Recently, several cases of intraductal oncocytic papillary
neoplasm (IOPN) of the liver and hepatic bile ducts have been reported. The author herein reports the first case of IOPN of the common bile duct (CBD). A 78-year-old man was admitted to our hospital because of
jaundice. Imaging modalities including US, CT, MRI revealed an intraductal
tumor of the middle CBD and biliary dilation distal to the
tumor. A partial resection of the CBD was performed. Grossly, a papillary
tumor measuring 20 × 15 mm was found within the CBD. Mucus is absent. Histologically, the papillary
tumor was composed of atypical oncocytes. The atypia was enough to be diagnosed as
adenocarcinoma. No invasive features were noted. Immunohistochemically, the
tumor cells were positive for pancytokeratins (CK), CK 7, CK 18, CK19, EMA, CA19-9, CEA, mitochondria, p53
protein, C-erbB2, Ki-67 (labeling = 80%), MUC2, MUC5AC and MUC-6,. The
tumor cells were negative for CK8, CK20,
chromogranin,
synaptophysin,
neuron-specific enolase,
S100 protein, CD56, MUC1, CD10 and CDX2. These immunohistochemical findings were compatible with IOPN. The patient died of other non-tumorous disease 7 year after the operation. In summary, the author presented the first case of IOPN of the CBD.