A PROBABLE CASE OF IGG4-RELATED LUNG DISEASE MIMICKING PNEUMOCONIOSIS

ABSTRACT

SESSION TITLE Autoimmune Diseases Gone Wild Rare Cases of Pulmonary Manifestations SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 0135 pm - 0235 pm INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a complex entity related to autoimmune dysfunction and inflammation that can cause mass-like lesions and fibrosis of a variety of organs, including pancreas and/or lungs. IgG4-RD in the lung can have diverse clinical and radiographic presentations. We present a case of suspected IgG4-RD that manifested as idiopathic pancreatitis and interstitial lung disease that mimicked coal workers' pneumoconiosis. CASE PRESENTATION A 72 year-old male with a decades-long coal mining history and a presumptive diagnosis of coal-worker's pneumoconiosis was admitted to the hospital for necrotizing pancreatitis. There was no evidence of gallstones, elevated triglycerides, history of alcohol use or medication known to precipitate pancreatitis. Two years prior, a presumptive diagnosis of coal-worker's pneumoconiosis had been reached largely on the basis of history and chest imaging (Figure 1) showing a progressive massive pulmonary fibrosis pattern. His hospital course was protracted and complicated by nosocomial COVID-19 treated with remdesivir and a 10-day course of dexamethasone. He then had persistent hypoxemia that worsened after dexamethasone was discontinued. Empiric high-dose methylprednisolone was given and the hypoxemia improved dramatically. However, the hypoxemia and pancreatitis repeatedly worsened with significant dose decrease. Inpatient CT chest showed worsening interstitial reticulation and ground-glass opacities superimposed on prior fibrosis (Figure 2). Serum IgG subclass levels were checked;IgG4 and IgG4IgG ratio were mildly elevated at 93mg/dL and 0.09, respectively. In the setting of idiopathic pancreatitis, pulmonary fibrosis, and steroid-sensitive hypoxemia, he was diagnosed with probable IgG4-RD involving pancreas and lungs. An association between inhaled occupational exposures and development of IgG4-RD has been observed. To confirm the diagnosis of pulmonary IgG4-RD, a tissue biopsy will be necessary. He is now discharged from hospital on a long steroid taper. DISCUSSION: A serum IgG4 level >125mg/dL or an IgG4total IgG ratio >0.08 support the diagnosis, as does clinical response to steroids. However, these criteria are nonspecific and will be in the normal range in a substantial minority of cases. Lymphocytes and a predominance of IgG4-positive plasma cells infiltrating fibrotic tissue in involved organs are pathologic hallmarks of IgG4-RD. Lung involvement in patients with pancreatitis due to IgG4-RD is common and likely under recognized. CONCLUSIONS: Pulmonary involvement in IgG4-RD can show a wide array of radiographic patterns, but that seen in this case with pseudotumor and fibrosis is among the most commonly reported. Given the overlap in risk factors and radiographic appearance between IgG4-RD and pneumoconiosis, vigilance for IgG4-RD is warranted. Reference #1 Hirano K., Kawabe T., Komatsu Y., et al. High-rate pulmonary involvement in autoimmune pancreatitis. Internal Medicine Journal. 2006;36(1)58–61. doi 10.1111/j.1445-5994.2006.01009.x Reference #2 Kamisawa T, Zen Y, Pillai S, Stone JH. IgG4-related disease. Lancet. 2015 Apr 11;385(9976)1460-71. doi 10.1016/S0140-6736(14)60720-0. Epub 2014 Dec 4. PMID 25481618. Reference #3 de Buy Wenniger, L. J., Culver, E. L., & Beuers, U. (2014). Exposure to occupational antigens might predispose to IgG4-related disease. Hepatology (Baltimore, Md.), 60(4), 1453–1454. https//doi.org/10.1002/hep.26999 DISCLOSURES No relevant relationships by Jordan Minish, source=Web Response No relevant relationships by Robert Ousley, source=Web Response No relevant relationships by Meagan Reif, source=Web Response No relevant relationships by Derek Russell, source=Web Response