Acute Motor Failure of the N. Peroneus Profundus Caused by a Cystic Tibiofibular Joint.

A ganglion cyst is rarely the cause of peripheral nerve compression. In the lower extremity, it is important to distinguish clinically the symptoms from a radiculopathy. In the literature, neural damage of the peroneal nerve due to a ganglion cyst has been described. An acute, isolated plegia of the foot/toe dorsiflexors with completely unaffected sensory function - as in our case - has not yet been described. After clinical examination and imaging, the ganglion cyst was surgically removed and the nerve decompressed, which was followed by complete recovery of the motoric function. Peripheral nerve compression due to a ganglion cyst is an important differential diagnosis in peripheral nerve deficit. The therapy of choice is the fastest possible surgical decompression. Recovery is expected within a few weeks.