Becker's nevus
Encyclopedia
Becker's nevus is a skin disorder predominantly affecting males. The nevus
generally first appears as an irregular pigmentation (melanosis
or hyperpigmentation
) on the torso or upper arm (though other areas of the body can be affected), and gradually enlarges irregularly, becoming thickened and often hairy (hypertrichosis
). This form of nevus was first documented in 1948 by American
dermatologist Samuel William Becker (1894–1964),.
, and the more or less aesthetic nature of the effects of the disease. Thus the pathophysiology
of Becker's nevus remains unclear. While it is generally considered an acquired rather than congenital disorder, there exists at least one case report documenting what researchers claim is a congenital Becker's nevus with genetic association: a 16-month-old boy with a hyperpigmented lesion on his right shoulder whose father has a similar lesion on his right shoulder.
The apparently most extensive study to date (a 1981 survey of nearly 20,000 young Frenchmen) served to disprove many commonly-held beliefs about the disease. In the French study, 100 subjects were found to have Becker's nevi, revealing a prevalence of 0.52%. Nevi appeared in one half the subjects before the age of 10, and between ages 10 and 20 in the rest. In one quarter of cases sun exposure seems to have played a role, a number apparently lower than that expected by researchers. Also surprising to researchers was the low incidence (32%) of Becker's nevi above the nipples, for it had generally been believed that the upper chest and shoulder area was the predominant site of occurrence. Pigmentation was light brown in 75% of cases (note: subjects were caucasian), and average size of the nevus was 125 cm² (19 in²).
or trimming can be effective in removing unwanted hair, while laser hair removal
may offer a longer-lasting solution. Different types of laser treatments may also be effective in elimination or reduction of hyperpigmentation, though the results of laser treatments for both hair and pigment reduction appear to be highly variable.
Nevus
Nevus is the medical term for sharply-circumscribed and chronic lesions of the skin. These lesions are commonly named birthmarks and moles. Nevi are benign by definition...
generally first appears as an irregular pigmentation (melanosis
Melanosis
Melanosis is a form of hyperpigmentation associated with increased melanin.It can can refer to:* Melanism* Ocular melanosis* Smoker's melanosis* Oral melanosis...
or hyperpigmentation
Hyperpigmentation
In dermatology, hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.-Causes:Hyperpigmentation may be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris...
) on the torso or upper arm (though other areas of the body can be affected), and gradually enlarges irregularly, becoming thickened and often hairy (hypertrichosis
Hypertrichosis
Hypertrichosis is an abnormal amount of hair growth on the body; extensive cases of hypertrichosis have informally been called werewolf syndrome. There are two distinct types of hypertrichosis: generalized hypertrichosis, which occurs over the entire body, and localized hypertrichosis, which is...
). This form of nevus was first documented in 1948 by American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
dermatologist Samuel William Becker (1894–1964),.
Clinical information
Medical knowledge and documentation of this disorder is inextensive, likely due to a combination of factors including recent discovery, low prevalencePrevalence
In epidemiology, the prevalence of a health-related state in a statistical population is defined as the total number of cases of the risk factor in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population...
, and the more or less aesthetic nature of the effects of the disease. Thus the pathophysiology
Pathophysiology
Pathophysiology is the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome...
of Becker's nevus remains unclear. While it is generally considered an acquired rather than congenital disorder, there exists at least one case report documenting what researchers claim is a congenital Becker's nevus with genetic association: a 16-month-old boy with a hyperpigmented lesion on his right shoulder whose father has a similar lesion on his right shoulder.
The apparently most extensive study to date (a 1981 survey of nearly 20,000 young Frenchmen) served to disprove many commonly-held beliefs about the disease. In the French study, 100 subjects were found to have Becker's nevi, revealing a prevalence of 0.52%. Nevi appeared in one half the subjects before the age of 10, and between ages 10 and 20 in the rest. In one quarter of cases sun exposure seems to have played a role, a number apparently lower than that expected by researchers. Also surprising to researchers was the low incidence (32%) of Becker's nevi above the nipples, for it had generally been believed that the upper chest and shoulder area was the predominant site of occurrence. Pigmentation was light brown in 75% of cases (note: subjects were caucasian), and average size of the nevus was 125 cm² (19 in²).
Malignancy
A 1991 report documented the cases of nine patients with both Becker's nevus and malignant melanoma. Of the nine melanomas, five were in the same body area as the Becker's nevus, with only one occurring within the nevus itself. As this was apparently the first documented co-occurrence of the two diseases, there is so far no evidence of higher malignancy rates in Becker's nevi versus normal skin. Nonetheless, as with any abnormal skin growth, the nevus should be monitored regularly and any sudden changes in appearance brought to the attention of one's doctor.Treatment
As Becker's nevus is considered a benign lesion, treatment is generally not necessary except for cosmetic purposes. ShavingShaving
Shaving is the removal of hair, by using a razor or any other kind of bladed implement, to slice it down to the level of the skin. Shaving is most commonly practiced by men to remove their facial hair and by women to remove their leg and underarm hair...
or trimming can be effective in removing unwanted hair, while laser hair removal
Laser hair removal
Laser hair removal was performed experimentally for about 20 years before it became commercially available in the mid 1990s. One of the first published articles describing laser hair removal was authored by the group at Massachusetts General Hospital in 1998...
may offer a longer-lasting solution. Different types of laser treatments may also be effective in elimination or reduction of hyperpigmentation, though the results of laser treatments for both hair and pigment reduction appear to be highly variable.