Development of a tibial intraneural ganglion cyst after surgery on a peroneal intraneural ganglion in a pediatric patient: further support for the articular origin of intraneural ganglion cysts. Illustrative case.

BACKGROUND

The articular origin of intraneural cysts has been previously described and well supported. Intraneural ganglion cysts most commonly occur in adults and in the common peroneal nerve arising from the anterior aspect of the superior tibiofibular joint (STFJ).

OBSERVATIONS: The authors report a pediatric patient who developed a tibial intraneural cyst arising from the posterior aspect of the STFJ within months after surgical treatment of a peroneal intraneural cyst from the anterior aspect of the same joint. Surgery consisted of disconnecting the articular branch of the peroneal nerve and decompression of the cyst. Three-month postoperative magnetic resonance imaging showed resolution of the peroneal intraneural cyst and anterior compartment denervation but demonstrated a clinically occult small tibial intraneural ganglion cyst arising from the STFJ with popliteus muscle atrophy.

LESSONS: This case underscores the importance of addressing the underlying etiology (articular synovitis) or the communication pathways (articular branches) whenever feasible to mitigate intraneural cyst recurrence. Furthermore, this report reinforces the validity of the articular theory. https://thejns.org/doi/10.3171/CASE24277.