Atypical Nevus

An atypical nevus, also known as a dysplastic nevus, is a benign pigmented lesion that shares clinical and histologic features with malignant melanoma, making the two difficult to distinguish on visual exam alone. While atypical nevi are not cancerous, they carry a small risk of malignant transformation into melanoma over time, and having multiple atypical moles is associated with a higher lifetime risk of developing this serious form of skin cancer. Melanoma is the most dangerous type of skin cancer because of its ability to invade surrounding tissue and spread to other organs. Treatment may require advanced procedures, such as Mohs surgery, depending on the lesion’s location and depth. Because early detection dramatically improves outcomes, routine skin exams and self-examinations between visits are essential. A board-certified dermatologist like Dr. Michele Green in NYC can biopsy a suspicious mole to confirm a diagnosis and protect your long-term health.

Atypical nevi are quite common, affecting roughly one in ten Americans. They tend to be larger than normal moles and have irregular borders, asymmetry, and color variation. Individuals with atypical nevi who also have a family history of melanoma face a significantly higher risk of developing skin cancer. Additional risk factors include fair skin, light eyes or hair, numerous moles or freckles, an inability to tan, photosensitivity, and a personal history of sunburn. Patients with several of these risk factors are often advised to schedule skin exams every four to six months, while everyone with atypical nevi is encouraged to do monthly at-home self-checks for new or changing lesions. Dr. Michele Green emphasizes this practice with every patient.

What Is an Atypical Nevus?

Nevus is the medical term for a mole. Melanocytes, the pigment-producing skin cells, clump together to form a nevus. A nevus is considered atypical when it contains unusual or abnormal cells within the tissue. Atypical nevi differ from common moles in their border appearance, color, size, and shape, and they often display a lentiginous growth pattern on microscopic examination. An atypical nevus, also referred to as a dysplastic nevus or Clark’s nevus, is a benign melanocytic pigmented lesion — it is NOT melanoma or any other form of skin cancer. However, it may share certain clinical or microscopic features with one.

Multiple atypical nevi can be a marker of increased risk of developing malignant melanoma later in life. If you have a personal history of atypical nevi, regular skin examinations with a board-certified dermatologist, such as Dr. Michele Green, should be a priority.

What Causes an Atypical Nevus?

No single, exact cause of atypical nevi exists, though a combination of genetics and cumulative sun exposure is generally believed to play the largest role. Ultraviolet radiation from the sun can trigger changes in melanocytes, contributing to the irregular growth pattern seen in dysplastic nevi. A family history of atypical moles or melanoma also increases the likelihood of developing them. Hormonal changes, such as those occurring during puberty or pregnancy, have been associated with the appearance of new atypical moles or changes in existing ones in some patients. Because the exact trigger can vary from patient to patient, Dr. Green recommends yearly skin examinations so that any new or evolving lesion can be evaluated promptly.

What an Atypical Nevus or Atypical Mole Looks Like

Atypical moles are often asymmetrical and irregular in shape, with borders that fade into the surrounding skin. Because of how they develop, they can vary considerably in color and size — a single lesion may be flesh-colored, pink, reddish-pink, dark brown, or a combination of pink and brown tones. They are often flat or slightly raised and have a pebbly texture. According to the Journal of the American Academy of Dermatology, atypical moles tend to be larger than common moles and typically have irregular, indistinct borders.

Atypical nevi share what is known in health care as the ABCDE characteristics of malignant melanoma, meaning they display similar surface features even though their underlying histology is different. Board-certified dermatologists such as Dr. Michele Green use the ABCDE mnemonic during skin examinations to help identify a suspicious lesion:

• Asymmetry – the mole is irregular in shape, size, diameter, and color.
• Border irregularity – imperfect edges that appear scalloped.
• Color – variation in pigmentation that is not uniform, ranging from flesh-colored to tan, brown, and even bluish.
• Diameter – melanomas are usually greater than 6mm in thickness at the time of diagnosis, though smaller lesions can occur.
• Evolving – There has been a change in the mole’s appearance over recent weeks or months

The “ugly duckling” method is sometimes used alongside the ABCDE criteria to identify the one mole that looks different from the others on the body. Many types of skin lesions — from atypical moles and melanoma to actinic keratosis, seborrheic keratosis, and basal cell carcinoma — can meet one or more of the ABCDE criteria, which is why it is essential to consult a board-certified dermatologist, such as Dr. Michele Green in NYC, for a proper assessment of any suspicious lesion.

