CA9 and cyst: On retrospective analysis of these 3 cases, one was a 26-year-old female with unilateral renal mass diagnosed morphologically as chromophobe RCC arising in a cyst, stage pT1b, positive for CD-10, E-cadherin, caveolin and parvalbumin; focally positive for AE1/AE3, CAM5.2, CK7, EMA, RCC antigen and colloidal iron; and negative for carbonic anhydrase IX and BerEP4.