Bilateral, Symmetrical, Congenital Becker's Nevus Melanosis: A Rare Presentation and Review of the Literature.

Becker's nevus, also known as Becker's melanosis or Becker's pigmentary hamartoma, is a concurrent melanosis first described by S. William Becker. It is a type of acquired hyperpigmentation characterized by well-defined, unilateral lesions with regular borders. It is associated with hypertrichosis and hyperpigmented brownish patches with a mean diameter of 15 cm. The shoulder, scapular area, and upper arms are the most commonly affected areas, but it can occur on any area of the body, including the forehead, face, neck, lower trunk, extremities, and buttocks. The lesion usually appears around puberty, and males are more likely to be affected than females. A 27-year-old male of Arabic descent who was medically free presented to the dermatology clinic complaining of bilateral, symmetrical, hyperpigmented patches on the upper back. The lesions started almost at birth, gradually growing in size and darkening in color over time. On local skin examination, the lesions were bilateral, symmetrical, hyperpigmented patches on the upper back. They were both homogeneous and brown in color with irregular borders and blotchy hyperpigmented macules on both sides of the upper back associated with sparse hair development. Histopathological examination revealed epidermal hyperkeratosis, acanthosis, and focal regular elongation of rete ridges with clubbing. Increased basal layer pigmentation was noticed. The dermis showed focal areas with pigment incontinence. Based on the above clinicopathological findings, the patient was diagnosed with Becker's melanosis. He was referred to the laser clinic for further treatment.