Classic Hodgkin lymphoma: An illustrative review of select diagnostic limitations and immunomorphological challenges

The diagnosis of classic Hodgkin lymphoma (CHL) in clinical practice remains reliant on tissue morphological and immunohistochemical evaluation. In this article, we illustrate specific scenarios that we have encountered in our clinical practice pertaining to diagnostic challenges in CHL. We begin with select presentations of morphologic variants of CHL and then discuss certain immunophenotypic deviations from what is deemed "normal patterns" of antigen expression by HRS cells. Lastly, we discuss mimickers of HRS cells, in lymphomatous and non-lymphomatous conditions.