Primitive cystic hepatic neoplasm of infancy with mesothelial differentiation: report of a case.

A malignant cystic neoplasm in the liver of a 6-month-old girl is reported. The neoplasm has unique clinical and morphological features, and despite ultrastructural and immunohistochemical studies, the tumor could not be clearly classified as any known primary hepatic neoplasm of infancy. A differentiated cystic component of the neoplasm had features of cystic peritoneal mesothelioma. Alpha-1-antitrypsin and alpha-fetoprotein were demonstrated in solid, anaplastic portions of the recurrent tumor by immunohistochemistry. The neoplasm recurred after surgical resection and proved fatal 11 months following diagnosis, despite multiple courses of chemotherapy.