Intramedullary and spinal canal tumors in patients with neurofibromatosis 2: MR imaging findings and correlation with genotype

PURPOSE: To determine the appearance of spinal tumors on magnetic resonance (MR) images of patients with neurofibromatosis 2 (NF2), to assess the biol ogic behavior of these tumors, and to determine the correlation between NF2 germline mutations and these tumors. MATERIALS AND METHODS: Spinal MR images in 49 patients with NF2 were review ed retrospectively. Intramedullary and intradural extramedullary tumors wer e counted, and imaging features and growth patterns of intramedullary tumor s were determined. Medical records were reviewed for spinal tumor surgery. Data on spinal tumors and NF2 germline mutations in 37 patients from 19 fam ilies were analyzed for genotype-phenotype correlation. RESULTS: Thirty-one patients (63%) had spinal tumors: Twenty-six (53%) had intramedullary tumors, 27 (55%) had intradural extramedullary tumors, and 2 2 (45%) had at least one tumor of each type. Three (12%) patients with intr amedullary tumors versus 16 (59%) with extramedullary tumors had undergone surgery for the respective types of tumors. Compared with patients with all other types of mutations, a higher percentage of patients with nonsense an d frameshift mutations had intramedullary tumors (P < .025); these patients also had higher mean numbers of all tumors (P < .001), intramedullary tumo rs (P < .001), and nerve sheath tumors (NSTs) (P < .001). CONCLUSION: in patients with NF2 and spinal tumors, extramedullary tumors ( predominantly NSTs) were present in higher numbers and were associated with more surgery than were intramedullary tumors. Our data suggest that the as sociation between nonsense and frameshift mutations and severe NF2 may exte nd to specific categories of spinal tumors.