Palmoplantar keratoderma (Voerner) with composite keratohyalin granules: studies on keratinization parameters and ultrastructures

A case of the Voerner type palmoplantar keratoderma was studied for abnormalities of keratinization parameters. An enzyme and materials used to build the marginal band or cellular envelope of the cornified cell were all abnormally expressed; i.e. transglutaminase I (TGK), loricrin, and involucrin were abnormally immunostained. In the normal controls, their expression was limited to the upper epidermis, mainly in the granular layer. In the lesional skin, they were detected from the suprabasal layer to the lower horny layer. Filaggrin, the protein of the keratohyalin granule, was also expressed more widely than in controls. Ultrastructural abnormalities included a significantly higher frequency of composite keratohyalin granules than controls, early formation of a marginal band in the midepidermis, and, most remarkably, the clumping of tonofilaments causing vacuolization of the cytoplasm of affected keratinocytes.