Combined hepatocellular-cholangiocarcinoma. Diagnostic challenge in hepatic fine needle aspiration biopsy.

OBJECTIVE

To study the cytohistologic features of combined hepatocellular-cholangiocarcinoma (CHCC-CC) in fine needle aspiration biopsy (FNAB) material.

STUDY DESIGN

Six hepatic FNAB cases with cell blocks (five) and hepatic resections (two) were analyzed cytohistologically and immunohistochemically.

RESULTS

The six cases were diagnosed as CHCC-CC based on clinicopathologic correlation. Unequivocal hepatocellular carcinoma (HCC) cells corresponding to Edmondson and Steiner's grade 3 lesions were identified in the FNAB in three instances. Adenocarcinoma, represented by cohesive columnar cells with ovoid, basal nuclei displaying nuclear palisading, acini and/or papillary structures with variable intracytoplasmic intraacinar or brush border mucin production, was identified in all cases. Intermediate cells with hybrid/polymorphic cytologic features straddling malignant hepatocytes and glandular cells were identified in five instances. Tissue alpha-fetoprotein was negative. There was brush border and/or diffuse cytoplasmic p-carcinoembryonic antigen immunoreactivity in the glandular elements.

CONCLUSION

FNAB diagnosis of CHCC-CC is possible if the clinical, cytohistologic and immunohistochemical findings support the presence of HCC and adenocarcinoma. Intermediate cells pose a great challenge to recognize and define: they tend to lose the classic cytologic features of malignant hepatocytes and acquire glandular characteristics. At the very least, there should be a high index of suspicion. These cases underscore the necessity for clinicopathologic correlation in enhancing the precision of FNAB diagnoses.