[Malignant fibrohistiocytoma of the bladder]

We report on new case of a rare vesical tumour. We result the importance of immunohistochemistry and ultrastructural study to support the diagnosis of malignant fibrous histiocytoma of the urinary bladder. There has been described another 16 cases of this tumour in the literature, however, only four of them -five with ours- reports an extensive immunohistochemical and ultrastructural study. The rarity of vesical localization of this tumour may delay its diagnosis. It must be supported by a immunohistochemistry and/or ultrastructural study, in order to differentiate from other tumours with fibrohistiocytoma-like pattern: leiomyosarcoma and sarcomatoid carcinoma of the bladder. After radical removal of tumour, adjuvant therapy is recommended both systemic chemotherapy and local radiotherapy, although survival rates are over 5.3 months after first therapeutical actuation.