Chiari type 1 malformation in neurofibromatosis type 1: experience of a center and review of the literature

OBJECTIVE: To evaluate the possible correlation and the true incidence between Neurofibromatosis type 1 and Arnold-Chiari malformation type I. MATERIALS AND METHODS: We reviewed all clinical charts, neurological consultations and MRI scans of 428 NF1 patients followed by 1994 to 2014 in our Department. NF1 patients in our clinic are seen usually every year by both the dermatologist and the neurologist. All patients also undergo a brain and spinal cord with the same 1.5 Tesla MRI scan. RESULTS: We found a diagnosis of Arnold Chiari malformation type I in 9 of the 428 NF1 cases (2%). CONCLUSION: This frequency is higher than that expected on the basis of a chance association. Therefore we underline the importance of serial MRI studies in patients with NF1 to assess the presence of cranio-cervical anomalies. Future studies should try to better understand what are the pathogenetic mechanisms underlying this close association.