Where on the Body Dysplastic Nevi Are Located

Dysplastic nevi can occur anywhere on the body. They are most common in areas with significant sun exposure, such as the arms, legs, back, and face. However, because most atypical or dysplastic nevi are genetically determined, they can also appear in non-sun-exposed areas, including the scalp — which is why it’s important to have your scalp examined during a skin check. Most individuals with dysplastic nevi also have an increased number of common nevi, making annual visits with your dermatologist, including a thorough head-to-toe examination, especially important.

Who Is at Risk for Atypical Nevi?

Anyone can develop an atypical nevus, but certain individuals are at higher risk. Those with fair skin, light eyes or hair, many common moles or freckles, an inability to tan, and photosensitivity are more likely to develop atypical nevi. A family history of melanoma or dysplastic nevi also substantially increases the risk, as does a personal history of significant sun exposure or sunburn, particularly in childhood. Patients who fall into one or more of these higher-risk categories should schedule skin examinations with Dr. Michele Green every four to six months and perform regular self-checks between visits.

What Is the Best Way to Diagnose a Dysplastic Nevus?

Distinguishing an atypical mole from a malignant melanoma can be challenging. Still, an experienced board-certified dermatologist should be able to determine which moles require biopsy or removal for further testing. Some dermatologists use a dermatoscope, a specialized magnifier for examining the skin’s surface, to help identify features of skin cancer during a skin exam — under dermoscopy, a dysplastic nevus can appear with the classic “fried egg” look. If you have a large number of moles, your dermatologist may also recommend mole mapping, which involves photographing the entire body to track changes in your moles over time and aid in the early detection of skin cancer.

In her private NYC dermatology office, Dr. Green first examines your entire body for any unusual moles or growths. If she suspects skin cancer, she will biopsy the mole and send the tissue to a laboratory, where a dermatopathologist will evaluate the sample’s cellular characteristics to determine whether it is benign, precancerous, or cancerous. Based on the biopsy results, Dr. Green will then recommend a treatment plan.

Do Atypical Moles Need to Be Removed?

Any suspicious skin lesion should be biopsied and sent to a laboratory for examination, since it can be difficult to visually distinguish a normal mole from other melanocytic lesions, even for a board-certified expert. A biopsy is the only definitive way to determine whether a mole is an atypical nevus or a malignant melanoma. The lesion’s size and clinical suspicion will determine which biopsy technique to use. An experienced dermatologist will perform a punch biopsy or shave biopsy and send the specimen to the lab for review. According to the Journal of the American Medical Association of Dermatology (JAMA), agreement between the clinical diagnosis of an atypical mole and a pathologist’s interpretation of dysplasia has been reported to be as low as 60%, underscoring the need to biopsy any suspicious lesion for accurate assessment.

If biopsy results show mild to moderate atypia, no further treatment is usually necessary, though your dermatologist may remove additional skin around the lesion in some cases. When a diagnosis indicates severe atypia, further treatment is generally recommended — most dermatopathologists will suggest a deeper shave or excisional biopsy to clear the margins and remove any remaining atypical cells. Once the margins are clear, there is very little concern that the atypical nevus will require further dermatologic treatment.

How Is an Atypical Nevus Treated?

Most atypical nevi do not require treatment beyond ongoing monitoring, as most remain stable and never progress to melanoma. When a biopsy shows mild to moderate atypia, dermatologists typically recommend continued surveillance rather than immediate removal. If the biopsy shows more significant atypia, or if the mole continues to change in size, shape, or color, Dr. Michele Green will recommend a deeper shave or excisional biopsy to remove the lesion entirely and clear the surrounding margins. Every treatment decision is individualized based on histologic findings, your personal and family history, and the mole’s clinical appearance.

What Is the Difference Between Atypical Nevus and Melanoma?

An atypical mole is a benign skin lesion with unusual clinical and histologic features. Atypical moles may resemble melanoma in several ways, appearing larger than normal moles, with irregular borders and color variation. There is no exact cause of atypical nevi, though genetics and sun exposure likely play a role. While atypical nevi are not skin cancer, having them increases the risk of malignant melanoma, and they carry the potential for malignant transformation over time, which may present as changes in size, color, or shape. Other risk factors for melanoma include fair skin, light-colored eyes or hair, a family history of melanoma, numerous moles or freckles, an inability to tan, and a history of sunburn.

