Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2013  |  Volume : 56  |  Issue : 1  |  Page : 57--59

Placental mesenchymal dysplasia: A report of two cases with review of literature


Sainulabdeen Sheeja1, Poothiode Usha1, Mohan P Shiny2, Thambi Renu2,  
1 Department of Pathology, Government Medical College, Kottayam, India
2 Department of Pathology, Pushpagiri Institute of Medical Sciences and Research centre, Tiruvalla, Kerala, India

Correspondence Address:
Sainulabdeen Sheeja
Department of Pathology, Government Medical College, Kottayam, Kerala
India

Abstract

Placental mesenchymal dysplasia (PMD) is a recently recognized, rare placental vascular anomaly characterized by placentomegaly and grape-like vesicles mimicking partial molar pregnancy. It is associated with significant fetal morbidity and mortality. We describe the histologic features of PMD in two different cases with different disease outcomes, one in a preterm intrauterine death (IUD) and another in a live birth. Placental examination in both the cases revealed large placenta with multiple vesicles and mesenchymal dysplasia.



How to cite this article:
Sheeja S, Usha P, Shiny MP, Renu T. Placental mesenchymal dysplasia: A report of two cases with review of literature.Indian J Pathol Microbiol 2013;56:57-59


How to cite this URL:
Sheeja S, Usha P, Shiny MP, Renu T. Placental mesenchymal dysplasia: A report of two cases with review of literature. Indian J Pathol Microbiol [serial online] 2013 [cited 2020 Nov 24 ];56:57-59
Available from: https://www.ijpmonline.org/text.asp?2013/56/1/57/116153


Full Text

 Introduction



Placental mesenchymal dysplasia (PMD) is a rare placental vascular anomaly of unknown etiology and resemble partial molar pregnancy. PMD was described by Moscoso et al. in 1991. [1] Since then it is recognized more often and 86 cases have been reported in the literature. [2] The reported incidence of PMD is low with 1 in 500 cases. PMD can be associated with normal fetus, fetus with intrauterine growth retardation (IUGR), or Beckwith-Wiedemann Syndrome (BWS). [3] We report 2 cases of PMD; one is intrauterine fetal demise at 28 weeks of gestation, placental examination showed large vesicles. Second case is PIH complicating pregnancy; cesarean section delivered a preterm female baby. Histopathology was diagnostic of PMD and the disease outcome was different in both cases.

 Case Report



Case 1

A 27-year-old lady, G 3 P 1 L 1 A 1 , came to our emergency department with leaking per vaginum. Her first pregnancy was uneventful and second was spontaneous abortion at 4 months. Now she presented at 28 weeks of gestation and on examination fetal heart was not localized. Speculum examination showed brown colored thick fluid and later was followed by IUD expulsion. Placenta sent for histopathologic examination weighed 300 g. Umbilical cord was normal and there was no gross fetal anomaly. Maternal surface of placenta showed multiple vesicles of varying sizes; largest measured 3.5 cm in diameter. Retroplacental clots were seen. Microscopic examination of the placenta revealed stem villi with edematous and fibrous stroma.

Case 2

A 34-year-old lady G 2 P 2 L 1 with pregnancy-induced hypertension (PIH), presented at 34 weeks of gestation. Renal function tests showed elevated blood urea (60 mg/dl) and uric acid (7.8 mg%). LDH was 699 U/L. Beta-HCG value was normal. Ultrasonogram revealed single live intrauterine gestation with cephalic presentation. Placenta was posterior and liquor adequate. Emergency cesarean done for uncontrolled PIH, delivered a preterm female baby weighing 1.85 kg. Peripheral blood karyotype of the neonate revealed a 46XX. Placenta sent for histopathologic examination weighed 850 g. Maternal surface showed multiple vesicles, largest measuring 2 cm. Microscopy showed enlarged stem villi with cistern formation admixed with normal villi. There were thick-walled blood vessels and focal chorangiosis. Trophoblastic proliferation was absent. Umbilical cord and membranes were within normal limits.

