IgG4-Related Lung Disease without Elevation of Serum IgG4 Level: A Case Report.

Since IgG4-related pancreatitis was first reported in 2001, IgG4-related disease has been identified in other organs such as salivary gland, gallbladder, thyroid, retroperitoneum and kidney; but lung invasion is rare. A 63-year-old man presented with hemoptysis at the pulmonary clinic and chest computed tomography revealed about 4.1 cm irregular shaped mass with spiculated margin at the left upper lobe. Despite no elevation of serum IgG4 level, he was finally diagnosed as IgG4-related lung disease by transthoracic needle biopsy. After treatment with oral glucocorticoids, hemoptysis disappeared and the size of lung mass was decreased.