C63-40 From Earache to Anca: An Atypical Grand Entrance for Pr3-anca Vasculitis

Abstract Introduction Granulomatosis with polyangiitis (GPA), an ANCA-associated vasculitis (AAV), is characterized by necrotizing granulomatous inflammation primarily involving the upper and lower respiratory tracts and kidneys. While otologic manifestations such as otitis media and hearing loss are recognized, they are rarely the initial or isolated presentation. Early recognition is crucial, as delayed diagnosis can lead to irreversible organ and neurologic damage. This case highlights an unusual presentation of PR3-ANCA-positive vasculitis that initially mimicked both infection and malignancy. Case Presentation A 69-year-old male with no smoking or autoimmune history presented with persistent ear pain, hearing loss, and extremity numbness. Despite multiple antibiotic courses and myringotomy with tympanostomy tube placement for presumed infection, symptoms persisted. Subsequent CT imaging revealed multiple large, mass-like pulmonary nodules and right lung consolidation, raising suspicion for malignancy. Bronchoscopy showed diffuse ulceration and tracheobronchial inflammation. Endobronchial and transbronchial biopsies initially were interpreted as cryptogenic organizing pneumonia (COP). The patient’s course rapidly progressed with new-onset atrial fibrillation (suggestive of myocarditis) and worsening peripheral neuropathy. Repeat testing revealed a strongly positive PR3-ANCA, elevated CRP (17.3 mg/dL), and mild proteinuria. With the clinical picture of multi-organ involvement, a diagnosis of PR3-ANCA-associated vasculitis was made. The patient was treated with pulse-dose intravenous methylprednisolone followed by rituximab and PPI prophylaxis, resulting in marked clinical and radiologic improvement, with near-resolution of pulmonary nodules within 5 weeks. Discussion Pulmonary manifestations of GPA range from nodules and cavitary lesions to diffuse alveolar hemorrhage. Mass-like nodules mimicking malignancy, as in this case, are uncommon but represent a well-documented diagnostic challenge. Organizing pneumonia as a histologic pattern can be misleading, potentially delaying recognition of vasculitis until systemic features emerge. This reinforces the importance of maintaining a broad differential diagnosis for non-resolving pulmonary infiltrates, particularly in the setting of refractory upper airway disease. This case underscores several key lessons: (1) GPA can initially masquerade as isolated otologic or pulmonary disease; (2) early ANCA testing should be considered when imaging or biopsy findings are incongruent with the clinical course; and (3) multidisciplinary evaluation between pulmonology, rheumatology, and otolaryngology is essential for timely diagnosis and initiation of immunosuppressive therapy. Prompt treatment with high-dose glucocorticoids and rituximab can prevent irreversible organ injury and lead to rapid recovery, as seen in this patient. Conclusion This case highlights the diagnostic complexity of ANCA-associated vasculitis presenting with atypical otologic and pulmonary findings. Awareness of these non-classical manifestations can guide earlier recognition and intervention, reducing morbidity and improving outcomes in this potentially life-threatening disease. This abstract is funded by: None