Cervical Lesions: What They Look Like, Causes & Diagnosis

Cervical lesions are areas of abnormal tissue on the cervix, and they range from completely harmless findings like small cysts and ectropion to precancerous changes caused by persistent human papillomavirus (HPV) infection. Most cannot be seen or felt without a clinical exam, and even then, telling a harmless lesion from a dangerous one usually requires testing rather than appearance alone. The path from a normal cervix to cervical cancer is slow and passes through identifiable stages, which is exactly why screening has been so effective at catching problems early.

What Cervical Lesions Actually Look Like

The cervix sits at the lower end of the uterus and can be viewed directly during a pelvic exam using a speculum. Under normal conditions it appears smooth and pink, but a variety of findings can alter that appearance. Some are entirely benign. Ectropion, for example, occurs when the softer, redder glandular cells that normally line the cervical canal extend onto the outer surface of the cervix. It looks like a reddish, velvety patch and is common in younger women and those on hormonal contraception. Nabothian cysts, small fluid-filled bumps on the cervical surface, are another routine finding. Small cervical polyps, which dangle from the cervical canal, round out the list of changes that look alarming but rarely require treatment.¹

Precancerous and cancerous lesions look different, but the differences are often subtle to the naked eye. During colposcopy, a magnified examination of the cervix, the clinician applies dilute acetic acid (essentially vinegar) to the cervical surface. Normal tissue stays relatively unchanged, while abnormal tissue turns white, a finding called acetowhitening. The degree and density of that whiteness, along with the sharpness of the border between white and normal areas, correlate with the severity of the underlying lesion. Abnormal blood vessel patterns also become visible under magnification: punctation (tiny dots of blood vessels seen end-on) and mosaicism (a tile-like pattern of vessels) indicate that something is happening beneath the surface.²

After applying acetic acid, clinicians sometimes follow with Lugol’s iodine solution. Healthy squamous cells contain glycogen and stain dark brown with iodine, while abnormal or immature cells do not take up the stain and remain pale or yellow. In a prospective study, this sequential approach picked up additional precancerous lesions missed by acetic acid alone, though the extra yield was modest and changed management in only about 5% of cases.³

Why HPV Is the Central Cause

The overwhelming majority of cervical precancers and cancers trace back to persistent infection with high-risk strains of HPV. More than a dozen high-risk types exist, but HPV 16, 18, 31, 33, 45, 51, 52, and 58 collectively account for over 90% of cervical cancers.⁴ Most HPV infections clear on their own within a year or two. The trouble starts when a high-risk strain lingers.

In early, mild abnormalities, the virus replicates quietly as a separate loop of DNA inside the host cell. As the disease progresses to more severe stages, the viral DNA often integrates into the cell’s own chromosomes, ramping up production of two key viral proteins that disable the cell’s built-in brakes on growth. This is the step that pushes a cell from mildly abnormal toward truly precancerous or cancerous behavior.⁴

The cervix is not uniformly vulnerable. Cancer and precancer typically arise near the squamocolumnar junction, where two types of epithelial tissue meet. A specialized population of stem cells in this zone appears to have a particular susceptibility to HPV-driven transformation.⁵

Non-HPV Causes of Cervical Lesions

HPV gets most of the attention, but it is not the only thing that can produce visible or biopsy-confirmed changes on the cervix. Infections with Chlamydia, gonorrhea, herpes simplex virus, and Trichomonas can all cause cervical inflammation, sometimes called cervicitis. When biopsied, these infections produce characteristic tissue changes including swelling, clusters of inflammatory cells within the lining, and in severe cases, ulceration and granulation tissue.⁶ These inflammatory lesions are not precancerous, but they can make the cervix look abnormal enough to warrant further evaluation.

Endometriosis, though more commonly associated with the pelvis and ovaries, can also involve the cervix. Cervical endometriosis sometimes forms cystic or polypoid masses that can be mistaken for cancer on both clinical exam and imaging. On MRI, cervical endometriosis and a rare form of cervical cancer called gastric-type adenocarcinoma can both appear as multicystic masses, making the distinction challenging without biopsy.⁷ Polypoid endometriosis of the cervix is rare enough to be published as case reports, but it belongs on the list of things that can mimic a tumor without being one.⁸

Symptoms That Prompt Evaluation

Most precancerous cervical lesions produce no symptoms at all, which is the entire rationale for routine screening. When symptoms do appear, they tend to occur at later stages. Bleeding after intercourse is one of the more recognized warning signs. Up to 9% of women experience postcoital bleeding at some point, and while it is more common in women with invasive cervical cancer, the vast majority of women who experience it do not have cancer.⁹ Other possible symptoms include unusual vaginal discharge, bleeding between periods, or pelvic pain, though all of these have many other explanations.

