Pyonephrotic kidney-An initial manifestation of cystic renal cell carcinoma

We describe an unusual and rare case of pyonephrotic kidney in a middle-aged man that ultimately turned out to be a concealed case of an underlying cystic renal cell carcinoma. In the present case an underlying renal cancer was probably the cause of cystic degeneration of the renal pelvicaylceal system complicated secondarily by pyonephrosis which was the initial presenting manifestation. We describe the second such unusual case to be reported in the English literature. We have described diagnostic problems and the underlying clinical manifestation of such a rare case.