Clinical and pathological significance of cutaneous manifestations in ANCA-associated vasculitides

Objectives Cutaneous manifestations (CM) in ANCA-associated vasculitides (AAV) are frequent, but data on clinical significance and clinical-pathological correlations are lacking. Methods We conducted a multicenter, retrospective study including 1553 AAV patients. Clinical, biological and pathological features have been analyzed, and tissue samples from 46 biopsies were reviewed in a blind manner. Results CM were more frequent in EGPA (53.0%) and MPA (51.9%) than in GPA (36.7%). Lesions more frequently associated with GPA were oral ulcers (4.6% vs. 2.5% in EGPA and 0.3% in MPA), while pyoderma gangrenosum and palpebral xanthoma were specific to GPA. Lesions associated with MPA were segmentary edema (19.5% vs. 12.7% in EGPA and 4.3% in GPA) and livedo (12.4% vs. 0.5% and 2.6%, respectively), whereas those associated with EGPA were urticarial lesions (11.5% vs. 1.9% in GPA and 3.5% in MPA) and nodules (12,2% vs. 8.9% in GPA and 4.7% in MPA). In GPA, CM patients had more frequent vasculitis than granulomatous phenotype, and poorer relapse-free and overall survival. Pathological analysis showed vasculitis and/or granulomatous infiltrates in 87.5% of GPA, in 61.1% of EGPA and in all MPA. Vasculitis was more frequently observed in purpura and nodules, while granulomas were differently located and organized within vessels or interstitium according to the type of lesions. Conclusion Each AAV seemed to be associated with a peculiar pattern of cutaneous lesions. CM are associated with poorer prognosis in GPA. Clinical-pathological correlations showed no specific feature of each AAV, whereas granulomatous infiltrates differ according to the type of lesions.