In the present work we report the histopathological features of the cerebriform plantar hyperplasia observed in two patients with a mild form of the Proteus syndrome. Light microscopy revealed increased fibro-adipose tissue and adnexal structures in the dermis. Ultrastructurally, densely packed collagen fibrils variable in diameter and configuration, described as composite fibrils and unraveled fibrils, as well as a few fragmented elastic fibrils presenting an altered ratio between the elastin and the microfibrillar components were the major features observed. We consider that these histopathological findings will contribute to further delineate cerebriform plantar hyperplasia and also to establish clues for the early diagnosis of the Proteus syndrome.