Unusual presentation of granulomatosis with polyangiitis causing periaortitis and consequent subclavian steal syndrome: A case report.

Background: Granulomatosis with polyangiitis (GPA) is a rare autoimmune disease that involves small-to-medium-sized vessels and forms necrotizing vasculitis with granulomatous inflammation. The formation of a large vessel lesion in GPA patients has been scarcely reported, and it can cause confusion in the diagnosis.

Case Summary: A 27-year-old man presented with mild left-sided pleuritic chest pain that started one year prior. An imaging study revealed up to 2.5 cm-sized two irregular nodular consolidation nodule in the left lower lobe. Both nodules showed central necrosis. Also, there was a periaortic mass occluding the branching porting of the subclavian artery. He had positive anti-neutrophil cytoplasmic antibodies (ANCAs), but myeloperoxidase-ANCAs and proteinase 3-ANCAs were negative. The patient also developed symptoms of subclavian vein syndrome during the follow-up. Wedge resection of the lung revealed necrotizing vasculitis, destructive parenchymal abscess and surrounding granuloma, and therefore diagnosed of GPA. The patient started on methotrexate and steroid therapy with a relief of symptomatic.

Conclusion: Here, we present an unusual manifestation of GPA with periaortitis and consequent subclavian steal syndrome, which has never been previously described. This case alerts us that we should include GPA in the differential diagnosis of large vessel vasculitis as well as subclavian steal syndrome.