Fine-needle aspiration cytology of pediatric patients with primary hepatic tumors: a comparative study of two hepatoblastomas and a liver-cell carcinoma.

The cytologic features of fine-needle aspirates (FNA) of two hepatoblastomas (HBs) and a liver-cell carcinoma (LCC) occurring in three children, ages 1, 3, and 14 yr, are presented. Electron microscopic features of one of the HBs and the LCC are also included. The HBs displayed single or small aggregates or larger clusters of cells with a high nuclear-cytoplasmic ratio and usually round, hyperchromatic nuclei with single, and occasionally double, prominent nucleoli. In addition, one patient had extramedullary hematopoiesis; both had osteoid-like material. These findings were very helpful in differentiating the HB cases from the LCC case, which had features similar to those of adult hepatocytes, including the presence of abundant, finely granular cytoplasm. Ultrastructural studies showed an absence of differentiation into adult hepatocytes in the HB, with scant organelles, rare bile canaliculi, lakes of glycogen, and rare lysosomal bodies. In contrast, the LCC showed features similar to adult hepatocytes, such as abundant cytoplasmic organelles, lysosomes, and bile canaliculi. In addition, intranuclear pseudoinclusions caused by cytoplasmic invagination were present in the LCC but not in the HB. Fine-needle aspiration of hepatic masses in children is a useful technique for rendering a diagnosis, especially in unresectable tumors. Ultrastructural studies on FNA material may be important in differentiating hepatoblastoma from hepatocellular carcinoma.