[A single bone metastasis as the initial manifestation of an undifferentiated bladder carcinoma]

The spread of Vesical Neoplasia occurs frequently through local or regional extension. Its systemic dissemination happens frequently in advanced phases but it is exceptional as initial manifestation. The case of an undifferentiated vesical carcinoma is described, its presentation was as a big size osteolytic lesion on the sacrum. Local manifestations of the tumor appeared later. The study performed both in bones as well as in the vesical mucosa showed an undifferentiated adenocarcinoma. The great resemblance and histological and immunohistochemical concordances of both biopsies confirmed that it was a primary vesical neoplasia with a metastasis in sacrum. The specific clinical evolution of this tumor is discussed which is probably related with the fact that it is an undifferentiated carcinoma.