An epithelial cell abnormality is a finding on a Pap smear indicating that the cells lining your cervix look different from normal under a microscope. Roughly 9% of Pap tests return some type of abnormal epithelial cell result. Most of these findings are not cancer. They range from minor, often temporary cell changes to more serious precancerous conditions that need treatment.
The term comes from the Bethesda System, a standardized way pathologists categorize and report cervical screening results. If your Pap result mentions an epithelial cell abnormality, it falls into one of several specific categories, and each one carries a different level of concern and a different next step.
The Two Main Types of Abnormal Cells
Your cervix is covered by two kinds of epithelial cells: squamous cells (flat cells on the outer surface) and glandular cells (column-shaped cells lining the cervical canal). Abnormalities can occur in either type, and the distinction matters because glandular abnormalities tend to be harder to detect and can signal problems in the uterus as well as the cervix.
Squamous cell abnormalities are far more common. They account for the vast majority of abnormal Pap results and are graded on a spectrum from mildly unusual to clearly precancerous. Glandular cell abnormalities are less frequent but clinically significant because they cover a wide range of possibilities, from benign inflammatory changes to dysplasia and, rarely, malignancy.
Squamous Cell Abnormalities: From Mild to Serious
ASC-US (atypical squamous cells of undetermined significance) is the mildest and most common finding. It means some cells look slightly off, but not enough to call them precancerous. Irritation, yeast infections, low estrogen from menopause, and even recent sexual activity can all trigger an ASC-US result. When HPV testing comes back negative alongside ASC-US, the cause is often hormonal or inflammatory, and your provider may simply recommend repeating the test in a year.
ASC-H (atypical squamous cells, cannot exclude a high-grade lesion) is a step up in concern. The cells still don’t look definitively precancerous, but they have features that could indicate a more serious change. Because the risk of a significant underlying abnormality is higher, a colposcopy (a magnified visual exam of the cervix, often with a small biopsy) is typically recommended right away.
LSIL (low-grade squamous intraepithelial lesion) means there are clear but mild cell changes, usually driven by an HPV infection. Many LSIL findings resolve on their own as the immune system clears the virus, often within a year. For most people, the next step is colposcopy to get a closer look, though in some cases monitoring with repeat testing is appropriate.
HSIL (high-grade squamous intraepithelial lesion) represents more advanced precancerous changes. About 60% of people with HSIL on a Pap will have confirmed moderate-to-severe precancerous tissue on biopsy. Around 2% will already have invasive cancer at the time of diagnosis, a figure that rises in older age groups. Women over 30 with HSIL face an 8% risk of cervical cancer within five years if the abnormality goes unaddressed. This is the category where prompt action matters most.
Glandular Cell Abnormalities
A result of atypical glandular cells (AGC) means the glandular cells from the cervical canal or uterine lining look abnormal, but not abnormal enough to be classified outright as cancerous. AGC is a broad category. It can reflect anything from a reactive change caused by inflammation to genuine precancer or early cancer of the cervix or endometrium. Interestingly, when pathologists investigate AGC results further, they most commonly find squamous lesions rather than glandular ones, which underscores how much overlap exists between these categories.
Because of the wide range of possibilities, AGC results almost always prompt a thorough workup, including colposcopy and sometimes sampling of the uterine lining, particularly in people over 35 or those with unexplained bleeding.
Why These Changes Happen
High-risk strains of HPV are the primary driver of true precancerous epithelial changes. The virus produces proteins that interfere with two of the cell’s most important tumor-suppressing mechanisms: the systems that stop damaged cells from dividing and that trigger self-destruction of cells with broken DNA. With those safeguards disabled, infected cells can accumulate genetic errors and gradually shift from mildly abnormal to precancerous.
Not every abnormal result traces back to HPV, though. Yeast infections, bacterial infections, polyps in the uterus, tissue irritation, and hormonal shifts during pregnancy or menopause can all cause cells to look unusual on a Pap smear without any precancerous process underway. This is one reason HPV co-testing has become standard: a negative HPV result alongside a mildly abnormal Pap is reassuring and often changes the follow-up plan to simple monitoring.
What Happens After an Abnormal Result
The follow-up depends entirely on which category your result falls into and whether HPV is present. For ASC-US with a negative HPV test, repeating screening in one to three years is often sufficient. If HPV is detected, or if the abnormality is ASC-H, LSIL, or HSIL, the standard next step is colposcopy. During this procedure, a provider examines the cervix under magnification and may take a small tissue sample to determine the exact severity of the changes.
For HSIL specifically, some providers offer an immediate excisional procedure rather than waiting for biopsy results, since the likelihood of significant precancerous tissue is high.
Treatment for Precancerous Changes
When a biopsy confirms moderate or severe precancerous tissue, the goal is to remove it before it has any chance of progressing. Two procedures are most commonly used.
LEEP (loop electrosurgical excision procedure) uses a thin, low-voltage electrified wire loop to cut away abnormal tissue. It’s done as an outpatient procedure in a clinic, often with local anesthesia, and serves double duty as both treatment and diagnostic tool since the removed tissue is sent to a lab. LEEP is the most frequently used option for high-grade cervical changes and can reach abnormal tissue higher in the cervical canal that isn’t visible during colposcopy.
Cone biopsy (conization) removes a cone-shaped section of tissue from the cervix. It’s done in a hospital or surgery center, though it doesn’t require an overnight stay. Cone biopsy is more precise and can remove a larger area of tissue than LEEP, making it the preferred choice when the abnormality extends deep into the canal or when a more detailed tissue sample is needed. In some cases, providers use both procedures together: conization to get the biopsy and LEEP to clear the remaining abnormal area.
Recovery from either procedure typically involves a few weeks of avoiding strenuous activity, with light spotting or discharge during healing. Both are highly effective at eliminating precancerous cells and preventing progression to invasive cancer when the abnormality is caught at a treatable stage.
Epithelial Cell Abnormalities Rarely Cause Symptoms
One of the most important things to understand about these findings is that they almost never produce symptoms you can feel. There’s no pain, no unusual discharge, and no visible change associated with precancerous cell shifts on the cervix. That’s precisely why routine screening exists. By the time cervical changes cause noticeable symptoms like bleeding or pelvic pain, the condition has usually progressed well beyond the precancerous stage. An abnormal Pap result, even a mild one, is the screening system working as designed: catching changes early, while they’re still easy to monitor or treat.