Melanoma is a form of skin cancer that accounts for approximately 1% of all skin cancers seen in dermatology, yet it is the most deadly. Cutaneous melanoma arises from damaged or mutated melanocytes, leading to uncontrolled cell growth that can become metastatic if not treated promptly. Most melanomas arise de novo rather than from a preexisting mole. High-risk factors include a family history of melanoma, high-risk sun exposure, excessive tanning, sunburns, and chemical exposure. Although fair-skinned individuals face a higher risk, people of all skin types can develop melanoma, which is why melanoma risk should be assessed at every annual skin exam — Dr. Green has found that many patients have no idea they have skin cancer until it is identified during a routine visit.

Skin Cancer Prevention, Early Detection, and Self-Examination

If you have a family history of skin cancer or a diagnosis of a dysplastic or atypical nevus, limiting sun exposure and practicing proper sun protection is essential. Try to limit time outdoors during peak hours, between 10 am and 4 pm, when the sun’s rays are strongest, and wear protective clothing such as wide-brimmed hats, long-sleeve shirts, and long pants when you’re outside. A broad-spectrum sunscreen with an SPF of 50 or higher should always be applied before heading outdoors for maximum UVA and UVB protection, and reapplied every two hours or after swimming or water sports.

According to the American Academy of Dermatology, yearly skin cancer examinations are extremely important for early melanoma detection. In her private Upper East Side dermatology office, Dr. Michele Green begins each consultation with a full-body skin exam and counsels every patient on sun avoidance and proper sun protection. Between visits, performing a monthly self-examination at home is also valuable — examine your entire body, including your fingers and toes, for new growths or lesions, as well as any changes in size, color, border, or shape of existing moles. Any lesion that doesn’t heal or is routinely irritated or itchy warrants further attention. Let Dr. Green know about any new or changing mole so she can evaluate it.

Where Can You Get Your Skin Examined for Melanoma and Atypical Moles?

Individuals with atypical moles face a higher risk of malignant melanoma, especially those with a personal or family history of skin cancer. Regular skin exams and self-examinations between visits should be a priority. A dermatologist can biopsy an atypical mole to confirm a diagnosis. A board-certified dermatologist, such as Dr. Green in NYC, should evaluate any new or evolving skin lesion to rule out skin cancer.

Dr. Michele Green has more than two and a half decades of experience performing skin examinations and biopsies to assess atypical nevi and other skin lesions in her private Upper East Side dermatology office, where she works with each patient to develop an individualized treatment plan tailored to their specific skin concerns.

Frequently Asked Questions (FAQs) About Atypical Nevi

What Are the Warning Signs of an Atypical Nevus?

The warning signs of an atypical nevus generally follow the ABCDE criteria: asymmetry, irregular borders, uneven color, a diameter larger than 6mm, and an evolving appearance over time. Additional symptoms that warrant prompt evaluation include itching, bleeding, oozing, crusting, or a mole that fails to heal like the surrounding skin. A new pigmented lesion that stands out from your other moles, sometimes called the “ugly duckling,” should also be brought to your dermatologist’s attention. If you notice any of these changes, Dr. Michele Green can perform a skin examination and, if necessary, a biopsy to determine whether further treatment is needed.

Does Atypical Mole Mean It’s Precancerous?

An atypical mole is not always precancerous. A skin biopsy is the only reliable way to determine whether an atypical mole is precancerous or represents actual skin cancer. Most people with atypical moles never develop skin cancer, although having many atypical moles is associated with an increased risk of melanoma. According to the National Cancer Institute and the National Skin Cancer Foundation, individuals with ten or more atypical moles have roughly a twelvefold increased risk of developing melanoma compared with the general population. In rare cases, an atypical mole can also indicate other forms of skin cancer, such as squamous cell carcinoma or basal cell carcinoma. If you have noticed abnormal changes in an existing mole, Dr. Green can perform a complete skin exam to screen for atypical moles and skin cancer.

How Serious Is an Atypical Nevus?

On its own, an atypical nevus is a benign lesion and not a serious medical condition. Its significance lies in what it may indicate about your overall risk profile: patients with multiple atypical moles, especially those with a family history of melanoma, face a meaningfully higher lifetime risk of developing skin cancer. The seriousness of any individual atypical nevus depends on its specific features and how it changes over time, which is why routine monitoring by a board-certified dermatologist, such as Dr. Michele Green, is so important.

Does an Atypical Nevus Need a Biopsy?

