Abstract
Placental mesenchymal dysplasia (PMD) is an uncommon placental lesion, which may mimic molar pregnancy at gross and microscopic examination. PMD can be associated with fetal growth restriction, Beckwith-Wiedemann syndrome, intrauterine fetal death, and preterm delivery. Nonetheless, it may also be associated with a normal appearing fetus. We aimed to emphasize that clinicians, radiologists, and pathologists should be aware of PMD as one of the etiologies of intrauterine growth restriction (IUGR). We presented the case of a 27-year-old gravida 1, para 1 woman who was admitted to Ayatollah Rouhani hospital, in Babol, Iran, at 30 weeks of gestation due to severe IUGR and fetal tachycardia. Ultrasound examination showed uteroplacental insufficiency and increased resistive index (RI) of umbilical artery. At last, a normal female fetus (1320 g) with no definitive anomalies was delivered by cesarean section. Pathological examination revealed cystically dilated stem villi with peripherally located thick-walled muscular stem vessels, and also stromal fibroblasts overgrowth in some stem villi. None of the examined sections revealed trophoblastic proliferation or stromal trophoblastic inclusion. The findings confirmed the diagnosis of PMD. Careful radiological and pathological examination should be performed in the case of IUGR for ruling out the rare placental abnormalities, including PMD.