The key point is that waiting for symptoms is a poor strategy. By the time a cervical lesion announces itself, the disease may be well advanced. This is why screening programs exist and why they have been so successful at reducing cervical cancer deaths since the Pap smear was introduced in the mid-twentieth century.

How Cervical Lesions Are Classified

The terminology around cervical lesions has been streamlined over the years. The current standard uses a two-tiered system for describing HPV-related squamous abnormalities found on biopsy: low-grade squamous intraepithelial lesion (LSIL) and high-grade squamous intraepithelial lesion (HSIL). This mirrors the language used on Pap smear reports, which makes communication between pathologists and clinicians more consistent.¹⁰

On Pap smear cytology, the Bethesda System categorizes squamous abnormalities along a spectrum. At the milder end sit atypical squamous cells of undetermined significance (ASC-US), which represent borderline changes that may or may not reflect a real problem. LSIL typically corresponds to HPV infection causing mild cellular changes. HSIL indicates more serious precancerous changes. A separate category, ASC-H, flags cells that look atypical but where a high-grade lesion cannot be ruled out.¹¹

When a biopsy falls into an ambiguous zone, a tissue stain for a protein called p16 can help settle the question. This stain helps pathologists distinguish true high-grade precancerous lesions from benign look-alikes.¹⁰

Screening and Diagnosis

The Pap smear remains a cornerstone of cervical cancer prevention. It works by collecting cells from the cervix and examining them under a microscope for abnormalities. What makes it so powerful is that precancerous changes develop slowly, often over years to decades, giving repeated opportunities to catch them.¹²

HPV DNA testing has become an increasingly important screening tool, either alongside or instead of the Pap smear. Because HPV is the root cause of nearly all cervical cancers, testing directly for the virus can catch problems at an even earlier stage. Self-collected HPV samples have shown performance comparable to clinician-collected ones. In a population-based study, self-sampling HPV testing detected precancerous lesions at the moderate-to-severe level with a sensitivity above 96%, similar to the 92% sensitivity seen with clinician-collected samples.¹³ Another study found self-collected HPV DNA and clinician-collected HPV mRNA testing had similar sensitivity for high-grade lesions, both above 90%.¹⁴

A newer approach tests for HPV mRNA rather than DNA, targeting active viral gene expression rather than mere presence of the virus. A systematic review and meta-analysis found that mRNA-based testing had similar sensitivity for precancerous lesions compared to DNA-based tests but slightly higher specificity, meaning fewer false alarms. For clinician-collected samples, mRNA testing could support screening intervals of around five years, though it performed less well on self-collected samples.¹⁵

When screening flags an abnormality, colposcopy is the next step. The clinician views the cervix under magnification, applies acetic acid and sometimes iodine, and takes small tissue samples from any suspicious-looking areas. The biopsy provides the definitive diagnosis.

Treatment When Precancerous Lesions Are Found

Low-grade lesions often resolve on their own, especially in younger women, so surveillance rather than immediate treatment is frequently appropriate. When a high-grade lesion is confirmed, the goal is to remove it before it progresses to cancer. The most commonly used procedure is the loop electrosurgical excision procedure (LEEP), which uses a thin, heated wire loop to cut away the abnormal tissue.¹⁶ It can be done in an office setting under local anesthesia.

Cold knife conization, a surgical procedure performed in an operating room, removes a cone-shaped piece of cervical tissue and is sometimes used when a larger or deeper sample is needed. A systematic review found that cold knife conization leaves behind less residual disease than LEEP, though LEEP has its own advantages: it is simpler, less expensive, and well suited for most cases.¹⁷ Cryotherapy, which freezes abnormal tissue, is still used in some resource-limited settings, but the same review found it carries a substantially higher risk of disease recurrence compared to LEEP.¹⁷

