Abstract Percutaneous conchotome muscle biopsy, a semi-open technique, provides significant diagnostic yields especially for inflammatory myopathies. In patients with small vessel vasculitis, muscle involvement could sometimes be sole or most prominent organ involvement. While open muscle biopsy has been reported to be useful for diagnosis of vasculitis, diagnostic utility with conchotome muscle biopsy for vasculitis remains unclear. Here we report four cases in which conchotome muscle biopsy made a significant contribution to their diagnosis of small vessel vasculitis. All cases presented with myalgia and weakness at the onset of their diseases and with elevation of myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA). Pathological examination of muscle tissues revealed the significant inflammatory infiltration with fibrinoid necrosis in perimysial arterioles measuring 50-100 mm in diameter in all of four cases. Disruption of elastic plates of arterioles was found with Elastica van Gieson staining in three cases. Low levels of patients’ pain evaluated with visual analogue scale (0-100) ranging 0-30 and no occurrence of adverse events in our cases indicated the safety of this technique. All patients were treated successfully with glucocorticoid with or without immunosuppressants. Conchotome muscle biopsy could yield the pathological features of small vessel vasculitis with minimal invasiveness.
Umezawa et al. (Tue,) studied this question.