IgG4-related lung disease with atypical CT imaging: a case report.

IgG4-related lung disease is a rare disease, diagnosed when typical pathologic features are seen in the context of increased serum levels of IgG4 and the elevated tissue's IgG4-positive plasma cells. Here we reported the case of a 24-year-old woman with IgG4-related lung disease. This patient presented with fever, cough and shortness of breath. Thoracic computed tomography (CT) images demonstrated multiple nodules or masses with high density in both lungs, and thickened interlobular septa. The 'halo sign' was observed around the high-density lesions of the upper lobes. This range of CT images' characteristics is atypical, which differs from previous reports of this condition.