Placental mesenchymal dysplasia: a case report and literature review

Abstract

Objective To summarize the clinical, sonographic and pathological characteristics, and the perinatal outcomes of pregnancies complicated by placental mesenchymal dysplasia (PMD). Methods We reported the diagnosis and treatment of a case of PMD in Tianjin Union Medical Center. Pertinent Chinese literatures on PMD were reviewed to analyze the clinical features and the outcomes for mothers and infants. Results (1) Case report: The patient was admitted to our hospital with elevated blood pressure in July 2011 and underwent caesarean section at 30+1 gestational weeks indicated by severe preeclampsia and fetal distress. PMD was diagnosed by placental pathological examination. The patient was discharged from the hospital after oral antihypertensives treatment with stabilized blood pressure. Both the mother and the child were healthy during follow-ups until August 2018. (2) Literature review: A total of 14 cases of PMD were reported domestically including the index case. The average maternal age was 27.9(23-42). Of all the 14 fetuses, half were born alive and half were died in the uterus; two were male, 10 were female and two of unknown sex. Sonographic findings of 10 cases showed thickened placenta with hypoechoic areas. Human chorionic gonadotropin (hCG) was tested in five cases, and the results were all normal. One case was tested for maternal serum alpha fetoprotein (AFP), which was increased. Among the 14 cases, there were two of preeclampsia, six of intrauterine death, three of fetal distress and one of the premature rupture of fetal membranes. Four out of the seven live births were born prematurely. According to the medical record, the average weight of placentas of seven gravidas was 665 g, and eight placentas were larger than the gestational age in size. Pathological examinations showed 11 placentas were covered with grape-like cystic vesicles. No trophoblastic proliferation or stromal trophoblastic inclusion was observed in 12 cases under the microscope. Conclusions PMD is mainly characterized by enlarged and cystic placenta with hypoechoic areas in sonographic findings as well as elevated AFP and normal hCG concentrations in serum. It is more likely to occur in female fetuses with normal karyotype. Placentas with significantly increased size and weight and grape-like cystic vesicles are typical features of PMD that can be detected by pathological examinations. Some gravidas may develop hypertensive disorders of pregnancy and deliver prematurely due to fetal distress, but the maternal and neonatal outcomes are usually good. Close monitoring of the gravidas and fetuses with PMD may help to improve pregnancy outcomes. Key words: Mesoderm; Placenta diseases; Diagnosis, differential; Pregnancy outcome