Giant Brunner’s Gland Adenoma Diagnosed by Endoscopic Ultrasound-guided Fine-needle Biopsy

Brunner's gland adenoma is a rare benign duodenal tumor often discovered incidentally during endoscopy.A 48-year-old male presented with weight loss, dizziness, and melena.Endoscopic examination revealed a large, smooth-surfaced, hyperemic polypoid lesion in the second portion of the duodenum.Computed tomography identified a 6-cm hypoechoic mass, and positron emission tomography demonstrated increased F-fluorodeoxyglucose uptake, raising the suspicion of lymphoma.However, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) confirmed the diagnosis of a giant Brunner's gland adenoma.EUS-FNB findings revealed a submucosal mass with clear margins, heterogeneous echogenicity, and cystic components.This case highlights the role of EUS-FNB in distinguishing Brunner's gland adenoma from other submucosal lesions, thereby avoiding unnecessary invasive procedures.Advanced diagnostic techniques are essential in the management of rare duodenal tumors.