Teaching NeuroImages: T2 hyperintensities in neurofibromatosis type 1.

A 4-year-old boy with neurofibromatosis type 1 (NF1), an asymptomatic optic glioma, and a right basal ganglia T2-hyperintense lesion (figure, A and B) developed a left hemiparesis with hyperreflexia over the course of a year. Neuroimaging revealed a cyst-like mass in the region of his previously identified T2 hyperintensity (figure, C and D). While it is often difficult to distinguish T2 hyperintensities from low-grade glioma without tissue diagnosis,1 even with advanced imaging methods,2 T2 hyperintensities typically disappear with age and do not become cystic with associated mass effect. Coupled with the development of new neurologic signs, these MRI features are worrisome for neoplasm in a patient with NF1.