Neurofibromatosis type 1 - focal areas of signal intensity in the brain

Case contributed by Bruno Di Muzio
Diagnosis almost certain


Patient with a known phakomatosis. Asymptomatic, first brain exam.

Patient Data

Age: 14-year-old
Gender: Male

Technique: Multiplanar and multisequence images have been obtained through the brain, including post-contrast sequences. 

Findings: There are T2/FLAIR hyperintensities foci the globus pallidus, thalami and mesencephalon without atrophic or mass effect, no contrast enhancement or restricted diffusion (not shown). The remainder brain has normal signal intensities and morphology. The ventricular system is normal. No intra or extra-axial mass or collections are identified. A right frontal neurofibroma is infiltrating the scalp. 

Conclusion: Focal areas of signal intensity involving the globus pallidus, thalami and mesencephalon and in keeping with the known diagnosis of Neurofibromatosis type I. 

Case Discussion

This case shows the most common brain finding in patients with neurofibromatosis type I: bright areas on T2-weighted images identified in the basal ganglia (often the globus pallidus), thalamus, brainstem, cerebellum, and subcortical white matter, which are referred as focal areas of signal intensity (FASI)

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