Development of systemic lupus erythematosus after chemotherapy and radiotherapy for malignant thymoma.

Autoimmune conditions such as systemic lupus erythematosus (SLE) are sometimes associated with thymoma. Recently we drew attention to the development of SLE some months or even years following surgical thymectomy or thymomectomy. We now describe the first patient who developed SLE after chemotherapy and radiotherapy alone for malignant thymoma. A 38-yr-old female presented with an anterior mediastinal mass, which was found to be a malignant thymoma. Chemotherapy and radiotherapy were performed with complete resolution of the tumour. She remained stable for 4 yr, but then developed polyarthritis, lymphopenia, high titre anti-dsDNA antibody and antinuclear antibody. The diagnosis of SLE was established 44 months after malignant thymoma was treated. We believe that cases as this highlight the relationship between the thymus and the development of SLE.