Relapse of idiopathic acute fibrinous and organising pneumonia 12 years after successful treatment with corticosteroids.

Acute fibrinous and organising pneumonia (AFOP) is a rare form of interstitial lung disease. It is a pathological diagnosis sharing similarities to organising pneumonia, diffuse alveolar damage and eosinophilic pneumonia, however, is histologically distinct, characterised by intra-alveolar fibrin deposition ('fibrin balls') and associated organising pneumonia. AFOP was first described in 2002, only 150 cases have been reported since. While it has been described in association with infection, autoimmune disorders, connective tissue diseases, drugs, environmental exposures and organ transplant, it can also be idiopathic in nature. AFOP follows an acute course with potential rapid fulminant respiratory failure, or a subacute trajectory with a more favourable prognosis. Corticosteroids are commonly prescribed to induce remission. While cases of relapse of AFOP during weaning or cessation of steroids have been described, there are no published cases of remote relapse of AFOP. We describe a case of idiopathic AFOP, which recurred after 12 years of good health.