Clinical and electrodiagnostic correlates of peroneal intraneural ganglia

OBJECTIVE: Intraneural ganglia (IG) are an underappreciated but treatable cause of common peroneal neuropathy (CPN). This study was designed to determine if there are clinical measures that distinguish CPN caused by IG from CPN without a clear proximate cause. METHODS: Clinical and electrodiagnostic features of 22 cases of IG were compared in a case-control study to 11 cases of CPN with imaging negative for IG. RESULTS: The IG group had a greater body mass index (30 vs 24; p < 0.005), more pain at the knee (52% of 22 vs 0% of 11; p < 0.005) or in the peroneal distribution (76% of 21 vs 27% of 1; p < 0.02), more frequent fluctuating weakness (48% of 21 vs 4% of 29; p < 0.01) with weight bearing (38%, p < 0.05), or a palpable mass (47% of 20, p < 0.01) at the fibular head. The IG group was less likely to present with a history of weight loss (0% vs 36%; p < 0.01), immobility (0% vs 21%; p < 0.03), or leg crossing (0% vs 80%; p < 0.05). There were no significant electrophysiologic differences. CONCLUSIONS: Presenting clinical features increase the likelihood of intraneural ganglia and may assist selection of patients with common peroneal neuropathy for diagnostic peroneal nerve imaging.