Abstract
INTRODUCTION: The association of systemic lupus erythematosus with malignancies is an uncommon occurrence. We present the case of an osteosarcoma of the urinary bladder developing in a patient with a prolonged history of active systemic lupus erythematosus. This is a previously unreported association. Primary osteosarcoma is an extremely rare disease in the urinary bladder. CASE PRESENTATION: A 24-year-old Caucasian woman with a 13-year history of systemic lupus erythematosus, who had been treated with high dose immunosuppressive agents, presented with pain and hematuria. A deeply invasive high-grade tumor was detected in the urinary bladder and the patient underwent radical surgery. A diagnosis of osteosarcoma was made based on the characteristic histology. CONCLUSION: Predisposing factors for primary sarcomas in the urinary bladder are mostly unknown; however, in our case, long-term administration of immunosuppressive agents, as well as long standing systemic lupus erythematosus, may both be of significance.