This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': '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: \nSelect and explain. \nA. Spitz nevus, B. Hypermelanosis of Ito, C. Becker’s nevus, D. Congenital melanocytic nevus', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ref. Rook's Textbook of Dermatology, Pg 75\n\xa0\nBecker Nevus\n\nSharply demarcated pigmented macule, often with localized hypertrichosis\nDermoscopy: network, focal hypopigmentation, skin furrow hypopigmentation, hair follicles, perifollicular hypopigmentation and vessels\nSex ratio close to 1:1\xa0\nSharply demarcated, unilateral, hyperpigmented tan macule on back, shoulder or chest\nHypertrichosis in 50%\n\n\xa0\nHistopathology\n\nIncreased basal layer pigmentation, mild acanthosis, hyperkeratosis and regular elongation of rete ridges\nVariable hypertrichosis\nAreas 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\nDoes not actually contain nevus cells", 'role': 'assistant'}]