[Huge retrovesical tumor as an incidental finding: desmoid-type fibromatosis: a case report].

We report the case of a 57-year-old patient with a huge, retrovesical, aggressive desmoid fibromatosis detected incidentally during preoperative staging for radical prostatectomy. The tumor was locally invasive consisting of monoclonal and fibroblastic proliferations. The etiology of such tumors is not well known but they are mostly sporadic and aggressive fibromatosis is sometimes associated with familial adenomatous polyposis (FAP) or Gardner's syndrome. Such desmoid tumors are slow growing and locally invasive but lack metastatic potential. Complete resection with wide margins is the therapy of choice and the tendency to recur is high. Radiotherapy following surgery is controversial. We discuss the pathogenesis, clinical manifestations and therapy of such rare tumors.