Histologic Changes in the Biopsy

Low-power view of a bronchiole and several of its respiratory bronchioles and alveolar ducts. Each portion of the airway is numbered: 1) bronchiole with circumferential epithelium, but no cartilage, 2) respiratory bronchiole with both respiratory epithelium and alveoli in the wall, and 3) alveolar duct with wall composed of alveoli only.

The prominent dilation of the respiratory bronchioles and alveolar ducts is caused by partial collapse of adjacent alveoli because of the inflammation. Persistence of this dilation along with fibrosis of collapsed alveolar walls produces honeycombing, but that is not a usual feature of this disease.

Clinical summaryImage 4

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