Abstract
Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a distinct neoplasm within the spectrum of Hodgkin lymphomas with characteristic clinical, morphological, and immunohistochemical features. According to the WHO definition, lymph nodes involved by NLPHL should have a nodular or nodular and diffuse proliferation of scattered large neoplastic lymphocyte-predominant (LP) cells in a small cell background that reside in expanded follicular dendritic cell meshworks; the LP cells must also have a distinct immunophenotypic profile. The LP cells are monoclonal B cells that are typically CD20, BCL6, CD79a, and CD45 positive and are CD30 and CD15 negative. In contrast, the Reed-Sternberg cells of classical Hodgkin lymphoma (CHL) are typically positive for CD15 and CD30. However, in CHL, CD20 staining is variable, and CD15 staining may be absent in some cases. Thus, CD30 is often considered to be the most distinctive marker between CHL and NLPHL. In order to better assess CD30 staining in NLPHL, we reviewed 220 cases of NLPHL and found 21 cases that showed at least focal staining of the neoplastic cells for CD30. The CD30 staining was often faint, but occasionally strong, and typically was found only on a subset of the LP cells. We evaluated the clinicopathologic features of these cases to determine whether they showed differences from typical CD30-negative NLPHL and found no significant difference with respect to clinical presentation, histology, other immunophenotypic features or outcome. In summary, we conclude that CD30 expression by LP cells in NLPHL can be seen and should not lead to a misdiagnosis of CHL. The presence of CD30-positive LP cells is not associated with other features of CHL or unusually aggressive behavior.