Bronchiolitis Obliterans with Organizing Pneumonia
Key Facts
Terminology
Synonyms: Cryptogenic organizing pneumonia (COP), bronchiolitis obliterans
Definition
Idiopathic interstitial and airway disease process with features of pneumonia
Etiology/Pathogenesis
No definitive etiology has been specified
Histopathologic features of BOOP may be seen secondary to diverse conditions
Clinical Issues
Symptoms
Cough
Dyspnea
Fever
Flu-like symptoms
Treatment
Corticosteroids
Top Differential Diagnoses
Usual interstitial pneumonitis (UIP)
Diffuse alveolar damage (DAD)
Organizing diffuse alveolar damage (O-DAD)
Inflammatory pseudotumor (IPT)
Diagnostic Checklist
Loose young fibrocollagenous polypoid plugs in alveoli and airway
Mild inflammatory changes
Loose organizing fibrosis
 BOOP is shown with areas of young fibrous plugs in alveolar spaces  . These features are characteristic of organizing pneumonia. Note the presence of an inflammatory component. |
 Young fibrous tissue  partially obstructs and destroys bronchial lumen and epithelium, respectively. This particular feature is also important in the diagnosis of BOOP. |
TERMINOLOGY
Abbreviations
Bronchiolitis obliterans with organizing pneumonia (BOOP)
Synonyms
Cryptogenic organizing pneumonia (COP), bronchiolitis obliterans
Definitions
Idiopathic interstitial and airway process with features of pneumonia
ETIOLOGY/PATHOGENESIS
Etiology
No definitive etiology has been specified for BOOP
Histopathologic features of BOOP may be seen secondary to diverse conditions
CLINICAL ISSUES
Epidemiology
Incidence
Definitive incidence of BOOP is not known
It has been stated at < 10 per 100,000 patient admissions
Age
Usually in adults
Gender
No gender predilection
Ethnicity
No ethnic predilection
Site
Process may appear in any lung or lung segment
Presentation
Cough
Dyspnea
Fever
Malaise
Flu-like symptoms
Headache
Laboratory Tests
Leukocytosis
Elevation of erythrocyte sedimentation rate
C-reactive protein is positive
Treatment
Drugs
Corticosteroids
Azathioprine or cyclophosphamide in some patients who do not respond to steroids
Prognosis
Most patients respond to corticosteroid therapy
Associated Conditions with Histology of BOOP
Infectious conditions
Viral
Bacterial
Fungal
Collagen vascular disease
Radiation
Hypersensitivity
Autoimmune process
MACROSCOPIC FEATURES
General Features
Diagnosis of BOOP is essentially done on open biopsy specimens
Thus, no specific macroscopic features have been associated with BOOP
MICROSCOPIC PATHOLOGY
Histologic Features
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