Background: An ovarian cyst is one of the most common types of cysts found in neonates. As a result of the introduction of the 20-week screening ultrasound, the detection of ovarian cysts will likely increase.
Case description: An abdominal cyst was detected by ultrasound in a female foetus in her 20th gestational week. This simple cyst remained smaller than 5 cm in diameter so an expectative course was opted for. Six months after her birth, however, the cyst's echographic appearance changed. A necrotic left ovary was resected during a diagnostic laparoscopy.
Conclusion: We recommend taking an expectative approach to asymptomatic simple or complex ovarian cysts, because they usually regress spontaneously in the first year of life. It is important to monitor the cyst by ultrasound and to repeatedly measure tumour marker concentrations as necessary.