A Case of MPO-ANCA-positive and PR3-ANCA-negative Granulomatosis with Polyangiitis

Abstract

Background. PR3-ANCA is a highly specific marker for granulomatosis with polyangiitis (GPA). Because of its high diagnostic value, the diagnosis in GPA patients with MPO-ANCA-positive or PR3-ANCA-negative is occasionally laborious. Case. A 75-year-old man was admitted with fever, cough and zygomatic pain. Computed tomography (CT) of the chest and magnetic resonance imaging (MRI) of the paranasal sinus demonstrated the segmental consolidation containing an air bronchogram in the right middle lobe bronchus and mucosal swelling in the left maxillary sinus, respectively. Laboratory data included MPO-ANCA was elevated (287 EU), but negative for PR3-ANCA. Bronchoscopy demonstrated multiple ulcerative lesions in the trachea and bronchi. Tissue specimens obtained from lung and paranasal mucous membranes resulted in the detection multinucleated giant cells which suggested GPA. Although we could not detect typical findings such as palisading granuloma, urinalysis showed proteinuria and hematuria, indicating affected kidneys besides upper and lower respiratory lesions. Hence, we finally diagnosed GPA for typical clinical and bronchoscopic findings. After initiation of prednisolone, cyclophosphamide and sulfamethoxazole trimethoprim, his clinical and imaging findings dramatically improved. Conclusion. Bronchoscopy enabled diagnosis and initiation of treatment for shortly after onset. We should consider the bronchoscopy early in patients whose GPA is suspected.