2016 Volume 30 Issue 5 Pages 895-902
A 63-year-old man was referred to our hospital for intensive examination of a bile duct stricture. Computed tomography (CT) with contrast medium showed the wall thickness of the middle bile duct with contrast enhancement. Endoscopic ultrasound (EUS) revealed malignant-like irregular wall thickness. With endoscopic retrograde cholangioscopy (ERC), stenosis of the middle bile duct was revealed, and intraductal ultrasonography (IDUS) showed cystic lesions of 1-2mm inside the wall. We also performed peroral cholangioscopy, which showed that the surface of the lesions had fine granular patterns with no vasodilation, suggesting inflammatory changes. Though there were no malignant cells detected by histological examination, cancer could not be ruled out, and surgical resection was necessary. Histologically, the lesion was diagnosed as adenomyomatosis of the common bile duct. Case reports of bile duct adenomyomatosis are rare. In most cases, adenomyomatosis of the bile duct is difficult to distinguish from a malignant tumor, but cholangioscopy may be useful to differentiate it from a malignant lesion. There are no reports describing adenomyomatosis of the bile duct that has become cancerous, but histologically, the mucosa of the bile duct showed gastric-type metaplasia, so malignancy could not be ruled out, and surgical resection was recommended. If we can diagnose adenomyomatosis preoperatively, limited surgery should be considered.
