An approach to fine-needle aspiration biopsy diagnosis of hepatic masses.

After reviewing collection techniques and the cytology of normal and reactive hepatocytes, a systematic approach to the evaluation of fine-needle aspiration biopsy smears of hepatic mass lesions is presented. One of the main problems facing the cytopathologist is the differentiation of cirrhosis from well-differentiated hepatocellular carcinoma. Smears from patients with cirrhosis often contain clusters of bile duct epithelial cells and chronic inflammatory cells, while properly sampled hepatocellular carcinoma smears should contain no bile duct epithelial cells and few inflammatory cells. Key criteria which favor the diagnosis of hepatocellular carcinoma over cirrhosis are: increased nuclear to cytoplasmic ratio, trabecular pattern, and atypical naked hepatocytic nuclei. Key criteria which favor the diagnosis of primary hepatocellular carcinoma over metastatic disease include polygonal cells with centrally placed nuclei, cells separated by sinusoidal capillaries, and bile. This systematic approach to the evaluation of hepatic fine-needle aspiration biopsies must be used with the realization that other uncommon mass lesions of the liver do exist (focal nodular hyperplasia, adenoma, hepatoblastoma, bile duct carcinoma, vascular tumors, mesenchymal tumors, and lymphomas).