Nevi of Ota and Ito Workup

Updated: Mar 26, 2019
  • Author: Omobola Onikoyi, DO, MSc; Chief Editor: Dirk M Elston, MD  more...
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Other Tests

Consider ophthalmologic examination and follow-up care for nevus of Ota because of a reported 10% association of nevus of Ota with increased intraocular pressure. Iris mammillations, sometimes occurring with nevus of Ota, should not be confused with other nodular alterations of the iris, such as the Lisch nodules of neurofibromatosis, as they are associated with a higher risk of malignant transformation. [33]

Lesions should be closely observed for any changes in size or color, as there is a mild risk for melanoma.


Histologic Findings

Histologic findings for nevi of Ota and Ito have some similarities. Overlying epidermis is normal. In the papillary and upper reticular dermis, dendritic melanocytes are present and surrounded by fibrous sheaths (which are not present in other dermal melanocytosis, such as blue nevus or Mongolian spots). Dermal melanophages may be present.

Nevi of Ota have been classified histologically into 5 types based on the locations of the dermal melanocytes, which are (1) superficial, (2) superficial dominant, (3) diffuse, (4) deep dominant, and (5) deep. [38]

This histologic classification correlates clinically with the observation that the more superficial lesions tend to be located on the cheeks, while deeper lesions occur on periorbital areas, the temple, and forehead.