Abstract
The Bethesda System revised in 2001 includes categories defining risk status rather than specific diagnosis, e. g., “atypical squamous cells” (ASC), and “atypical glandular cells of undetermined significance” (AGUS).
ASC is divided into : atypical squamous cells “of undetermined significance” (ASC-US) and atypical squamous cells that “cannot exclude high-grade squamous intraepithelial lesion (HSIL) ” (ASC-H). It has been shown that a significant number of women with ASC-US are histologically diagnosed with squamous intraepithelial lesion (SIL) including HSIL (CIN 2 or 3) in subsequent or follow-up biopsies. Several studies have shown that women with ASC-H are more likely to have HSIL in subsequent biopsy than those with ASC-US, and that postmenopausal women with ASC-H are usually associated with low-grade SIL or benign change. Non neoplastic processes that could be interpreted as ASC include reactive atypia due to inflammation, irradiation effects, atrophy, immature metaplasia, and transitional metaplasia.
Follow-up in women with AGC has shown that high-grade lesions are identified in 10% to 40% of cases, and are more often squamous than glandular. Benign endocervical glandular lesions include reactive atypia due to inflammation or irradiation, tubal or tuboendometrioid metaplasia, endometriosis, endocervical polyps, and endocervical gland hyperplasia, and Arias-Stella reaction.