Not every atypical nevus requires a biopsy, but any mole that appears suspicious on clinical or dermoscopic exam should be biopsied to rule out melanoma. A biopsy is the only definitive way to determine whether a lesion is a benign atypical nevus or a malignant melanoma, as the two can look remarkably similar even to a trained eye. Dr. Michele Green will assess each mole’s asymmetry, border irregularity, color, diameter, and evolution during your skin exam and recommend a punch, shave, or excisional biopsy for any lesion that raises concern.

Can an Atypical Nevus Come Back After Removal?

Once an atypical nevus has been fully excised with clear margins, recurrence at the same site is uncommon. Occasionally, if a small amount of pigmented tissue remains after a shave biopsy or partial removal, a recurrent nevus can appear. This is why dermatologists aim to achieve clear margins whenever removal is indicated. Even after a mole has been successfully removed, patients with a history of atypical nevi remain at increased risk of developing new ones elsewhere on the body, so continued skin exams and self-checks with Dr. Green remain important.

Do Atypical Moles Change?

Yes — atypical moles can change in appearance over time. They may change shape or color, grow in size, or begin to itch or bleed. It’s important to perform regular self-examinations, paying close attention to the appearance of all moles on your body. If you notice a mole changing over time, make an appointment with a board-certified dermatologist for further assessment.

Can an Atypical Nevus Become Melanoma?

An atypical nevus is benign, but it can undergo malignant transformation into melanoma over time, particularly in patients with multiple atypical moles or a family history of melanoma. This transformation is thought to occur gradually, often triggered or accelerated by ongoing sun exposure. Signs that an atypical nevus may be transforming include new asymmetry, changing borders, shifting color, growth in diameter, and overall evolution in appearance. Because most melanomas arise independently of an existing mole rather than from within one, comprehensive skin exams that assess every lesion on the body are essential for early detection with Dr. Michele Green.

What Is the Difference Between Atypical Moles and Freckles?

There are clear differences between moles and freckles that can be distinguished by appearance. Freckles are superficial and result from pigment changes in the outer layer of skin. They form when melanocytes absorb too much ultraviolet light and increase melanin production. Atypical moles, or atypical nevi, are typically darker than freckles and are not superficial — they look more like true skin growths, often more deeply pigmented and larger, with more irregular features. While freckles can be treated with laser treatments and chemical peels, atypical nevi must be removed through excision, shave, or punch biopsy and sent to a lab for further assessment.

What Is the Difference Between an Atypical Nevus and a Normal Mole?

A normal or common mole is typically small, symmetrical, uniform in color, and has smooth, well-defined borders — most are under 6mm in diameter and remain stable in appearance for years. An atypical nevus, by contrast, tends to be larger, asymmetrical, and irregularly bordered, often blending into the surrounding skin, with color variation that can range from tan to dark brown or even black. While both are benign, atypical nevi share more visual overlap with melanoma and require closer monitoring than normal moles.

What Is an Atypical Spitz Nevus?

An atypical spitz nevus is a rare, benign growth that can resemble melanoma. While a typical atypical nevus consists of melanocytes, an atypical spitz nevus contains epithelioid or spindled cells. A spitz nevus can appear red, pink, blue, brown, tan, or black, and may be raised or flat, with irregularities such as an asymmetrical border or a mix of colors. Atypical spitz nevi are very rare, and although they can resemble melanoma, there is no need for alarm, as these growths are not skin cancer. Most people with an atypical spitz nevus do not require treatment, though it’s still important to see a dermatologist for an accurate diagnosis.

What Is Familial Atypical Multiple Mole Melanoma Syndrome?

According to the American Academy of Dermatology, Familial Atypical Multiple Mole Melanoma (FAMMM) syndrome is a genetic condition characterized by multiple melanocytic nevi — usually more than 50 — and a family history of malignant melanoma. This syndrome is linked to mutations in the CDKN2A gene, and some patients also face an increased risk of pancreatic cancer and other malignancies. Patients with this syndrome have a significantly increased lifetime risk of developing melanoma and must be monitored closely with frequent self-examinations and in-person skin exams.

Is Atypical Nevus Hereditary?

Atypical nevi can run in families, and genetics is believed to be a primary factor in their development. Patients with a first-degree relative who has atypical moles or melanoma are more likely to develop atypical nevi, and in some families this pattern is significant enough to meet the criteria for Familial Atypical Multiple Mole Melanoma (FAMMM) syndrome. Dr. Michele Green takes a detailed family history at your first visit to help determine how often you should be screened.

What Is Atypical Mole Syndrome?

