An aneurysmal bone cyst within the proximal fibula causing common peroneal nerve palsy.

The case of a 15-year-old patient presenting with pain as well as paraesthesia over the lateral aspect of the leg is reported. Clinical and radiological investigations showed an aneurysmal bone cyst arising from the proximal fibula and pressing on the common peroneal nerve. Surgical decompression of the nerve and curettage of the cyst was performed resulting in complete resolution of his symptoms. Our aim is to alert surgeons that this problem may occur and that the entire nerve needs to be exposed when dealing with the cyst.