Cryptogenic Organizing Pneumonia (COP)

Bronchiolitis Obliterans Organizing Pneumonia (BOOP)

Epidemiology and Etiology:

•  Unknown etiology
• nonspecific pattern which may be seen in infections or inflammatory injury

Common sites:

Gross features:

Histologic features:

• Patchy distribution
• Uniform temporal appearance
• polypoid plugs of loose organizing connective tissue within alveolar ducts, alveoli, and often bronchioles
• all connective tissue is the same age
• mild chronic interstitial inflammation
• underlying lung acrchitecture is normal
• alveolar walls relatively normal
• no interstitial fibrosis or honeycombing

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• unknown etiology
• radiology:
• subpleural or beribronchial patchy airspace consolidation
• may regress spontaneously, most require steroids for recovery

References:

• Robbins 2005
• AFIP Non-neoplastic Disorders of the Lower Respiratory Tract 2002