Skin biopsy and dermatopathology

Abstract

Knowledge about principles and techniques of skin biopsy is the prerequisite for an accurate histopathologic diagnosis. This comprises correct selection of the biopsy site as well as correct sampling and fixation of the tissue. Histopathologic diagnosis is primarily based on hematoxylin and eosin. Additionally histochemical and immunohistochemical stainings as well as direct immunofluorescence may be performed. Molecular biologic investigation methods such as polymerase chain reaction or fluorescence in situ hybridization become increasingly important for selected diagnoses. One of the most important aspects, however, is a thorough clinical-histopathologic correlation. Dermatohistopathologic diagnosis of occupational dermatoses in most cases does not allow defining causative relations. Vast majority of occupational dermatoses is related to occupational contact dermatitis, in terms of either allergic or irritant contact dermatitis, differing substantially histopathologically. Histopathology of occupationally induced photosensitivity, acne and chloracne, pigmentary disturbances, urticaria, granulomatous reactions, autoimmune diseases, disorders caused by physical and mechanical agents, and neoplastic diseases does not considerably differ from histopathology of the nonoccupational forms. Dermatohistopathologists should be aware of artifacts. Artifacts often show peculiar histopathologic changes, which may easily lead to over- or misinterpretation in terms of primary inflammatory dermatoses.