Use of immunohistochemistry in melanocytic lesions.

The great majority of cutaneous melanocytic lesions can be readily classified as one of the defined diagnostic entities, either benign or malignant. Therefore, only in a minority of lesions, it is necessary to employ ancillary techniques to help in the diagnosis. The most popular and probably the most helpful of these is immunohistochemistry: an area in which Dr McNutt has made some of his most important scholarly contributions. Following Dr McNutt's lead, in this article, we describe the use of immunohistochemistry as a diagnostic aid in dermatopathology as well as the potential pitfalls commonly encountered in practice.