Human chorionic gonadotropin-positive cystic duct carcinoma with trophoblastic differentiation that exhibited an...

A man in his 60s diagnosed with perihilar cholangiocarcinoma underwent radical surgery. CT on postoperative day 26 showed multiple liver metastases in the remnant liver that rapidly grew and spread to the entire liver. The patient died 70 days following surgery due to highly aggressive tumour progression. In the surgical specimen, the tumour at the margin was histologically identified as predominantly conventional adenocarcinoma, but a few components of the invasive carcinoma and liver metastasis exhibited significant nuclear atypia and rich cytoplasm. The autopsy revealed human chorionic gonadotropin (hCG)-positive multinucleated tumour cells like syncytiotrophoblast with haemorrhage at the metastatic sites in the liver, which finally diagnosed with cystic duct carcinoma with trophoblastic differentiation. hCG-positive carcinomas with trophoblastic differentiation generally carry poor prognoses. For those with significant nuclear atypia and rich cytoplasms with haemorrhage, additional immunostaining for hCG and progression to trophoblastic differentiation should be considered.