Infectious mononucleosis with pulmonary consolidation.

Infectious mononucleosis occurs most commonly among adolescents and young adults. Moreover, intrathoracic involvement by infectious mononucleosis, especially pulmonary consolidation, is uncommon. Thoracic computed tomography (CT) showed a massive pulmonary consolidation in the right lower lobe, multiple mediastinal lymphadenopathy, and pleural effusion in a 41-year-old man with infectious mononucleosis. Histopathology confirmed that lymphocytes and plasma cells had infiltrated the peribronchial areas and alveolar septa, and showed alveolar exudates composed of amorphous fibrinous debris, lymphocytes, and macrophages.