IgG4-related disease-like fibrosis as an indicator of IgG4-related lymphadenopathy. Ann Diagn Pathol. 2013;17:416-420. [PMID: 23702322 DOI: 10.1016/j.anndiagpath.2013.04.010]

IgG4-related lymphadenopathy

IgG4-related lymphadenopathy is a nodal manifestation of IgG4-related disease (IgG4RD) which is characterized by increased polytypic IgG4+ plasma cells and IgG4+/IgG+ plasma cell ratio in lymph nodes and morphologically manifested as various patterns of reactive lymphadenopathy: Castleman disease-like, follicular hyperplasia, interfollicular expansion, progressive transformation of germinal centers and inflammatory pseudotumor-like. It typically presents with solitary or multiple, mild to moderate lymph node enlargement in otherwise asymptomatic patients. The serum IgG4 level is frequently elevated but C-reactive protein often remains normal. In patients not having a history of IgG4RD or manifestation of extranodal IgG4RD, a diagnosis of IgG4-lymphadenopathy should only be made with great caution given the non-specific morphologic features that can overlap with ANCA-associated vasculitis, interleukin-6 syndromes, Rosai-Dorfman disease, inflammatory myofibroblastic tumor, syphilis, lymphoma, and plasma cell neoplasia. Elevated IgG4 parameters, appropriate morphologies, and clinical correlation are essential to make the diagnosis of IgG4-lymphadenopathy more specific and clinically meaningful.

IgG4-related Lymphadenopathy: A Comparative Study of 41 Cases Reveals Distinctive Histopathologic Features

Lymphadenopathy is common in patients with immunoglobulin G4-related disease (IgG4-RD). However, the described histopathologic features of IgG4-related lymphadenopathy have been shown to be largely nonspecific. In an attempt to identify features specific for nodal IgG4-RD we examined the histopathologic features of lymph nodes from 41 patients with established IgG4-RD, with comparison to 60 lymph nodes from patients without known or subsequent development of IgG4-RD. An increase in immunoglobulin (Ig) G4-positive plasma cells >100/HPF and IgG4/IgG ratio >40% was identified in 51% of IgG4-RD cases and 20% of control cases. Localization of increased IgG4-positive plasma cells and IgG4/IgG ratio to extrafollicular zones was highly associated with IgG4-RD, particularly when identified in regions of nodal fibrosis (P<0.0001; specificity: 98.3%), or in the context of marked interfollicular expansion (P=0.022; specificity: 100%). Other features characteristic of IgG4-RD included frequent eosinophils associated with IgG4-positive plasma cells, phlebitis (P=0.06), and perifollicular granulomas (P=0.16). The presence of an isolated increase in intrafollicular IgG4-positive plasma cells and IgG4/IgG ratio was more frequently present in control cases than IgG4-RD (P<0.0001). This study confirms that increased IgG4-positive plasma cells and IgG4/IgG ratio are neither sensitive nor specific for the diagnosis of IgG4-related lymphadenopathy, and most described morphologic patterns are nonspecific. In contrast, nodal involvement by IgG4-rich fibrosis akin to extranodal IgG4-RD or diffuse interfollicular expansion by IgG4-positive plasma cells are highly specific features of true IgG4-related lymphadenopathy. Our findings provide for a clinically meaningful approach to the evaluation of lymph nodes that will assist pathologists in distinguishing IgG4-related lymphadenopathy from its mimics.

Perifollicular granulomas with IgG4 plasmacytosis: A case report and review of literature

Perifollicular granuloma is a unique histologic feature and whether it is associated with immunoglobulin G4 (IgG4)-related disease is controversial. We report a case of a 38-year-old man who presented with worsening left eye pain, proptosis, tearing, gritty sensation, blurred vision and multiple lymphadenopathy. An axillary lymph node resection showed reactive follicular and interfollicular lymph node hyperplasia, and increased eosinophils and plasma cells (at least 80% of IgG⁺ plasma cells were positive for IgG4). A distinct feature was the presence of multifocal, perifollicular histiocytic granulomas, which formed a wreath around the entire follicles. The human herpes virus 8 was not detected by immunohistochemistry. In addition, an extensive panel of special stains, immunohistochemistry, and flow cytometry was negative for lymphoma, fungal, or mycobacterial infection. The findings were suggestive of IgG4-related sclerosing disease-associated lymphadenopathy. Further laboratory testing showed a significant increase of serum immunoglobulin E (> 23000 IU/mL) and slight increase of total IgG, but normal serum IgG4. Even though perifollicular granuloma is a nonspecific histopathologic feature and can be seen in other diseases, such as nodular lymphocyte predominant Hodgkin lymphoma, IgG4-related lymphadenopathy should be listed in the differential diagnoses of benign reactive lymph nodes, especially when perifollicular granuloma and plasmacytosis coexist.

