Bronchiolitis obliterans organizing pneumonia. An unusual cause of solitary pulmonary nodule.

Bronchiolitis obliterans organizing pneumonia (BOOP) is a pulmonary disorder with a wide spectrum of radiologic features. Usually, these are bilateral, patchy, alveolar, or ground-glass infiltrates, but other presentations have also been described. We present a case in which the radiologic appearance was a cavitated pulmonary solitary nodule. We think that this finding may justify the inclusion of BOOP in the differential diagnosis of the pulmonary solitary nodule.