label: Placental mesenchymal dysplasia
label_lc: placental mesenchymal dysplasia
description: "Placental mesenchymal dysplasia is a rare anomaly characterized by placentomegaly, dilatation of chorionic vessels and hydropic stem villi with cistern-like formation. It is often clinically mistaken for a partial hydatidiform mole but there is no trophoblastic proliferation. P57 immunohistochemical expression is discordant, showing a normal positive expression in the cytotrophoblastic cells, and loss of expression in the stromal cells."