Thickened Epidermis
This usually results from keratinocyte hyperplasia and features acanthosis of the epidermis. Often there is associated hyperkeratosis.
Check it to see if there is any cytological atypia of the keratinocytes to indicate Bowen's disease.
Otherwise a lot of chronic diseases eg Lichen simplex and Psoriasis will show a thickened epidermis but look out for some Deep fungal infections, TB of the skin and Reactive perforating collagenosis and the much rarer halogenodermas.
