Answer
From question on page 1409
At this point, the diagnosis of intraductal polypoid lesion was suspected, and the patient underwent common bile duct exploration that revealed a polypoid tumour protruding from the left hepatic duct (LHD). A left liver resection combined with en bloc resection of the extrahepatic biliary tree was performed. The resected specimen contained a solitary polypoid tumour (12×12×48 mm in size) originating from the LHD, spreading into the lumen and protruding into the main hepatic duct (fig 1). Tumour histology revealed mixed patterns of both cholangiocellular and hepatocellular carcinoma of the LHD without any extension beyond the subserosal layer. Additionally, immunohistochemical examination was positive for cholangiocarcinoma markers within the cholangiocellular component. Liver histology showed features of major cholestasis but no cirrhosis. Thus, the diagnosis of intraductal mixed hepatocellular‐cholangiocarcinoma (MHC) was established (fig 2,3).
Figure 1 Macroscopic appearance of the polypoid tumour originating from the left hepatic duct, spreading into the lumen and protruding into the main hepatic duct.
Figure 2 Microscopic view of the tubular pattern of the cholangiocarcinoma component (H&E, X400).
Figure 3 Microscopic view of the trabecular pattern of the hepatocellular carcinoma component (H&E, X400).
Intraductal polypoid tumours are mainly represented by papillary‐type cholangiocarcinoma and hepatocellular carcinoma with bile duct invasion. MHC is known as a rare primary liver tumour that is usually associated with chronic liver disease. The lesion behaves as a parenchymal mass and has characteristic biological markers and radiological features according to the predominant component. Curative treatment involves liver resection. In contrast, intraductal MHC originates from the bile duct, leads to biliary obstruction, and necessitates a combined liver and bile duct resection for complete excision. Its prognosis is not known.