Neurofibromatosis type 2 diagnosed in the absence of vestibular schwannomas. A case report and guidelines for a screening protocol for children at risk.

UNLABELLED: A 5-year-old girl presented with multiple tumours of the central nervous system. As on the first MRI scan bilateral vestibular schwannomas were not detected due to their small size, she initially did not meet the criteria for neurofibromatosis type 2 (NF2), although her clinical symptoms were highly suggestive for the diagnosis. Using molecular studies, a mutation in the NF2 gene was found confirming the clinical suspicion at an early age and indicating the value of molecular analysis. Follow-up MRI 3 years later demonstrated bilateral vestibular schwannomas more clearly, since they had increased in size.

CONCLUSION

In children, magnetic resonance imaging can be inconclusive for the diagnosis of neurofibromatosis type 2, since very small vestibular schwannomas may be missed. In these cases molecular studies may provide additional evidence for the diagnosis. We propose guidelines for a screening protocol for children at risk for having neurofibromatosis type 2.