Limb Undergrowth in Intraneural Perineuriomas: An Under-recognized Association.

BACKGROUND Intraneural (IN) perineuriomas are a rare benign hypertrophic nerve tumor, most frequently occurring in young patients. Patients with IN perineurioma have been anecdotally found to have limb undergrowth; however, this has not been systematically evaluated. METHODS Archived electronic records from 1990 to 2018 from a single institution were reviewed for pathology or radiology reports documenting a diagnosis of IN perineurioma. This identified 111 patients; 3 patients with IN perineurioma of cranial nerves were excluded. We further reviewed the 108 patients and identified those with a documented limb length discrepancy (LLD) or hand/foot size discrepancy (HFD) and tried to correlate findings with nerve-territory distribution. RESULTS Twenty-seven (25.0%) patients had either LLD or HFD. Nine patients had only an LLD, 6 patients had only an HFD, and 12 patients had both. Patients with undergrowth were significantly younger at diagnosis than patients without (6.14 vs. 22.9 years, respectively). Although there was a trend toward a greater incidence of LLD in lower extremity IN perineuriomas, this was not statistically significant. Patients with proximal IN perineuriomas had a higher incidence of LLD or HFD than patients with distal IN perineuriomas. The difference between the 2 groups was statistically significant (P < 0.0001). All instances of undergrowth were explained by nerve-territory bone innervation. CONCLUSIONS Limb undergrowth occurs in the affected nerve territory and is likely under-reported in patients with IN perineuriomas. Within our series, patients with documented LLD and HFD were likely to be significantly younger at diagnosis than patients without undergrowth.