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Chorionic villus sampling in the prenatal diagnosis of placental mesenchymal dysplasia

2010; Wiley; Volume: 36; Issue: 5 Linguagem: Inglês

10.1002/uog.7666

1469-0705

M. Arigita, M. Illa, Alfons Nadal, Célia Bádenas, Anna Soler, N. Alsina, A. Borrell,

Prenatal Screening and Diagnostics

Placental mesenchymal dysplasia (PMD) is a rare condition presenting with macroscopic features of molar changes, placentomegaly and grape-like vesicles in the placenta, but in contrast to partial mole it can coexist with a normal fetus. Although the karyotype is normal, the fetus is at increased risk for intrauterine growth restriction, perinatal demise, Beckwith–Wiedemann syndrome and liver and skin hemangiomas1-5. Increasing evidence suggests that PMD may originate from a mixed population of androgenetic (paternally-derived genome only) and biparental cells, confined predominantly or exclusively to the placenta6. A 26-year-old Caucasian woman, gravida 2 para 1, was referred to our center at 14 weeks' gestation on suspicion of a partial mole. An ultrasound scan showed an anterior enlarged placenta with multiple vesicle-like images, suggesting molar degeneration, accompanied by areas of structurally normal placenta (Figure 1). The fetal measurements were consistent with the menstrual age and no structural anomalies were detected. Chorionic villus sampling (CVS) was performed at 14 + 3 weeks and two samples were obtained and sent for genetic analysis and for pathological examination. The histopathology was consistent with a partial hydatidiform mole. Quantitative fluorescent polymerase chain reaction (QF-PCR) of chorionic villi revealed the expected triploid (triallelic) profile, whereas both the semi-direct method and long-term culture showed a normal male karyotype. An amniocentesis was carried out at 15 + 2 weeks confirming a normal karyotype. Normal fetal growth and anatomy were observed at the 20-week scan. At 33 + 5 weeks premature preterm rupture of membranes occurred, and labor was induced 5 days later. A male infant weighing 2190 g was delivered with no obvious dysmorphic features at neonatal examination. At 2.5 years of age, the child was developing normally. Ultrasound image of the placenta with multiple vesicle-like features suggesting molar degeneration, accompanied by areas of structurally normal placenta (calipers) at 14 weeks' gestation. After delivery, the placenta was found to be large for gestational age (1702 g) with normal areas coexisting with cystic regions. The chorionic plate vessels were dilated and tortuous, with some of them partly floating in the amniotic cavity (Figure 2). Microscopic examination showed a mixture of normal and abnormal villi. The latter showed stromal cell proliferation with dilated villi and thick-walled vessels (characteristic signs of PMD) but no evidence of trophoblastic hyperplasia (seen in moles). The sample previously obtained by CVS was reviewed and PMD was the final diagnosis. Postnatal QF-PCR investigation was performed in five placental samples—two of which were indicative of placental androgenetic/biparental mosaicism—because of the observed triploid mosaicism pattern in diploid cell lines (XX and XY) demonstrated by interphase fluorescence in-situ hybridization analysis. Section of the partly fixed placenta. The placental disc is thickened with some cystic lesions readily apparent. Abnormal vessels arise from the chorionic plate. The differential diagnosis between PMD and partial mole is crucial to prevent unnecessary terminations of pregnancy, because in contrast to partial moles, in PMD the fetus is usually fully viable. This case report demonstrates the difficulties encountered in the interpretation of unexpected results, particularly when unusual pathologies are involved. Although the final diagnosis was achieved postnatally, pathological examination of chorionic villi obtained by early CVS has proven to be able to provide the diagnosis once the suspicion of PMD has been raised. M. Arigita*, M. Illa*, A. Nadal , C. Badenas , A. Soler ¶, N. Alsina§, A. Borrell* ¶, * Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, Maternitat Campus, Sabino Arana 1, 08028 Barcelona, Catalonia, Spain, Pathology Service, Biomedical Diagnosis Center, Hospital Clinic, Maternitat Campus, Sabino Arana 1, 08028 Barcelona, Catalonia, Spain, Biochemistry and Molecular Biology Service, Biomedical Diagnosis Center, Hospital Clinic, Maternitat Campus, Sabino Arana 1, 08028 Barcelona, Catalonia, Spain, § Hospital Sant Jaume de Calella, Calella de la Costa, Catalonia, Spain, ¶ CIBERER, IDIBAPS