A Large Growing Occipital Meningocele with Dandy-Walker Syndrome: A Case Report and Review of the Literature.

Background:Dandy-Walker syndrome (DWS) is a well-known developmental anomaly. An occipital meningocele (OMC) is recognized as a malformation that is relatively often associated with DWS, but the association of DWS with OMC has been reported in approximately 40 cases. We present herein a rare clinical course of DWS with OMC, in which the sac was small at birth and became progressively larger.Case Description:A 5-day-old baby boy was referred to our hospital due to OMC. He was born at 33 gestational weeks due to premature rupture of the membranes. He was diagnosed as having DWS associated with OMC. The OMC was covered with skin and its maximum diameter at birth was 3 cm. Magnetic resonance imaging showed an occipital bone defect and continuity of the fourth ventricle, posterior fossa cyst, and OMC sac. The aqueduct was patent, and no hydrocephalus was found. The OMC sac increased progressively with moderate hydrocephalus and reached 7 cm at the age of 54 days when his weight was 2508 g. A cystoperitoneal shunt and repair were performed after sinus venography by contrast computed tomography (CT). At the age of 1 year and 8 months, he had moderate developmental disabilities.Conclusion:In most cases reported, the OMC was relatively small, and large and giant sizes were reported in only six cases. Almost all cases remained the same size as at birth and underwent surgical intervention as early as possible. It was possible to understand the relationship between the occipital bone defect and abnormal running of sinuses such as the superior sagittal sinus, torcular Herophili, and transverse sinus preoperatively from the CT venography (CTV) image. CTV may be an effective and important method for safely performing repair and shunt.