BACKGROUND: IgG4-related disease (IgG4-RD) is a systemic inflammatory condition with a myriad of presentations related to the pattern of organ involvement. Diagnostic workup for IgG4-RD requires a high index of suspicion, and further workup often includes the results of serological testing for elevated levels of IgG4. Correlation of presentation, past medical history, and histopathologic analysis are required to make a diagnosis.

CASE REPORT: In this case, incidental discovery of non-infectious aortitis and pulmonary mass lesions were the specific signs that led to the consideration of IgG4-RD. It was only after careful consideration of the patient’s past medical history and examination of previously stored surgical specimens (pericardial tissue) that a conclusive, retrospective diagnosis of IgG4-related disease was reached.

CONCLUSIONS: This case demonstrates that the natural history of IgG4-related disease can be indolent and variable in presentation. Appropriate diagnosis requires consideration of all manifestations of the disease, sometimes with surveillance over several years.

Keywords: Aortitis, Immunoglobulin G, Pericarditis