SESSION TITLE: Pleural Case Report Posters
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Immunoglobulin G4-related sclerosing disease (ISD) is a newly recognized systemic fibroinflammatory process with protean clinical and radiographic manifestations. Hallmark histopathological findings of lymphoplasmacytic infiltrates containing IgG4-positive plasma cells and T-lymphocytes with fibrosis and obliterative phlebitis have been described in bile duct, salivary gland, lacrimal gland, kidney, and lymph nodes specimens. Circulating IgG4 levels are commonly elevated. Pulmonary involvement including mediastinal adenopathy, mass lesions, bronchiectasis, pleural thickening and interstitial disease has been increasingly recognized as presentations of ISD. Fibrosing mediastinitis due to ISD is rare.
CASE PRESENTATION: A 47-year-old Asian male presented with fever, night sweats, weakness and fatigue. Computed tomography scan of the chest demonstrated 6x8 cm heterogeneous anterior mediastinal mass with multiple enlarged lymph nodes (Figure 1). No parenchymal disease was noted. Mass was PET avid with maximal SUV uptake of 4.4 (Figure 2) Acetylcholine receptor antibody was negative. Complete blood count showed mild anemia with a hemoglobin of 11.2 g/dl, thrombocytopenia with a platelet count of 63,000 per microliter and normal white count. Since the differential diagnosis included thymoma, thymic carcinoma and lymphoma, patient underwent a complete surgical resection of the mass which extended from the lower pole of the thymus into the mediastinum and parietal pleura, obliterating all anatomical tissue planes. Pathology demonstrated benign thymic tissue with extensive fibrosis; immunohistochemistry was notable for a marked increase (55%) in IgG4-positive cells. Serum IgG4 was 125 mg/dl (normal 2.4-121). Post-operatively, patient’s symptoms and cytopenias resolved.
DISCUSSION: Patients with ISD may have no pulmonary symptoms or present with cough, exertional dyspnea, or chest pain. Constitutional symptoms are rare. Imaging may demonstrate parenchymal infiltrates, nodules, ground-glass opacities, honeycombing, pleural effusions/thickening, and adenopathy. PET avidity is not uncommon raising suspicion for malignancy and sarcoidosis. Pulmonary function tests demonstrate a restrictive pattern and decreased diffusing capacity. Although majority of patients have an elevated serum IgG4 level, this finding is neither sensitive nor specific. Histopathology shows lymphoplasmacytic inflammation, fibrosis and increased numbers of IgG4-positive plasma cells (>30%).
CONCLUSIONS: It is increasingly recognized that ISD can present with a variety of thoracic manifestations. Although serum IgG4 levels are typically elevated, this finding is not diagnostic and histological confirmation is required. Clinical response is typically favorable to systemic steroids thus mandating the need for accurate and timely diagnosis.
Reference #1: Ryu JH, Sekiguchi H, Yi ES. Pulmonary manifestations of immunoglobulin G4-related sclerosing disease. Eur Respir J. 2012;39(1):180-6.
DISCLOSURE: The following authors have nothing to disclose: Satish Chandrashekaran, Lioudmila Karnatovskaia, Margaret Johnson
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