Combined nerve/muscle/skin biopsy could increase diagnostic sensitivity for vasculitic neuropathy

Abstract

Objective Combined nerve/muscle biopsy is widely carried out to improve the diagnostic sensitivity for vasculitic neuropathy. However, an additional yield of muscle biopsy is modest. Therefore, we investigated whether skin biopsy in combination with nerve/muscle biopsy increases the detection rate of vasculitis. Methods A total of 25 combined nerve/muscle/skin biopsy samples from patients with biopsy-proven necrotizing vasculitis (n = 16) or clinically probable vasculitic neuropathy (n = 9) were reviewed. Specimens from the sural nerve, peroneus brevis muscle and skin were obtained simultaneously by a single incision. Results Skin biopsy substantially contributed to diagnosis of vasculitic neuropathy. Additional skin biopsy enhanced diagnostic sensitivity from 88% to 100% in patients with pathologically confirmed vasculitis (n = 16). Vasculitis was detected only in skin specimens from two of the entire cohort (n = 25). There were no complications related to skin collection, such as anastomotic leakage or wound infection. Conclusion Combined nerve/muscle/skin biopsy could be a less invasive option to improve the diagnostic sensitivity for vasculitis.

Vasculitic neuropathy: Comparison of clinical predictors with histopathological outcome

“…Biopsy of non‐nerve tissue can strengthen the evidence for vasculitis, particularly when there is evidence of systemic vasculitis . In one small study of patients with biopsy‐proven peripheral nerve vasculitis or clinically probable vasculitis, cutaneous vasculitis was identified in some patients without nerve or muscle biopsy evidence of vasculitis, suggesting that concomitant full‐thickness skin biopsy may increase diagnostic yield . Another small study of patients with sural nerve biopsy‐proven NSVN showed that quantification of perivascular macrophages on skin punch biopsies had a sensitivity of 94% and specificity of 79% for NSVN using a cut‐off of 2.9 macrophages per vessel .…”

“…18 In one small study of patients with biopsy-proven peripheral nerve vasculitis or clinically probable vasculitis, cutaneous vasculitis was identified in some patients without nerve or muscle biopsy evidence of vasculitis, suggesting that concomitant full-thickness skin biopsy may increase diagnostic yield. 19 Another small study of patients with sural nerve biopsy-proven NSVN showed that quantification of perivascular macrophages on skin punch biopsies had a sensitivity of 94% and specificity of 79% for NSVN using a cut-off of 2.9 macrophages per vessel. 20 Quantifying scattered macrophages in skin biopsy may differentiate vasculitis from controls and other axonal neuropathies, with one study demonstrating sensitivity of 71% and specificity of 79% using a cut-off of 13 macrophages/mm 3 .…”

Nerve biopsy: Current indications and decision tools

“…In terms of improving diagnostic yield, a small study performed combined nerve/muscle/skin biopsy through a single incision in patients suspected to have vasculitic neuropathy 31 . Among patients without evidence of definite or probable vasculitis on nerve and muscle biopsy, cutaneous vasculitis was identified in 20%.…”

Additional skin biopsy could widen the diagnostic window of vasculitic neuropathy

“…A biopsy of the peroneus brevis muscle is occasionally carried out in addition to a sural nerve (or superficial peroneal nerve) biopsy to improve the diagnostic accuracy; however, a substantial percentage of possible vasculitic neuropathy patients remained undiagnosed even after this combined nerve/muscle biopsy . In this issue of the journal, Masuda et al . described the merit of a skin biopsy in addition to a nerve/muscle biopsy in the detection of vasculitis.…”

“…A biopsy of the peroneus brevis muscle is occasionally carried out in addition to a sural nerve (or superficial peroneal nerve) biopsy to improve the diagnostic accuracy; however, a substantial percentage of possible vasculitic neuropathy patients remained undiagnosed even after this combined nerve/muscle biopsy. 1 In this issue of the journal, Masuda et al 2 described the merit of a skin biopsy in addition to a nerve/muscle biopsy in the detection of vasculitis. Although there were no statistical differences between the sensitivity of the nerve/muscle biopsy and that of the nerve/muscle/skin biopsy, vasculitic changes were detected only in the skin biopsies of two in their entire cohort, showing an increase of diagnostic sensitivity by 12%.…”