Thoracic paravertebral involvement in patients with IgG4-related disease: CT and MR imaging findings

Paravertebral fibrous pseudotumor: Four cases of a distinctive tumefactive lesion overlapping with eosinophilic angiocentric fibrosis and tumoral erythema elevatum diutinum

Eosinophilic angiocentric fibrosis (EAF) is a rare tumefactive fibroinflammatory disease with predilection for the upper respiratory tract, characterized by concentric (onionskin) fibrosis around small arterioles with variable intervening storiform fibrosis admixed with chronic inflammatory infiltrates rich in eosinophils. Erythema elevatum diutinum (EED), another autoimmunological disorder that mainly affects acral sites and extensor surfaces, is characterized by neutrophilic leukocytoclastic vasculitis. Rarely, older EED lesions may present as tumefactive nodular (pseudotumoral) fibrous masses closely mimicking EAF. We herein describe four patients (all males) aged 66-70 years who presented with large (median, 7 cm) tumor-like fibrous lesions in the paravertebral region not associated with a known clinical autoimmune disease. All cases were resected surgically with the suspicion of a neoplasm. They displayed a strikingly similar histological appearance with combined features of EAF and nodular fibrous EED. None had evidence of obliterative phlebitis or increased IgG4: IgG ratio. The etiology of this distinctive lesion and its predilection for the paravertebral area of males remains obscure. A distinctive tumefactive localized reaction to trauma caused by degenerative disease of adjacent vertebrae might be a possible explanation.

American College of Rheumatology and the European League Against Rheumatism classification criteria for IgG4-related disease: an update for radiologists

IgG4-related disease (IgG4-RD) is an immune-mediated, multiorgan, chronic inflammatory disease. The three-step classification criteria proposed in 2019 by the American College of Rheumatology and the European League Against Rheumatism (ACR/EULAR) encompass a wide range of clinical, radiological, serological, and histopathological findings. The ACR/EULAR proposed a three-step classification process, i.e., entry step, exclusion step, and scoring system. Radiologists need to know that the radiological findings observed in the five domains of the lacrimal and salivary glands, chest, pancreas and biliary ducts, kidney, and retroperitoneum are independently weighted with different points in the scoring system. A total score < 20 points indicates that the patient should not be classified as having IgG4-RD; conversely, a total score ≥ 20 points indicates that the patient should be classified as having IgG4-RD. In this review, the 2019 ACR/EULAR classification criteria are discussed, focusing on the interpretation of each radiological item, with the aim of applying them to the diagnosis of IgG4-RD in clinical practice.

Immunoglobulin G4-related disease involving multiple systems: A case report

BACKGROUND

IgG4-related disease (IgG4-RD), an immune-mediated chronic progressive fibroinflammatory disease, can affect the functions of several organs. Some common characteristics can be observed in different IgG4-RDs, such as higher prevalence in middle-aged and elderly male patients, raised serum IgG4 levels, abundant infiltration of IgG4-positive cells and fibrosis, diffuse or localized swelling of the affected organs, and good response to glucocorticoids treatment.

CASE SUMMARY

A 72-year-old man complained of left upper abdominal pain 3 mo ago, and he was diagnosed with acute onset of chronic cholecystitis and acute pancreatitis in the local hospital. Pain improved after relevant treatment. Several days ago, his abdominal pain worsened, and he was admitted to our hospital for further treatment. Doppler ultrasound showed that the pancreas presented with sausage-like swelling and the parenchymal echo was diffusely reduced. Gallbladder volume was increased, while the wall was rough and thickened with bilateral signs. Furthermore, the left submandibular gland was enlarged, accompanied with significantly increased blood flow signals. Finally, we found that the adventitia of the abdominal aorta and right iliac artery was thickened locally. Serum IgG4 was elevated to 12600 mg/L. Therefore, the patient was diagnosed with IgG4-RD. After treatment with methylprednisolone, he had an uneventful course and was discharged in good condition.

CONCLUSION

IgG4-RD can involve almost any organs. Ultrasound has a significant role in timely and accurately diagnosis.

[Immunoglobulin G4-Related Disease in the Thorax: Imaging Findings and Differential Diagnosis]

Immunoglobulin G4-related disease (IgG4-RD) is a chronic inflammatory condition involving multiple organs, including the salivary or lacrimal glands, orbit, pancreas, bile duct, liver, kidney, retroperitoneum, aorta, lung, and lymph nodes. It is histologically characterized by tissue infiltration with lymphocytes and IgG4-secreting plasma cells, storiform fibrosis, and obliterative phlebitis. In the thoracic involvement of IgG4-RD, mediastinal lymphadenopathy and perilymphangitic interstitial thickening of the lung are the most common findings. Peribronchovascular and septal thickening and paravertebral band-like soft tissue are characteristic findings of IgG4-RD. Other findings include pulmonary nodules or masses, ground-glass opacity, alveolar interstitial thickening, pleural effusion or thickening, mass in the chest wall or mediastinum, and arteritis involving the aorta and coronary artery. Radiologic differential diagnosis of various malignancies, infections, and inflammatory conditions is needed. In this review, we describe the imaging findings of IgG4-RD and the radiologic differential diagnoses in the thorax.