Isolated granulomatous pulmonary artery vasculitis associated with Hughes-Stovin syndrome: a case report.

Background: Hughes-Stovin syndrome (HSS) is an exceptionally rare vasculitis, characterized by pulmonary artery aneurysms with Case summary: We describe a 71-year-old male who presented with progressive dyspnoea and chest pain. Serial imaging demonstrated rapid enlargement of a main pulmonary artery aneurysm from 5 mm to 68 × 55 mm over 18 months, prompting surgical repair. Histopathological examination of the resected pulmonary artery demonstrated granulomatous arteritis with multinucleated giant cells, transmural inflammation, and disruption of the elastic lamina, confirming isolated pulmonary artery vasculitis. In the context of pulmonary artery aneurysm, normal coagulation studies and systemic exclusion of alternative causes including Behcet disease, giant cell arteritis, Takayasu arteritis, infection, and malignancy, the findings were considered most consistent with HSS. Following multidisciplinary review, immunosuppression was commenced with corticosteroid and methotrexate before transition to tocilizumab and mycophenolate mofetil. Recurrent pulmonary thrombosis despite therapeutic apixaban required conversion to therapeutic enoxaparin. At latest follow-up, the patient remained clinically stable with no evidence of active vasculitis or recurrent aneurysm. Conclusion: This case highlights a rare presentation of isolated granulomatous pulmonary artery vasculitis associated with HSS in an older patient. The case demonstrates the importance of cautious diagnostic classification and exclusion of alternative diagnoses through serial multimodal imaging, timely surgical intervention, prompt commencement of immunosuppression, and multidisciplinary care.