Neurofibromatosis type 1 and the pediatric neurosurgeon: a 20-year institutional review

Children with neurofibromatosis type 1 (NF1) undergo costly surveillance scanning for a variety of asymptomatic central nervous system lesions whose natural history is poorly understood. We performed a 20-year retrospective chart review of 25 patients with clinically proven NF1 who required surgery (group A) and contrasted this cohort with 150 NF1 patients who did not require surgery (group B). In group A, 52% of patients underwent multiple procedures for more than one lesion (p = 0.043). Group A patients were further distinguished from those in group B by exhibiting a greater number of optic gliomas (p = 0.015), nonoptic intracranial tumors (p = 0.006), cranial nerve (p = 0.000), paraspinal (p = 0.0062), craniofacial (p = 0.001) and visceral (p = 0.03) neurofibromas and moyamoya disease (p = 0.00), as well as a higher frequency of seizure disorder, sphenoid wing dysplasia and poor academic performance. Gadolinium enhancement occurred in 43% of optic gliomas, 50% of parenchymal gliomas, 100% of cranial nerve, 100% of plexus, 67% of paraspinal, 50% of craniofacial and 50% of visceral neurofibromas in group A, while only 1 group B tumor enhanced. In group A, radiological progression occurred after a median of 4 years from initial diagnosis for optic gliomas as well as cranial nerve, plexus and visceral neurofibromas, 2 years for paraspinal neurofibromas and brainstem gliomas and 2.7 years for craniofacial neurofibromas. Only 1 tumor progressed in group B. Therefore, a small subgroup of NF1 patients (12.5%) who require treatment are at risk of subsequently needing further surgical attention, whereas a larger group of NF1 patients (87.5%) carry an indolent form of the disease. We recommend imaging for asymptomatic, gadolinium-enhancing lesions every 2 years for optic pathway and parenchymal gliomas and cranial nerve and visceral neurofibromas, and every year for brainstem gliomas and paraspinal as well as craniofacial neurofibromas. Nonenhancing optic pathway lesions could be followed up radiographically much less often since they do not show progression.