Concurrence of IgG4-related disease and Kimura disease with pulmonary embolism and lung cancer: a case report.

Background: Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a systemic disease that involves the infiltration of IgG4-positive plasma cells in multiple organs. Kimura disease (KD) presents as subcutaneous masses on the head and neck, frequently accompanied by eosinophilia and high immunoglobulin E (IgE) levels. Here, we report a rare case of concurrence of IgG4-RD and KD with manifestations of asthma, pulmonary embolism, and central diabetes insipidus accompanied by lung carcinoma.

Case Presentation: A 65-year-old Chinese male with an eight-year history of KD was admitted to our hospital with complaints of dyspnea and expectoration for one month. Laboratory examination showed a considerable elevation in the serum eosinophil count and total IgE and IgG4 levels. Chest enhanced computed tomography showed filling defects in the right pulmonary artery and a nodule in the left inferior lobe. Pancreatic enhanced magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography showed a swollen pancreatic tail and local stricture of the pancreatic duct section of the common bile duct. Enhanced MRI of the pituitary gland showed thickening of the pituitary stalk. Additionally, immunohistochemistry of the specimens collected eight years prior revealed IgG4-positive cells. Following the diagnosis of IgG4-RD with KD, glucocorticoids with immunosuppressants were initiated; there was a prompt improvement in the patient's condition. One-year post-discharge, the patient underwent wedge-shaped resection of the lung due to enlargement of the pulmonary nodule, and the pathology revealed lung squamous carcinoma.

Conclusions: This case presents a rare clinical condition in which the concurrence of IgG4-RD and KD causes various rare manifestations including asthma, pulmonary embolism, central diabetes insipidus, and complicated lung carcinoma. This highlights the importance of monitoring for malignancies in IgG4-RD patients during follow-up.