What Is Congenital Melanocytic Nevus, A Rare Birthmark? Causes, Symptoms, Complications And Treatments

Add as a preferred source on Google

New York mom Nicole Lucas Hall is all over the internet as she shares her journey celebrating her 13-month-old daughter Winry's unique beauty, who was born with a birthmark that covers a quarter of her face.

Image source: © nicolelucashall / Instagram

In an interview with a YouTube channel, Nicole mentioned feeling confused and worried earlier due to the birthmark and being concerned about the safety of her daughter.

However, medical experts assured them that the birthmark is not concerning or fatal, and is a rare inborn condition known as congenital melanocytic nevus (plural nevi), or CMN. Nevus is another name for mole.

According to a study, the prevalence of CMN in newborns ranges between 0.2 to 6 per cent around the world. [1]

So, what is congenital melanocytic nevus?

What Is Congenital Melanocytic Nevus?

Congenital melanocytic nevus is a non-cancerous/benign skin lesion that can range in size and is often present at birth. Studies say that the lesion is mainly developed during gestation. However, experts also include melanocytic nevus developed between six months and two years under the category of CMN.

Larger melanocytic lesions are rare, have a higher chance of becoming cancer and require frequent medical attention. [2]

How Does Congenital Melanocytic Nevus Differ From Acquired Nevus?

Congenital melanocytic nevus is primarily different from an acquired nevus due to its larger size. The size of such giant congenital melanocytic nevi can even reach a diameter of 20 cm in adulthood. [3]

The prior is spread to the deep layers of the skin (dermis) or in rare cases, to subcutaneous tissues while the latter is present above the skin.

CMN is mainly recognised due to its highly pigmented black-to-brown shades. It can affect any part of the body but is usually found in the limbs or trunk. Also, CMN is independent of ethnic factors like skin colour.

Causes Of Congenital Melanocytic Nevus

Congenital melanocytic nevus appears in newborns as a result of genetic abnormalities during the 5-24 weeks of pregnancy, resulting in over-proliferation of melanocytes, the skin pigment that is responsible for giving skin and eyes their natural colour.

As a result of the overproliferation of melanocytes, melanoblasts are formed that start migrating to the skin cells between 8-10 weeks of pregnancy, causing dysfunction in the main skin-colour producing cells, and leading to the formation of CMN. [4]

Image By Researchgate.net

Symptoms Of Congenital Melanocytic Nevus

Some of the symptoms of congenital melanocytic nevus include:

• An overly-sized lesion on the body with an irregular border.
• Some larger lesions may present with itching, skin erosion or ulceration. [5]
• Black or tan coloured lesions that can become darker or lighter with time.
• Raised and thick lesions
• Excessive hair growth over the lesion, in some cases.

Complications Of Congenital Melanocytic Nevus

Some of the complications of congenital melanocytic nevus may include:

• Present of some or many small nevi on the skin (satellite nevi).
• Low confidence, behavioural or emotional problems due to appearance.
• Spread of the lesion to the brain area, leading to cognitive issues and seizures.
• Risk of developing melanoma, a type of skin cancer. [6]

Diagnosis Of Congenital Melanocytic Nevus

In many cases, CMN is usually diagnosed by its physical appearance. A medical expert may ask for a biopsy or dermatoscopy to confirm the condition.

Treatments Of Congenital Melanocytic Nevus

Some of the treatment methods for congenital melanocytic nevus include:

• Surgery: It includes surgical methods like skin grafts or tangential excision.
• Non-surgery: It includes methods like chemical peels, dermal abrasion, ablative lasers and electrosurgery.

Note: The surgical and non-surgical treatments are mainly done to improve the appearance of the patient and reduce the risk of developing skin cancer.

To Conclude

Congenital melanocytic nevus is not a life-threatening condition- they only cause appearance-related problems. However, it requires monitoring to prevent the risk of skin cancer, especially in the case of large congenital nevi.