Leukoderma syphiliticum: ultrastructural observations on melanocyte function

Abstract

A case of genital leukoderma syphiliticum was analysed submicroscopically. No treponema pallidum organisms could be detected intra- or extracellularly in the epidermis or in the dermis. The melanocytes were only slightly reduced in number and had mostly normal outlines. The melanogenesis was impaired and small melanosomes with decreased deposition of melanin were mostly produced at the expense of normal melanin granules. A partial block in the melanin transfer mechanism seems to be in evidence. As no direct destructive action of spirochetes on the melanocytes is observed, an indirect effect is assumed, e.g. by a tyrosinase inhibitor.