Uncommon pulmonary presentation of IgG4-related disease in a 15-year-old boy.

IgG4-related disease was first described in adults with autoimmune pancreatitis but is now known to affect multiple organs. Lung involvement has never been described in children to our knowledge. Here, we report an adolescent presenting with recurrent dry cough and hemoptysis who was found to have venous ectasia in the left upper lobe, and diffuse bronchiectasis. Sustained high levels of IgG4 (1,090 mg/dL) were found, and the endobronchial biopsy revealed a marked infiltration of plasma cells producing IgG4 (ratio of IgG4 plasma cells to IgG plasma cells >50%). This unique case highlights the occurrence of IgG4-related disease in a child and underscores the importance of careful scrutiny of all investigations in complex pediatric respiratory cases.