A 24-year -old male presents with a hyperpigmented patch over the right upper chest 4 years ago, thick hair over the same with time. Diagnosis is:

Ref. Rook's Textbook of Dermatology, Pg 75   Becker Nevus Sharply demarcated pigmented macule, often with localized hypertrichosis Dermoscopy: network, focal hypopigmentation, skin furrow hypopigmentation, hair follicles, perifollicular hypopigmentation and vessels Sex ratio close to 1:1  Sharply demarcated, unilateral, hyperpigmented tan macule on back, shoulder or chest Hypertrichosis in 50%   Histopathology Increased basal layer pigmentation, mild acanthosis, hyperkeratosis and regular elongation of rete ridges Variable hypertrichosis Areas associated with smooth muscle hamartoma have more pronounced smooth muscle bundles irregularly dispersed within the dermis and unrelated to either hair follicles or vascular channels Does not actually contain nevus cells