title: Cavitating Lung Disease: A Novel Presentation of IgG4-Related Disease.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Jinnur
authors.affiliation: Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Eunhee S
authors.initials: ES
authors.lastname: Yi
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Jay H
authors.initials: JH
authors.lastname: Ryu
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Vivek N
authors.initials: VN
authors.lastname: Iyer
mesh_terms: D006801:Humans; D007074:Immunoglobulin G / Q000502:physiology*; D008171:Lung Diseases / Q000175:diagnosis* / Q000209:etiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged
chemical_list: D007074:Immunoglobulin G