RESUMEN
A thymic carcinoma is a rare malignant neoplasm of the thymus epithelium, which can be distinguished from a benign or invasive thymoma. Contrary to a thymoma, the association of a thymic carcinoma and autoimmune disease is rare, with only a few cases having been reported. Herein, a case of thymic carcinoma diagnosed concurrently with systemic lupus erythematosus (SLE) is reported. A 49 year-old man presented at our clinic with myalgia. He was diagnosed with SLE, based on an oral ulcer, lymphopenia, and positive ANA and anti-Sm antibodies. Incidentally, a routine chest X-ray showed a large mediastinal mass. Pathological examination of the mediastinal mass revealed an undifferentiated thymic carcinoma, of WHO classification type C. Further work-up for staging showed multiple bone and lung metastases. With a palliative aim, he received systemic chemotherapy, but refused further chemotherapy after the 2nd course. Currently, the patient has not been followed up since the chemotherapy.