Cerebral anomalies and Chiari type 1 malformation.

Objective: To analyze the association of diverse cerebral anomalies in a series of pediatric patients with cerebellar tonsillar ectopia.

Methods: We reviewed the medical records of 60 children diagnosed with Chiari type 1 malformation (CM1), of these, 20 patients (11 boys and 9 girls; mean age 7.2 years, range 2-16 years) had an associated cerebral anomaly. Symptoms of tonsillar ectopia evolved over a mean of 12 months (range 3 months to 4 years). Syringomyelia was present in 5 cases. All patients underwent a posterior fossa decompression.

Results: Disclosed anomalies included: congenital hydrocephalus (n = 11), cervicomedullary kinking (n = 5), focal cerebral heterotopia with epilepsy (n = 4), partial agenesis of the corpus callosum (n = 4), hypoplastic brain stem (n = 2), holoprosencephaly (n = 1), and subcortical dysplasia in the context of neurofibromatosis type 1 (n = 1). Other malformations included: subcortical hamartoma associated with neurofibromatosis type 1, craniofacial dysmorphism secondary to Noonan syndrome, congenital occipital plagiocephaly, os odontoideum, craniofacial cleft, juvenile rheumathoid arthritis with platybasia, and osteogenesis imperfecta with bathrocephaly and scoliosis.

Conclusion: Craniocerebral anomalies in children treated for CM1 may be found consistently. The association of hydrocephalus, which was the most common anomaly in this cohort, with cerebellar tonsillar ectopia may contribute to a poor outcome in regard to tonsillar herniation symptoms.