Nevus of Ota: Clinical Aspects and Management

Henry H.L. Chan, MB, FRCPG, FRCPE, Taro Kono, MD

In This Article

Nevus of Ota: A Form of Congenital Dermal Melanoses

While nevus of Ota is widely considered to be a form of dermal melanocytic hamartoma, previous authors have proposed that nevus of Ota, Mongolian spot, and the blue nevus represent different manifestations of the same abnormality.[9] It has also been suggested that the nevoid cells originate from Schwann cells or other neural elements, and that abnormalities of neural crest migration lead to the development of these congenital dermal melanoses.[10,11] The exact embryologic events that result in such abnormalities are unknown, but changes in the local embryonic environment could be important. Glycosaminoglycans, macromolecular substances that fill the cell free space in early embryologic development, play an important role in neural crest migration. It has been proposed that changes in the concentration of glycosaminoglycans affect neural crest migration, with the formation of dermal melanosis as the consequence.[12] The phenotype (nevus of Ota, Mongolian spot, or blue nevus) and the extent of involvement depend upon the stage at which the change occurs, as well as the extent of that change.


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