© 2012 The Korean Society of Pathologists/The Korean Society for Cytopathology This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License

of renal epithelial tumors, which is the current one, is based on the histopathologic, immunohistochemical, and genetic fea-tures.1 As the knowledge of and experience with renal epithelial tumors have increased, new entities and morphologic variants of the main tumor categories have emerged2,3 including tubulo-cystic carcinoma, thyroid follicular carcinoma-like tumor, clear cell papillary renal cell carcinoma (CCPRCC), and oncocytic papillary renal cell carcinoma. A precise understanding and cor-rect diagnosis of renal tumors are essential not only for the in-vestigation of cancers but also for prognostic and therapeutic purposes.4-6 CCPRCC has been recently established as a new type of renal tumor.7-15 Initially, this tumor was known as renal cell carcino-ma (RCC) occurring in association with end-stage renal disease (ESRD),7 but several studies have reported cases of CCPRCC i