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| Actinic Keratosis |
| Etiology •Actinic keratosis is, as the name implies, associated with sun exposure. •Long term exposure to the sun is the causative factor. |
| Pathogenesis •Believed to represent a response of the skin to UV rays., |
| Epidemiology •It is seen primarily in the area of the face, upper back in light-skinned men and the legs of light-skinned women. |
| General Gross Description •The lesion may appear as a roughened area of skin with some evidence of hyperemia and a tendency to ulceration. |
| General Microscopic Description •Histologically, the actinic keratosis lesion may be visualized as a carcinoma in situ of the skin. •Thus, instead of the normal orderly progression of basal layer, stratum spinosum, granular cell layer, stratum corneum, there is a loss of polarity of cells. •Mitoses are seen at layers above the basal layer. •There is a failure of orderly maturation of the nucleus from vesicular to condensed to fragmentaton and loss of nuclear materials •There is a tendency to abrupt and unscheduled keratinization •There is a tendency to hyperchromatic and aberrant nuclear morphology. •In addition, some evidence of infiltration of the upper dermis with inflammatory cells is often noticed. •Actinic keratosis is almost always accompanied by a bluish discoloration of the papillary dermis indicative of UV damage to the connective tissue of the papillary dermis. |
| Clinical Correlation •May progress to frank malignancy. |
| References • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th edition. Philadelphia, W.B. Saunders, 1994, pp. 1185. |
| Actinic Keratosis |
| Synopsis by: T.V.Rajan, M.D., Ph.D. (T01000M72850)[513] |
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