RESUMO
Malignant renal cysts are extremely rare. Their symptomatology has been the same as of renal tumors or common renal cysts (pain, hematuria, elevated blood pressure, palpable tumor, subfebrile temperatures). Diagnostic procedures applied, which have been the same as for tumors or solitary renal cysts, comprise the following: plain x-ray IVP, retrograde ureteropyelography, scintigraphy, echotomography and diagnostic cyst puncture, arteriography, CT. Preoperative diagnosis of malignant cyst has been rather rare, i.e. the operative is more frequent during surgical exploration. In our study malignant renal cyst was present in six (8.5%) patients; in three (4.3%) patients malignant cyst was preoperatively suggested by echotomographic findings, in three (4.3%) patients the diagnosis was established intraoperatively.