Fine needle aspiration cytology of focal nodular hyperplasia of the liver.

In five cases, the fine needle aspiration (FNA) cytologic study of ultrasonically detected solitary liver tumors yielded a diagnosis of focal nodular hyperplasia. Cytomorphologically, the lesions were characterized by the presence of both abundant normal hepatocytes and numerous epithelial cells in ductal formations, clusters or tightly packed groups in the FNA samples. In two of the five cases, the cytologic diagnosis was confirmed by subsequent histologic studies; in the remaining three cases, the clinical data were consistent with focal nodular hyperplasia of the liver. All five patients were women, four of whom had used oral contraceptives for long periods of time (5 to 15 years), which has previously been linked to the development of focal nodular hyperplasia of the liver. Based on the findings in this study, FNA cytology should be adequate for making the differential diagnosis of focal nodular hyperplasia versus liver-cell adenoma when solitary liver tumors are detected in such cases; it can yield a morphologic diagnosis and facilitate the decision as to whether surgical intervention is required.