Pigmented hairy epidermal nevus, also known as Becker\'s nevus, has a typical description as a unilateral, hairy in appearance, light to dark brown patch with an irregular but clearly defined border. However, the exact aetiopathogenesis is still poorly comprehended. We report the case of a 19-year-old female who presented with asymptomatic brownish-pigmented macular lesions on the right breast that had slowly increased in size over the past three years. Upon cutaneous inspection, the right breast had 3-5 mm rounded and oval perifollicular macules that ranged from light to dark brown hue without increased hair growth. The macules were discrete and in no particular pattern. Dermoscopy of the lesions showed well-defined perifollicular hypopigmentation surrounded by a pigmented network-like pattern. Histopathology of a punch biopsy taken from one of the follicular lesions demonstrated an increase in basal layer pigmentation with elongation of rete ridges and acanthosis, consistent with Becker\'s nevus. The patient underwent three sittings of diode laser therapy, once in four weeks, with slight improvement in pigmentation.

Becker\'s nevus is a relatively common skin lesion with brown hyperpigmentation and hypertrichosis. It may be expressed simultaneously with other cutaneous, muscular, or skeletal defects, such as hypoplasia of the breast or scoliosis, for which the term \"Becker\'s nevus syndrome\" has been proposed. An 8-year-old boy presented with a Becker\'s nevus on the right cheek, chin, and upper neck with alveolar bone hypertrophy in the anterior mandible, which led to an anterior crossbite and severe canting of the mandibular anterior teeth. Through orthopedic treatment using a face mask, the anteroposterior jaw relationship was improved. In phase 2 treatment, we corrected the canting of the mandibular anterior teeth with a segmental intrusion of the mandibular anterior right teeth into the hypertrophic alveolar bone area. The facial profile was improved along with acceptable occlusion, and the treatment result was stable at 1 year after the end of the treatment, without any periodontal attachment loss, root resorption of mandibular anterior teeth, or increase in the size of the hypertrophic region. This case report describes the successful comprehensive treatment of a growing patient with skeletal Class III malocclusion and multiple characteristics of Becker\'s nevus syndrome.