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 cell changes may go away without treatment. But sometimes they turn into more serious cell changes. Types of minor cell changes include:
Atypical squamous cells (ASC). These are changes for which the cause is unknown. They may be caused by an HPV infection. Or they may be caused by inflammation, another infection, or atrophic vaginitis. ASC is further classified as:
ASC of undetermined significance (ASC-US). These changes usually stay the same or return to normal.
ASC that cannot exclude high-grade squamous intraepithelial lesions (HSIL) (ASC-H). These changes are also minor. But they are more likely to become more serious.
A low-grade squamous intraepithelial lesion (LSIL). This is also called mild dysplasia. This change is usually caused by HPV and may be more likely to become more severe over time. But even when it does, it usually returns to normal.
Moderate to severe cell changes
Moderate to severe cervical cell changes (also called moderate to severe dysplasia) mean 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 is needed, and treatment may be 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.
Medical Review:Sarah Marshall MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine & Kevin C. Kiley MD - Obstetrics and Gynecology
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