Diagnosis: Unclassified renal cell carcinoma with microscopic features of tumors associated to end stage and/or cystic acquired kidney disease.

Comment: The vacuolation of the cytoplasm in this tumor kidney is similar to the microscopic feature of one type of tumors associated to end stage and/or cystic acquired kidney disease (Tickoo SK et al. Spectrum of epithelial neoplasms in end-stage disease. Am J Surg Pathol 2006;30:141). However the patient has no nephropathy and the rim of normal renal parenchyma seen in Fig.5 is in favor of the clinical information. We favored the diagnosis of unclassified renal cell carcinoma because the microscopic features in this case are unusual for the common kidney tumors.