Cervical Intraepithelial Neoplasia (CIN)

CIN is a pre-cancerous (pre-invasive) condition, where abnormal (dysplastic) cells are present within the cervical epithelium that have NOT invaded through the basement membrane (thus “intraepithelial”).

CIN can be classified into 3 grades based on histological findings, primarily according to the proportion of the epithelium involved by dysplastic cells

• CIN I = lower 1/3 of epithelium
• CIN 2 = lower 2/3 of epithelium
• CIN 3 = > lower 2/3 to full thickness of epithelium

CIN is asymptomatic; it can only be detected via cervical screening (see the Cervical Cancer article).

Management depends on the CIN grade:

*Certain patients with CIN 2 can undergo active observation (conservative management) as an alternative to immediate treatment, but only if they meet very specific safety criteria (e.g. small lesion, MDT approval, committing to strict 6-monthly check-ups)