Mongolian Spot(redirected from Blue bum)
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Mongolian spot[mäŋ′gō·lē·ən ′spät]
a bluish color of the skin, sometimes found in the sacral region in children. It is caused by deposits of the pigment melanin in the connective tissue of the skin. Mongolian spots were first described among children of Mongoloid ancestry, but they also occur among children of other races.