A rare case of resection of a mucinous cystic neoplasm originating from the extrahepatic bile duct with cholangioscopic imaging

Abstract

A 29-year-old woman was admitted to our hospital for examination of obstructive jaundice and an extrahepatic bile duct lesion. Contrast-enhanced computed tomography revealed a 20 mm cystic lesion with a thin external capsule in the common hepatic duct. Cholangioscopy revealed translucent oval masses with capillary vessels attached to the bile duct walls. The surface was mostly smooth yet partially irregular with redness, suggesting that the masses were epithelial neoplasms. Histological findings of cholangioscopy-guided targeted biopsies of the mass showed subepithelial spindle cell proliferation with no atypical epithelium. The patient underwent an extrahepatic bile duct resection to confirm the pathological diagnosis. Immunohistochemistry of surgical specimens revealed that the spindle cells were positive for estrogen and progesterone receptors. Finally, the cystic lesion with ovarian-like stroma was diagnosed as a mucinous cystic neoplasm with low-grade intraepithelial neoplasia. This is the first report of cholangioscopic imaging of a biliary mucinous cyctic neoplasm. Cholangioscopic imaging can be helpful in the differential diagnosis of biliary neoplasms and in the determination of treatment strategies.

Keywords: biliary cystadenoma; cholangioscopic imaging; extrahepatic bile duct; mucinous cystic neoplasm; obstructive jaundice.

FIGURE 1

Radiological findings of the extrahepatic bile duct lesion. (a) Contrast‐enhanced computed tomography (CECT) revealed a 20 mm cystic lesion with a thin external capsule in the common hepatic duct. (b) Magnetic resonance cholangiopancreatography (MRCP) showed strong hyperintensity in the extrahepatic bile duct on T2 weighted imaging, suggesting that the lesion mainly consisted of a cystic component. (c) Endoscopic retrograde cholangiography (ERC) showing diffuse bile duct dilation and three round contrast defects in the extrahepatic bile duct. (d) Intraductal ultrasonography (IDUS) shows anechoic lesions with a 2–5 mm low echoic external capsule (arrow); however, the bile duct wall is not thickened (arrowhead).

FIGURE 2

Image findings of peroral digital cholangioscopy (SpyScope DS II; Boston Scientific) for the extrahepatic bile duct mass. (a) Cholangioscopic imaging revealed translucent oval‐shaped masses with capillary vessels. The surface was mostly smooth yet partially irregular with redness. (b) Cholangioscopic imaging in proximity. (c) The mass is attached to the bile duct wall (* mass; ** bile duct wall). (d) After targeted biopsy using dedicated biopsy forceps (SpyBite Max; Boston Scientific), the lesion had a small hole.

FIGURE 3

Histopathological findings of the resected specimen. (a, b) Histopathological evaluation demonstrating a layer of cubic and columnar epithelium with few atypical changes in the nucleus. The epithelial cells contain mucin. Furthermore, we observed spindle‐shaped cell proliferation without atypical changes or nuclear division in the stroma. (a) low‐magnification image and (b) high‐magnification image. (c, d) Immunohistochemistry showing that the spindle cells are positive for the estrogen receptor (ER) and progesterone receptor (PgR). The cystic lesion with ovarian‐like stroma was diagnosed as a mucinous cystic neoplasm with low‐grade intraepithelial neoplasia.