IgG4-Related Disease With Larynx Involvement: A Case Report and Literature Review.

IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder with diverse organ involvement. Laryngeal involvement is exceptionally rare and easily misdiagnosed due to its non-specific symptoms and tumor-like appearance. We report a unique case of a 60-year-old woman who presented with progressive dyspnea and was ultimately diagnosed with laryngeal IgG4-RD after multiple biopsies. Imaging revealed additional asymptomatic lesions in the palatine tonsils, subcutaneous tissue, ribs, and lymph nodes. Histology confirmed dense IgG4-positive plasma cell infiltration in the laryngeal lesion, and serum IgG4 levels were markedly elevated. The patient responded well to staged CO₂ laser surgeries and systemic glucocorticoid therapy. This case emphasizes the importance of considering IgG4-RD in patients with unexplained upper airway obstruction and highlights the value of early multidisciplinary evaluation and timely intervention.