Dermal nevus
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A dermal nevus (Latin: naevus intradermalis) is a benign pigmented skin lesion belonging to the group of melanocytic nevi. It forms as a result of the accumulation of melanocytes, i.e., melanin-producing cells, exclusively within the dermis. Unlike many other pigmented nevi, it does not show activity at the junction of the epidermis and dermis, which is why it usually has a flesh-colored or light brown coloration and a dome shape. A dermal nevus is one of the most common skin lesions in adults. Most often, it is completely benign and remains unchanged for many years; however, any lesion showing growth, change in color, bleeding, or ulceration requires dermatological and dermoscopic evaluation to rule out skin cancers.
Dermal nevus - what it is
A dermal nevus is the final stage of maturation of a melanocytic nevus. During natural evolution, pigment cells gradually migrate from the dermo-epidermal junction to deeper layers of the dermis. As a result, a lesion is formed whose cells are located exclusively in the dermis.
This process is a physiological phenomenon and explains why many flat nevi appearing in childhood become increasingly raised, lighter, and less intensely pigmented with age.
The most important characteristics of a dermal nevus include:
- benign histopathological nature,
- presence of melanocytes exclusively in the dermis,
- slow growth,
- long-term stability,
- very low risk of neoplastic transformation.
These lesions can be present from childhood or appear gradually during puberty and in early adulthood. Their number depends on genetic predisposition, skin phototype, and exposure to ultraviolet radiation.
In a dermoscopic examination, a dermal nevus shows characteristic features indicating its benign nature. Dermoscopic evaluation allows distinguishing it from lesions requiring further diagnostics or surgical excision.
Dermal nevus - what it looks like
The appearance of a dermal nevus is quite characteristic, although it may vary depending on the location and the patient's age.
Most often, the lesion:
- has the shape of a dome or a small nodule,
- is symmetrical,
- has a smooth surface,
- has well-defined borders,
- reaches a diameter of a few to several millimeters,
- grows very slowly.
The color can be highly varied:
- flesh-colored,
- pinkish,
- light brown,
- dark brown,
- less commonly, almost black.
In many people, single or multiple hairs grow from the nevus. This is a completely normal phenomenon and does not indicate malignant transformation of the lesion. On the contrary, the presence of hair often points to its benign nature.
The most common locations include:
- face,
- neck,
- scalp,
- back,
- chest,
- limbs.
The lesions usually do not cause any symptoms. Sometimes they can be chronically irritated during shaving, hair combing, or by clothing, which leads to periodic redness or minor bleeding.
Dermal nevus - how it differs from other types of nevi
Dermal nevus must be distinguished from other melanocytic nevi, as they differ in the location of pigment cells, clinical appearance, and the potential for developing neoplastic lesions.
Type of nevus | Location of melanocytes | Typical appearance |
|---|---|---|
At the boundary of the epidermis and dermis | Flat, darker | |
At the dermo-epidermal junction and in the dermis | Slightly raised, brown | |
Dermal nevus | Exclusively in the dermis | Dome-shaped, flesh-colored or light brown |
Abnormal architecture of melanocytes | Asymmetric, multicolored, irregular | |
Deep dermis | Blue-gray or steel-blue |
Dermal nevus also differs from viral warts, soft fibromas, or seborrheic keratoses.
The most important features pointing to a dermal nevus are:
- symmetrical shape,
- regular borders,
- uniform coloration,
- very slow growth,
- characteristic dermoscopic image.
In case of diagnostic doubts, the primary examination remains dermoscopy performed by a dermatologist. In selected cases, videodermoscopy is also used, enabling digital monitoring of lesions over time.
Dermal nevus - when to remove it
Most dermal nevi do not require treatment and can remain on the skin throughout life. The decision to remove them is made only when there are medical or functional indications.
The most common indications include:
- the appearance of asymmetry,
- color change or uneven coloration,
- rapid enlargement of the lesion,
- bleeding without injury,
- ulceration,
- chronic mechanical irritation,
- recurrent inflammation,
- diagnostic difficulties after a dermoscopic examination,
- aesthetic reasons reported by the patient.
The most reliable method of removing a nevus remains surgical excision with a margin of healthy tissue and a mandatory histopathological examination. Microscopic examination enables definitive confirmation of the diagnosis and the exclusion of neoplastic lesions.
In the case of unequivocally benign lesions, it is also possible to use less invasive removal methods, such as laser therapy or electrosurgery. These methods can bring a very good aesthetic effect, but they do not allow for histopathological evaluation of the entire lesion, which is why they are not recommended in case of any diagnostic doubts.
Every nevus that begins to change according to the ABCDE criteria (Asymmetry, Border, Colour, Diameter, Evolution) should be evaluated by a dermatologist as soon as possible. Regular skin self-examination and periodic dermoscopic examinations are the basis for the early detection of melanoma and other skin cancers.
