Extraneural cyst compression of the common and deep peroneal nerve: A case report and review of the literature

Cysts are very common lesions around the knee although they seldom cause complications. Peripheral neuropathy caused by these structures most commonly occurs by compression of the common peroneal nerve and its branches, at the level of the fibular neck. We report a case of a 44-year-old male admitted to the emergency department with complaints of right foot drop and numbness on the lateral side of the right leg caused by an extraneural synovial cyst compressing the peroneal nerve. Ultrasonography and magnetic resonance aided on the diagnosis. The cyst was removed surgically. Three months after the procedure, the patient was without complaints, with full motor and sensory function.