IgG4‐related systemic disease and lymphoplasmacytic aortitis

We describe herein a patient who developed a dissection of the ascending aorta in the setting of IgG4‐related systemic disease, linking IgG4‐related systemic disease with a newly‐recognized subset of noninfectious aortitis. At the time of aortic surgery, a transmural lymphoplasmacytic infiltrate was detected in the patient's aorta, with a principal focus of inflammation within the media. Immunohistochemical studies demonstrated that >50% of the plasma cells in the lesion stained for IgG4. By in situ hybridization, the plasma cells showed polytypic staining for kappa and lambda light chains, consistent with a polyclonal plasma cell infiltrate. Serologic evaluation revealed that the patient's IgG4 levels were elevated nearly 10‐fold. Four years before aortic surgery, the patient had undergone a mediastinal lymph node biopsy. Reexamination of the lymph node revealed features consistent with IgG4‐related systemic disease, which had not been recognized at the time of the original biopsy. Glucocorticoid therapy for the IgG4‐related systemic disease yielded a prompt response. Recognition that IgG4‐related systemic disease can involve the ascending as well as the descending abdominal aorta indicates the need for a change in the way idiopathic aortitis is regarded. This case offers new potential considerations for short‐ and long‐term management of noninfectious aortitis, because of the frequent good response of IgG4‐related systemic disease to glucocorticoid treatment without additional therapy. Treatment of the aortitis may prevent progression of the IgG4‐related systemic disease to involvement of other organs. IgG4‐related systemic disease should be considered in all patients with aortitis judged to be of unknown etiology.