Brunnerʼs Gland Hyperplasia: An Unusual Cause of Biliary Obstruction with Successful Endoscopic Treatment

Abstract

Introduction: Benign neoplasms of the duodenum are uncommon and only about 0.3-4.6% can be found via endoscopy. We present a rare case of Brunner's gland hyperplasia arising from the duodenal bulb and causing biliary obstruction as a result of its intermittent mass effect on the ampulla of Vater. This is only the fourth case of Brunner's gland hyperplasia associated with biliary obstruction that has been reported.Figure: Polyp prolapsing into the second part of the duodenum; gross and endoscopic sonogram.Case: A 69-year-old man presented with several episodes of right upper quadrant abdominal pain, diarrhea, and dark-colored urine over a 3-month period. Physical examination was unremarkable and laboratory investigation revealed elevated liver enzymes as follows: alanine aminotransferase 293 IU/L, aspartate aminotransferase 95 IU/L, alkaline phosphatase 225 IU/L, total bilirubin 2.3 mg/dL, and direct bilirubin 0.79 mg/dL. Hemoglobin and white blood cell count were marginally reduced and viral hepatitis serology, smooth muscle antibody, antinuclear antibody, and mitochondrial antibody were negative. Magnetic resonance imaging (MRI) of the abdomen identified a 3.5 x 1.5 cm ovoid-enhancing intraluminal mass in the second portion of the duodenum with no evidence of intra- or extrahepatic biliary duct dilatation. On upper endoscopy, a large pedunculated polyp measuring approximately 3 x 3 cm was noted in the duodenal bulb with abnormal overlying mucosa and prolapsing into the second portion of the duodenum. The homogeneous mass appeared to arise from the submucosal layer on endoscopic ultrasound, without further invasion into the mucosa. It had a thick stalk, which measured 1.5 cm in diameter. Endoscopic polypectomy was successfully performed and histopathologic examination confirmed a diagnosis of Brunner's gland hyperplasia with no evidence of malignancy. At a 1-month follow-up visit, the patient's symptoms had completely resolved and liver enzymes had returned to normal levels. Discussion: Brunner's gland hyperplasia is a rare benign condition and is usually of no clinical consequence. However, an unusual presentation with biliary obstruction can occur and poses a diagnostic challenge in the differential workup of obstructive jaundice. Resolution of this obstruction can be achieved via endoscopy or surgery depending on features of the polyp.