A Comparative Analysis of Serum IgG4 Levels in Patients With IgG4-Related Disease and Other Disorders

The great imposter: A case report of IgG4-RD hypertrophic pachymeningitis with skull lytic lesion and pulmonary nodules

Immunoglobulin G4-related disease (Ig4RD) is an inflammatory condition with unique clinical, serological, and pathological features. In this study, we report a challenging diagnostic clinical case of Ig4RD diagnosed based on histopathology. This unique imitating nature reinforces that it is crucial to consider the diagnosis of IgG4-RD in those presenting with pachymeningitis.

IgG4-Related Skin Disease Presenting as a Pseudolymphoma in a White Adolescent Girl

Immunoglobulin gamma (Ig) type 4-related disease (IgG4-RD) is a chronic immunologic systemic disorder that has gained worldwide recognition in the past decade. This entity can affect almost every organ system, and its characteristic lesions have been found in a variety of organs such as lacrimal and salivary glands, pancreas, liver, bile ducts, lungs, kidneys, retroperitoneum, breast, aorta, thyroid, and prostate. This case reports a very rare case of IgG4-RD presenting with a cutaneous lesion in a young female patient mimicking a lymphoproliferative disorder. IgG4-RD affecting the skin is a rare entity and has mostly been reported in Japanese men of middle to older age. IgG4-RD with cutaneous involvement should be in the differential of non-neoplastic, lymphomas, autoimmune, and infectious disorders of the skin.

Immunoglobulin G4 related disease: a single-centre experience from South Australia

BACKGROUND

IgG₄ related disease (IgG4RD) is a newly described multisystem fibro-inflammatory disorder. There is a paucity of literature describing the Australian experience of this rare condition.

AIMS

To characterise the Royal Adelaide Hospital IgG4RD cohort with biopsy-proven disease.

METHODS

A search of the Frome Road SA Pathology database was performed for all tissue biopsies containing the phrase 'IgG₄ positive'. Case notes were reviewed for clinical details, laboratory and radiology results. Histological features according to the Boston Criteria were used. Patients with available case notes, highly suggestive or probable histology and clinical features to suggest IgG4RD were included.

RESULTS

Twenty patients had definite or probable IgG4RD and suggestive clinical features; median age 59 (20-76), male : female 1.5:1. There was considerable delay in diagnosis (median diagnosis at 64 months). Organ involvement included: 11 exocrine gland, seven pancreatobiliary, seven nodal, seven soft tissue, five retro-orbital, three retroperitoneal fibrosis and two renal. Systemic symptoms at diagnosis were seen in eight patients. Seven (35%) had an elevated serum IgG₄ (>1.35 g/L) at diagnosis. Only 12 (60%) required immunosuppressive treatment (corticosteroids); of these, four (20%) required a steroid-sparing agent and four (20%) required B-cell depleting therapy (rituximab). The median duration of follow up was 18 months.

CONCLUSIONS

This is the first characterised Australian cohort with generalised IgG4RD, a rare, relatively indolent and under-recognised multisystem disorder. Diagnosis is difficult given lack of awareness of this rare condition among physicians, its presentation as a great disease mimic, challenges with histopathological assessment and the absence of a suitable serum biomarker.