Nevus Becker in adults and children

The pigmented hair-covered birthmark (epidermal nevus) has another name - Becker's nevus, after the American dermatologist William Becker, who first described the disease in the late 40s of the 20th century.

Epidemiology

According to some data, the prevalence of this pathology among patients with dermatological diseases ranges from 0.52 to 2%; in 0.5% of cases, these are male patients under 25 years of age. [1]

The ratio between men and women is about 1: 1, according to other sources - 5: 1.

Causes of the nevus Becker

Experts believe that Becker's nevus is one of the sporadically occurring and rarely encountered types of epidermal melanocytic  nevus, that is, a pigment mass on the skin. It is also defined as non-form melanosis or Becker gamartome pigment.[2]

What are the specific reasons for the emergence of this pathology, is currently unknown.

A Becker nevus may develop in a child or in a teenager; with such a defect, some children are born. And, perhaps, this is due to an anomaly of a gene that has not yet been identified. [3]Often associated with other congenital diseases.[4], [5], [6], [7]

The formation of epidermal melanocytic nevus occurs due to increased proliferation of epidermal cells, melanocytes and hair follicles. True, how this happens, too, while no one can explain exactly.

Since the increase and darkening of the birthmark with increased hair growth on its surface is observed during adolescence (with the onset of puberty), it is assumed that male sex hormones (androgens) circulating in the blood are involved in their occurrence. [8]

Risk factors

Not knowing the exact origin, dermatologists have not established the risk factors for the appearance of this type of nevus. But according to many, the main factor is hereditary. Although according to the results of a few studies, family cases account for 0.52-2% of all patients diagnosed with non-informal melanosis. 

Genetics emphasize the possibility of the existence of heterozygous individuals in several generations with the manifestation of pathology under the condition of the formation of a clone of homozygous cells as a result of a prolonged somatic mutation.

Pathogenesis

The pathogenesis of Becker's melanosis, included in the category of congenital melanocytic nevi, is also unclear . As already mentioned, there may be a hormone-dependent nature of the pigment abnormality, which may be associated with a local increase in the expression of androgen receptors in the skin.

And the assignment of the Becker nevus to the types of  hyperpigmentation of the skin  makes it possible to consider its connection with a violation of the synthesis of the skin pigment melanin by dendritic cells (melanocytes) of the basal layer of the epidermis.

Symptoms of the nevus Becker

At birth or later, the first signs of Becker's nevus appear as a clearly defined light-brown birthmark on the skin of the upper body — on the shoulders, chest, or back, occasionally elsewhere, but only on one side. Any other symptoms are not observed.

With age, the spot becomes darker, showing a progressive hyperpigmentation, and the skin in its borders is thicker. In addition, a lot of hair grows on the spot (this is called hypertrichosis). Sometimes, acne appears on the affected skin.

Usually, only the skin is affected, but there may be congenital concomitant ipsilateral anomalies, that is, on the same side as the nevus. In such cases, we are talking about the so-called Becker nevus syndrome.

Becker nevus syndrome may manifest itself: [9], [10]

• hamartoma (growth) of smooth muscle tissue;
• hypoplasia (underdevelopment) of the breast or aplasia of the pectoral muscle;
• the presence of an extra nipple;
• hyperplasia of adipose tissue outside the breast;
• hypoplasia of the scapula, shoulder, or arm;
• hemivertebra (congenital spinal curvature);
• bulging the sternum and ribs (also called the pigeon chest0;
• dystrophy of subcutaneous adipose tissue;
• enlarged adrenal glands.

Complications and consequences

Nevus Becker - the formation of a benign character; long-term effects in the form of malignancy of the birthmark were recorded in medical sources only in a few patients.[11]

Musculoskeletal and other abnormalities relate to Congenital Becker Nevus Syndrome.

Diagnostics of the nevus Becker

As a rule, diagnosis is limited to a clinical examination of the affected area of koi using  dermatoscopy.

For details, see -  Diagnosis of moles

If doubts creep in at the doctor regarding the good quality of the birthmark, a biopsy is taken and a histological examination of a tissue sample is taken.

Differential diagnosis

Differential diagnostics includes postinflammatory hyperpigmentation, congenital hamartoma of smooth muscle tissues, genetically determined McCune-Albright syndrome, and a congenital abnormality such as a giant melanocytic nevus. [12]

Treatment of the nevus Becker

To date, positive treatment of most cases of Becker nevus is impossible, and the tactics of medical care is developed for each individual patient on an individual basis.

Since Becker's nevus creates cosmetic problems that reduce the quality of life of patients, cosmetic surgical treatment can be carried out: removal of a nevus with a ruby laser or fractional grinding with a neodymium laser. [13], [14], [15], [16]However, the effectiveness of such treatment is leveled by a high level of relapses.

It is much easier and safer to remove hair growing on a nevus, for example, using external means for epilation. A case of treatment with the antitumor agent Flutamide has been described. [17]And in order for birthmarks to darken even more, you need to protect them from direct sunlight.

Prevention

No preventive measures for this pathology exist.

Forecast

Unfortunately, there are no pills for Bevker's nevus, for ointments, but he does not pass. So the forecast is not comforting.