Unusual peroneal nerve palsy caused by intraneural ganglion cyst: pathological mechanism and appropriate treatment.

The origin of the peroneal intraneural ganglion and the outcome of treatment are still controversial. We report here three cases with peroneal intraneural ganglion and discuss the appropriate treatment. In our cases, 58-, 62-, and 65-year-old patients were operated on with extraneural decompression and epineurotomy within 4 months after onset of drop foot. Two cases demonstrated intraneural ganglion connecting to the articular branch and traversing to the deep and common peroneal nerve. At the 1-year follow-up, paralyzed peroneal nerve could be recovered in all patients even with residual ganglion. We propose correct early diagnosis, simple exoneural dissection, and atraumatic epineurotomy for the successful treatment of peroneal intraneural ganglion. Disruption of the stalk in the articular branch is a key point to prevent recurrence. For early diagnosis, clinicians should be aware of the existence of this rare lesion.