Résumé
Sarcomatoid carcinoma is a rare malignant tumor that has both malignant epithelial and mesenchymal components. We describe a sarcomatoid carcinoma arising in the left renal pelvis of a 49-year-old man. The dominant component of the tumor was chondrosarcomatous, but there were also focal carcinomatous areas. The carcinomatous tumor cells consisted of papillary urothelial carcinoma. Immunohistochemical assay showed that the sarcomatous tumor cells were positive for vimentin and S 100 and negative for cytokeratin. The papillary urothelial carcinoma was positive for cytokeratin and negative for vimentin. The patient underwent neoadjuvant chemotherapy and after downsizing the tumor, radical nephrectomy was performed with excision of the cuff of bladder.