๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
BECKER NEVUS
BECKER NEVUSย ย ICD-10: D22,502
โข Becker nevus is a distinctive asymptomatic clinical lesion that is a pigmented hamartoma, that is, a developmental anomaly consisting of changes in pigmentation, hair growth, and a slightly elevated smooth verrucous surface (Fig. 9-40).
โข It occurs mostly in males and in all races. It appears not at birth but usually before 15 years of age, although sometimes after this age.
โข The lesion is predominantly a macule but can have a slight verrucous surface not unlike the lesion of acanthosis nigricans. It is light brown in color and has a geographic pattern with sharply demarcated borders (Fig. 9-40A).
โข Most common locations are the shoulders and the back. The increased hair growth follows the onset of the pigmentation and is localized to the areas that are pigmented (Fig. 9-40B). The pigmentation is related to increased melanin in basal cells and not to an increased number of melanocytes.
โข It is differentiated from a hairy congenital melanocytic nevus, because Becker nevus is not usually present at birth, and from cafรฉ-au-lait macules because these are not hairy.
โข The lesion extends for a year or two and then remains stable, only rarely fading.
โข There is very rarely hypoplasia of underlying structures, e.g., shortening of the arm or reduced breast development in areas under the lesion.
โข Management: The hypertrichosis can be of cosmetic concern to some individuals.
A
B
FIGURE 9-40 โข A and B Becker nevusโ(A) A slightly raised light-tan plaque with sharply defined and highly irregular border and slight hypertrichosis on the chest of a 16-year-old male patient. (B) In this case of Becker nevus, the massive hypertrichosis conceals the tan background plaque.