IgG4-Related Sclerosing Disease Involving the Superior Vena Cava and the Atrial Septum of the Heart
A 55-year-old woman was admitted to our institution with recurrent episodes of syncope and dizziness. She had no underlying disease, including autoimmune diseases. The patient's past medical history was not significant for any medications or illicit drugs. The electrocardiogram on admission showed first-degree atrioventricular block with a prolonged PR interval of 240 ms (). Furthermore, the patient demonstrated atrial fibrillation () and a sinus pause of six seconds during an exercise test (). During ambulatory Holter monitoring, frequent episodes of sinus pauses and atrial fibrillation were observed.\nTransthoracic echocardiography and magnetic resonance imaging demonstrated a mass extending from the superior venacava (SVC)-right atrium (RA) junction to the right atrium posterior wall and interatrial septum (). Fluorodeoxyglucose positron emission tomography showed increased uptake in a mass involving the RA wall and interatrial septum (). No other evidence of abnormal uptake was noted. Transcutaneous cardiac biopsy was performed, however, failed to obtain enough tissue to confirm the histologic diagnosis. Therefore, the patient underwent open chest biopsy. Histologically, the lesion was composed of proliferating IgG4-positive plasma cells and lymphocytes (). The ratio of IgG4/IgG positive cells was 68% in average. And absolute number of IgG4-positive cells was approximate 146.5 per high-power field in the hottest area. These findings are consistent with IgG4-related sclerosing disease.\nThe cardiac mass involved the SVC and interatrial septum, and was inoperable. Additional chemotherapy or steroid therapy was not performed because of patient's preference. A permanent VVI-type pacemaker was implanted due to frequent sinus pauses and syncope. During a one-year follow-up, the patient had no additional episodes of syncope, and the mass showed no evidence of progression ().