[Clear-cell sarcoma of the kidney: the clinico-morphological, immunohistochemical and electron microscopic study of 22 cases].

22 cases of clear cell sarcoma of the kidney (CCSK) were studied, 15 of them ultrastructurally and 7--immunohistochemically. CCSK is a rare malignant tumour of children, predominantly males, with an involvement of one kidney and frequent multiple metastases to the bones. Typical, epithelioid-trabecular, hyalinizing, cystic and myxoid variants are distinguished at the light microscopic level. As vimentin was found in tumour cells in all cases, antibodies against vimentin and cytokeratin can be recommended for differential diagnosis between CCSK and Wilms tumour and rhabdoid tumour. Peculiar vascular pattern can be revealed by means of antibodies against factor VIII. Immunohistochemical properties (presence of vimentin) and electron microscopy allow suggesting histogenic relation of CCSK with pericytes.