Résumé
INTRODUCTION: Bladder sarcomatoid carcinoma is a very rare variant of transitional cell carcinoma. With disputed nomenclature, the tumor has been described previously under a variety of names such as sarcomatoid carcinoma, pseudosarcoma, malignant mixed mesodermal/Müllerian tumor, metaplastic carcinoma and spindle cell carcinoma. This malignancy represents 0.3 percent of all bladder tumors and has an aggressive behavior yielding a poor prognosis despite radio and chemotherapy. CASE REPORT: An 81 y/o man presented with a transitional cell carcinoma and underwent a transurethral resection. Adjuvant onco-BCG was introduced. After 9 months of follow-up, a local tumoral recurrence occurred and a new transurethral resection revealed sarcomatoid carcinoma with osseous elements. A radical cystoprostatectomy was then carried out.