a malignant neoplasm derived from transitional epithelium, occurring chiefly in the urinary bladder, ureters, or renal pelves (especially if well differentiated); frequently papillary; these carcinomas are graded according to the degree of anaplasia. So-called transitional cell carcinoma of the upper respiratory tract is more properly classified as squamous cell carcinoma. Transitional cell carcinoma is also a rare tumor of the ovary. SYN: transitional cell carcinoma.