2427: US and MR imaging of peroneal intraneural ganglia: Emphasis on the articular branch

Abstract

Objectives: To describe US and MR imaging findings in patients with peroneal intraneural ganglia. Methods: Seventeen patients with a palpable mass in the fibular neck area and foot-drop suggesting dysfunction of the peroneal nerve were evaluated with US and MR imaging. All patients had abnormal nerve conduction studies. Results: In all but one patient, US and MR imaging identified ganglia of variable size and shape in relation to the superior tibiofibular joint. Based on their relationship with the peroneal nerve, US and MR imaging divided these cysts in extraneural ganglia (n = 9/16), which developed outside the nerve, and intraneural ganglia (n = 7/16), developing within the nerve. Intraneural ganglia had a stereotypical appearance: US found the bulk of the ganglion on the anterolateral aspect of the superior tibiofibular joint, located remotely from the position of the peroneal nerve. The ganglion was invariably associated with a dilated articular branch of this nerve. This branch appeared as a long tubular process coursing along the posterolateral aspect of the fibula to join the bulk of the ganglion with the nerve. It was markedly enlarged and assumed a cystic appearance. Conclusions: US and MR imaging are promising for evaluating patients with peroneal neuropathy caused by superior tibiofibular joint ganglia.