Clear Cell Papulosis: Report of a Case With Unique Clinical and Histologic Findings

Clear cell papulosis is a rare, self-limited, benign disease of early childhood, characterized by white macules and flat papules over the milk line. Histopathologically, it is characterized by scattered clear cells throughout the basal and/or suprabasal epidermal layers, which-as clear cells of Toker of the nipple do-typically express cytokeratin 7. They also exhibit other markers expected for adenoid differentiation, such as low-molecular weight cytokeratins, carcinoembryonic antigen, epithelial membrane antigen, and mucin. The age of onset, distribution of lesions, histopathology, and its benign behavior nature help to exclude clinically similar conditions, either benign or malignant. The authors report a case of clear cell papulosis in a 7-year-old Brazilian girl in whom lesions were observed on the legs and histologically formed by solid and adenoid aggregates of clear cells, in a similar fashion than clear fetal cells of Toker.