Neuroimaging of thigh malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1

44-year-old male with neurofibromatosis 1, with plexiform neurofibroma showing rapid enlargement, resulting from malignant transformation in right thigh.

(A) Coronal T1-weighted MRI shows mass (arrows) with slightly heterogeneous signal intensity.

(B) Coronal T2-weighted fat-saturated MRI shows large mass (arrowheads) of heterogeneously high intensity but no cystic change and plexiform neurofibroma (dashed arrows) in right thigh.