1354960 - Cardiac pseudotumor in a rare case of IgG4-related disease

We present a case of a 79-year-old male veteran with mediastinal adenopathy and pericoronary soft tissue mass incidentally found on chest CT (Fig. 1). Patient establishing VA care presented with new onset atrial fibrillation and cough having initial and abnormal chest radiograph. Cardiology/Endocrinology workup followed including dedicated coronary CTA (CCTA), cardiac MRI (CMR), and PET/CT with imaging presented. Patient currently asymptomatic.


Diagnostic Techniques and Their Most Important Findings:

Follow-up imaging with CMR (Fig. 2) and coronary CTA (Fig. 3a-b) further demonstrated the extent of extensive encasing nonenhancing pericoronary pseudotumors. There was no appreciable vascular invasion or narrowing. Prominent FDG uptake was seen on PET-CT (Fig. 3c). Mediastinoscopy with lymph node biopsy was performed, which revealed lymphocytic infiltrates without evidence of malignancy. Serology showed high serum IgG4 level (636mg/dL) and high eosinophil count (710 cell/μL).


Learning Points from this Case:

IgG4-related disease is a chronic systemic disorder characterized by fibroinflammatory infiltration of various organs, predominantly by IgG4-secreting plasma cells, resulting in masslike lesions. While usually indolent and diagnosed incidentally, these lesions may result in secondary findings of obstruction or compression of the affected organs; for example hypophysitis, sialadenitis, periarteritis of the aorta and/or coronary arteries, pancreatitis, cholangitis, esophageal or bowel obstruction, renal failure, and prostatitis, among others. Imaging findings correlate with organ involvement, such as pseudotumor formation, inflammatory vasculitis, and aneurysmal changes seen with vascular involvement. Eosinophilia and elevated serum IgG4 levels may be seen. As seen in our case, tissue biopsy is required to exclude malignancy and confirm diagnosis, with characteristic histopathological appearance of lymphoplasmacytic infiltration of the tissues, focal fibrotic changes, and obliterative phlebitis. Prompt response to oral steroids is usually seen, with resolution of clinical symptoms and imaging findings. In our case, patient was also started on CellCept (mycophenolate mofetil) which showed decrease in serum IgG4 levels.