Placental Mesenchymal Dysplasia

Abstract

Context.—Placental mesenchymal dysplasia is characterized by placentomegaly and may be mistaken for molar pregnancy both clinically and macroscopically because of the presence of “grapelike vesicles.” It may be associated with a completely normal fetus, a fetus with growth restriction, or a fetus with features of Beckwith-Wiedemann syndrome. Objective.—To review the etiology, molecular pathology, gross and microscopic features, clinical presentation, complications, and differential diagnosis of placental mesenchymal dysplasia. Data Sources.—The PubMed and the Medline databases were systematically searched for articles between 1970 and 2006. The following keywords were used: placental mesenchymal dysplasia, mesenchymal hyperplasia, molar pregnancy, pseudomolar pregnancy, Beckwith-Wiedemann syndrome, and placentomegaly. Relevant references from review articles were also searched. Conclusions.—Placental mesenchymal dysplasia should be considered in the differential diagnosis when the ultrasonographic findings show a cystic placenta. Close attention should be paid to fetal morphology for early recognition of fetal complications and to prevent unnecessary termination of pregnancy in cases associated with a normal fetus.

A Challenging Diagnosis: Placental Mesenchymal Dysplasia—Literature Review and Case Report

“…In contrast, in the third trimester, underneath and at the level of the chorionic plate, we can observe broad vascular zones with a turbulent blood flow with either arterial or venous blood [ 48 ]. Further, color Doppler helps to differentiate between PMD and other placental abnormalities with similar sonographic vesicular aspects: chorioangioma (large vessel/increased vascularity), spontaneous abortion with hydropic changes (no vessels), molar pregnancy (high velocity with low resistance flow), complete mole with coexisting normal fetus (the lesion affects the entire placental thickness, the cysts lack blood flow signal, the lesion is beyond the fetal sac), subchorionic hematoma (no vessels), and partial hydatidiform mole [ 48 , 51 , 52 ]. Three-dimensional (3D) ultrasound reconstruction usually demonstrates a multicystic placental mass with cysts that do not communicate with each other, have various diameters and are separate but adjacent to a normal-appearing placenta [ 49 ].…”

Placental mesenchymal dysplasia- A case report

“…Serum ßHCG is normal or slightly elevated, and serum alfa-feto protein is elevated because of increased surface area of placenta in PDM. 14 In patients with PMD, intrauterine growth restriction, intrauterine death, premature delivery, may be due to poor perfusion of the placenta. The complications of the fetus are mainly anemia, thrombocytopenia or microangiopathic hemolysis, which may be related to the abnormal distribution of blood vessels.…”

“…Also abnormal umbilical cords, including tortuous, marked twisted cords, excessively long cords, etc. 3,14 Absence of trophoblastic proliferation in PMD placentas is a histological difference from partial moles. 5 In this case report imaging studies were suggestive of a molar pregnancy.…”

Placental Mesenchymal Dysplasia; Current Understanding of the Sonographic, Histologic, and Molecular Findings of a Rare and Challengin Disorder

“…Microscopic findings include mesenchymal hyperplasia and edema of stem-cell villi, which contain thick-walled vessels (Figure 6). A characteristic feature is the absence of trophoblastic hyperplasia (Figure 7), which is a hallmark of gestational trophoblastic disease [7,10,21].…”

“…In contrast, dilated placental vessels on the fetal side became apparent at 38 weeks [9]. Based on similar sonographic findings of enlarged, and thickened placenta with cystic spaces, PMD is most often mistaken for molar pregnancy, chorioangioma, complete mole with coexisting normal fetus, subchorionic hematoma, spontaneous abortion with hydropic changes and partial hydatidiform mole [10]. The utilization of color Doppler might be helpful in differentiate PMD from other cystic placental abnormalities.…”