Squamous intraepithelial lesions

C ervical carcinoma is a significant contributor to cancer-related morbidity and mortality worldwide and the role of human papillomavirus (HPV) in the development of preinvasive and invasive cervical lesions is well established. 2 Although significant advances have been made in elucidating the potential mechanisms of cellular transformation by HPV and in the molecular detection of HPV in cytological and surgical specimens, morphological assessment of surgical material remains the ‘‘gold standard’’ in the diagnosis of cervical intraepithelial neoplasia (CIN). Although management of preinvasive cervical disease depends on many factors including the age of the patient, parity and size of the lesion, clinical management often requires confirmation of CIN by histological examination with subsequent surgical treatment of highgrade lesions (CIN 2 or CIN 3). This has fueled attempts at more objective, reproducible diagnostic parameters to accurately diagnose CIN. The histological features of preinvasive cervical neoplasia (CIN 2 and 3) are well understood, however inconsistent use and misinterpretation of the morphological criteria could lead to significant intraobserver and interobserver variability. This lack of reproducibility and the fact that there are many benign changes that can mimic dysplasia of the cervical epithelium (eg, cervical atrophy and immature squamous metaplasia) have led to significant efforts to identify a surrogate marker for high-grade CIN. In the following discussion, we will present the criteria that we use in our general surgical pathology practice, along with potential pitfalls and approaches to histological mimics of cervical neoplasia. We will propose incorporating the use of ancillary techniques such as immunohistochemistry for p16 and MIB-1 (Ki-67), as well as the role of HPV in situ hybridisation, in the grading of CIN.