Ichthyosis with laminated membrane structures.

Clinical, light-microscopic, and electron-microscopic features of a new type of ichthyosis are presented. The ichthyotic disease of a 75-year-old woman appeared in early childhood as dry and scaly skin. It slowly progressed to thickened and folded hyperkeratosis on her neck and axillae. The skin on the other parts of her body was shiny, red and hard. Her physical development was normal. Light microscopy showed acanthosis and papillomatosis with hyperkeratosis. The granular cells were vacuolated. Electron microscopy revealed diagnostic changes, i.e., concentric or parallel lamellar membrane structures and amorphous material in upper epidermal cells. Corresponding lamellar material was also seen in the cornified cells. The keratinosomes were abnormal and a hypothesis is presented indicating that a defect in keratinosome formation results in vacuolization and abnormal desquamation in this disease. According to the current classification, the present type of ichthyosis is one subgroup of lamellar ichthyosis. We have called it ichthyosis with laminated membrane structures, because they are electron-microscopically diagnostic. The mode of inheritance is unknown.