A tale of autoimmunity: thymoma, thymectomy, and systemic lupus erythematosus.

The thymus plays an integral role in immune system regulation, modulating the development, diversity, and selection of T lymphocytes, a critical feature for the prevention of T cell-mediated autoimmunity. Thymoma is a rare tumor of the thymus. Autoimmune diseases and paraneoplastic syndromes such as myasthenia gravis, pure red blood cell aplasia, and systemic lupus erythematosus, although relatively uncommon, have been described in association with thymomas. Rare cases of post-thymectomy autoimmune related diseases, including systemic lupus erythematosus and pure red cell aplasia, have been reported in the literature. Here, we present the case of a 65-year-old male who developed systemic lupus erythematosus 2 years after thymectomy in the setting of thymoma-associated pure red cell aplasia.