[Multiple synchronous primary malignant tumors of fibrosarcoma and squamous cell carcinoma in the urinary bladder: a case report].

: A 65-year-old housewife presented with a diagnosis of malignant spindle cell tumor of the bladder which had been diagnosed by work up for chance hematuria. Urine cytology revealed a small number of squamous epithelial cells showing dyskeratosis but no spindle cells. Computed tomography and magnetic resonance images showed a markedly enhanced mass, 4 cm in diameter, on the anterior wall of the urinary bladder, which appeared to be adhesive to the pubic bone. However, no metastasis was found. Under the suspicion of sarcoma of the urinary bladder, we performed anterior pelvic exenteration with construction of an ileal conduit. Although the anterior wall of the urinary bladder was mildly adhesive to the pubic bone, the surgical margin was negative for malignant cells. The tumor corresponded to a fibrosarcoma that infiltrated the adipose tissue surrounding the urinary bladder. The entire mucosa of the bladder showed diffuse squamous metaplasia, and well differentiated squamous cell carcinoma with pearl formation was found in part. These two malignant tumors were clearly apart from each other, resulting in the histologic diagnosis of synchronous multiple malignant tumors of the bladder. The patient developed a local relapse and pulmonary metastasis of fibrosarcoma one month postoperatively and died two month later without any response to chemotherapy (CYVADIC) and radiotherapy. The current case seems to be the first one in Japan (third in the world) of a patient with multiple synchronous primary malignant tumors, carcinoma and sarcoma, airsing in the urinary bladder.