BRONCHIOLITIS OBLITERANS WITH ORGANIZING PNEUMONIA - CLINICAL-FEATURES, PATHOLOGY AND IMAGING FINDINGS

Bronchiolitis obliterans with organizing pneumonia (BOOP) is a clinico pathological syndrome of unknown etiology, Histopathologically, it is characterized by plugs of fibroplastic connective tissue within respir atory bronchioles, mononuclear cell infiltrates in parenchyma adjacent to the affected bronchioles and foam cells within alveolar airspaces. The disease usually presents as a subacute illness with complete reso lution. A subset of BOOP. however, is associated with a fulminant cour se and a high lethality due to respiratory failure. Early diagnosis an d therapy are mandatory, Chest radiography, computed tomography (CT), bronchoalveolar lavage (BAL) and open lung biopsy are the primary diag nostic techniques. Radiographically, BOOP is characterized by patchy a reas of consolidation that are usually bilateral, peripheral and often migratory, In some cases small, round opacities may be observed as th e only abnormality, CT can show the pattern of ground glass opacities, areas of airspace consolidation and small, round opacities, while con siderable fibrotic change is usually not seen. A reticular roentgenogr aphic pattern, fibrotic changes mainly in subpleural location at CT, l ack of lymphocytosis in BAL fluid and histological features of usual i nterstitial pneumonitis and BOOP in biopsy specimens are all considere d risk factors for a fatal outcome.