BACKGROUND: Immunoglobulin (Ig) G4-related disease, previously referred to as IgG4-related sclerosing disease or hyper-IgG4 disease, may occur in the lung, involving alveolar parenchyma, airways, and pleura. Various pulmonary manifestations of IgG4-related disease have been reported, but to the best of our knowledge a cavitating lung disease has not been reported previously.

CASE REPORT: We describe a 60-year-old man who presented with hemoptysis and cavitating lung disease with clinical, laboratory, and histopathologic findings compatible with IgG4-related disease. Other potential causes of cavitation were excluded. Treatment was initiated with oral prednisone and subsequently mycophenolate mofetil was added. Follow-up 1 year later shows stable pulmonary function with complete resolution of the cavitary lesions.

CONCLUSIONS: We present a case of cavitating lung disease as a previously unreported manifestation of IgG4-related disease. Our patient had an excellent response to immunosuppression. An increased awareness of IgG4-related disease and its myriad of manifestations is very important for pulmonologists.

Keywords: Immunoglobulin G - physiology, Lung Diseases - therapy