- Acquired melanocytic nevocellular nevi, commonly called skin moles, are pigmented lesions made up of groups of melanocytes or melanocytic nevus cells that are small (1.0 cm), benign, and well-circumscribed.
- They can be divided into three categories:Junctional nev, Dermal nevi and Compound nevi. All three categories, however, have clinical overlap.
Epidemiology of Pigmented Nevi
- Nevi emerge between the ages of 6 and 12 months, peak in the third decade, and then fade away.
- In comparison to darker skin types, Caucasians have greater total body nevi. Asians and blacks, on the other hand, have more nevi in unusual places (palms, soles, nail beds, and conjunctivae) than whites.
- Increased numbers of nevi tend to cluster in families, and clinically abnormal nevi are more common in melanoma families.
- Seborrheic keratoses, dermatofibromas, neurofibromas, fibroepithelial polyps, basal cell carcinomas, and melanomas must all be distinguished from melanocytic nevi.
History of a Nevus
What age do moles first appear?
- Lesions form between the ages of 6 and 12 months and peak between the ages of 20 and 29. Most moles fade and/or disappear by the age of 60.
Nevocellular Nevi Symptoms
- Nevocellular nevi do not cause any symptoms.
- If a mole is causing you problems, you should have it checked and/or removed.
How do You Know When to Remove a Mole?
- Indications for removal of acquired melanocytic nevi are:
Shape asymmetry
- One half is not the same as the other.
The edging
- There are irregular borders.
Color
- The color is variegated or will become variegated.
- Gray, black, and white shades are unsettling.
Dimensions
- Approximately 6 mm (may be congenital mole, but should be evaluated).
Signs and Symptoms
- The lesion begins to itch, pain, or bleed incessantly.
The location
- It may be necessary to remove a lesion if it is frequently traumatized in the same region or if it is in a high-risk/difficult-to-monitor spot, such as the mucous membranes or anogenital area.
Types of Nevi
Junctional Nevi
- In junctional nevi, cells are located in the lower epidermis.
- Junctional naevi are usually uniform tan, brown, or dark-brown and are macular or very thinly papular with only minimal elevation above the level of the skin.
- It occurs at any site on the body and are regularly shaped, Round or oval with smooth regular border.
- A junctional naevus is an acquired lesion that can change their characteristics to that of a compound naevus, where melanocytes accumulate in the dermis and at the dermo-epidermal interface, causing the lesion to grow progressively papular.
- They are usually uniform in colour and the pigmentation varies from light brown to dark brown.
Intradermal Nevi
- Intradermal nevus (or intradermal melanocytic nevus) is the classic mole or birthmark. It appears as an elevated and dome-shaped bump on the surface of the skin.
- In the dermal nevus, cells are located beneath the most external layer of skin.
- The birthmark is pigmented to the same degree as the surrounding skin. Cells are found beneath the skin's outermost layer. In most cases, it appears after adolescence.
- Intradermal nevi is a dark bumps on the surface of the skin, they can also be brown. Sometimes, there are some brown spots of small blood vessels.
- Intradermal nevi can appear anywhere on the skin: scalp, neck, upper arms, legs, and neck are the most frequent locations. They also appear even on the eyelid.
- Nevi are usually small, ranging from 0,5 to 1 centimeter (cm). They're usually flat and a similar tint to the person's skin tone in children. The nevus normally becomes more noticeable after adolescence. Almost all nevi have lost much of their pigmentation by the time a person reaches the age of 70.
- Nevi appear raised from the skin surface and feel rubbery. An intradermal nevus is typically round and well-defined. It can be hairy, warty and dome shaped.
Compound Nevi
- Compound Nevi are the last class of acquired Nevi
- They are dome shaped papules or small nodules and mesures 1cm in diameter.
- Melanocytes prolifere at the epidermal-dermal junction.
- A hign number of nevi increases the risk for developing malignant tumors.
- Compound nevi are sometimes hairly.
- They can be smooth ( most cases), or hyperkarotic (thickened stratum corneum) or papillomatous (wart like appearance).
- Compound Nevi occur commonly in childhood or adolescence, then regress throughout adulthood.
Summary
- An acquired melanocytic nevus is a type of mole that generally appears after birth. These moles are usually benign or noncancerous.
- However in some cases they can develop into melanoma which is a type of skin cancer.
- It’s important to keep an eye on any changes in your moles and to see a doctor if you have any concerns.
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