Histopathological diagnostic value of the IgG4+/IgG+ ratio of plasmacytic infiltration for IgG4-related diseases: a PRISMA-compliant systematic review and meta-analysis

This article aims to perform a meta-analysis to evaluate the diagnostic value of the immunoglobulin G (IgG)4/IgG ratio of plasmacytic infiltration for IgG4-related diseases.Four databases-EMBASE, ISI Web of Knowledge, PubMed, and the Cochrane Library-were systematically searched. Approximately 200 participants from several studies were included in this research. STATA 11.2 software (Stata Corporation, College Station, TX) and Meta-DiSc 1.4 (Unit of Clinical Biostatistics, Ramon y Cajal Hospital, Madrid, Spain) were used to perform the meta-analysis.Nine studies were included in the meta-analysis. The pooled diagnostic odds ratio was 18.94 [95% confidence interval (CI), 2.89-124.30]. The sensitivity was 58.80% (95% CI, 50.90-66.30) and the specificity was 90.20% (95% CI, 81.20-95.80). The positive and negative likelihood ratios were 3.12 (95% CI, 1.07-9.16) and 0.26 (95% CI, 0.09-0.70), respectively. The area under the curve of the summary receiver-operating characteristic was 0.88.To conclude, the IgG4/IgG ratio of plasmacytic infiltration is modestly effective in diagnosing IgG-related disease.

Severe IgG4-Related Disease in a Young Child: A Diagnosis Challenge

Immunoglobulin G4-related disease (IgG4-RD) is an increasingly recognized syndrome that can appear with multiple organ involvement, typically with tumor-like swelling, lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, and elevated serum IgG4 concentrations. We report the case of a 22-month-old female child with failure to thrive and recurrent respiratory tract infections since 8 months of age. Physical examination was normal except for pulmonary auscultation with bilateral crackles and wheezes. Laboratory tests revealed elevated erythrocyte sedimentation rate, and elevated serum IgG and IgG4 with polyclonal hypergammaglobulinemia. Thoracic CT and MRI showed multiple mediastinal lymphadenopathies and a nodular posterior mediastinal mass in right paratracheal location with bronchial compression. Initial fine needle aspiration biopsy was compatible with reactive lymphadenopathy but after clinical worsening a thoracoscopic partial resection of the mass was performed and tissue biopsy revealed lymphoplasmacytic infiltrate and increased number of IgG4-positive plasma cells and a ratio of IgG4/IgG positive cells above 40%. Glucocorticoids therapy was started with symptomatic improvement, reduction in the size of the mass, and decrease of serum IgG4 levels after 6 weeks. There are very few reports of IgG4-RD in children. Long-term follow-up is necessary to monitor relapses and additional organ involvement.

The clinical spectrum of IgG4-related disease

IgG4-related disease (IgG4-RD) is an emerging immune-mediated disease with the capability of involving essentially any organ. The epidemiology of this disease has not been explored in detail. A majority of patients reported in the literature to date are from Japan, but the condition has been described all across the world and there is no strong evidence to suggest a predilection for Asian populations. The mean age at diagnosis is approximately 60 years and there is a decided male predominance for many clinical features, with an overall male:female ratio of 8:3. A cardinal feature of IgG4-RD is single or multiple organ swelling that often raises concern for malignancy. IgG4-RD should be suspected in patients presenting with unexplained enlargement or swelling of one or more organs. Presenting features vary substantially according to the specialty to which patients present first; in addition, the disease can be diagnosed unexpectedly in pathological specimens or identified incidentally on radiology studies. Involvement of major organs is common and IgG4-RD may lead to organ failure, particularly in the pancreas, liver and biliary tree, kidneys, thyroid gland, lungs, and aorta. The diagnosis of IgG4-RD relies on the coexistence of various clinical, laboratory and histopathological findings, although none is pathognomonic by itself.