Section Editor: Allison Osmond MD FRCPC
June 9, 2026
A junctional nevus is a common, noncancerous (benign) skin growth made up of cells called melanocytes. Melanocytes are the cells in the skin that make melanin, the pigment that gives skin its color. The word “junctional” describes where these cells sit: at the junction between the two main layers of the skin, the epidermis (the thin outer layer) and the dermis (the thicker layer underneath). A junctional nevus is one of the most common kinds of mole, the everyday word for any growth made of melanocytes.
Junctional nevi (the plural of nevus) can appear anywhere on the body and are seen most often in people with lighter skin. They are usually flat and evenly colored. A junctional nevus is harmless, and it is one of the most reassuring findings that can appear on a skin pathology report. This article explains what a junctional nevus is, what the findings in your report mean, and why this growth is considered safe.
What causes a junctional nevus?
A junctional nevus forms when melanocytes grow together in small clusters instead of being spread evenly through the skin. Most junctional nevi carry a single change (called a mutation) in a gene named BRAF. This one change prompts the melanocytes to divide a limited number of times and then stop. That built-in “off switch” is the reason a nevus grows to a certain size and then stays stable for years, and it is part of why a junctional nevus is not cancer.
Sun exposure and an inherited tendency also play a role. People who had more sun exposure, especially as children, and those whose close relatives have many moles, tend to develop more nevi over their lifetime.
A junctional nevus that is present at birth or appears in the first months of life is called a congenital nevus. One that appears later, during childhood or adulthood, is called an acquired nevus. Acquired junctional nevi are far more common.
What are the symptoms of a junctional nevus?
A junctional nevus usually causes no symptoms. Most are flat or only slightly raised and round to oval in shape. The boundary between the nevus and the surrounding normal skin is usually smooth and easy to see. The color is most often a single, even shade of tan, brown, or black, although some can look pink. A junctional nevus does not normally itch, bleed, or change quickly. Any mole that does change in size, shape, or color, or that begins to itch or bleed, should be checked by a doctor.
How is the diagnosis made?
A junctional nevus is diagnosed after a skin sample is examined under the microscope by a pathologist, a doctor who specializes in identifying disease in tissue. The sample is obtained by a skin biopsy. Depending on the size and location of the mole and how it looks to the naked eye, the doctor may use a shave biopsy (a thin slice taken from the surface), a punch biopsy (a small round core of skin), or an excisional biopsy (removal of the whole mole with a small rim of normal-looking skin).
Under the microscope, the pathologist looks for melanocytes arranged in small, well-organized clusters called nests. In a junctional nevus, these nests sit only within the epidermis, the thin outer layer of the skin, usually along its lower edge. Scattered single melanocytes may also be seen. The cells look small, regular, and similar to one another, and this orderly appearance tells the pathologist that the growth is benign rather than melanoma (a cancer made of melanocytes).
Over time, the melanocytes in a junctional nevus often move down into the dermis, the layer just beneath the epidermis. When melanocytes are found in both the epidermis and the dermis, the growth is called a compound nevus. When they are found only in the dermis, it is called a dermal (or intradermal) nevus. These three patterns are stages of the same normal process and do not mean anything is wrong.
When a mole shows any unusual features, the pathologist may use immunohistochemistry (special stains that highlight specific proteins within cells) or consult a dermatopathologist (a pathologist who specializes in skin diseases) to review the slides before issuing a final diagnosis.
Can a junctional nevus turn into melanoma?
The chance that any single junctional nevus will turn into melanoma is very low. While some melanomas are found next to a pre-existing mole, most melanomas develop on their own in previously normal skin rather than from an existing nevus. Because junctional nevi are so common and melanoma arising from any one of them is so rare, having a junctional nevus is not, by itself, a cause for concern.
What matters more than any single mole is change over time. A nevus that grows quickly, develops an irregular or uneven border, takes on more than one color, or begins to itch or bleed should be examined by a doctor. People who have many moles, one or more dysplastic nevi (moles with unusual features under the microscope), or a personal or family history of melanoma may be advised to have regular skin checks.
What happens after this diagnosis?
In most cases, a junctional nevus needs no further treatment. It is harmless and can simply be left in place and watched for change. When a junctional nevus is removed, it is usually for one of the following reasons:
- Change in appearance — A mole that has changed in size, shape, or color, or developed an irregular border, may be removed so it can be examined under the microscope to rule out atypical cells or, rarely, an early melanoma.
- Irritation — Moles in areas where clothing, a waistband, or jewelry rubs against the skin may be removed to prevent discomfort or repeated injury.
- Uncertain diagnosis — If the mole is hard to tell apart from other skin growths by eye, removal allows a definite diagnosis to be made under the microscope.
- Cosmetic reasons — Some people choose to have a mole removed because of where it is or how it looks.
When a junctional nevus is removed by a shave biopsy, a few melanocytes can sometimes be left behind at the edge of the sample. These cells may grow back and make new pigment, a harmless situation called a recurrent nevus. A recurrent nevus can look irregular both to the eye and under the microscope, and it can be mistaken for melanoma. For that reason, it helps your doctor to know if the area was treated before. Telling a new doctor about any previously removed or treated moles and sharing the earlier pathology report when possible help avoid confusion.
Because distinguishing a benign mole from an early melanoma can occasionally be difficult from a small or partial sample, a pathologist may recommend complete removal of a mole that shows borderline features. This is done to be certain of the diagnosis, not because cancer has been found. Whether or not a nevus is removed, regular skin self-checks and routine examination by a doctor are the best way to notice any concerning change early.
Questions to ask your doctor
- Was my mole a junctional nevus, or was it a compound or dermal nevus?
- Did the pathologist see any atypical or unusual features?
- Was the whole mole removed, or could some of it have been left behind?
- If some of the mole was left behind, does the rest need to be removed?
- Is there any chance this could grow back as a recurrent nevus?
- Was a dermatopathologist asked to review my slides?
- Do I have any features that increase my risk of melanoma, such as many moles or dysplastic nevi?
- How often should I have my skin checked?
- What changes in a mole should prompt me to call you?
- Should any of my other moles be examined or removed?
- Do I need any follow-up because of this result?
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