Cystic lesions of peripheral nerves: Are we missing the diagnosis of the intraneural ganglion cyst?

Figure 1 A shows a diagrammatic representation of the intraneural ganglion cyst associated with the proximal tibiofibular joint in the coronal plane; B-D are serial, coronal, T2-weighted, fast spin echo images of the knee show the origin of the lobulated tubular cyst from the proximal tibiofibular joint also called the “tail sign” demonstrated by the black arrows. The further extension along the descending limb (yellow arrows) of the articular branch represents the “vertical limb sign”. The ascending limb of the articular branch (red arrows) demonstrates the “transverse limb sign” which continues to the CPN (blue arrows). Extension of the cyst into the two limbs of the articular branch and further ascent into the parent nerve represents the “u-sign”. T: Tibia; F: Fibula; CPN: Common peroneal nerve.