Metastatic urinary tract cancers in pap test: Cytomorphologic findings and differential diagnosis

Although the cervical Pap test was devised for the detection of primary cervical neoplasia, it can provide additional diagnostic information, and in some cases, be diagnostic for noncervical processes. The diagnosis of metastatic extrauterine cervical cancers on the Pap test is extremely rare; and in most cases, it is the result of an ovarian or fallopian tube primary. Further, urinary tract cancers, including renal and urinary primaries are exceedingly rare. To our knowledge, six surgical cases of metastatic clear cell renal cell carcinoma (RCC) have been described. We report the first case of metastatic clear cell RCC detected on the cervical Pap test. Additionally, to our knowledge, we report the second case of metastatic high-grade urothelial carcinoma detected on the cervical Pap test. Both patients had a history of malignancy, which underscore the importance of broadening the differential diagnosis to rule out cytomorphologic features consistent with a patient's primary diagnosis when interpreting the cervical Pap test. Diagn. Cytopathol. 2016;44:1078–1081.