Microscopic polyangiitis presenting as idiopathic pulmonary fibrosis.

The most detectable form of pulmonary fibrosis in MPA (microscopic polyangiitis) is UIP (usual interstitial pneumonia), occurring in 48 % of MPA patients with pulmonary fibrosis. In some cases, ILD (interstitial lung disease) is the initial clinical manifestation of MPA (22 % of cases). Here, we describe a patient diagnosed with IPF (idiopathic pulmonary fibrosis) who later developed pulmonary infiltrates on CT and hemoptysis, found to have diffuse alveolar hemorrhage on bronchoscopy and ultimately was diagnosed with MPA. There are no guidelines recommending routine screening of vasculitis in cases of suspected IPF, which may result in more misdiagnoses of vasculitides.