Differentiating congenital ovarian cysts from other abdominal cystic lesions in female infants: A study by the Canadian Consortium for Research in Pediatric Surgery (CanCORPS)

Purpose: The origin of congenital abdominal cysts in the female fetus often dictates management. While most arise from the ovary and are often managed non-operatively, some are non-ovarian and are frequently removed. We analyzed a national sample of female infants with congenital abdominal cysts to elucidate prenatal and postnatal factors associated with the diagnosis of a non-ovarian cyst. Methods: A retrospective cohort study of female infants who were prenatally diagnosed with abdominal cysts between 2013 and 2017 at 10 Canadian pediatric surgical centres was performed. Clinical characteristics, pre- and postnatal sonographic findings, and cyst trajectories were compared between patients with proven ovarian etiology and those with cysts arising from other organs. Results: Of 185 infants with prenatally diagnosed abdominal cysts, 22 (12%) were non-ovarian, five of which had clear non-ovarian organ of origin on prenatal ultrasound. Comparison of the other 17 cysts with 163 congenital ovarian cysts showed the following factors to be associated with a non-ovarian origin: earlier gestational age at diagnosis (23.5 vs 33.5 weeks, p <0.001), smaller diameter on first prenatal ultrasound (15.8 vs. 39.7 mm, p <0.001), change in sonographic character from simple to complex (87% vs 22%, p <0.001), and postnatal sonographic characteristics of complex cyst (87% vs. 48%, p = 0.004). Conclusion: Clear organ of origin, diagnosis earlier in gestation, smaller initial prenatal cyst diameter, and sonographic cyst character change differentiate congenital non-ovarian cysts from their ovarian counterparts. These characteristics may be used to guide diagnosis and management.