SESSION TITLE: Miscellaneous Cases III
SESSION TYPE: Affiliate Case Report Slide
PRESENTED ON: Sunday, October 27, 2013 at 03:00 PM - 04:00 PM
INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a newly discovered inflammatory disorder characterized by infiltration of key organs by IgG4-positive plasma cells. It typically presents with systemic lymphadenopathy in the setting of autoimmune pancreatitis and sclerosing sialadenitis, but isolated lymphadenopathy is now being increasingly recognized as an early manifestation of this disease. We present a patient with mediastinal and right hilar lymphadenopathy thought to be due to recurrence of his diffuse large B-cell lymphoma (DLBCL) until mediastinoscopy confirmed reactive lymphoid hyperplasia with unexpected findings of IgG4 plasmacytosis.
CASE PRESENTATION: A 62-year-old man with a history of Stage IV DLBCL manifesting as a chest wall mass presented with a surveillance computerized tomography (CT) scan showing enlarging mediastinal and right hilar lymph nodes. FDG-PET activity was surprisingly low and serum LDH was 124. Mediastinoscopy revealed marked IgG plasmocytosis comprised almost exclusively of IgG4. Serum IgG4:IgG ratio and IgE levels were both significantly elevated, but IL-6 levels were normal. Collagen-vascular disease serologies were unremarkable. The original chest wall mass biopsy was re-reviewed, but did not show increased levels of IgG4. Therefore, this patient was diagnosed with probable IgG4 lymphadenopathy and given high-dose steroids with good response.
DISCUSSION: IgG4-lymphadenopathy is considered a sub-category IgG4-RD in which no other organ is involved. It is characterized by marked IgG4 plasmocytosis in lymph nodes, a serum IgG4:IgG of greater than 40%, and elevated IgE levels. Mass effect on surrounding organs is the main issue; otherwise, this disease is relatively benign. Because the clinical presentation of IgG4-lymphadenopathy can mimic lymphoma, Castleman’s disease, and hyper-IL-6 autoimmune conditions, IL-6, and CRP levels should be ordered to help exclude these. In contrast to IgG4-RD in other organs, findings of storiform fibrosis and obliterative phlebitis are usually absent. Instead, five different histological subtypes are increasingly being recognized, which complicates the diagnosis: Multicentric Castleman’s Disease-Like, Follicular Hyperplasia, Interfollicular Expansion, Progressively Transformed Germinal Centers-Like, and Inflammatory Pseudotumor-Like. However, regardless of the histologic subtype, all forms of IgG4-lymphadenopathy respond readily to glucocorticoids with an excellent prognosis overall.
CONCLUSIONS: Our patient was initially suspected to have mediastinal recurrence of his DLBCL, but was found to have a completely different disease (IgG4-lymphadenopathy) on subsequent biopsy. This underscores the importance of pursuing tissue confirmation in the setting of prior lymphoma to exclude other potential etiologies which may obviate the need for toxic chemoradiotherapy and significantly affect prognosis.
Reference #1: Sato et al. International Journal of Rheumatology 2012
DISCLOSURE: The following authors have nothing to disclose: Aarti Mittal, Sara Acree, Ching-Fei Chang
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