Mesenchymal hamartoma of the liver.

A surgically treated case of a mesenchymal hamartoma, a rare, benign liver tumor of infants and occasionally children, is reported. The clinical picture is characterized by marked, usually rapid abdominal enlargement. If untreated, the tumor may compromise other organ systems, resulting in death. The treatment is surgical removal. The tumor is characterized by proliferation of collagenous connective tissue, immature mesenchyme, and multiple cysts or pseudocysts of varying sizes. The origin of the tumor has not yet been definitely determined. Ultrasonography combined with radionuclide scanning was useful in establishing a working, preoperative diagnosis.