IgG4-related disease confined to the laryngopharynx: a case report highlighting the complexities in diagnosis for this rare cause of stridor.

This case represents only the 15th reported incidence of IgG4-related disease (IgG4-RD) affecting the laryngopharynx, adding diagnostic and therapeutic data for this rare condition and helping to inform the future management of these patients. A 66-year-old man presented with airway symptoms, and investigations by otolaryngology, cardiology and respiratory teams did not provide a clear diagnosis. Repeat biopsies of the laryngopharynx eventually confirmed a clinicopathological diagnosis of IgG4-RD. Treatment with prednisolone and methotrexate was successful. When infective and malignant causes of adult stridor have been excluded, inflammatory causes should be considered. The diagnosis of IgG4-RD isolated to the laryngopharynx may be delayed when using the widely accepted American College of Rheumatology classification criteria because it excludes upper aerodigestive tract features. IgG4-RD isolated to the laryngopharynx is extremely rare. This means a multidisciplinary approach is vital in ensuring timely diagnosis and treatment. Better diagnostic criteria are also needed.