Estrogens influence many physiological processes and play a crucial role in the development of several diseases, including autoimmune disorders and hormone-sensitive cancers. Systemic lupus erythematosus is one of the most common systemic autoimmune rheumatic diseases affecting young and middle-aged females. The coexistence of multiple autoimmune disorders is well recognized, whereas the association between systemic lupus erythematosus and malignancies, especially hormone-sensitive cancers, remains enigmatic. We report the unusual case of a middle-aged woman that presented with concomitance of lupus erythematosus, Hashimoto's thyroiditis, and bilateral breast cancer.