A Rare Mimicker in the Placenta

A 24-year-old primigravida with monochorionic monoamniotic pregnancy presented to our institution at 31+3 weeks of gestation with leaking per vaginum. The ultrasound findings were that of an enlarged and cystically dilated placenta, which raised the possibility of a differential diagnosis of partial mole. In view of foetal distress she was taken up for emergency caesarean section. Two healthy female twins were delivered with no features of Beckwith Wiedermann syndrome. On gross examination the placenta weighed 800 gm and measured 17x15x2.5cm. The two umbilical cords attached measured 20cm and 24cm respectively [Table/Fig-1]. Foetal surface showed prominent, dilated blood vessels. The maternal surface was intact with cotyledons. Tiny, white nodules were seen on the foetal side. The cut surface of the placenta was beefy red with no pale areas. A focal area showed pinkish white vesicle like area [Table/Fig-2]. [Table/Fig-1]: Enlarged placenta (M) 17x15x2.5cm with two umbilical cords. [Table/Fig-2]: Placenta showing multiple grape like vesicles. The umbilical cords showed three vessels each. Multiple sections from the placenta showed villi of varying sizes [Table/Fig-3]. Some of the stem villi appeared markedly hydropic with stromal fibroblast proliferation. Concentric fibrosis was seen around the blood vessels [Table/Fig-4]. There was thick walled blood vessels with organising thrombus formation noted [Table/Fig-5]. Rest of the villi showed chorangiosis like change [Table/Fig-6]. Few villi showed central cistern formation, however, there was no trophoblastic proliferation. Sections from the villi appeared unremarkable. [Table/Fig-3]: Histopathology showed dilated stem villi (H&E 40x). [Table/Fig-4]: Histopathology showed concentric fibrosis in the villi (H&E 100x). [Table/Fig-5]: Histopathology showed organising thrombus (H & E 100x). [Table/Fig-6]: Histopathology showed increased number of blood vessels per villi, showing chorangiosis like change (H&E 200x).