Cervical cell changes are classified according to their degree of
abnormality using
the
Bethesda system (TBS). Further evaluation decisions are guided by the
kinds of changes seen in the cells.
Minor cell changes
Minor cervical cell changes are also called:
- Atypical squamous cells (ASC). ASC is further
classified as:
- ASC of undetermined significance
(ASC-US).
- ASC that cannot exclude high-grade squamous
intraepithelial lesions (HSIL) (ASC-H).
- Low-grade squamous intraepithelial lesions
(LSIL).
- Mild dysplasia.
Minor cervical cell changes found during a Pap test may be caused
by:
- Infection (including infection with the
human papillomavirus, or HPV).
- Inflammation of cervical
cells.
- Natural changes called
atrophic vaginitis, caused by
menopause.
- Unknown causes.
Minor cervical cell changes may:
- Disappear without treatment, so follow-up Pap
tests would be normal. Most cell changes that go away without treatment will do
so within 24 months.1
- More than 65% of ASC-US changes go away on
their own.
- More than 45% of LSIL changes go away on their
own.
- Be precancerous and begin to develop into
moderate to severe cell changes that eventually may become cancer. Follow-up
Pap tests or colposcopy can detect cell changes.
Moderate to severe cell changes
Moderate to severe cervical cell changes (also called moderate to
severe dysplasia) indicate cell changes that are more likely to be precancerous
and develop into cervical cancer if left untreated. Moderate to severe cervical
cell changes are classified in the Bethesda system (TBS) as high-grade squamous
intraepithelial lesions (HSIL) or atypical glandular cells (AGC). Follow-up
evaluation and treatment is needed.
All abnormal Pap tests require follow-up to identify development of
more severe cell changes, including
cervical cancer. Most abnormal cells can be removed or
destroyed before they become cancerous.