Establishing the First Diagnosis of Hepatocellular Carcinoma in Lung Biopsy in a 47-Year-Old Man: A Case Report

Abstract

Hepatocellular carcinoma (HCC) is a primary tumor of the liver.  The most common metastatic sites include lung, lymph node, and bone. The diagnosis of HCC is usually through radiological examination and liver biopsy. The first diagnosis of HCC through a metastatic site is very rare. Here, we report a case that the first diagnosis of HCC was not through liver biopsy, but rather by a lung biopsy. The patient was a 47-year-old man with elevated AFP level. Abdominal CT and MRI showed liver nodules and lung nodules. A liver biopsy was performed, showing cirrhotic liver with extensive fibrosis. No malignancy can be identified. A lung biopsy was performed. Microscopic examination showed abundant polygonal cells with eosinophilic cytoplasm forming trabecular pattern with endothelial wrapping. These cells are positive for HepPar-1, and focally positive for Glypican-3, and negative for CK7, CK20, TTF-1, Napsin A, synaptophysin and chromogranin, consistent with metastatic hepatocellular carcinoma. The negative staining results of PAX-8, CD10, and EMA do not support differential diagnosis of metastatic renal cell carcinoma. This case raises the awareness that the first diagnosis of HCC can be through a metastatic site, especially when well-differentiated HCC is difficult to distinguish from benign hepatic masses, such as macroregenerative nodules, adenoma, or focal nodular hyperplasia. [N A J Med Sci. 2025;18(1):005-008.   DOI: 10.7156/najms.2025.1801005]

Key Words: Hepatocellular carcinoma (HCC), well-differentiated HCC, immunohistochemistry, Glypican-3, HepPar-1