[Acute progressive paralysis caused by intraneural ganglion--a neurosurgical emergency]

Intraneural ganglia, particularly of the peroneal and ulnar nerves may produce rapidly progressive paresis after minor trauma, for instance, following a sport injury. The chance of recovery of nerve function depends on the timing of surgical treatment. A patient with a ganglion of the peroneal nerve is reported in order to stress the relevance of intraneural ganglia, the danger of missing the lesion and the importance of early treatment. It is stressed that in the presence of rapidly progressing paralysis and the clinical suspicion of an intraneural ganglion, early decompression offers the best prognosis for recovery.