Giant Brunner's gland hyperplasia of the duodenum successfully resected en bloc by endoscopic mucosal resection: A case report

BACKGROUND Duodenal Brunner's gland hyperplasia (BGH) is a therapeutic target when complications such as bleeding or gastrointestinal obstruction occur or when malignancy cannot be ruled out. Herein, we present a case of large BGH treated with endoscopic mucosal resection (EMR). CASE SUMMARY An 83-year-old woman presented at our hospital with dizziness. Blood tests revealed severe anemia, esophagogastroduodenoscopy showed a 6.5 cm lesion protruding from the anterior wall of the duodenal bulb, and biopsy revealed the presence of glandular epithelium. Endoscopic ultrasonography (EUS) demonstrated relatively high echogenicity with a cystic component. The muscularis propria was slightly elevated at the base of the lesion. EMR was performed without complications. The formalin-fixed lesion size was 6 cm x 3.5 cm x 3 cm, showing nodular proliferation of non-dysplastic Brunner's glands compartmentalized by fibrous septa, confirming the diagnosis of BGH. Reports of EMR or hot snare polypectomy are rare for duodenal BGH > 6 cm. In this case, the choice of EMR was made by obtaining information on the base of the lesion as well as on the internal characteristics through EUS. CONCLUSION Large duodenal lesions with good endoscopic maneuverability and no evident muscular layer involvement on EUS may be resectable via EMR.