[A mucoid pseudo-cyst of the peripheral nerve. Apropos of a surgical case].

The authors report a case of a twelve old young man, operated on for a ganglion cyst of the common peroneal nerve. The lesion is rare, and is characterized by an accumulation of a mucoïd substance in the sheath, compressing progressively the fibres of the nerve. The case was revealed with pain, paralysis and tumefaction of the nerve. The pathogenic is uncertain. An early treatment, consisting of evacuation of the cyst and interfascicular neurolysis through the dissecting microscope, obtains usually a good functional result.