The experience in dealing with abnormal signal intensities in Children with Neurofibromatosis type 1

Abstract Background: We sought to define the radiologic features which could differentiate non-neoplastic from neoplastic T2 hyperintensities (T2Hs) identified on MRI in children with neurofibromatosis type 1(NF1) and identify lesions that most likely to require oncologic surveillance. Methods: We conducted a single-center retrospective review of all available brain MRIs from 49 children with NF1 and 50 healthy pediatric controls. All T2Hs identified on MRI were characterized based on location, presence of T1 hypointensity, mass effect, contrast enhancement, edma, cystic lesion, or lesion related symptoms. Subsequently, all T2Hs were classified using newly established criteria as either unidentified bright objects (UBOs) or probable tumors. Lesion classification was pathologically confirmed in 6 NF1 cases. Results: T2Hs were present in 35 (71.4%) individuals of the NF1 cohort. UBOs constituted the majority of T2Hs and were most frequently located in basal ganglia, cerebellar hemispheres, and brainstem. T2Hs of 7 NF1 patients were classified as probable tumors, and 6 children with probable tumors received surgical treatment. Five lesions of the six surgical children proved to be glioma. Conclusion: T2Hs has been found to be a highly sensitive and specific marker for the diagnosis of NF1. With the application of standardized radiologic criteria, a high prevalence of probable brain tumors will be identified in this at-risk population of children, of which nearly 70% require treatment, emphasizing the need for appropriate oncologic surveillance for NF1 patients with probable brain tumors.