Eosinophilic Granulomatosis with Polyangiitis: Diagnostic Dilemmas

Introduction. Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as Churg-Strauss syndrome, is a systemic vasculitis of the small vessels that often associates asthma and blood/tissue eosinophilia.Case presentation. A 58-year-old woman was admitted to our hospital for progressive exertional dyspnea. She had been diagnosed with asthma three years earlier. Recent multiple thoracic computed tomography scans displayed non-fixed interstitial lung abnormalities, whereas the infectious workup (HIV, parasites) was negative.On admission, the clinical examination noted prolonged expiratory phase. Paraclinical tests revealed biological inflammatory syndrome, eosinophilia, polyclonal hypergammaglobulinemia, elevated total IgE level, negative anti-neutrophil cytoplasmic antibodies and proteinuria of nephritic pattern.The pulmonary evaluation reconfirmed the obstructive ventilatory dysfunction and interstitial lung abnormalities - interlobular septal thickening and diffuse ground-glass opacification. The histopathological examination of a transbronchial biopsy specimen identified leukocytoclastic necrotizing vasculitis and tissue eosinophilia.Provided the clinical and paraclinical setting, specifically the asthma, blood and extravascular eosinophilia, paranasal sinus abnormalities, non-fixed pulmonary infiltrates and the histopathologically confirmed necrotizing vasculitis, the diagnosis of EGPA seemed appropriate.Conclusion. In the absence of diagnostic criteria, EGPA diagnosis is often challenging. Although certain clinical and imaging features could assist the diagnosis, biopsy remains the diagnostic gold standard.In the setting of lung involvement, open lung biopsy is usually required for EGPA histopathological proof, but few cases diagnosed by transbronchial biopsy have been reported. This method often identifies discrete, nonspecific lesions or an incomplete spectrum of pathognomonic abnormalities but has the advantage of minimal invasivity that justifies its use as an alternative diagnostic technique.