Becker nevushttps://en.wikipedia.org/wiki/Becker's_nevus
Becker nevus is a benign skin disorder predominantly affecting males.The nevus usually shows up around puberty. It generally first appears as an irregular pigmentation on the torso or upper arm, and gradually enlarges irregularly, becoming thickened and often become hairy (hypertrichosis).

Treatment
The hair overlaying on the nevus can be removed with a laser. However, due to the high recurrence rate, it is almost impossible to remove nevi with lasers.

  • It is characterized by a large nevus with abundant hair growth over the area.
  • Laser treatment may be challenging due to persistent hyperpigmentation.
References Becker’s nevus - Case reports 35519166 
NIH
Becker's nevus is also known as Becker melanosis. It is a benign lesion which can be presented as congenital or acquired with hairless or hypertrichotic lesions. It's a rare case which affects mainly male individuals. It is often pigmented and gets darker by time and excessive hair growth can be seen over it. A 29-year-old transgender patient presented with hyperpigmentation with the lesion which started at the age of 15 as a small hyperpigmented macule. The lesion increased gradually to form giant patches. On examination a right-side hyperpigmentation involving the anterior chest, shoulder, scapular region, upper arm with hypertrichosis and irregular margins.
 Lasers for Becker’s Nevus 30762191 
NIH
Becker's nevus is a common pigmented dermatosis, usually featured by ipsilateral pigmented patch with hypertrichosis. Becker's nevus is often treated with various types of lasers although other regimens are available. A variety of lasers had been used alone or in combination to treat Becker's nevus. Laser wavelengths used for Becker's nevus ranged from 504 to 10,600 nm, while the number of treatment varied from 1 to 12 sessions. The clinical outcomes were mixed although combination of lasers with different wavelengths appeared to achieve a better efficacy. Adverse effects were usually mild to moderate erythema. While lasers are relatively safe, their efficacy for Becker's nevus is moderate.