Background/aim: Cholangioblastic variant of intrahepatic cholangiocarcinoma (CVICC) is an exceedingly rare primary biliary tract tumor and typically occurs in young patients with a median age of 24.5-year-old. It can mimic metastatic well-differentiated neuroendocrine tumors in the liver with its similar histologic and immunophenotypic features.
Case report: We hereby report a CVICC in a 68-year-old female patient with distinctive biphasic cytologic features. The patient was diagnosed and treated as a metastatic well differentiated neuroendocrine tumor. The recurrent liver tumor was resected and the tumor cells were strongly positive for Inhibin A and cytokeratin 19 (CK19), focally and weakly positive for synaptophysin and chromogranin, and negative for Insulinoma associated protein 1 (INSM1). Ribonucleic acid (RNA) sequencing showed that the tumor bared a characteristic Nipped-B-like protein (NIPBL)-Nucleus accumbens-associated protein 1 (NACC1) gene fusion.
Conclusion: To the best of our knowledge, this is the first documented case in an elder patient of this entity with NIPPL-NACC1 gene fusion. Acknowledgment of the biphasic cytology, screening with Inhibin A in suspicious cases, and coupled with a molecular study may facilitate accurate classification of this aggressive tumor and lead to proper clinical management.
Keywords: Intrahepatic cholangiocarcinoma; NIPBL-NACC1 fusion gene; biphasic cytology; cholangioblastic variant; inhibin A; liver.
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