Hyperkeratosis lenticularis perstans (Flegel's disease).

A 62-year-old female with a 20-year history of small horny papules on the skin of the legs is described. Light microscopy revealed a hyperkeratotic papule with atrophic epidermis and a dense dermal inflammatory cell infiltrate with many cerebriform lymphocytes not earlier described in connection with hyperkeratosis lenticularis perstans (HLP). The electron-microscopic picture showed membrane-coating granules (MCG) and keratohyalin located in different cells, indicating that the disorder of keratinization in HLP is possibly caused by reduced co-operation between these cells and that the keratinization process occurs in the absence of MCG. Perpetual treatment with oral retinoid was successful.