Lymphocyte depleted Hodgkin lymphoma: an evaluation with immunophenotyping and genetic analysis

Lymphocyte depleted classical Hodgkin lymphoma (LDHL) is a vanishing category of classical Hodgkin lymphoma (CHL); many cases previously placed in this category are now recognised as diffuse large B-cell lymphoma (DLBCL), anaplastic large-cell lymphoma (ALCL), or nodular sclerosis CHL with lymphocyte depletion. In addition, the recent recognition of high grade B-cell lymphomas intermediate between DLBCL and CHL (grey-zone lymphomas) raises the question of whether LDHL exists at all as a category of CHL. We studied eight cases that fulfilled diagnostic criteria of LDHL according to the 2008 WHO Classification. The cases involved lymph nodes (7 cases) and pleura (1 case) from four males and four females (age 30-71 years; median 62 years). All tumors contained numerous Hodgkin-Reed-Sternberg (HRS) cells, fibroblasts and histiocytes and scattered lymphocytes. In three cases the tumors had a more diffuse fibrotic appearance, while in five cases they appeared reticular and anaplastic. Neoplastic cells in all cases expressed CD30, CD15, fascin, weak PAX5 and MUM-1 and lacked CD45, Alk-1, EMA, CD3, CD68, Mart-1 and cytokeratin. Oct.2 and/or Bob-1 were expressed in all cases. Two cases variably expressed CD20 but were CD79a negative. Four cases were positive for EBV. All the four cases with adequate DNA had clonally rearranged IGH genes. The combined morphologic, immunophenotypic and molecular genetic features of this group of cases distinguish LDHL from other disease entities, including grey-zone lymphomas.