Mongolian Blue Spots

"Mongolian blue spots are common among darker-skinned races, such as
Asian, East Indian, and African. They are flat, pigmented lesions with
unclear borders and irregular shape. They appear commonly at the base
of the spine, on the buttocks and back. They may also can appear as
high as the shoulders and elsewhere. Mongolian spots are benign skin
markings and are not associated with any conditions or illnesses."
[p://www.nlm.nih.gov/medlineplus/ency/article/001472.htm]