A male newborn demonstrated an extensive unilateral hystrix-like hyperkeratosis. The child died 17 days post partum with the clinical sign of congestive right heart failure. The autopsy revealed various anomalies of the blood and lymph vessel system. Lightmicroscopically the affected skin demonstrated a saw-edge configuration of the orthohyperkeratotic epidermis due to a prominent papillomatosis with a narrow basis. An acanthokeratolytic (epidermolytic) hyperkeratosis was absent. Round granules (phi 0,25-1,3 micrometer) bounded by a double membrane and with tubulovesicular structures within an electron dense matrix were conspicious in karatinocytes of the stratum granulosum. The case is termed "Ichthyosis hystrix gavior unilateralis".