Fig. 3

a-c Diffuse plexiform neurofibroma of the thigh. a Axial SE T1- WI. Diffuse infiltrating mass lesion in the popliteal fossa causing scalloping (black arrows) of the posterior cortex of the left femur. b Sagittal fat-suppressed TSE proton density WI. The lesion is of high signal (white arrows). c Axial fat-suppressed SE T1-WI after IV administration of gadolinium contrast. Diffuse enhancement of the lesion (white arrows). Although a rare occurrence, a plexiform neurofibroma may present as a diffuse infiltrating mass causing pressure erosion of the adjacent bone. Experience with a large series of rare pathology allowed the expert center to suggest a correct tissue-specific diagnosis