A preauricular sinus is a common congenital malformation characterized by a nodule, dent or dimple located anywhere adjacent to the external ear. Frequency of preauricular sinus differs depending the population: 0.1–0.9% in the US, 0.9% in the UK, and 4–10% in Asia and parts of Africa.Preauricular sinuses are inherited features, and most often appear unilaterally. [Source: Wikipedia 
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