Primary Hepatic Mesothelial Cyst: A Rare Entity to Be Considered in the Differential Diagnosis of Neonatal Cystic Lesions.

We report two cases of primary hepatic mesothelial cysts in neonates previously identified during perinatal imaging. Both neonatal cases were reimaged in the postnatal period, demonstrating the persistence of these cystic hepatic lesions. In both instances, the decision was made to treat with surgical resection and both patients tolerated the surgery well with no significant postoperative complications. Histopathological examination of these lesions discovered a cuboidal lining that was calretinin and WT1 positive and CD31 negative, indicating the diagnosis of a mesothelial cyst of hepatic origin. These cases bring attention to the broad differential diagnosis of congenital primary hepatic cystic lesions, as well as the diagnostic pathway to confirm a primary hepatic mesothelial cyst.