Confluent and reticulated papillomatosis: a clinical, histopathological, and electron microscopic study.

The clinical, histopathological, and electron microscopic features of ten patients with confluent and reticulated papillomatosis (CRP) of Gougerot and Carteaud were studied. Histopathologically, hyperkeratosis, decreased granular layer, irregular papillomatosis, and hypermelanosis of the basal layer were present. In an electron microscopic study, we found transitional cells between the stratum granulosum and stratum corneum that were increased in CRP. This finding supported the suggestion that this is a defect of keratinization.