Clinicopathologic study of 43 patients with sural nerve vasculitis.

Vasculitis is a relatively uncommon finding in sural nerve biopsy specimens and is associated with significant morbidity. This study retrospectively reviewed the clinicopathologic features of 43 patients (44 sural nerve biopsy specimens) with sural nerve vasculitis, defined as infiltration of vessel walls by inflammatory cells. These biopsy specimens were obtained over a 19-year period, during which 1503 nerve specimens were reviewed. The study group comprised 29 females and 14 males, ranging in age from 19 to 94 years (mean, 72.5 years) at the time of biopsy. The most frequent clinical presentations included paresthesias in 19 patients (61%), pain in 17 patients (57%), weakness in 10 patients (32%), and weight loss in 9 patients (29%). Histologically, 26 of 44 biopsy specimens (59%) demonstrated necrotizing vasculitis. The remaining 18 biopsy specimens demonstrated a nonnecrotizing lymphocytic vasculitis. Eosinophils were identified in 4 biopsy specimens, intravascular thrombi in 10 (22%) specimens, and granulomatous inflammation in 1 specimen. In 39 biopsy specimens (89%), multiple vessels were involved by vasculitis. Epineurial vessels were the most common target of vasculitis, (n = 42; 95%). Evidence of vascular wall scarring, indicative of healed vasculitis, was observed in 13 biopsy specimens (30%). All biopsy specimens showed evidence of axonopathy, with mild axonal loss noted in 14 specimens (32%), moderate loss in 18 specimens (41%), and severe loss in 12 specimens (27%). Concomitant muscle biopsy was performed in 31 patients. Fifteen muscle biopsy specimens demonstrated evidence of vasculitis (48%), which was necrotizing in 11 cases. All muscle biopsy specimens demonstrated features of neurogenic atrophy. Twenty-five out of 32 patients were known to have been treated with steroids and demonstrated some degree of clinical improvement. In conclusion, sural nerve vasculitis is a relatively uncommon pathological finding (prevalence of 2.9% in this study). In most cases, multiple vessels were involved. Concomitant vasculitis was also identified in about half of the muscle biopsy specimens obtained at the time of nerve biopsy. In most patients, the vasculitis appeared to be at least partially responsive to immunosuppressive therapy.