Pathological Features of Vasculitic Neuropathy and the Role of Nerve Biopsy

OBJECTIVE: To compare the pathological features of patients with different forms of vasculitic neuropathy (VN). METHODS: Patients with clinically probable VN were enrolled. Clinical characteristics and ancillary examinations were collected and evaluated. Nerve biopsies were performed. RESULTS: A total of 48 patients with VN were involved, including 20 primary systemic VN (PSVN), 17 secondary systemic VN (SSVN), and 11 non-systemic VN (NSVN). Patients that fulfilled the pathologically definite, probable, and possible VN were 20 (41.67%), 8 (16.67%), and 12 (25.00%), respectively. The frequencies of acute vascular damage showed no significant difference across three subgroups (PSVN 80.00%, SSVN 82.35%, NSVN 90.91%). Chronic vascular damage was more frequently observed in PSVN (90.00%) and SSVN (76.47%) than in NSVN (54.55%) with no significance. Perivascular inflammatory cell infiltration in the endoneurium was more common in NSVN (45.45%) than PSVN (15.00%, p = 0.004) and none with SSVN (0.00%, p = 0.002). CONCLUSION: The overall rate of pathologically definite and probable VN in nerve biopsy was 58%. Acute vascular lesion is commonly seen in all forms of VN, while chronic vascular damage is more frequently observed in SVN. Perivascular inflammatory cell infiltration in the epineurium is primarily found in NSVN. SIGNIFICANCE: The study further elucidated the clinical significance of nerve biopsy in VN.