[Transitional-cell sarcomatoid carcinoma of the renal pelvis with osteoclast-type giant cells. Review of the literature].

One case of transitional cells carcinoma with sarcomatoid pattern, located in the renal pelvis in a 77 year-old male with haematuria. The tumour also expressed a non-neoplastic component of osteoclast-like giant cells which probably represent a stromal reaction of the host to the neoplasia. The tumoral cells co-express keratin and vimentin, two strands of the cytoskeleton specific for epithelial and mesenchymal cells, respectively. We speculate with the possibility of the tumoral cells fusocellular morphology being related to the vimentin expression. A review of the literature is also included.