A giant cystic mesenchymal hamartoma of the liver: diagnosis, management, and study of cyst fluid.

A 21-yr-old West Indian woman with a giant hepatic cyst is reported. Preoperative investigations revealed that it was not a simple congenital cyst but that it was highly vascular. Studies of the cyst fluid obtained by percutaneous catheter drainage suggested that the epithelial lining was of bile duct origin. Fluid output was increased by secretin administration, but remained unchanged after amiloride. Bromsulphthalein did not enter the cyst fluid after intravenous injection. A hemihepatectomy was performed and the histologic appearances of the lesion were consistent with cystic mesenchymal hamartoma, a rare lesion in this age group. The patient is well 4.5 yr later.