The clinicopathological findings of eight children with hepatic adenoma in the absence of cirrhosis are presented. The lesions ranged in diameter from 0.1 to 14.5 cm. Associated disorders were Fanconi's anemia, type I glycogen storage disease. Hurler's disease, and severe combined immunodeficiency with ADA deficiency. The remaining three children had adenoma without known associated disorders. In the children with glycogenosis and Hurler's disease the adenomas were multiple. Significant dysplasia occurred in the two children with Fanconi's anemia; however, the lesions behaved in a benign fashion--one with regression of the tumor after cessation of androgen therapy and the other with nonrecurrence after complete resection. Proliferating cell nuclear antigen (PCNA) labeling index (LI) of the adenoma arising in patients with Fanconi's anemia was significantly greater than the PCNA-LI of adenoma in the other children (mean 4.1% versus 0.9% of nuclei), approaching the lower end of the spectrum for reported hepatocellular carcinoma cases. We emphasize that the worrisome pathology that may occur in hepatic adenoma in children, particularly with Fanconi's anemia, does not necessarily predict malignant behavior. The association of hepatic adenoma with Hurler's disease or severe combined immunodeficiency has not been reported previously.