A Clear-cell carcinoma is a carcinoma (i.e. not a sarcoma) showing clear cells. A Clear-cell carcinoma is a carcinoma (i.e. not a sarcoma) showing clear cells. 'A rare type of tumor, usually of the female genital tract, in which the insides of the cells look clear when viewed under a microscope. Also called clear cell adenocarcinoma and mesonephroma.'