Introduction: Segmental neurofibromas affecting the C2 nerve roots in patients with neurofibromatosis type 1 (NF1) can be particularly aggressive, though their clinical course and imaging characteristics are unexplored. The aim of this study was to present clinical and radiological outcomes of C2 neurofibromas in patients referred to a supra-regional NF1 centre.
Methods: Imaging review of regional NF1 referrals 2009-2016. Inclusion criteria: (1) diagnosis of NF1; (2) at least one C2 root neurofibroma; (3) magnetic resonance imaging of the C-spine or whole spine. Multivariate logistic regression analysis was used to identify factors associated with need for surgery.
Results: 54 patients with 106 neurofibromas were included. The median age was 32.5 years (range 15-61 years) and there was a slight male excess (M:F, 33:21). 32% had myelopathy. Neurofibromas were distributed in all spine regions (65%) or the cervical spine alone (22%). Intradural invasion and cord compression in the cervical spine included the C2 level in 95% and 80% of patients, respectively. Compared to all other cervical spine neurofibromas, C2 neurofibromas had higher rates of intraspinal extension (75% vs. 33%; OR = 6.03, 95% CI 3.75 - 9.71; p < 0.001), intradural invasion (53% vs. 26%; OR = 3.13, 95% CI 2.04 - 4.82; p < 0.001) and cord compression (25% vs. 13%; OR = 2.20, 95% CI 1.32 - 3.69; p = 0.003). However, C2 neurofibromas had lower rates of extraforaminal growth beyond the transverse process (12% vs. 63%; OR = 0.08, 95% CI 0.04 - 0.15; p < 0.001). 13% of patients underwent surgery to decompress the C2 level. Factors associated with surgery included myelopathy (p = 0.03) but not radiological cord compression (p > 0.99).
Conclusions: C2 neurofibromas are particularly aggressive tumours due to preferential intraspinal growth.
Patient Care: NF1 is a common hereditary condition. By raising awareness of the aggressiveness of C2 neurofibromas, clinicians working in centres with a lower case load of NF1 patients can better understand the relevance of these tumours.
Learning Objectives: By the conclusion of this session, participants should be able to:
- Appreciate the burden of spinal disease in a series of patients with NF1
- Appreciate neurofibroma growth patterns in the spine, with particular emphasis on the cervical spine
- Appreciate C2 neurofibromas characteristics that make them particularly aggressive compared to other segmental neurofibromas
- Appreciate that radiological cord compression is not always an indication for surgery