Clear cell carcinoma of the female genital tract (CCCa) shares many histologic features with clear cell renal cell carcinoma (CCRCC) and translocation-associated renal cell carcinoma (TA-RCC), the latter in particular. When CCRCC or TA-RCC metastasizes to the female genital tract, or when patients have a history of both CCCa- and RCC-developed metastatic lesions, it is critical to distinguish the 3 lesions. Such a distinction is not always possible based on the morphology alone and often requires immunostains. We therefore investigated the utility of a panel of routinely used immunohistochemical markers including cytokeratin (CK) 7 and 20, CD10, α-methylacyl-CoA racemase, carbonic anhydrase IX (CA IX), TFE3, and WT-1 in the distinction of the 3 lesions on a tissue microarray of 12 CCCa, 5 TA-RCC, and 23 CCRCC cases. CK7 was positive in all CCCa cases, but only in 20% of TA-RCCs and 4.3% of CCRCCs. In contrast, CD10 was positive in all TA-RCCs and 91.3% of CCRCCs, but in only 7.5% of CCCa cases. TFE3 was positive in all TA-RCCs, but negative in all CCCa and CCRCC cases. CA IX was positive in 87% of CCRCCs, but in only 20% of TA-RCCs, and was negative in all CCCa cases. CK20, α-methylacyl-CoA racemase, and WT-1 were not contributory to the distinction. Although morphologically similar, CCCa can be reliably distinguished from TA-RCC and CCRCC. CCCa is mostly CK7+/CD10−/CA IX−/TFE3−, TA-RCC is usually CK7−/CD10+/CA IX−/TFE3+, whereas CCRCC is mostly CK7−/CD10+/CA IX+/TFE3−. To the best of our knowledge, this was the first study to directly compare the immunophenotypes of these 3 lesions.
Department of Anatomic Pathology (H.H., M.Z., L.C.), Cleveland Clinic, Cleveland, OH
Department of Pathology (H.H.), Peking University, Health Science Center, Beijing, China
Department of Public Policy (G.X.Z.), Duke University, Durham, NC
Address correspondence and reprint requests to Longwen Chen, MD, PhD, Pathology and Laboratory Medicine Institute, Cleveland Clinic, 9500 Euclid Avenue/L25, Cleveland, OH 44195. e-mail: Chenl@ccf.org