Organizing Pneumonia: Causes and Associations

The histologic hallmark of organizing pneumonia is granulation tissue polyps in the alveolar ducts and alveoli. The granulation tissue is all the same age, contains few inflammatory cells, and results from organization of inflammatory intraalveolar exudates. Patchy lung involvement with preservation of lung architecture is typical.

When a definite cause or characteristic associated context is not present, organizing pneumonia can be referred to as cryptogenic.

A wide variety of conditions may result in organizing pneumonia. Other conditions have reported associations with organizing pneumonia.

Determined causes

• Infection: Non-resolving pneumococcal pneumonia. Variety of viral, bacterial, fungal, and parasitic infections.
• Drugs: For example, bleomycin.
• Radiation: May involve irradiated or nonirradiated areas of the lung. May be migratory.
• Toxins: Aerosolised textile dye Acramin FWN, benzalkonium compounds, cocaine use.
• Gastroesophageal reflux: Possibly related to occult aspiration.

Manifestation of an inflammatory and/or immune process

• Connective tissue disorders: Dermatomyositis–polymyositis, rheumatoid arthritis, systemic lupus erythematosus, scleroderma, CREST, primary biliary cirrhosis (case shown above), and Sjögren syndrome.
• Lung transplantation:
• Bone marrow transplant:
• Hematological disorders: Acute myelomonocytic leukemia, acute lymphoblastic leukemia, chronic myelomonocytic leukemia, myelodysplastic syndrome, T-cell adult leukemia, Evans syndrome.
• Cancer: Ewing sarcoma, Hodgkin disease, other cancers with or without radiation therapy to the chest, lung cancer.
• Inflammatory bowel disease:

References

• Cordier JF.Cryptogenic organising pneumonia. Eur Respir J. 2006 Aug;28(2):422-46.
• Mueller-Mang C, Grosse C, Schmid K, Stiebellehner L, Bankier AA. What every radiologist should know about idiopathic interstitial pneumonias. Radiographics. 2007 May-Jun;27(3):595-615.
• Strobel ES, Bonnet RB, Werner P, Schaefer HE, Peter HH. Bronchiolitis obliterans organising pneumonia and primary biliary cirrhosis-like lung involvement in a patient with primary biliary cirrhosis. Clin Rheumatol. 1998;17(3):246-9.