Published online Nov 6, 2019. doi: 10.12998/wjcc.v7.i21.3615
Peer-review started: July 16, 2019
First decision: September 9, 2019
Revised: September 20, 2019
Accepted: October 5, 2019
Article in press: October 5, 2019
Published online: November 6, 2019
Adenomyomatous hyperplasia of the distal common bile duct (CBD) is very rare, with only scarce case reports in the literature. Diagnosis is usually based on imaging findings, and endoscopic biopsy is very difficult before operation. It is believed that adenomyomatous hyperplasia has little or no risk of malignant transformation.
A 68-year-old woman with abdominal pain in the right upper quadrant was referred to our hospital. Abdominal ultrasonography in the emergency ward revealed acute cholecystitis and dilated CBD. Laboratory findings showed elevated levels of transaminases, phosphatase, and γ-glutamyltranspeptidase. Pharmaceutical treatment for 3 d did not relieve the symptoms. Magnetic resonance cholangiopancreatography (MRCP) and computed tomography (CT) showed proximal bile duct dilatation but could not identify the cause. Endoscopic ultrasonography (EUS) demonstrated a mixed echogenic mass in the distal CBD. During surgery, a firm mass was found in the distal CBD and the Whipple procedure was performed with the initial concern of malignancy. Histology showed diffuse adenomyomatous hyperplasia.
EUS may be a useful choice to diagnose adenomyoma of the distal CBD before operation, especially in patients with ambiguous MRCP/CT findings.
Core tip: The distal common bile duct is an extremely rare site of adenomyomatous hyperplasia. Diagnosis is usually based on imaging findings, and endoscopic biopsy is difficult before operation. We present here a rare case of adenomyomatous hyperplasia of the distal common bile duct demonstrated by endoscopic ultrasound, which revealed a nodular change and bile duct wall thickening. We concluded that the mass was a benign, non-neoplastic lesion. This case highlights how endoscopic ultrasound may be a useful choice for the diagnosis of adenomyoma of the distal common bile duct, especially in patients with ambiguous magnetic resonance cholangiopancreatography/computed tomography findings.