Histopathology of cervical precursor lesions and cancer

The most frequent types of cervical cancer are squamous-cell carcinoma and adenocarcinoma, which develop from the distinctive precursor lesions cervical intraepithelial neoplasia (CIN) / squamous intraepithelial lesion (SIL), and adenocarcinoma in situ (AIS), respectively. Their tumorigenesis is HPV-related. High-risk HPV (e.g., types 16 and 18) is integrated into the genome and leads to tumor progression. Cytological screening leads to detection of precursors and their mimics. P16 and Ki-67 immunohistochemistry assists in the histological differential diagnosis of precursors to reactive and metaplastic epithelium. For invasive cervical carcinoma, stage is the strongest prognostic factor. Per definition, microinvasive (pT1a1 / pT1a2) carcinoma is diagnosed histologically on cone biopsies and treated less radically. The distinction between adenocarcinomas of the cervix and endometrial adenocarcinomas is important and can be supported by immunohistochemistry (e.g., ER, p16, CEA, and vimentin) and HPV in-situ hybridization. The rarer adenoid-basal and neuroendocrine carcinomas are less frequently HPV-related.