Pulmonary manifestation of immunoglobulin G4-related disease in a 7-year-old immunodeficient boy with Epstein-Barr virus infection: a case report

Background: Immunoglobulin G4-related disease (IgG4-RD) is a multiorgan fibroinflammatory condition with lymphoplasmacytic infiltrates containing abundant IgG4-positive plasma cells. The immunopathogenesis of the disease and the potential role of triggering autoantigens or infectious factors have not been clearly defined. Immunoglobulin G4-related lung disease is a new and emerging condition in pediatric patients and to date, there have been only two reports regarding pulmonary manifestation of IgG4-RD in children recently published. This is the first report of IgG4- related lung disease in an immunodeficient child with Epstein-Barr virus infection. Case presentation: We report on the case of a 7-year old atopic boy who was hospitalized with an initial clinical and radiological diagnosis of pneumonia, positive Epstein-Barr virus (EBV)-DNA in the blood and defective adaptive immunity. The lung CT showed a consolidated mass lesion adjacent to the posterior wall of the chest and the diaphragm. The child underwent surgical resection of the tumor, and the histologic examination of the lung specimens revealed lymphoplasmacytic infiltrates with fibrosis and vasculitis correlating with IgG4- related lung disease. Subsequent monitoring of the patient with lung CT, pulmonary function tests and IgG4 levels did not show signs of active disease. Conclusions: The diagnosis of IgG4-related lung disease in children is challenging because of its rarity, nonspecific symptomatology and heterogeneous morphological manifestations. Further studies are required in children with pulmonary presentation of IgG4-RD to better understand pathogenesis of this condition, possible immunological or infectious triggering factors, and finally, to determine pediatric patient-targeted therapeutic interventions.