Dermatopathology is both exciting and exasperating. tum corneum cells. This occurs in disorders of keratiniza Skin has an elegant simplicity in its functions yet a tion because the process of desquamation is disturbed (Figure 1. 1). ferocious complexity in its structure. This is one of the paradoxes that underly the pathology of skin disease Parakeratosis. The presence of nucleated horn cells in and may go some way in explaining the multitudinous the stratum corneum. Normally the horn cells (corneocy disorders to which the skin is subject. The ready visibility tes) are thin lamellae of less than 1 f. lm thickness. They of the skin may also help explain why straightforward contain no detectable cytoplasmic contents as these are histological examination cannot always provide an lost in the granular cell layer. Parakeratosis occurs when answer to a clinicians's question. Quite dramatic appear the process of keratinization is disturbed such as when ances may be due to alterations of the relative rates of the rate of epidermal cell production is increased (as in blood flow, with or without oedema, in the different psoriasis) so that nuclei are not broken down before the vascular plexuses or around different structures in the stratum corneum is reached and when damage occurs horizontal dimension, neither of which may result in to the upper epidermis (Figure 1. 2). 'much to see' histologically. The inherent sampling error Porokeratosis.

This is a pre-1923 historical reproduction that was curated for quality. Quality assurance was conducted on each of these books in an attempt to remove books with imperfections introduced by the digitization process. Though we have made best efforts - the books may have occasional errors that do not impede the reading experience. We believe this work is culturally important and have elected to bring the book back into print as part of our continuing commitment to the preservation of printed works worldwide.