Granulomatosis with polyangiitis presenting with endobronchial involvement: a case report

Abstract Background Granulomatosis with polyangiitis (GPA) is an ANCA-associated vasculitis that commonly affects the upper respiratory tract, lungs, and kidneys. Although sinonasal involvement is common, tracheobronchial disease is relatively uncommon and may lead to diagnostic uncertainty, particularly in the absence of classic systemic manifestations. Case presentation We report a 29-year-old woman with long-standing chronic otitis media who presented with subacute necrotizing sinusitis, purulent blood-tinged postnasal discharge, cough, and dyspnea. High-resolution computed tomography (HRCT) of the chest demonstrated bilateral multilobar ground-glass opacities that initially raised suspicion for diffuse alveolar hemorrhage. However, flexible bronchoscopy revealed focal, non-bleeding endobronchial involvement characterized by erythematous, edematous mucosal thickening at the orifice of the right mainstem bronchus, without a discrete mass, ulcer, or critical luminal narrowing. Histopathologic examination of nasal mucosal and bronchial biopsies showed necrotizing granulomatous inflammation compatible with GPA, and laboratory investigations revealed elevated inflammatory markers and strongly positive PR3-ANCA, with preserved renal function. Bronchoalveolar lavage (BAL) was negative for mycobacteria, fungi, and galactomannan but grew Pseudomonas aeruginosa , which was treated with intravenous antibiotics. The patient received high-dose corticosteroids and rituximab as induction therapy, resulting in marked clinical and inflammatory improvement. Conclusion This case illustrates that GPA-related endobronchial involvement may manifest as focal inflammatory mucosal changes and may not be apparent on chest CT alone. Careful bronchoscopic inspection, systematic exclusion of infectious and non-infectious mimics, and integration of ENT, serologic, and histopathologic findings were essential to establishing the diagnosis in this young PR3-ANCA–positive woman with ENT-predominant, renal-sparing disease. Early recognition of tracheobronchial involvement and timely initiation of immunosuppressive therapy may prevent airway damage and improve clinical outcomes.