Thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin.
Modes of keratinization characterized by the retention of the nuclei in the stratum corneum. On mucous membranes, parakeratosis is normal.
Hyperplasia of the stratum granulosum, often due to intense rubbing.
Diffuse epidermal hyperplasia.
Surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae.
Abnormal keratinization occurring prematurely within individual cells or groups of cells below the stratum granulosum.
Loss of intercellular connections resulting in loss of cohesion between keratinocytes.