ABSTRACT
Behcet's disease is a systemic inflammatory disorder of unknown etiology, characterized by recurrent oral aphthous ulcers, genital ulcers, uveitis, and skin lesions. Renal involvement is rare in patients with Behcet's disease particularly immunoglobulin A (IgA) nephropathy. Other autoimmune diseases have been associated with increased risk of malignancy, but not Behcet's disease. Some cases of Behcet's disease accompanied by bladder cancer, thyroid cancer, stomach cancer, or hematologic malignancies have been reported. However, to the best of our knowledge, co-occurrence of Behcet's diseases with thymic carcinoma has not yet been reported. We experienced a 49-year-old male patient who had been treated for Behcet disease and IgA nephropathy, who presented with a large mediastinal mass on chest x-ray. After thymectomy, he was diagnosed with thymic carcinoma with complete resection.