Abnormal cutaneous nerves in incontinentia pigmenti.

Cutaneous nerves showed multiple ultrastructural abnormalities in a patient with incontinentia pigmenti. Fetal nerve bundles were seen both in the dermis and entering the epidermis. A cell with some Schwann cell features was identified above the basal layer amid keratinocytes. Dermal melanophages were in close apposition to Schwann cells. All of these features suggest that neural structures may be abnormal in incontinentia pigmenti and play a role in transfer of melanin from epidermis to dermis.