[Bladder carcinosarcoma with osteosarcomatous differentiation].

Osteoid tissue can eventually be identified outside the bone skeleton adopting the form of metastasis, osteoid metaplasia or primitive osteosarcoma. This latter presentation is most frequently located in soft tissues and exceptionally at the visceral level. The term used for any of these forms is extra-bone osteogenic sarcoma. This paper reports the case of a 62 year-old female patient diagnosed with vesical urothelial carcinosarcoma treated with external radiotherapy. After a disease-free period of 20 years the patient developed osteosarcomatous-differentiated vesical carcinosarcoma. A literature review is made to analyze, from a clinical and histopathological perspective, several items of interest presented by this pathology. The role of sarcomatous radio-induction is also highlighted. Finally, we emphasize the relevance of using radical treatments from the start, so as to restrain the highly malignant potential of this condition.