MRI
Sagittal T1
Sagittal T2
Sagittal STIR
Coronal STIR
Axial T2
Axial STIR
There is a well-defined mass in the posteromedial aspect of the ankle just posterior to the flexor hallucis longus tendon. This lesion measures 33 x 17 x 38 mm and it appears hypointense on T1 and hyperintense on T2 and STIR images. It is causing marked compression on the flexor hallucis longus tendon. This lesion is arising from the posterior tibial nerve with high signal intensity of lateral and medial branches of the posterior tibial nerve.
Features are consistent posterior tibial nerve sheath tumour (likely schwannoma )