Erythrokeratodermia Variabilis :An Ultrastructural Study

There have been conflicting views as to the precise nature of erythrokeratodermia variabilis. It has been suggested that it is a "retention' hyperkeratosis. Light and electron microscopic studies were undertaken to study the morphological changes that take place in, the epidermal cells and their bearing on the pathogenesis in two sisters, suffering from this rare disorder. Histopathologic changes as seen under the light microscope were non-specific. Ultrastructural studies showed a thickened basement membrane and presence of large amount of tonofibrils in the basal cells, some aggregating to form clumps. In the suprabasal and lower spinous cells keratohyihne granules were present. The cells of the upper spinous layer were full of keratohyaline material. Normally material is only seen in the granular layer (transforming phase). Membrane-coated granules were decreased in the cells of upper spinous layer. Formation of keratohyaline granules in the suprabasal and spinous cells (synthetic phase) is possibly a major factor in the pathogenesis of erythrokeratodermia variabilis leading to an early or accelerated process of keratinisation and thus, it is unlikely to be a retention hyperkeratosis.