title: Primary osteosarcoma of the urinary bladder following cyclophosphamide therapy for systemic lupus erythematosus: a case report.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Pathology, Hacettepe University Hospital, Ankara, Turkey. dertoy@hacettepe.edu.tr.
authors.forename: Dilek Ertoy
authors.initials: DE
authors.lastname: Baydar
authors.forename: Cigdem
authors.initials: C
authors.lastname: Himmetoglu
authors.forename: Sertac
authors.initials: S
authors.lastname: Yazici
authors.forename: Halil
authors.initials: H
authors.lastname: Kiziloz
authors.forename: Haluk
authors.initials: H
authors.lastname: Ozen