Affiliation: Moscow regions Research Institute of Obstetrics and Gynecology, Medical-Genetics Department, Moscow, Russia.

A 29-year-old (G2P1) woman was referred to our hospital at 21 weeks of gestation because of a suspected presence of a posterior fossa cyst identified during a routine ultrasound examination. The patient and her husband’s medical history were unremarkable. An ultrasound obtained in our hospital revealed a cystic mass measuring 33mm x 30mm with echogenic component of 10 mm. Color Doppler showed no vascularity in or around the mass. There was no ventriculomegaly. The final diagnosis based on ultrasound examination was dural sinus thrombosis, and the parents opted for termination of the pregnancy.