Metastatic Urothelial Carcinoma to the Uterine Cervix: A Case Report of a Rare Entity and Review of the Diagnostic Differential.

Urothelial carcinoma (UC) rarely metastasizes to the gynecologic tract, occurring in descending order of frequency, within the vagina, uterus, ovaries, and cervix. Significant morphologic overlap exists between primary gynecologic squamous lesions (both benign and malignant) and metastatic UC, thus potentially hindering a timely and accurate diagnosis. We present a case of UC metastatic to the uterine cervix in a 69-year-old female initially found to have noninvasive high-grade papillary UC of the bladder. Complaints of vaginal spotting lead to identification and biopsy of a mass in the uterine cervix. Histologic evaluation of the cervical mass showed a neoplastic proliferation of atypical epithelioid cells arranged in a papillary architecture. The differential in this case included primary uterine cervical tumors such as condyloma acuminatum, immature condyloma, verrucous carcinoma, warty/condylomatous carcinoma, and papillary squamotransitional cell carcinoma, as well as metastatic UC. A careful evaluation of histologic variances and a selective immunohistochemical panel allows differentiation of these tumors. We herein review the subtle, albeit significant, histologic and immunohistochemical differences of the aforementioned lesions.