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

Abstract

We describe a 22-year-old woman (2-gravid) case who was referred to our clinic at 18 weeks of gestation for a placenta with vesicular lesions discovered on prenatal examination routine. An ultrasound exam at 31 weeks of gestation showed numerous vesicular lesions, which gradually augmented as the pregnancy advanced. A live normal-appearing fetus was confirmed by intrauterine growth restriction (IUGR). The maternal serum β-human chorionic gonadotropin level remained in normal ranges. At some point, a multidisciplinary medical consensus considered the termination of the pregnancy, but the patient refused to comply. At 33 weeks of gestation, preterm premature rupture of membranes (pPROM) occurred, and she spontaneously delivered a 1600 g healthy female baby with a good long-term outcome. Placental mesenchymal dysplasia (PMD) was retrospectively diagnosed after confronting the data from ultrasound, chorionic villus sampling (CVS), amniocentesis, pathological examination, and immunohistochemical stain. The lack of sufficient reports of PMD determines doctors to be cautious and reserved, approaching these cases more radically than necessary. We reviewed this disease and searched for all cases of PMD associated with healthy, live newborns.

Keywords: alpha-fetoprotein; molar pregnancy; placental mesenchymal dysplasia; β-human chorionic gonadotropin.

Figure 1

Placentomegaly with severe oligohydramnios.

Figure 2

“Swiss-cheese” or “Moth-eaten” appearance of the placenta.

Figure 3

MRI scan showing placentomegaly, with no signs for abnormal adherence and the fetus head.

Figure 4

Doppler showed normal vascularization at 30 weeks of gestation.

Figure 5

Placentomegaly with dilated vessels on the chorionic plate.

Figure 6

Hydropic cysts with features for partial hydatiform mole.

Figure 7

(A) Normal placental villi with intravillous vascularity present and villi with absent vascularity with perivillous fibrinoid. Perivillous hematic overflow HE, 200×;(B) Placental villi with absent intravillous vasculature and circumferential perivascular amyloid deposits. Affected syncytiotrophoblast with scattered cells among fibrinoid deposits, HE, 200×; (C) Normal placental villi, with normal capillary density. Immunohistochemical staining with anti-CD34 antibody (marks capillary endothelium in brown), 200×; (D) Normal p57 expression in the trophoblast, but absent stromal staining in placental mesenchymal dysplasia, IHC staining with DAB chromogen 10×; (E) p53 protein expressed in the nuclei of some trophoblastic cells (p53 wild-type pattern), IHC staining with DAB chromogen 10×; (F). Intense positive cytokeratin 7 staining of the villous trophoblastic cells, IHC staining with DAB chromogen 10×.