Cryptogenic organizing pneumonia: Low power

Photomicrograph of specimen from open lung biopsy in a patient with cryptogenic organizing pneumonia. Polypoid masses of granulation tissue fill the lumens of a respiratory bronchiole and alveolar ducts (right side). Adjacent alveolar interstices are broadened by a lymphoplasmacytic inflammatory infiltrate. Hematoxylin and eosin stain.

Low-power photomicrograph of normal lung tissue shows open alveoli with thin, capillary-containing interstitial spaces. An artery (A) is identifiable by its thick, muscular wall; the accompanying bronchus (B) contains mucoid material and is lined by columnar respiratory epithelial cells.