MRI ganglion cyst

MRI of intraneural ganglion cyst involving the posterior tibial nerve. The cyst is both supra- and infrapatellar.
(A) Sagittal T1 image of the knee showing an extensive intraneural ganglion cyst (bracket) of the posterior tibial nerve (arrows). The signal is higher than expected for simple fluid, likely from elevated protein content.
(B) With gadolinium administration, there is extensive enhancement of the tumor (bracket) suprapatellar and less extensive below the knee.
(C) Axial image showing gadolinium enhancement of the ganglion cyst with neural elements surrounding it.