Diagnosis of primary hepatic neoplasms by fine-needle aspiration cytology.

This article describes the cytologic features of various primary hepatic neoplasms as seen in fine-needle aspirates. Hepatocellular carcinoma can be differentiated from metastatic carcinoma by its tendency to recapitulate the characteristics of normal hepatocytes, namely, resemblance of the neoplastic cells to liver cells, growth in trabeculae, and bile production. Fibrolamellar hepatocellular carcinoma is characterized by larger, polygonal tumor cells with clearly defined cell outline, deeply eosinophilic granular cytoplasm, and extremely large solitary nucleoli. Lamellae of fibrocytes are seen dividing the tumor cells into small groups. Hepatocellular adenoma and focal nodular hyperplasia exhibit cells that are benign-appearing or minimally atypical. Cholangiocarcinoma is an adenocarcinoma and cannot be differentiated from metastatic adenocarcinoma on purely morphologic grounds. Primary hepatic sarcoma is exceptionally rare and shows malignant spindle cells. Some inflammatory conditions such as abscess, cysts, and tuberculoma often present as space-occupying lesions and should be included in the differential diagnosis of hepatic neoplasm.