Clear cell Mullerian-type adenocarcinoma of the testis is an exceedingly rare entity, and its histogenesis and clinical behavior are still poorly understood. We discuss three cases of clear cell carcinoma of the testis, compiled from a review of the literature and our personal experience. Microscopically, the tumors closely resembled clear cell carcinoma of the ovary, displaying papillae lined by clear cells with areas of hobnailing. The reported immunophenotypic features were also similar to that of ovarian tumors, as positivity for epithelial markers (CK7, CAM5.2, AE1/AE3, EMA) and Mullerian markers (PAX8, CA125) with negativity for estrogen and progesterone receptors have been observed. The pathogenesis of testicular clear cell carcinoma is still poorly understood, with reported cases displaying evidence of both mesothelial and Mullerian origin. In addition, molecular characterization of testicular clear cell carcinomas has yet to be accomplished; however, studies performed on ovarian clear cell carcinomas may provide insight to the origin, biologic behavior, and potential therapeutic modalities for this obscure, aggressive malignancy.
Keywords: Clear cell tumors; Molecular pathology; Mullerian tumors; Ovarian-type; Targeted treatment.
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