Squamous intraepithelial lesion

Author: Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, 2015.

What is squamous intraepithelial lesion?

Squamous intraepithelial lesion (SIL) is the current preferred terminology to use when referring to superficial non-invasive mucosal neoplasias of the anogenital region associated with human papillomavirus (HPV) infection. The tumours can be classified as high grade (HSIL) or low grade (LSIL).

SIL is also commonly known by older names relating to the specific site of the lesion, as squamous cell carcinoma in situ, or as Bowen disease.

Contribute to Dermnet

Did you find this page useful? We want to continue to deliver accurate dermatological information to health professionals and their patients — for free. Funding goes towards creating articles for DermNet, supporting researchers, and improving dermatological knowledge around the world.

Donate now with credit card or Paypal


Related information


On DermNet NZ

Books about skin diseases

See the DermNet NZ bookstore.