Hepatoblastoma. Report of a case with cytologic, histologic and ultrastructural findings.

Hepatoblastoma, although rare, is the most common primary malignant neoplasm of the liver in children. In this paper we describe a case of hepatoblastoma with unusual cytologic features and present the histologic, immunocytochemical and ultrastructural features of this neoplasm. A 7-month-old girl presented with a large hepatic mass and metastatic nodules in both lungs. Intraoperative biopsy revealed a hepatoblastoma. Aspiration biopsy yielded a highly cellular aspirate with cords of pleomorphic cells embedded in a mucoid matrix. Histologic sections showed a diffusely infiltrative neoplasm composed of sheets and cords of highly pleomorphic cells. The neoplastic cells stained strongly positive for cytokeratin CAM 5.2 and AE1 and focally positive for a-fetoprotein, ferritin, carcinoembryonic antigen and vimentin