IgG4+ Plasma Cells in Isolated Reactive Lymphadenopathy
IgG4+ Plasma Cells in Isolated Reactive Lymphadenopathy
Objectives IgG4-related disease is a recently recognized condition that can be associated with lymphadenopathy, with several histologic patterns and increased absolute number and ratio of immunoglobulin G4 (IgG4)-positive plasma cells. However, these findings are considered to be not exclusively specific for IgG4-related disease.
Methods The occurrence of the histologic patterns reported in patients with isolated lymphadenopathy was studied and correlated with the clinical presentation to determine their predictive value for IgG4-related lymphadenopathy.
Results We found cases meeting all histologic criteria for IgG4-related lymphadenopathy, without clinical signs of IgG4-related disease. The only pattern that was not seen in this series was an inflammatory pseudotumor-like picture.
Conclusion Without a clinical suspicion of IgG4-related disease, these morphologic patterns and high numbers of IgG4-positive plasma cells should be interpreted with care to avoid an erroneous diagnosis of IgG4-related disease.
Immunoglobulin G4 (IgG4)-related disease is a recently described spectrum of systemic diseases that is characterized by mass-forming lesions in different organs with extensive lymphoplasmacytic infiltration, fibrosis or sclerosis, an elevated IgG4 serum level, an increase of IgG4+ plasma cells in the affected tissues, and a good response to steroid therapy. Concomitant, usually generalized, lymphadenopathy is a common feature in patients with an IgG4-related disease, seen in up to 80% of the cases. In most patients, the lymph nodes show a moderate enlargement because of various histologic patterns of hyperplasia that have been divided into five histologic subtypes: (1) multicentric Castleman disease–like, (2) reactive follicular hyperplasia, (3) interfollicular expansion and immunoblastosis, (4) progressively transformed germinal center–like, and (5) inflammatory pseudotumor-like. A unifying feature of all subtypes is an increase in IgG4+ plasma cells with an IgG4/IgG plasma cell ratio exceeding 0.4, combined with an absolute number of IgG4+ plasma cells of more than 50/high-power field (hpf).
These characteristics of lymphadenopathy were defined in patients with lymphadenopathy in the context of clinically confirmed IgG4-related disease. The diagnostic value of these criteria in patients with lymphadenopathy of unknown origin is, however, still unclear. Several authors have reported similar histologic features in autoimmune disease.
The aim of this study was to determine the incidence of the histologic patterns described in IgG4-related lymphadenopathy and the increase in IgG4+ plasma cells in solitary reactive lymphadenopathy without clinical signs of IgG4-related disease.
Abstract and Introduction
Abstract
Objectives IgG4-related disease is a recently recognized condition that can be associated with lymphadenopathy, with several histologic patterns and increased absolute number and ratio of immunoglobulin G4 (IgG4)-positive plasma cells. However, these findings are considered to be not exclusively specific for IgG4-related disease.
Methods The occurrence of the histologic patterns reported in patients with isolated lymphadenopathy was studied and correlated with the clinical presentation to determine their predictive value for IgG4-related lymphadenopathy.
Results We found cases meeting all histologic criteria for IgG4-related lymphadenopathy, without clinical signs of IgG4-related disease. The only pattern that was not seen in this series was an inflammatory pseudotumor-like picture.
Conclusion Without a clinical suspicion of IgG4-related disease, these morphologic patterns and high numbers of IgG4-positive plasma cells should be interpreted with care to avoid an erroneous diagnosis of IgG4-related disease.
Introduction
Immunoglobulin G4 (IgG4)-related disease is a recently described spectrum of systemic diseases that is characterized by mass-forming lesions in different organs with extensive lymphoplasmacytic infiltration, fibrosis or sclerosis, an elevated IgG4 serum level, an increase of IgG4+ plasma cells in the affected tissues, and a good response to steroid therapy. Concomitant, usually generalized, lymphadenopathy is a common feature in patients with an IgG4-related disease, seen in up to 80% of the cases. In most patients, the lymph nodes show a moderate enlargement because of various histologic patterns of hyperplasia that have been divided into five histologic subtypes: (1) multicentric Castleman disease–like, (2) reactive follicular hyperplasia, (3) interfollicular expansion and immunoblastosis, (4) progressively transformed germinal center–like, and (5) inflammatory pseudotumor-like. A unifying feature of all subtypes is an increase in IgG4+ plasma cells with an IgG4/IgG plasma cell ratio exceeding 0.4, combined with an absolute number of IgG4+ plasma cells of more than 50/high-power field (hpf).
These characteristics of lymphadenopathy were defined in patients with lymphadenopathy in the context of clinically confirmed IgG4-related disease. The diagnostic value of these criteria in patients with lymphadenopathy of unknown origin is, however, still unclear. Several authors have reported similar histologic features in autoimmune disease.
The aim of this study was to determine the incidence of the histologic patterns described in IgG4-related lymphadenopathy and the increase in IgG4+ plasma cells in solitary reactive lymphadenopathy without clinical signs of IgG4-related disease.
