16y/o F w/ persistent pain after a fall 5 months ago.
Findings: Knee joint and internal structures are normal. Lobular, T2 hyperintense thickening of the posterior tibial and common peroneal nerves throughout their visualized course, consistent with a plexiform neurofibroma, which is the hallmark lesion of neurofibromatosis type 1. When the referring clinician was called, additional history of maternal neurofibromatosis was given, further consistent with NF type 1, an autosomal dominant disease. Appearance of a plexiform neurofibroma is likened to “a bag of worms”, and has a predilection for the sciatic and brachial plexus.