Immunoperoxidase techniques. II. Application to cutaneous neoplasms

Skin disorders are readily accessible to inspection, palpation, and biopsy. In many instances, the physician's discovery of a neoplasm leads to excision of part or all of the lesion. By combining the clinical presentation and histopathologic appearance, most of these disorders can be diagnosed with accuracy. In some instances, however, it may be difficult to differentiate one neoplastic process from another with routine stains. Traditionally, the histologic diagnosis of cutaneous neoplasms has been facilitated by application of special histochemical stains and electron microscopy. Despite the use of these techniques, some neoplasms in the skin defy definitive diagnosis. With the availability of antibodies against certain characteristic cellular antigens, the immunoperoxidase technique has proven to be a useful tool in the diagnosis of a number of infectious, autoimmune, and neoplastic skin diseases. In this review, I will examine the application of the immunoperoxidase technique to the histogenetic assessment of a number of dermatologic neoplasms, its practical benefits, and its limitations in the differential diagnosis of some commonly encountered neoplasms of the skin.