• Journal of the Korean Society of Radiology
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• v.79 no.5
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• pp.276-281
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• 2018

Immunoglobulin G4 (IgG4)-related lung disease has been actively studied over the past few years. Radiologic findings of IgG4-related lung disease vary among patients, but there are no long-term follow up studies regarding variations in imaging features over the course of disease progression. In two cases with relatively long-term follow up, diverse early and late computed tomography (CT) findings of IgG4-related lung disease are reviewed in this report. In contrast to nodular or diffuse ground-glass opacity, which was predominantly noted in CT scans at earlier stages of disease, honeycombing and traction bronchiectasis were regarded as late radiologic manifestations. Solid nodules might be visible in both early and late stages; however, development of new solid nodules and enlargement of preexisting nodules could occur during disease progression. Interlobular septal thickening and mediastinal/hilar lymphadenopathy were persistent, even in later stages of the disease. These findings might be useful in making an accurate and timely diagnosis of IgG4-related lung disease.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.487-492
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• 2021

Immunoglobulin G4 (IgG4)-related disease is a systemic disease characterized by dense lymphoplasmacytic infiltrates with abundant IgG4-positive plasma cells and fibroblast proliferation. The retroperitoneal involvement of IgG4-related disease usually appears as a soft-tissue mass covering the abdominal aorta or entrapping the ureters, resulting in hydronephrosis. Here, we present a case of IgG4-related disease with retroperitoneal involvement in a 75-yearold woman with an unusual manifestation. A preoperative computed tomography (CT) scan revealed an irregular infiltrative retroperitoneal mass invading the normal anatomic barriers, raising the suspicion of malignancy or inflammation. Contrast-enhanced CT revealed a homogeneous progressive enhancement of the mass.

• Journal of the Korean Society of Radiology
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• v.83 no.4
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• pp.910-917
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• 2022

Immunoglobulin G4 (IgG4) related disease (IgG4-RD) is currently considered an immune-mediated condition and is recognized as a disorder group with common pathological, hematological, and clinical characteristics. This disease may involve diverse organs of the head and neck, and include mainly the lacrimal gland, orbit, thyroid gland, pituitary gland, and the meninges. Here, we report a case of IgG4-RD in a 65-year-old female showing head- and neck-limited but synchronously and mainly manifesting as otalgia and facial neuritis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.1
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• pp.3-11
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• 2020

Immunoglobulin G4 (IgG4)-related dacryoadenitis and sialoadenitis (IgG4-DS) are part of a multiorgan fibroinflammatory condition of unknown etiology termed IgG4-related disease (IgG4-RD), which has been recognized as a single diagnostic entity for less than 15 years. Histopathologic examination is critical for diagnosis of IgG4-RD. CD4+ T and B cells, including IgG4-expressing plasma cells, constitute the major inflammatory cell populations in IgG4-RD and are thought to cause organ damage and tissue fibrosis. Patients with IgG4-RD who have active, untreated disease exhibit significant increase of IgG4-secreting plasmablasts in the blood. Considerable insight into the immunologic mechanisms of IgG4-RD has been achieved in the last decade using novel molecular biology approaches, including next-generation and single-cell RNA sequencing. Exploring the interactions between CD4+ T cells and B lineage cells is critical for understanding the pathophysiology of IgG4-RD. Establishment of pathogenic T cell clones and identification of antigens specific to these clones constitutes the first steps in determining the pathogenesis of the disease. Herein, the clinical features and mechanistic insights regarding pathogenesis of IgG4-RD were reviewed.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.575-588
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• 2021

Immunoglobulin G4 (IgG4)-related disease is a systemic fibro-inflammatory disease characterized by pathologic findings in various organs. Imaging is critical for the diagnosis and treatment assessment of patients with IgG4-related disease. In this pictorial essay, we review the key features of multiple imaging modalities, typical pathologic findings, and differential diagnosis of IgG4-related disease. This systematic pictorial review can further our understanding of the broad-spectrum manifestations of this disease.

• Journal of the Korean Society of Radiology
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• v.83 no.5
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• pp.1168-1174
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• 2022

Immunoglobulin G4 (IgG4)-related disease is a rare systemic fibroinflammatory condition characterized by elevated serum IgG4 levels and infiltration of IgG4-positive plasma cells in various organs. IgG4-related lung disease shows varied radiologic features on chest CT. Patients usually present with a solid nodule or mass mimicking lung cancer; therefore, distinguishing between IgG4-related disease and other conditions is often challenging. Additionally, co-existing radiologic findings of IgG4-related lung disease may mimic metastasis or lymphangitic carcinomatosis of the lung. We report two cases of histopathologically confirmed IgG4-related lung disease mimicking lung cancer. Chest CT revealed a solid nodule or mass with ancillary radiologic findings, which suggested lung cancer; therefore, IgG4-related lung disease was radiologically indistinguishable from lung cancer in both cases. Measurement of serum IgG4 levels and clinical evaluation to confirm involvement of various organs may be useful to establish the differential diagnosis. However, surgical biopsy evaluation is needed for confirmation.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.757-762
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• 2023

First described in 1930 as a lipoid granulomatosis, Erdheim-Chester disease (ECD) is a rare histiocytosis encompassing a group of disorders caused by overproduction of histiocytes, a subtype of white blood cells. This disease most commonly involves the bones and can affect organs in the abdomen; however, biliary involvement is rarely reported. We report a case of ECD with biliary involvement, which rendered it difficult to radiologically distinguish ECD from immunoglobulin G4-related disease.

• Journal of the Korean Society of Radiology
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• v.84 no.6
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• pp.1373-1377
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• 2023

Immunoglobulin G4 (IgG4)-related lung disease can have various clinical courses. To our knowledge, reports of IgG4-related lung disease with waxing and waning pulmonary infiltrates only are very rare. A few lung nodules and ground glass opacities were incidentally found in a pre-operative evaluation in a 36-year-old female. The lung lesions showed waxing and waning in the follow-up chest CT. She underwent a surgical biopsy, and IgG4-related lung disease was confirmed.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.719-725
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• 2023

Immunoglobulin G4 (IgG4)-related disease is a rare systemic fibroinflammatory condition characterized by organomegaly or tumefactive lesions associated with lymphoplasmacytic infiltration rich in IgG4 plasma cells. We report a case of IgG4-related disease involving the subcutaneous layer of the left upper arm in a 48-year-old female presenting with an unusual soft tissue mass. US and MRI showed an irregular infiltrative soft tissue mass, indicating possible malignancy or inflammation. We discuss the diagnostic criteria, histopathologic features, radiological features, and treatment of IgG4-related disease.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.301-306
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• 2018

Immunoglobulin G4-related disease (IgG4RD) is a chronic inflammatory condition characterized by tissue infiltration with lymphocytes and IgG4-secreting plasma cells, as well as varying degrees of fibrosis. We report a case of a 70-year-old man with a rapid-growing cervical mass for several months. Computed tomography and positron emission tomography showed a huge, ill-defined mass involving left thyroid lobe and encasing the common carotid artery, which was clinically and radiologically suspicious for anaplastic thyroid carcinoma. Ultrasonography-guided core needle biopsy was performed and histopathology examination revealed to be consistent with IgG4RD, and the IgG4/IgG ratio was 0.6. After oral corticosteroid was administered, the mass was dramatically resolved. Because IgG4RD often presents as a single localized and infiltrated mass lesion, it can be confused and misdiagnosed as a malignancy. Thus, clinicians should consider IgG4RD as a differential diagnosis in a rapid-growing neck mass to prevent unnecessary and excessive treatments.