A mild degree of alveolar wall fibrosis is often associated with respiratory bronchiolitis
and should not be interpreted as evidence of respiratory bronchiolitis
-interstitial lung disease, which remains a diagnosis that should be considered only in conjunction with clinical information.
These alterations have been described over decades as separate diseases, including emphysema, (4) respiratory bronchiolitis, (3) respiratory bronchiolitis-interstitial lung disease, (5) desquamative interstitial pneumonia, (6) and pulmonary Langerhans' cell histiocytosis.
Respiratory bronchiolitis causing interstitial lung disease: a clinicopathologic study of six cases.
In addition to traditional entities, such as emphysema, respiratory bronchiolitis
, and desquamative interstitial pneumonia, it is now recognized that cigarette smoke may result in alveolar wall fibrosis, a pathologic change that, in combination with emphysema, may have significant clinical and physiologic implications.
3) We have suggested that, to avoid confusion with other forms of smoking-related interstitial lung disease (ILD), the lesion be referred to as respiratory bronchiolitis with fibrosis (RBF).
Respiratory bronchiolitis (RB) can be identified by microscopic examination of the lungs of essentially all current cigarette smokers and many ex-smokers, (5) and it consists of collections of pigmented macrophages ("smoker's macrophages") in the lumens of respiratory bronchioles and surrounding alveoli.
The main pathologic findings in respiratory bronchiolitis-associated interstitial lung disease are respiratory bronchiolitis, with lightly pigmented macrophages and mild inflammatory changes that are primarily centered on respiratory bronchioles.
American Thoracic Society/European Respiratory Society 2002 International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias (a) Histologic Pattern Clinical-Radiologic-Pathologic Diagnosis Usual interstitial pneumonia Idiopathic pulmonary Nonspecific interstitial fibrosis or cryptogenic pneumonia fibrosing alveolitis Organizing pneumonia Nonspecific interstitial Diffuse alveolar damage pneumonia (provisional) Respiratory bronchiolitis Acute interstitial pneumonia Desquamative interstitial pneumonia Respiratory bronchiolitis Lymphoid interstitial pneumonia interstitial lung disease Desquamative interstitial pneumonia Lymphoid interstitial pneumonia (a) Data adapted from American Thoracic Society; European Respiratory Society.
Membranous Bronchiolitis and Respiratory Bronchiolitis
Histologically, both membranous bronchiolitis and respiratory bronchiolitis contain cellular infiltrates made up predominantly of lymphocytes and histiocytes within the bronchioles and infiltrating into surrounding peribronchiolar tissue.
The concept of respiratory bronchiolitis
/interstitial lung disease (RBILD) was introduced in 1987 by Myers et al (1) as a morphologic explanation for clinical interstitial lung disease (explicitly, in their article, restrictive pulmonary function tests and/or interstitial markings on plain chest radiographs) in 6 patients in whom nothing besides smoker's respiratory bronchiolitis
(RB) could be found on surgical lung biopsy.
One of the primary, nonchronic, obstructive, smoking-related lung pathologies is respiratory bronchiolitis
interstitial lung disease, which was included in the diagnostic categories in the 2002 American Thoracic Society and European Respiratory Society consensus article (6) on interstitial lung disease.