Prenatal diagnosis of an epidermal scalp cyst simulating an encephalocoele.

The majority of extracranial masses detected by prenatal ultrasound screening are encephalocoeles. Several recent publications have drawn attention to extracranial masses which resemble encephalocoeles. The uncertainty in these situations can result in the unnecessary termination of a pregnancy. We report a case of an epidermal cyst of the scalp presenting as an encephalocoele at a routine second-trimester ultrasound scan.