P482 Massive parietal skull depression in a late preterm neonate

Case report An 1810 g female was born via emergency caesarean section at 34 weeks gestation to a primigravid 44-year-old mother for the indication of non-reassuring cardiotocograph tracing in the setting of failed induction of labour and premature rupture of membranes. Antenatal history was significant for maternal pre-eclampsia and intrauterine growth restriction with oligohydramnios on ultrasound ten days prior to delivery. The baby was delivered in good condition with Apgar scores of 8 and 10 at one and five minutes. On newborn examination a left parietal skull depression (SD) 3 cm in diameter and 0.8 cm deep was noted with no associated bruising or oedema. The anterior fontanelle was patent and soft. Head circumference was 30 cm. Detailed newborn examination including neurological examination was otherwise unremarkable. The neonate was admitted to the neonatal unit for observation due to prematurity and for investigation of the SD. A skull X-ray revealed a depression in the left parietal bone with no associated fracture and normal bone density. Appearances were consistent with congenital depression due to in utero moulding. An ultrasound of the cranial contents demonstrated a structurally normal brain and ventricular system. Due to the absence of an associated fracture or neurological deficits, no further imaging was performed and the SD was managed conservatively. When seen in the paediatric outpatient clinic at six weeks corrected gestation, normal development and a resolving SD were noted. She will be followed until six months of age as the literature recommends. Discussion Congenital depression of the neonatal skull is rare with an estimated incidence of 1/10,000 in western countries. The majority of cases have been linked to obstetric trauma, however a minority are believed to occur in utero. The cause is usually unknown, however it has been suggested that compression of the soft foetal skull by pressure from the sacral promontory or ischial spines of the maternal pelvis, intrauterine fibroids, myomas or the foetal limbs could result in deformation. In the case described the history of oligohydramnios may have contributed to skull depression by bringing the foetal skull into contact with the solid structures within the maternal pelvis. Proposed treatments for congenital SD include conservative management, surgical and non-surgical interventions. The majority of skull depressions resolve spontaneously, therefore as in this case, in the absence of neurological symptoms a conservative approach of a six-month observation period is recommended.