A hepatobiliary tumor board is reviewing the pathologic and immunohistochemical findings of five distinct hepatic lesions to finalize their diagnoses. Which definitive pathologic diagnosis best matches each histopathologic description and biomarker profile?
- A biopsy of an unencapsulated hepatic mass in a young woman reveals bland hepatocytes in plates 1-2 cells thick, completely lacking portal tracts; immunohistochemistry demonstrates loss of liver fatty acid-binding protein (LFABP) expression.HNF1A-inactivated Hepatocellular Adenoma
- A biopsy of a circumscribed hepatic mass reveals benign-appearing hepatocytes compartmentalized by fibrous septa containing malformed arteries and ductular reactions; immunohistochemistry shows a classic 'map-like' pattern of glutamine synthetase positivity.Focal Nodular Hyperplasia
- A biopsy of a large mass in a cirrhotic liver shows thickened hepatocyte trabeculae ( cells thick) with nuclear atypia; immunohistochemistry is strongly positive for arginase-1, and CD34 staining highlights diffuse capillarization of the sinusoids.Hepatocellular Carcinoma
- A biopsy of a firm, white hepatic mass reveals infiltrating malignant glandular structures inciting a dense desmoplastic stroma; the tumor cells are positive for cytokeratin 7 and mucicarmine, but negative for arginase-1 and HepPar-1.Intrahepatic Cholangiocarcinoma
- A biopsy of a hemorrhagic liver lesion in an older man reveals an infiltrative proliferation of highly pleomorphic, mitotically active spindle cells forming irregular vascular channels; tumor cells are strongly positive for CD31 and ERG.Hepatic Angiosarcoma
Answer
The correct matches pair precise histomorphological patterns and unique immunohistochemical signatures (LFABP, Glutamine Synthetase, Arginase-1, CK7, CD31/ERG) with their corresponding benign, malignant, or vascular primary hepatic neoplasms.
Accurate diagnosis of primary hepatic tumors relies on integrating cellular morphology, architectural patterns (e.g., trabecular vs. glandular), and specific immunohistochemistry. HNF1A-inactivated adenomas uniquely lose LFABP expression. Focal Nodular Hyperplasia displays characteristic map-like glutamine synthetase positivity. Hepatocellular Carcinoma is confirmed by arginase-1 and diffuse CD34 sinusoidal capillarization. Intrahepatic Cholangiocarcinoma shows a biliary phenotype (CK7+, mucin+) with intense desmoplasia. Hepatic Angiosarcoma is identified by malignant endothelial channels expressing CD31 and ERG.
Step-by-Step Solution
Key Concept
Integration of morphologic patterns with specific immunohistochemical markers is required to accurately subtype hepatic neoplasms and distinguish benign mimics from aggressive malignancies.