Invasive squamous cell carcinoma and cervical intraepithelial neoplasia III of uterine cervix. Morphologic differences other than stromal invasion.

The authors compared 69 cases of surgically proven invasive squamous cell carcinoma (ISCC) of uterine cervix with 48 cone biopsy specimens that showed cervical intraepithelial neoplasia (CIN) grade III. Histologic features that were preferentially associated with ISCC included the following: giant bizarre cells (66.7% in ISCC, 6.26% in CIN III, P < .01); large keratinized cells (87% in ISCC, 0% in CIN III, P < .01); keratin pearls (40.6% in ISCC, 0% in CIN III, P < .01); necrosis (79.7% in ISCC, 8.3% in CIN III, P < .01); and neovascularization (56.5% in ISCC, 0% in CIN III). In 51 (74%) cases of ISCC, a CIN III component was present, of which 18 (35.3%) showed large keratinized cells or keratin pearls in the in situ components. None of the CIN III cases showed more than one of the above features. In the ISCC group, the above features occurred with similar frequency in microinvasive and frankly invasive tumors. The authors' results agree with previous Papanicolaou-smear cytologic studies, which found that ISCC can be distinguished accurately from CIN III by the morphology of the neoplasm. The authors concluded that cervical biopsy specimens that show two or more of the above features are highly suggestive of ISCC, even when stromal tissue is absent or insufficient for the assessment of invasion. Furthermore, in cervical biopsy specimens showing CIN III, the presence of large keratinized cells or keratin pearls may signify the presence of invasive lesions elsewhere in the cervical mucosa.