Becker’s nevus is a pigmented skin formation that has a benign course and a low risk of degeneration into melanoma. The exact causes of the appearance of nevus have not been established, among the predisposing factors are genetic defects, intrauterine pathologies, connective tissue diseases. Pathology is manifested by polygonal pigmentation on the body, upper extremities, which is accompanied by pathological hair loss. For diagnosis, a clinical examination by a dermatologist, digital dermatoscopy, and histological examination of the tissue are prescribed. The task of treatment is to get rid of the cosmetic defect by minimally invasive or surgical methods.
ICD 10
D22.5 Melanoform nevus of the trunk
General information
The disease is named after the American dermatologist S. Becker, who described a typical clinical picture in 1949. In the medical literature, pathology has several synonymous names: hair epidermal nevus, Becker’s melanosis, pigmented hair hamartoma. Occasionally, the syndrome bears the double surname of Becker-Reuter, in order to emphasize the merits of a German dermatologist who supplemented information about the disease. In practical dermatology, this type of nevus occurs in 0.5% of men and 0.1% of women, the peak of diagnosis occurs in childhood and adolescence.
Causes
Etiological factors of the disease are not precisely defined. In dermatology, family cases of Becker’s melanosis are described, therefore, theories about the hereditary origin of dermatosis or intrauterine developmental abnormality are considered. Some authors note the similarity of the disease with the epidermal nevus of Siemens – hamartoma of the trunk. Possible predisposing factors:
- Complicated pregnancy. The appearance of nevus is facilitated by violations of the level of progestins and estrogens, genitourinary infections in the mother, the impact of teratogenic factors. The risk of developing pathology increases in children born to mothers with extragenital chronic diseases, prolonged intoxication.
- Exposure to UV rays. The manifestation of skin symptoms is associated with the excessive influence of ultraviolet light, which happens when living in warm regions of the country, frequent and long walks, excessive tanning. The correlation between insolation and nevi is best traced in adolescence.
- Somatic diseases. Becker’s nevus is often combined with scleroderma, muscle dysplasia, lichen planus. The associations of the disease with annular granuloma, lymphangioma, basal cell carcinoma are described.
Pathogenesis
Multiple changes in dermal tissues are typical for Becker’s nevus. Hyperkeratosis and acanthosis are determined, horn cysts are less common. The disease does not belong to typical pigmented nevi, since there are no nevus cells in the dermis, the number of melanocytes is not increased. An increase in melanocytic activity and the level of melanin in keratinocytes cause the external manifestations of the disease.
Symptoms
Half of the cases of the disease manifest themselves in children under 10 years of age, another 25% of cases are in the age range of 10-15 years. Less often, Becker’s nevus manifests in adolescence and at a young age. In 80% of patients, the pathology is manifested by focal spotty hyperpigmentation, which is accompanied by hyperkeratosis. The spots have an irregular shape, are clearly located on one half of the body (up to the median line). Favorite localization: upper shoulder girdle, shoulders and forearms.
At first, small brown spots appear on the skin. Gradually, they are grouped into irregularly shaped foci and reach 20 cm in diameter. Often the rashes are located along the Langer lines. Additional pigmented islets appear along the edges of the neoplasm, which merge with the primary focus. By the end of puberty in 56% of patients, the rash is covered with hair that reaches several centimeters in length.
In the center of the pigmented focus, the skin becomes rough and wrinkled, but there are no outgrowths and other alarming changes. In most cases, Becker’s nevus remains unchanged throughout life. Against the background of hormonal factors, hair loss can spread to non-pigmented areas of the skin, which causes discomfort in patients.
Complications
Becker’s nevus is characterized by a benign course. It is extremely rarely accompanied by bleeding and ulceration, cases of malignancy have not been described, therefore the disease is considered melanomoneurophic. A significant medical and social problem is a cosmetic defect that causes psychological problems in patients, embarrassment when wearing swimsuits, discomfort during intimacy.
Becker-nevus syndrome, which occurs only in women, deserves special attention from dermatologists. In addition to typical skin changes, unilateral hypoplasia of the mammary gland on the affected side is observed. Shortening of the upper limb and underdevelopment of the musculoskeletal structures of the chest on the same side are also characteristic. Occasionally, the syndrome is accompanied by spina bifida.
Diagnostics
The initial examination of the patient is carried out by a dermatologist. It is necessary to find out how long ago the nevus appeared, how its appearance changed over time. Clinical examination of the skin surface is crucial for diagnosis: assessment of the shape, size and location of hyperpigmented areas, the presence of hair on the skin and other features. Additional information is provided by the following diagnostic methods:
- Digital dermatoscopy. When examining the skin under multiple magnification, it is possible to examine the outer surface of the Becker nevus, exclude signs of malignancy and other pathological processes. Creating a map of moles and age spots allows you to monitor the course of the disease in a particular patient.
- Histological diagnostics. Examination of a tissue sample under a microscope is required to verify the diagnosis of an atypical course of the disease. Pathognomonic signs include an increase in the activity of melanocytes without increasing their number, the absence of nevus-specific cells in the dermis.
- Consultation of a geneticist. Since Becker’s nevus is occasionally accompanied by hereditary syndromes and intrauterine malformations, an extended diagnosis is required. In the genetic center, a full examination of the patient and his immediate relatives is carried out, karyotyping, molecular genetic studies are carried out according to indications.
Treatment
Minimally invasive methods
Given the benign nature and harmlessness of the disease, medical care is required only to eliminate the cosmetic defect. Treatment is carried out at the request of the patient. Methods of combating pigmentation are selected individually, taking into account the size, localization and appearance of the neoplasm. The most effective methods include the following:
- Laser grinding. The combination of ablative and non-ablative types of laser exposure gives a good cosmetic result. This method is shown when foci are located on open areas of the body. Nanosecond lasers are used to reduce traumatization and controlled exposure.
- Dermabrasion. With deep mechanical grinding, the upper layer of the skin with pigment cells is removed, after which regenerative processes are activated at this place. Dermabrasion requires long-term healing, but is highly effective.
- Laser hair removal. The procedure solves the problem of increased hair growth in pigmented areas. For complete removal of hypertrichosis, up to 8-10 sessions on a diode or carbon dioxide laser are required.
Patients with Becker’s nevus are advised to avoid prolonged exposure and sunburn during dangerous midday hours. On sunny days, it is advisable to apply sunscreens to exposed areas of the body with pigmentation. The neoplasm should not be subjected to traumatization, constant friction with clothes, cosmetic procedures, except those prescribed by a dermatologist.
Surgical treatment
If it is ineffective or impossible to carry out minimally invasive procedures, the possibility of surgical removal of hyperpigmented areas is considered. Surgical intervention is rarely resorted to, since it leaves visible scars and requires extensive excision of the skin according to the rules of oncological alertness. Operations are used for large sizes of Becker’s nevus and give a 100% relapse-free cure.
Prognosis and prevention
Becker’s nevus has a favorable prognosis, since it almost never transforms into melanoma. At the same time, some patients develop psychological problems, especially with a large amount of pigmentation and its visibility to others. Since the etiological factors of pathology have not been definitively studied, primary preventive measures have not been developed. Patients are shown regular follow-up with a dermatologist to control the course of the nevus.
