Curriculum · Gynecology / Women's Health / Infertility / Perinatal Care / Birth Spacing
Cervical intraepithelial neoplasia, colposcopy and LLETZ
What it is
Cervical intraepithelial neoplasia is the change in the cervix that lies between a normal epithelium and an invasive carcinoma. The order runs normal epithelium, HPV infection with koilocytosis, CIN1, CIN2, CIN3 and then invasive carcinoma, taking years, with an increasing probability of viral DNA integration. Three naming systems are laid over the same tissue. In the Bethesda system the cytology is LSIL or HSIL and the histology is CIN 1, CIN 2 or CIN 3. In the LAST system the cytology is again LSIL or HSIL, while the histology is LSIL, then a step in which p16 staining should be performed, then HSIL. The previous terminology called them mild dysplasia, moderate dysplasia, severe dysplasia and carcinoma in-situ, and CIN type III is that carcinoma in situ.
Causes and risk
The risk factors are HPV 16 and 18, early onset of sexual activity, multiple sexual partners, smoking and immunosuppression such as HIV. HPV is the most common sexually transmitted infection, and up to 79% of sexually active women contract HPV infection in their lifetime, so the lack of other STIs does not preclude it.