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.
