Diagnosis and management of pregnancy with placental mesenchymal dysplasia

Placental mesenchymal dysplasia is a rare, benign condition that shows an enlargement of the placenta with multiple vesicles that can resemble a molar pregnancy by ultrasound and gross pathologic examination. Clinical presentation is various, and fetal anomalies and fetal overgrowth can be associated with this condition. MRI could help differentiate between a complete hydatidiform mole with coexistent. We present a case of a 26-year-old patient, primiparous, with sonographically suspicious hydatiform mole. In the 16th week of pregnancy, her β-hCG levels were normal and alpha-fetoprotein values were elevated. TORCH, Parvo B-19, Lysteria, Brucellosis, and TPH were negative. Amniocentesis shoved normal fetal karyotype, and triploidy, e.g. molar pregnancy was excluded. Microarray was also normal. Serial ultrasound exams were performed with normal fetal growth pattern, extremely enlarged placenta, and lower amount of amniotic fluid. MRI showed normal fetal morphology and enlarged, multicystic placenta (AP diameter 99mm). The delivery by emergency Caesarean section was conducted at 31 weeks of gestation due to premature rupture of fetal membranes, spontaneous onset of labour, and fetal asphyxia. An alive female fetus was born, length of 39cm, weight of 1160g, and head circumference of 28cm, Apgar score was 6/7. Placental weight was 1312g, the size was 20 × 19 × 4.5-6cm, with tumour-like formation 12 × 8 × 1cm resembling an old organised hematoma. Placental tissue was diffusely but unevenly permeated with vesicles filled with gelatinous content 5-20mm in diameter. 70% of placental parenchyma was formed from devitalised, degeneratively changed and very enlarged chorionic villi with totally attenuated trophoblast. Regarding possible complications of pregnancy, placental mesenchymal dysplasia requires a comprehensive and multidisciplinary approach.