Squamous carcinoma of the uterine cervix with CIN 3-like growth pattern: An under-diagnosed lesion

Podoplanin and SOX2 Expression in CIN 3-like Squamous Cell Carcinoma of the Cervix

Squamous cell carcinoma (SCC) of the uterine cervix occasionally demonstrates a deceptive growth pattern that mimics endocervical crypt involvement by cervical intraepithelial neoplasia, grade 3 (CIN 3). Such CIN 3-like SCCs may be misinterpreted as noninvasive or minimally invasive leading to delays in diagnosis. Little is known of the factors that influence the growth patterns of cervical SCC but we suggested recently that CIN 3-like tumors might demonstrate "collective cellular invasion," which is characterized by a retained epithelial phenotype. This contrasts with the more overtly infiltrative growth of conventional SCC, which exhibits features suggestive of epithelial-mesenchymal transition. In the current study we investigated podoplanin (PP) and SOX2 expression in normal squamous epithelium, in CIN 3 and in 16 CIN 3-like SCCs 11 of which also showed a conventional invasive component. Compared with normal epithelium, CIN 3 often showed a focal loss of basal PP staining and most cases showed increased, typically diffuse, SOX2 expression. Although the immunohistochemical findings were not uniform, they generally supported collective cellular invasion in CIN 3-like tumor areas as these were often PP positive and showed diffuse SOX2 expression. In contrast, most conventional SCCs showed only focal SOX2 staining and they were typically negative, or only focally positive, for PP. The staining patterns did not reliably distinguish CIN 3 from CIN 3-like SCC. Small infiltrative tumor nests around the margins of CIN 3 or deeply invasive CIN 3-like SCC often showed a localized reduction in SOX2 expression suggesting SOX2 downregulation during the transition to invasive growth.

Cervical intraepithelial neoplasia (CIN) 3-like squamous cell carcinoma of the cervix: a review of 14 cases with comparison of E-cadherin and cyclin D1 expression in the CIN 3-like and infiltrative tumour elements

AIMS

To review the clinicopathological features of 14 cases of CIN 3-like squamous cell carcinoma (SCC) of the cervix and to investigate possible mechanisms of tumour invasion in the CIN 3-like and 'conventional' (infiltrative) tumour components.

METHODS AND RESULTS

The median patient age was 43.4 years. Of the 12 cases with known stage, eight were stage IB and four were stage II. Initial biopsies were often misinterpreted as CIN 3 alone or CIN 3 with only superficial stromal invasion, and eight patients underwent multiple biopsy procedures prior to definitive diagnosis: upon review, an earlier diagnosis was possible in six of these cases. Nine tumours exhibited both CIN 3-like and conventional tumour components. The former usually demonstrated an E-cadherin-positive and cyclin D1-negative immunophenotype, whereas conventional SCC more often showed loss of E-cadherin and cyclin D1 staining at the margin of larger tumour nests and in smaller invasive clusters.

CONCLUSION

Cervical SCCs demonstrating a CIN 3-like growth pattern continue to present diagnostic difficulty and are often misinterpreted as non-invasive/minimally invasive disease. The morphology and immunophenotype suggest a process of collective cellular invasion in CIN 3-like SCC, whereas corresponding conventional SCC elements show features consistent with epithelial-mesenchymal transition.

Problematic issues in the staging of endometrial, cervical and vulval carcinomas

The International Federation of Gynecology and Obstetrics (FIGO) staging of tumours of the uterine corpus, cervix and vulva was revised in 2009. The greatest impact of the revised staging was on carcinomas of the uterine corpus. Uterine sarcomas are now staged separately. Changes to the staging system for vulvar carcinomas largely reflect the significance of lymph node status. Only minor amendments have been introduced for cervical carcinomas, which remain the only gynaecological tumours to be staged clinically. These revisions, based on recent evidence, require careful, more detailed assessment of several histological parameters at each anatomical site. The present review deals with the evidence and rationale underpinning the revisions, and includes practical guidance on tumour staging. This covers the assessment and measurement of myoinvasion and evaluation of cervical, parametrial, serosal and vaginal involvement in carcinomas of the uterine corpus; the identification and accurate measurement of stromal invasion in cervical and vulvar carcinomas; the assessment of unusual variants of carcinoma at each of these sites; and the assessment of lymph node involvement.