Fibrosing organising pneumonia.

Organising pneumonia (otherwise referred to as bronchiolitis obliterans organising pneumonia) is characterised histologically by plugs of granulation tissue, which are present predominantly within small airways, alveolar ducts and peri-bronchiolar alveoli. This pattern is not specific for any disorder or cause, but is one type of inflammatory response to pulmonary injury, which may be seen in a wide variety of clinical conditions. Typically, organising pneumonia responds very well to corticosteroid treatment; however, a small percentage of patients appear to develop progressive fibrosis.