Placental mesenchymal dysplasia associated with hepatic and pulmonary hamartoma.

This report describes a 31-week stillborn female infant with placental mesenchymal dysplasia (PMD) in association with hepatic mesenchymal hamartoma (HMH) and pulmonary hamartoma. Placental mesenchymal dysplasia was initially misdiagnosed as a partial mole. However, histologically, no trophoblastic proliferation or inclusions were observed. Differential diagnosis of the hepatic mass with similar tumors is discussed. To our knowledge, this is the first case of lung hamartoma reported in a fetus and the first case related to PMD and HMH. A common anomalous development of the mesoderm, a reparative post-injury process and a genetic mechanism, have been proposed to explain their pathogenesis.