Hepatic mesenchymal hamartoma in a neonate: a case report and review of the literature.

To describe an unusual presentation of mesenchymal hamartoma in a critically ill neonate necessitating a novel therapeutic embolization before definitive resection. An unusual presentation of a large hepatic mass in a newborn complicated by pulmonary hypertension and vascular "steal" with renal insufficiency is presented. The mass was initially successfully embolized, but then revascularized, necessitating resection in an attempt to improve the clinical status of the critically ill neonate. The resected mass was a mesenchymal hamartoma with a necrotic center and extensive arterial collateralization. The patient began improving immediately after resection. Mesenchymal hamartoma may present in the neonate as a diagnostic dilemma. This is the first case report describing persistent pulmonary hypertension and renal compromise from this tumor. Embolization as a therapeutic modality to address this tumor is described. The cause of the persistent and severe pulmonary hypertension remains unclear,but may be related to the tumor.