Conditions associated with organising pneumonia (OP)#

Connective tissue disorders
Hypersensitivity pneumonitis (acute)
Adverse drug reactions
Bone marrow, stem cell or solid organ transplantation
Airway diseases complicated by infection
Airway obstruction (distal changes)
Inhalation injury
Aspiration syndromes
Chronic eosinophilic pneumonia
Radiation pneumonitis
Inflammatory bowel disease
Neoplasms and myeloproliferative disorders
Organising diffuse alveolar damage
Coexistent with pathologic changes of IIP (e.g. UIP or NSIP)
Acute exacerbation of IPF (OP lesions superimposed on chronic UIP pattern)
Proximal bronchial obstruction (OP found distal to focus of obstruction)
  Immunodeficiency syndromes
  Granulomatosis with polyangiitis
  Other vasculitis

IIP: idiopathic interstitial pneumonia; UIP: usual interstitial pneumonia; NSIP: nonspecific interstitial pneumonia; IPF: idiopathic pulmonary fibrosis. #: conditions other than cryptogenic organising pneumonia (idiopathic OP) that have been associated with histopathologic findings of OP in lung tissue specimens.