Immunoglobulin G4-related disease: case report and literature review

IgG4-related disease: Case report and 6-year follow-up of an elusive diagnosis mimicking malignancy

Key Clinical Message

IgG4-related disease is a rare and emerging pathology, characterized by the appearance of pseudotumors. Due to the ability to mimic other pathologies, it is essential to consider it as a differential diagnosis in multisystemic processes. The diagnosis is challenging, requiring a multidisciplinary approach, to minimize the associated morbidity and mortality.

Abstract

IgG4-related disease (IgG4-RD) is a rare, emerging, systemic and chronic pathology, characterized by the appearance of pseudotumors resulting from tissue infiltration by IgG4-positive plasma cells that promote eosinophilic inflammation of the tissue with subsequent fibrosis. We present the case of a male, 45-year-old patient, with marked weight loss and skin pallor detected by his family doctor during a child health consultation of his daughter. When questioned, the patient referred complaints of postprandial discomfort in the left hypochondrium with a feeling of fullness, weight loss, chronic fatigue and hyperhidrosis that had lasted for a month. On physical examination, he was pale, and had pain at palpation of the left hypochondrium. Laboratory data showed increased inflammation markers, abdominal ultrasound and CT demonstrated numerous enlarged lymph nodes in the upper quadrants, raising concern for a malignant lymphoproliferative process. Serological, imaging, clinical and laparoscopic excisional biopsy revealed features of IgG4-related disease and excluded malignant lymphoproliferative disease. The immediate response to treatment with oral prednisolone 30 mg/day also contributed for diagnosis confirmation. Due to refractory disease after gradual prednisolone reduction, second-line therapy with rituximab was initiated. Over the 6 years of follow-up, the patient presented multiple exacerbations characterized by the emergence of systemic symptoms, being maintained under close clinical and imaging follow-up by reumathology, infectious diseases, and family medicine specialists.

Immunoglobulin G4-related hypertrophic pachymeningitis with an isolated scalp mass mimicking a brain tumor: a case report and literature review

Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune disorder associated with fibroinflammatory conditions that can affect multiple organs. Hallmark histopathological findings of IgG4-RD include lymphocytic infiltration of IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis. However, little is known about central nervous system involvement of IgG4-RD. Hypertrophic pachymeningitis (HP) has recently been reported as a manifestation of IgG4-RD, which may have previously been demonstrated in a significant percentage of idiopathic cases. Herein, we report a rare case of a 63-year-old male who presented with a scalp mass that mimicked a brain tumor. He was diagnosed with IgG4-related HP (IgG4-RP) after surgery. This case suggests that awareness of a possibility of IgG4-RP in patients with isolated scalp masses, even in the absence of systemic symptoms, is crucial. A combination of careful history taking, evaluation of serum IgG4-levels and imaging as an initial work-up, followed by tissue biopsy, is important for the differential diagnosis of IgG4-RP, malignancy, and other infectious diseases.

IgG4-related hypertrophic pachymeningitis with ANCA-positivity: A case series report and literature review

Background

Hypertrophic pachymeningitis (HP) is a rare inflammatory disorder characterized by local or diffuse thickening of the intracranial or spinal dura mater. The most frequent cause of HP is antineutrophil cytoplasmic antibodies (ANCA), followed by IgG4. However, few cases of IgG4-HP coexpressing ANCA have been reported. Herein, we present three cases of IgG4-HP coexpressing ANCA and review the relevant literature to document the overlap of these two HP causes as a potential clinical pattern.

Methods

We retrospectively analyzed three patients with IgG4-HP coexpressing ANCA in our center and consulted the PubMed database to find other relevant cases reported in English from 1976 to April 2022. We used the following keywords: pachymeningitis, meningitis, dura, antineutrophil cytoplasmic antibody, myeloperoxidase, and proteinase-3. We analyzed the clinical, serological, radiological, and pathological characteristics of the obtained cases based on the ACR and Chapel Hill criteria and the exponential moving average (EMA) algorism for ANCA-associated vasculitis (AAV) and the IgG4-RD Comprehensive Diagnostic Criteria.

Results

We analyzed a total of 10 cases: seven literature reports and our three patients (52- and 61-year-old women and a 65-year-old man). The IgG4-related disease (IgG4-RD) diagnoses were definitive in four cases, and probable and possible in three cases. Eight patients had ANCA against myeloperoxidase (MPO), and two had ANCA against proteinase-3 (PR3). Two patients had both IgG4-RD and AAV, while the others only had ANCA seropositivity without additional clinical or pathological markers of AAV.

Conclusion

With regard to HP, we reconfirmed the existence of the IgG4-RD and AAV overlap syndrome. Meanwhile, our review does not support the hypothesis that ANCA positivity in IgG4-RD results from an excessive B-cell response. We speculate that IgG4-RD and AAV have similar or associated pathogeneses, although uncovering the role of IgG4 and ANCA in these pathophysiological processes requires further investigation.