Isolated IgG4 related disease of the trachea.

IgG4 related disease (IgG4-RD) is a multisystem inflammatory disease and can affect several organs including salivary glands, orbits, lungs, pancreas, kidneys and lymph nodes. Up to 40 % of patients have allergic manifestations including asthma, chronic rhinosinusitis, eczema and asthma. Commonly pulmonary manifestations include pulmonary nodules ranging from <1 to 5 cm in diameter, interstitial opacities and mediastinal lymphadenopathy. Rarely, IgG4-RD presents as isolated tracheal disease. Symptoms include dyspnea and stridor due to airway narrowing. Diagnosis of IgG4-RD including tracheal IgG4-RD requires a biopsy. The histologic specimen is characterized by lymphoplasmacytic infiltrate with high density of IgG4 positive plasma cells, and storiform fibrosis (a cartwheel appearance of fibroblasts and inflammatory cells). Up to 30 % of patients with IgG4-RD have normal serum IgG4 levels. The mainstay of therapy is glucocorticoids for those with systemic disease. Rituximab is an alternative for those who cannot tolerate glucocorticoids or those with disease recurrence. Patients with tracheal disease often require balloon dilation. Recurrence is common in patients and up to two thirds of patients have residual disease despite treatment. These patients often require surgical resection of affected area for symptomatic relief.