IgG4‑related disease with endobronchial nodules: A case report and literature review.

The present case report describes the case of a rare presentation of IgG4-related lung disease (IgG4-RLD) with endobronchial nodules and systemic involvement. An 84-year-old male presented with unexplained weight loss and enlarged submandibular lymph nodes. Diagnostic examinations revealed elevated serum IgG4 levels, along with findings of endobronchial nodules during bronchoscopy. Biopsies of endobronchial nodules revealed benign bronchial mucosa with fibrosis and inflammatory infiltration; however, he was not diagnosed with IgG4-RLD. A histological examination of the left salivary gland and submandibular lymph nodes confirmed the diagnosis of IgG4-related disease, revealing storiform fibrosis and abundant IgG4-positive plasma cells. The patient was treated with prednisolone, resulting in a reduction in submandibular swelling and decreased serum IgG4 levels. This case emphasizes the importance of considering IgG4-RLD as a potential diagnosis in patients presenting with endobronchial nodules and systemic disease. Accurate sampling methods, such as surgical lung biopsy or transbronchial cryobiopsies, are crucial for definitive diagnosis. Increased awareness among physicians can lead to timely recognition and appropriate management of this rare condition.