Atypical mole syndrome, or dysplastic nevus syndrome, is characterized by more than 100 moles, one or more moles 8mm or larger in diameter, and one or more atypical moles. Individuals with 10 or more atypical moles face roughly a 12-fold higher risk of developing malignant melanoma, and atypical moles are often found in people with a family history of atypia. If you have atypical moles or a family history of them, vigilant surveillance of existing and new moles, along with proper follow-up, is essential.

Can Children Develop Atypical Nevi?

Yes, children and adolescents can develop atypical nevi, especially if they have a family history of dysplastic nevi or melanoma, fair skin, or a history of sun exposure and sunburns. Atypical moles often first appear or become more numerous around puberty, when hormonal changes can influence melanocyte activity. Parents who notice a new or changing mole on a child should schedule an evaluation with a board-certified dermatologist, such as Dr. Michele Green, who can determine whether the lesion needs to be biopsied or simply monitored over time.

Are Melanocytic Nevi Cancerous?

A regular melanocytic nevus is not cancerous. It is a common mole composed of a cluster of melanocytes in the skin. It is benign and requires no treatment. Changes in the appearance of a melanocytic nevus can result from simple irritation in the area or from cellular changes within the mole itself. A dermatologist, such as Dr. Green in NYC, should evaluate any melanocytic nevus that has changed in appearance.

Are Atypical Moles Cancerous?

Not all atypical moles are cancerous. Atypical moles share certain physical characteristics with melanoma, but they are benign. However, having multiple atypical moles increases the risk of developing melanoma. If you have atypical moles, your dermatologist may recommend monthly self-examinations to track them and watch for any changes in shape, color, size, or texture.

Can Atypical Moles Grow?

Yes — atypical moles can grow in size and change over time, sometimes rapidly, becoming larger than the tip of a pencil eraser. If you notice this kind of change, consult a dermatologist for a skin examination. A board-certified dermatologist, such as Dr. Michele Green, can biopsy the mole and send it to a lab for an accurate diagnosis.

Why Remove an Atypical Mole?

An atypical mole, while non-cancerous, has unusual clinical and histologic features that can allow it to develop into skin cancer over time. Atypical moles can change in size, color, and shape, which may indicate malignant transformation. Removing them before this occurs helps prevent malignant melanoma — the most serious type of skin cancer due to its invasive nature and lethality. This is especially important for individuals with a personal or family history of skin cancer, who face a higher baseline risk.

How Often Should an Atypical Nevus Be Checked?

Most patients with a history of atypical nevi should have a professional skin examination once a year. Those with multiple atypical moles, a personal or family history of melanoma, or other significant risk factors are often advised to be seen every four to six months. In between office visits, monthly self-examinations at home are recommended for everyone with atypical nevi. At your initial consultation, Dr. Michele Green will help determine the right examination schedule for your individual risk profile.

When Should I See a Dermatologist for an Atypical Nevus?

You should see a board-certified dermatologist promptly if you notice an asymmetrical mole, an irregular border, uneven or changing color, a mole larger than 6mm in diameter, or a mole that has changed in size or shape in recent weeks or months. Bleeding, itching, oozing, crusting, or a sore that doesn’t heal are also warning signs that warrant evaluation. Even without concerning changes, anyone with a personal or family history of atypical nevi or melanoma should maintain a consistent schedule of skin exams with Dr. Michele Green.

Schedule Your Skin Evaluation with Dr. Michele Green Today

An atypical nevus is a benign lesion, but its resemblance to melanoma and potential for malignant transformation make ongoing monitoring essential to your long-term skin health. From understanding what causes an atypical nevus and recognizing its warning signs to knowing when a biopsy or removal is necessary, staying informed helps you catch changes early and seek care promptly. Whether you’re managing a single atypical mole or navigating a family history of dysplastic nevi or melanoma, partnering with an experienced, board-certified dermatologist like Dr. Michele Green gives you the best chance of detecting any concerning change before it becomes serious.

Dr. Michele Green is an internationally recognized, board-certified dermatologist with over 25 years of experience providing discerning patients throughout New York City with expert skin cancer screening and mole evaluation. Castle Connolly, New York Magazine, Super Doctors, and The New York Times consistently name Dr. Green among NYC’s top dermatologists for her clinical expertise and commitment to patient care. She customizes each skin examination and treatment plan to each patient’s risk factors and concerns, helping you stay safe, healthy, and confident in your skin. To schedule your atypical nevus evaluation today, contact us online or call the NYC-based office at 212-535-3088.