Acute fibrinous and organizing pneumonia (AFOP) is a rare form of organizing pneumonia that may be under-diagnosed if a lung biopsy is not performed.
Clinical features may include:
(1) rapid progression.
(2) the presence of cough, fever, wheezing, hemoptysis and dyspnea.
Some patients respond to corticosteroid therapy. Others are less responsive. The presence of a fulminant course, nonresponse to steroids and the need for mechanical ventilation is associated with a poor prognosis.
Associations:
(1) autoimmune disease (SLE, dermatomyositis, ankylosing spondylitis, etc)
(2) drugs (amiodarone, decitabine, abacavir)
(3) infection (influenza, HIV, Chlamydia, PCP)
(4) idiopathic (cryptogenic)
Histologic features:
(1) the dominant feature is intra-alveolar fibrin rather than fibroblastic/myofibroblastic proliferation
(2) absence of hyaline membranes in the alveolar spaces
