Cystic mesenchymal hamartoma arising in intrathoracic heterotopic liver: a case report.

Intrathoracic heterotopic liver tissue is an exceedingly rare clinical entity. In most patients, it is associated with other congenital defects, including cardiac anomalies, congenital diaphragmatic hernia, pectus excavatum, and intralobar pulmonary sequestration. Although heterotopic liver could potentially lead to the same benign liver diseases that can affect the mother liver, the association of heterotopic liver tissue with tumors in childhood is extremely rare. We describe a unique case of cystic mesenchymal hamartoma arising from an intrathoracic heterotopic liver that was found incidentally during a diaphragmatic eventration repair. Association of ectopic liver tissue with mesenchymal hamartoma has not previously been reported in the literature.