Bronchiolitis obliterans organizing pneumonia (BOOP) in a child with mild-to-moderate asthma: Evidence of mast cell and eosinophil recruitment in lung specimens

Bronchiolitis obliterans with organizing pneumonia (BOOP) is rarely describ ed in children and little is known about its pathogenesis. This paper repor ts on an Ii-year-old patient suffering from mild-to-moderate asthma. He pre sented with a retrocardiac density at chest computed tomography scan that w as slow to resolve and failed to respond to antibiotic therapy. Open lung b iopsy revealed a histological picture with buds of granulation tissue in re spiratory bronchioles and alveolar ducts, with organized extensions into th e alveoli. The use of monoclonal antibodies on biopsy specimens demonstrate d the presence of an inflammatory process affecting not only the thickened alveolar walls, but also the remaining lung parenchyma, the pulmonary arter ies, and the bronchioles. The inflammatory infiltrate consisted mainly of m ast cells and eosinophils. The clinical condition improved with steroid the rapy. To the best of the authors' knowledge, this is the first report of BO OP in an asthmatic child with recruitment of mast cells and eosinophils doc umented by using monoclonal antibodies. (C) 2001 Wiley-Liss, Inc.