Functions and uses of immunohistochemical stains in cutaneous infiltrates of hematopoietic origin: A review for the practicing dermatologist

Background: Immunohistochemical stains, particularly those for cutaneous lymphomas, have similar-sounding names, which may lead to confusion among dermatologists who are not well versed in the terminology of the tools used for pathologic diagnosis. Also aiding in this is the fact that some familiar stains are constantly investigated for novel utility in different tumors, and a plethora of new stains regularly emerge in the peer-reviewed literature. Objective: To review the major stains encountered in dermatopathologic reports for cutaneous lymphomas. A select number of other stains are reviewed that are either new and under investigation in several cutaneous processes or have a new use described in recent reports. Methods: The peer-reviewed literature was searched and analyzed for the accepted purposes of using these markers. Results: All pertinent findings for these immunostains are reported with the purpose of educating the dermatology community. Conclusion: This review serves as a reference to clarify potentially confusing immunohistochemical stains.