Microscopic polyangiitis (MPA) is a rare disease in which the pathogenesis is unknown. Patients with this disease present with similar findings to several other conditions such as granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) and polyarteritis nodosa. Which of the following characteristics of polyarteritis nodosa best distinguishes it from MPA?