Intraepithelial neoplasia mimicking microinvasive squamous-cell carcinoma in endocervical brushings

The interpretation of endocervical brush specimens requires familiarity with the various benign, atypical, dysplastic, and invasive neoplastic changes in cells located in the endocervical canal. There are several pitfalls in the cytologic evaluation of brush specimens that may result in diagnostic difficulty and error. We report seven cases of high-grade squamous intraepithelial lesions that were sampled by endocervical brushing and confirmed by cone biopsy or hysterectomy in which the cytologic changes in the Papanicolaou smears mimicked those of microinvasive squamous-cell carcinoma. The cells in the smears were compared with those in the tissue sections to determine their sites of origin. Results of this study indicate that cells with features fulfilling the criteria for microinvasive carcinoma were found primarily in brushing smears and corresponded with the features of cells involving the endocervical glands rather than those in the surface epithelium. We conclude that the criteria that have been promulgated for the cytologic diagnosis of microinvasive squamous-cell carcinoma have limited value in the examination of endocervical brush specimens.