Sullivan, M.

Abstract Introduction Lung involvement is common in ANCA-associated vasculitis (AAV), presenting in various forms: necrotizing granulomatous inflammation, tracheobronchial inflammation, pulmonary capillaritis and diffuse alveolar hemorrhage (DAH), interstitial lung disease (ILD), and asthma.1 Radiologic manifestations are diverse, often complicating diagnosis based on imaging alone. Typical patterns include lung nodules, cavitation, pulmonary hemorrhage, and peripheral consolidation; however, cystic-like lesions are rarely seen.2 We present a case of AAV with bilateral cystic-like lung lesions. Case presentation A 54-year-old male with childhood asthma initially presented to an outside hospital due to progressive exertional dyspnea for 6 years and dysphonia for 1 year. Initial computer tomography (CT) revealed pulmonary cysts (Figure 1), and a CT-guided biopsy of a right upper lobe cystic lesion revealed intra-alveolar hemorrhage, though pathology was non-diagnostic. He received a diagnosis of congenital cystic lung disease and prescribed Trelegy and fluticasone inhalers. He was instructed to take oral prednisone with taper whenever dyspnea recurs for presumed asthma exacerbation. His exertional dyspnea indeed respond to prednisone but not to inhalers, and it would recur a few weeks later, and his dysphonia persisted. He came to our facility for second opinion given being told lung transplantation is the only ultimate treatment in his case. Additional history revealed chronic ear infection, bilateral rupturesd tympanic membrane, chronic rhinosinusitis, and recurrent nasolacrimal duct infection. He had been on oral prednisone for 4 weeks and remained on 10mg daily. Physical exam noted inspiratory wheezing. Further workups were notable for normal eospinophils, normal renal function, positive C-ANCA and PR3, normal pulmonary function test. High-resolution CT deomnstrated numerous areas of parenchymal lucency with circumferential surrounding groundglass opacity (GGO). At this point, the diagnosis of PR3-AAV is made. Patient is subsequently referred to rheumatology for further management. Discussion The diagnosis of AAV relies on clinical, serologic, radiologic, and pathologic data. The atypical presentation may delay diagnosis, especially in cases limited to ear, nose, and throat involvement and the radiological findings are of low specificity.3 While cystic lesions in AAV-related interstitial pneumonia are documented4, this case lacked a defined cyst wall. The central lucency may present partially destroyed lung parenchyma due to GPA-related necrosis (emphysema or pneumatocele) with surrounding areas of blood products deposited from prior peri-lesional hemorrhage. Clinicians should consider a broad differentials when encounter a cystic-like lesion with thorough history-taking being essential.