Combined hepatocellular-cholangiocarcinoma with variable sarcomatous transformation

Area of Science:

• Hepatobiliary pathology
• Oncology
• Surgical pathology

Background:

• Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver tumor with features of both hepatocellular carcinoma and cholangiocarcinoma.
• Understanding the diverse histological presentations and potential transformations of cHCC-CCA is crucial for accurate diagnosis and treatment planning.

Observation:

• A unique adult case of cHCC-CCA exhibiting significant sarcomatous differentiation is detailed.
• Histological analysis revealed distinct hepatocellular carcinoma, cholangiocarcinoma, and various sarcomatous components (spindle-shaped, pleomorphic, osteoplastic).
• Transitional cell morphology was observed between carcinomatous and sarcomatous elements, indicating a potential link.

Findings:

• The tumor demonstrated both independent and concurrent metastatic potential across its different histological components.
• Immunohistochemistry showed keratin positivity in carcinomatous and some sarcomatous cells, but not in osteoplastic immature cells.
• Vimentin staining was positive in a subset of sarcomatous cells, supporting their mesenchymal origin.

Implications:

• The case supports the hypothesis of sarcomatous transformation occurring within combined hepatocellular-cholangiocarcinoma.
• This highlights the aggressive nature and complex behavior of cHCC-CCA, necessitating comprehensive diagnostic approaches.
• Further research into the mechanisms of sarcomatous transformation in liver cancer is warranted.