Placental Mesenchymal Dysplasia with Fetal Gastroschisis

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Placental mesenchymal dysplasia (PMD) is a rare, benign condition characterized by placentomegaly and abnormal chorionic villi with vesicle formation, fibroblastic hyperplasia, and vascu-lar abnormalities. This condition can be misdiagnosed as molar pregnancy due to similar ultrasonographic findings; 1 however, unlike molar pregnancy, a fetus is usually present and there is no risk of trophoblastic proliferative disease in PMD. The authors report a case of placental mesenchymal dysplasia at 15 weeks of gestation associated with fetal gastroschisis and high serum beta human chorionic gonadotropin (β-hCG) that mimicked molar pregnancy. A 29-year-old female with abnormal ultrasonographic findings was transferred to our institution. The patient had a normal sequential screening with the exception of an elevated serum β-hCG of 165,870 mIU/mL. Serum α-fetoprotein was not evaluated. Transabdominal ultrasound at 14 +0 weeks of gestation revealed a thick globular placenta measuring 6.5×4.5 cm with multiple small, hypoechoic areas. Subsequent ultrasound at 14 +5 weeks of gestation demonstrated a large multicystic honeycomb like placenta measuring 8.8×5.7 cm with no sign of blood flow within the lesion (Fig. 1A). A fetus was identified with a crown-rump length of 9.6 cm (Fig. 1B). Based on the clinical setting, partial hydatidiform mole was suspected. Therapeutic termination was performed at 15 +0 weeks of gestation. Grossly, the placenta was markedly enlarged with a diameter of 10 cm and the placental disc had multiple cystic vesicles; enlarged chorionic vessels were not found (Fig. 1C). A nonviable male fetus with a body weight of 73.57 g and with a crown-rump length of 9.8 cm, which were appropriate for gestational age, was delivered. However, he had a left lateral abdominal wall defect from which the liver and bowels protruded (Fig. 1D). Microscopic examination of the placenta revealed several enlarged villi with cistern formation and abnormally thick vessels scattered among normal-sized terminal villi without abnormal trophoblast proliferation. Some chorionic villi showed proliferation of primitive stromal cells (Fig. 2A–C). Cytotrophoblasts were diffusely positive for p57KIP2 on immunohistochemical staining (Fig. 2D). Macroscopic and microscopic morphology confirmed a diagnosis of PMD accompanied by gastroschisis of the fetus. DISCUSSION PMD was first described as a rare, benign condition associated with an enlarged placenta in 1991 by Moscoso et al. 2 …