Placental mesenchymal dysplasia and hepatic cyst.

Placental mesenchymal dysplasia (PMD) is a rare benign vascular anomaly of the placenta. It can be misdiagnosed as a molar pregnancy resulting in unnecessary termination of pregnancy. A 30-year-old woman was referred to our hospital at 18 gestational weeks due to suspicion of molar pregnancy. The ultrasound showed a bulky placenta with multiple cysts. Oligohydramnion and fetal hypoechogenic cystic area without doppler flow were diagnosed at 23 weeks. The baby was operated on after delivery, and an 80 mm multifocal cyst originating from the right lobe of the liver was removed. The placenta demonstrated swelling stem villi with enlarged vessels and increased interstitial cells without trophoblast proliferation. PMD and fetal hepatic cyst can coexist; however, the relationship between those conditions remains to be elucidated. PMD is associated with adverse pregnancy outcomes but also with a good prognosis.