A case of placental chorioangioma diagnosed by scraping cytology

Chorioangioma is the most common benign placental tumor, occurring in approximately 1 percent. Large tumors are but are more commonly associated with maternal and neonatal complications. We report a case which histologic type could be diagnosed by means of scraping cytology after delivery. A 27 year old primipara delivered a female weighing 2, 280 gr. spontaneously at 39 gestational weeks. Her prenatal course was uneventful. Placental weight was 1, 158 gr. as a whole. A large 15×10×8cm-sized mass was attached to the fetal membrane on the maternal surface and another three, 4×4×3, 3×2×2, 2×2×2 cm sized masses were found in the center of the placenta. Scraping cytology showed clusters of cells with oval to spindle shaped nuclei against bloody but clean background. Some clusters had a characteristic feature of blood filled capillary-like structure. These cells were considered to be originated from placental chorioangioma. Histologically, masses were typical chorioangioma and immunohistochemically, factor VIII was positive in the tumor cells by PAP method. The result confirms that the origin of chorioangioma is the fetal vessels. No severe maternal and fetal complication was observed except for slight degree of IUGR, though the size of the tumor was very large.