Intraneural ganglion cyst of the peroneal nerve in a four-year-old girl: a case report.

Intraneural ganglion cysts of the peroneal nerve are rare, usually occurring in adult men with a typical presentation of knee or proximal leg pain preceding motor weakness and/or sensory disturbances in the peroneal nervous distribution. A history of knee trauma and a palpable mass of the lateral knee in the region of the peroneal nerve are common. We present the unusual case of an intraneural ganglion cyst of the peroneal nerve in a 4-year-old girl. Although extremely rare in the pediatric population, the condition should be considered in the differential diagnosis of children presenting with new-onset foot deformities, foot drop, or clinical examinations consistent with a peroneal nerve lesion. Surgical treatment consisting of ganglion decompression with exploration and ligation of the articular branch of the peroneal nerve may result in improved functional recovery in the pediatric population compared with the adult population. Greater access to magnetic resonance imaging may allow diagnosis of cases that were not previously identified.