Abstract

A carcinosarcoma implies a mixed neoplasm containing epithelial and mesenchymal elements, each of which displays a different morphological criterion of malignancy. These neoplasms are relatively rare and mainly encountered in various organs, such as uterus, breast, esophagus, larynx, lung, urinary bladder, prostate and salpinx. In kidney, malignant neoplasm comprised of epithelial and sarcomatous components are usually, designated as Wilms' tumor or nephroblastoma and commonly occur in children. Although most of authors have thought that carcinosarcoma is an adult Wilms' tumor, there well documented cases of carcinosarcoma in adult kidney. We reported a case of carcinosarcoma arising in 42-year-old male kidney, who had underwent three times of operation because of recurrent transitsonal cell carcinoma of urinary bladder. Histologically the neoplasm was composed of epithelial components of transitional and squamous cell carcinoma, and mesenchymal components of fibrosarcoma, myxosarcoma, myosarcoma, and undifferentiated sarcoma.