Synchronous Chiari III Malformation and Polydactyly

Chiari III malformation is an extremely rare congenital anomaly. At present, its primary and associated pathognomonic factors remain poorly understood. The authors report a case of a male neonate born with an occipital encephalocoele with herniation of posterior fossa contents associated with bilateral postaxial polydactyly.

The patient is a dichorionic, diamniotic twin conceived via assisted reproductive methods; his twin sister has no congenital anomaly. Neurosurgical management included successful repair of the encephalocoele and subsequent cerebrospinal fluid diversion via a ventriculoperitoneal shunt.

Owing to the uniqueness of this patient's presentation, the concurrent diagnoses of Chiari III malformation and polydactyly are discussed in concordance with updated literature.