Transitional cell carcinoma of the endometrium and endometrial carcinoma with transitional cell differentiation

Transitional cell carcinoma (TCC) is rare in the female genital tract. Although it is most common in the ovary, small series of cases in the cervix have been reported, with isolated cases described in the fallopian tube, adnexa uteri, and endometrium.

Eight cases of primary TCC involving the endometrium and 1 case of ovarian TCC metastatic to the endometrium were retrieved from the files of the Armed Forces Institute of Pathology and the University of Texas Southwestern Medical Center. Cases were selected based on the presence of endometrial TCC, whether pure or combined with other patterns, and regardless of the relative amount. Immunostaining for cytokeratins 7 and 20 was performed.

Among the 8 women with primary endometrial tumors, the mean age was 61.6 years (range, 41-83 years). Uterine bleeding was the presenting symptom in 7 women. Macroscopically, the tumors were polypoid, and infiltrated the myometrium, although the extent of infiltration varied. Seven endometrial tumors showed a papillary component. TCC was always admixed with other patterns (predominantly squamous, but also endometrioid, papillary, and serous patterns), with the proportion of the TCC component ranging from 5% to 95% (mean, 63.8%). TCC was the main invasive pattern observed in all three of the cases that had deep myometrial invasion; these cases also had vascular invasion. Seven tumors were confined to the uterus; one was metastatic to the ovary. The ovarian TCC metastatic to the endometrium had a pure TCC pattern. Five of 7 cases of TCC had cytokeratin 7+/20- immunoreactivity; 2 cases were cytokeratin 7-/20-. Treatment of primary endometrial tumors was mainly surgical, with adjuvant radiation therapy in 4 cases or chemotherapy in 1 case. Survival ranged from 3 months to 12.9 years (mean, 5.1 years). Of five women for whom follow-up was available, three were alive with no evidence of disease, one was alive with a local recurrence, and one died of unrelated disease.

TCC is a rare, distinct subtype of endometrial carcinoma with morphologic features of urothelial differentiation, but retention of a mullerian immunoprofile. While the overall prognosis does not appear to be worse than what might be anticipated for the stage of tumor present, TCC appears to be the more aggressive histologic subtype among the patterns with which it is admixed.