[Peroneal nerve palsy in children: Uncommon diagnosis of a proximal tibiofibular synovial cyst].

Compression of the common peroneal nerve by synovial cysts of the tibiofibular joint is a rare disease. Two macroscopic forms may be encountered: extraneural cysts and intraneural cysts. In a review of the literature, we found only three pediatric cases of common peroneal nerve palsy due to extraneural cysts and about 60 cases reported in adults. Taking advantage of the clinical history of two children operated in our department for this disease, we describe this uncommon entity, which must be diagnosed and treated rapidly. Even in the presence of severe clinical and electrophysiological symptoms, a full clinical recovery is possible, as observed in these two children. However, follow-up is needed because recurrence is possible.