Striate palmoplantar keratoderma (Brunauer–Fohs–Siemens syndrome)
A 64-year-old man presented with focal hyperkeratotic plaques on the fingers, palms, and soles. Histopathologic and electron microscopic results were consistent with striate palmoplantar keratoderma. Treatment with topical keratolytics was unsuccessful. Striate palmoplantar keratoderma or Brunauer-Fohs-Siemens syndrome is an autosomal dominant condition that presents with linear hyperkeratosis on the palms and fingers and focal plaques on the plantar aspects of the feet. Histopathologic features include hyperkeratosis, hypergranulosis, and acanthosis with no epidermolysis. Electron microscopic examination shows diminished desmosomes, clumped keratin filaments, and enlarged keratohyalin granules. The syndrome has been linked to mutations in desmoglein 1, desmoplakin, and keratin 1. Treatment may include keratolytics, oral retinoids, and surgical debridement.