 Discussion



PMD is a rare clinicopathologic entity characterized by enlarged placenta with cystic villi and dilated vasculature. Cystic villi forming grape-like vesicles suggest partial molar pregnancy on gross examination and ultrasonogram. It is associated with significant fetal morbidity and mortality in the form of IUGR and IUD. [4] A definite female preponderance has been noted. Exact etiology is not known. A few hypotheses suggested are congenital malformation of the mesoderm, hypoxia, and hypoperfusion of unknown etiology and androgenetic/biparental mosaicism. [1] These heterogenous factors stimulate the fibroblasts to produce increased connective tissue and release of vascular endothelial growth factor (VEGF). VEGF leads to angiogenesis and vascular malformation. All these contribute to overgrowth of the placental tissue. The female preponderance and relationship to X chromosome can be explained by androgenetic/biparental mosaicism. Literature search revealed 89% of PMD are associated with normal karyotype and about 23% of cases with BWS. [1],[5] Other abnormal karyotypes very rarely associated with PMD are Trisomy 13, Klinefelter syndrome, or 69XXY or triploidy. Placental mesenchymal proliferative disorders, such as chorangioma, chorionic vessel dilation, and hemangioma of the fetus, are also observed in PMD. [4] Most cases have nonspecific clinical features and are diagnosed postpartum because of a large placenta. Other presentations are IUGR, IUD, and BWS.

The USG shows thickened placenta with hypoechoic spaces in both molar pregnancy and PMD. Chorangiomas, subchorionic hematomas, and dilated chorionic vessels are also other sonographic findings. A large cystic placenta along with phenotypically well-formed fetus is more suggestive of PMD. [1],[2] Maternal alpha-fetoprotein (AFP) levels are frequently elevated. Antenatal fetal karyotypying in PMD is diploid and is an important investigation to distinguish it from partial mole, which is triploid. Examination of the accompanying fetus may provide a clue. The fetus in PMD is either normal or show features of BWS. In partial mole fetus is typically growth restricted or show a wide variety of external defects. [6]

On gross examination there is placentomegaly with widely distributed large edematous villi. In both cases placenta were large with widely spaced vesicles [Figure 1]a and b and normal fetuses. Histologic findings irrespective of gestational age are stem villi with loose myxoid stroma and overgrowth of fibroblasts. Similar to stem villi, the terminal villi may also show mesenchymal cell hypercellularity and stromal fibrosis. In between normal appearing and hydropic secondary and tertiary villi are seen. In PMD, placentas at third trimester have dilated and thick-walled chorionic plate vessels with fibromuscular hyperplasia and fresh or organizing thrombi obliterating the lumen. The vessel wall shows some degree of fibrinoid necrosis. The important diagnostic features of PMD include the absence of trophoblastic proliferation, stromal trophoblastic inclusions, and scalloping of the villous surface, which are characteristics of a molar pregnancy. [1],[6],[7] Histopathologic examination of our cases showed enlarged stem villi with cistern formation admixed with normal villi. There was fibroblastic proliferation of the stroma with absence of trophoblastic proliferation. Focal areas of chorangiosis and retroplacental hemorrhages were also seen in our cases [Figure 2]a-e. All these findings confirmed the diagnosis of PMD.{Figure 1}{Figure 2}

We are reporting these cases because PMD still remains unfamiliar to many pathologists and clinicians. This condition has to be distinguished from its mimicker, partial mole. It should be included in the differential diagnosis of cystic lesions of placenta, especially when a phenotypically normal appearing fetus is delivered. A detailed gross and microscopic examination of placenta confirms the diagnosis.

 Acknowledgment



We thank Dr. M.O. Annamma, Professor and HOD, pathology, PIIMS, for her motivation and permission for doing this work. We acknowledge Dr. Sini Das and Dr. Babitha, Junior residents of Pathology, MCH, Kottayam, for collecting the details and doing all the intial work.

References

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