Cervical Lesions During Pregnancy

Pregnancy actually creates an opportunity for early detection, since prenatal care typically includes a pelvic exam and cervical screening. When an abnormal Pap smear turns up during pregnancy, it is generally managed the same way as outside of pregnancy: colposcopy can be performed, and biopsies can be taken to assess the lesion. Despite a common worry that cervical biopsies during pregnancy cause excessive bleeding, studies have found that they do not increase obstetric complications.¹⁸

The important difference is that treatment is handled more conservatively during pregnancy. For precancerous lesions, the primary aim of colposcopy and biopsy is to rule out invasive cancer. If only precancerous changes are found, treatment is typically deferred until after delivery, because many lesions remain stable or even regress postpartum.¹⁹

HIV and Weakened Immunity

Women living with HIV face a meaningfully higher risk of developing cervical precancer and having it progress. The reason ties back to HPV: a weakened immune system is less able to clear HPV infections, so high-risk strains are more likely to persist and drive abnormal cell changes. Studies have consistently found that lower CD4 counts correlate with higher rates of cervical lesion development and progression.²⁰

Antiretroviral therapy appears to help. In a prospective cohort study of women in Soweto, South Africa, treatment with antiretroviral therapy reduced the risk of cervical lesion progression, with the strongest risk for progression seen in women with CD4 counts below 200.²¹ For this reason, cervical screening guidelines for women with HIV tend to call for more frequent screening than for the general population.

How Vaccination Is Changing the Landscape

HPV vaccines have started to bend the curve on cervical precancer in real-world populations. Among vaccinated women in the United States, the share of high-grade cervical lesions caused by HPV types 16 and 18 dropped from about 54% to 28% over a four-year period. Vaccine effectiveness for preventing HPV 16/18-related precancer climbed the longer a woman had been vaccinated, reaching roughly 72% for those who had received at least one dose more than four years before their screening test.²²

Even in places with lower vaccination coverage, the effect is showing up. A study in Tennessee found declining rates of high-grade cervical lesions among women in the age groups most likely to have been vaccinated, suggesting vaccine impact even where uptake has been slow.²³ More granular data have shown that the incidence of precancer linked specifically to HPV 16, 18, 31, and 33 has dropped significantly among young vaccinated women, with reductions in HPV 16/18-positive precancer approaching 44%.²⁴

An important wrinkle: as the vaccine-targeted types become less common, the proportion of precancers caused by non-vaccine types appears to be rising. This does not mean the vaccine is causing new problems; it means that with the dominant types suppressed, the remaining types make up a bigger share of a smaller pie. Screening will remain necessary even in highly vaccinated populations.

The Psychological Side of Abnormal Results

Getting an abnormal Pap result is stressful in a way that can be disproportionate to the actual level of risk. In a survey of nearly 600 women who received abnormal results, about 69% reported feeling anxious and roughly a quarter reported panic. Even after speaking with their doctor, only about a quarter felt reassured.²⁵ A separate study found that women with borderline Pap results reported significantly worse anxiety and lower mental quality of life than women with normal results, and they were nearly three times as likely to describe screening as frightening.²⁶

This matters because anxiety can either push women to avoid follow-up appointments or, conversely, to demand unnecessary procedures. The reality is that many mild abnormalities resolve without treatment, and even a high-grade result caught early is highly treatable. Clinicians who take time to explain what a result actually means, rather than just delivering a label, help close the gap between perceived and actual risk.

Artificial Intelligence in Cervical Screening

A significant challenge in global cervical cancer prevention is that colposcopy requires trained specialists who are scarce in many parts of the world. Researchers have been developing deep-learning tools that analyze photographs of the cervix, taken with a smartphone or basic camera, and flag areas suspicious for precancer. This approach, called automated visual evaluation (AVE), aims to improve on traditional visual inspection with acetic acid, which has had limited sensitivity.²⁷

In a prospective validation study in Zambia, an AVE tool identified precancerous and cancerous lesions with a sensitivity of 85% and specificity of 86%, a considerable improvement over naked-eye visual inspection, which per a WHO meta-analysis achieves only about 66% sensitivity.²⁸ The same tool performed equally well in women living with HIV. When combined with HPV genotyping, AVE added finer accuracy to risk prediction across different HPV types.²⁹

These tools are not yet replacing clinicians, but in settings where no colposcopist is available, a smartphone-based system that can identify most precancers could dramatically expand who gets screened. The technology is still being refined, and questions about how well it generalizes across different populations and camera equipment remain open. But the direction is promising, and it represents one of the more practical near-term applications of medical AI.