Introduction:
Congenital melanocytic nevi (CMN) are skin growths that are pigmented and apparent from birth. Congenital melanocytic nevus is a benign, tumor-like malformation made up of an aberrant combination of skin cells that develop improperly from precursors of pigment cells (melanocytes) in the embryo. A few millimeters in diameter to enormous sections of the body are covered in defined zones of these melanocytic proliferations at the base of the epidermis. The congenital melanocytic nevi (single or multiple) extends vertically into the deeper dermis and, less frequently, into the hypodermis or even subcutaneous tissues in the bigger forms. The congenital melanocytic nevi's outermost layer has the highest pigmentation, giving the epidermis above it hues ranging from brown to black.
What Is the Cause of Congenital Melanocytic Nevus?
An alteration in the skin's pigment cells is what leads to congenital melanocytic nevi. Moles are a result of chance. The parents do not pass on congenital melanocytic nevi to their children. One cannot stop their child from being born with a mole.
Neurocutaneous melanosis is a disorder that congenital melanocytic nevus may occasionally signify. In cases where the congenital melanocytic nevus is big and located on the back, neurocutaneous melanosis may develop. The moles in this situation may cause seizures by affecting the spine and brain. Additionally, this kind of congenital melanocytic nevus frequently results from pure chance and is not inherited from the parents.
What Are the Signs and Symptoms Seen in Congenital Melanocytic Nevus?
The confined, light brown to black patch or plaque that can be extremely heterogeneous in consistency and covers any size surface area and any section of the body is the congenital melanocytic nevus.
Congenital melanocytic nevi can contain extra terminal hair, a condition known as hypertrichosis, and are often bigger in diameter than melanocytic nevi. It is sometimes referred to as a giant hairy nevus if the projected adult diameter is over 40 cm (16 inches) and it has hypertrichosis, but more often than not, the largest forms are referred to as enormous or giant congenital melanocytic nevi. The biggest types are thought to be present in 0.002 % of births.
As a child grows, melanocytic nevi frequently increase in size according to that of the body. Although these characteristics can also be present from birth, they frequently get thicker and more raised as they mature. Particularly after puberty, prominent terminal hairs often develop. When a nevus reaches maturity, its color may vary, and its surface may become rough from proliferative growths.
Giant congenital melanocytic nevus or non-giant nevi of the skin are both related to neurocutaneous melanosis. According to estimates, 2 % to 45 % of patients with massive congenital melanocytic nevi have neurocutaneous melanosis.
How to Diagnose Congenital Melanocytic Nevus?
Examining clinical and dermoscopic signs is the most common way to diagnose a congenital melanocytic nevus. On the basis of their size alone, the larger congenital melanocytic nevus can be diagnosed with ease. Smaller can be diagnosed more easily if their history of existence since infancy, surface topography, the presence of hair, or globular dermoscopic pattern are known. The histological characteristics of congenital melanocytic nevus are comparable to those of common acquired nevi that develop later in life when biopsied; however, congenital melanocytic nevus tend to be more cellular with deeper nevus cell extension into the deep dermis and subcutaneous layer, and cells extend along adnexal structures like hair follicles and around blood vessels and nerves. To determine whether a nevus is congenital or acquired with absolute confidence, histological criteria alone cannot be used.
Clinical Evaluation and Testing
Any person with multiple CMN or a large CMN with more than 20 satellite nevi should undergo magnetic resonance imaging (MRI) with a contrast of the brain and spine because those with 20 or more satellite nevi are five times more likely to have neurocutaneous melanosis than those with fewer, and some of these will become symptomatic. A neurologic evaluation and the appropriate imaging should be performed on any patient who has recently developed neurological symptoms, such as enuresis (prolonged nighttime bedwetting) or tiptoeing that could be signs of a tethered spinal cord, epilepsy, or ‘sunset eyes’ (a sign of increased intracranial pressure from hydrocephalus). A neurologist should also monitor asymptomatic neurocutaneous melanosis patients once a year or more frequently if there are any concerns.
The need for additional MRIs in those asymptomatic patients is unclear; however, the majority of doctors advise against them until symptoms manifest. Before the prognosis is certain, patients with substantial symptomatic neurocutaneous melanosis should think about delaying elective surgical excision of the CMN.
Regardless of the treatment used, patients with significant CMN require lifelong monitoring, which includes both self-exams of the skin and visits to a competent dermatologist's office. Physicians may be helped in the early detection of melanoma by the use of serial pictures, dermoscopy, probing of nevi and scars, evaluation of lymph nodes, and a complete assessment of systems. An expert pathologist should remove suspicious lesions and perform a histological analysis.
How to Treat Congenital Melanocytic Nevus?
There are surgical and non-surgical treatment methods. Tangential excision, curettage, serial or en bloc excision, and direct closure, as well as excision with reconstruction employing tissue expansion, skin graft, or flap, are all surgical possibilities.
Dermal abrasion, cryotherapy, chemical peels, ablative lasers, and electrosurgery are examples of non-surgical treatments. Without completely eradicating nevi cells, they could be taken into consideration to lighten pigmentation and enhance the nevus's aesthetic appeal.
Historically, congenital melanocytic nevus or CMN therapies were justified by lowering the risk of malignant transformation and enhancing aesthetic appearance. Excision surgery to lower the risk of cancer, however, is still debatable. Surgery proponents contend that groups of individuals who have had excision have a lower incidence of melanoma than patients who are managed with observation. The low absolute prevalence of melanoma in congenital melanocytic nevus weighed against the dangers of surgery is one argument against surgery.
Conclusion:
Many kids with congenital melanocytic nevi are unconcerned with how their skin looks. However, for some kids, especially when there are numerous, huge, or highly visible moles, the condition can be embarrassing or result in a negative self-image and low self-esteem. Additionally, some kids could endure taunts or believe that their appearance makes people look at them strangely or behave differently toward them. Families must understand that there is nothing they could have done to trigger congenital melanocytic nevus. It is unrelated to anything the pregnant mother did or did not do during pregnancy. Additionally, birth-related skin injuries do not result in congenital melanocytic nevi.
