS images were highly suggestive of a lipomatous lesion in the setting of symptomatic anemia, a decision was made to perform polyloop assisted endoscopic mucosal resection (EMR). A detachable polyloop was deployed at the base of the lesion for tamponade effect followed by resection using a 33 mm captivator snare. Successful EMR was performed without evidence of residual polyp at the resection site. Pathology was suggestive of submucosal lipoma. The overlying duodenum had fibrofatty replacement with the presence of granulation tissue and ulceration. Additionally, immunohistochemical stain was positive for pan-keratin highlights in the epithelium. Discussion: Symptomatic, ulcerated duodenal lipomas are rare and may appear malignant on endoscopy. An EUS should be considered to rule out a liposarcomal component followed by mucosal resection for symptomatic relief.