Hodgkin lymphoma is a histologically defined disorder. The term encompasses two distinct types of disease, which differ in aetiology, epidemiology, clinical features, pathology and prognosis [1–3]. They are designated classical Hodgkin lymphoma (classical HL) and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). Both types of Hodgkin lymphoma are mature B-cell neoplasms at a germinal centre stage of differentiation. Despite of the absence of expression of B-cell markers with the exception of PAX5, the Reed–Sternberg cells have clonally rearranged immunoglobulin (IG) chain genes. However, because of the fairly distinctive features of this condition, subdivision of lymphoma into Hodgkin lymphoma and non-Hodgkin lymphoma (NHL) has been maintained. The differences between the two types of Hodgkin lymphoma are summarized in Table 28.1. Histologically Hodgkin lymphoma is defined by the presence of characteristic neoplastic cells (Reed–Sternberg cells and Hodgkin cells or their variants) in a setting of inflammatory cells with or without fibrosis. Often, the neoplastic cells are ringed by non-neoplastic T lymphocytes forming a rosette. Classical HL is further subdivided into lymphocyte-rich, mixed cellularity, nodular sclerosis (or nodular sclerosing) and lymphocyte-depleted subtypes on the basis of the ratio between neoplastic cells and reactive cells, the specific cytological features of the neoplastic cells and the presence or absence of fibrous bands. Although there is variability in the frequency of these subtypes in relation to geographical regions, nodular sclerosis is the most common whilst lymphocyte depleted is the rarest.
Table 28.1A comparison of features of classical and nodular lymphocyte-predominant Hodgkin lymphoma (HL) ||Download (.pdf) Table 28.1 A comparison of features of classical and nodular lymphocyte-predominant Hodgkin lymphoma (HL)
| ||Classical HL ||Nodular lymphocyte-predominant HL |
|Frequency ||95% of cases ||5% of cases |
|Aetiology ||Some cases associated with EBV infection ||No association with EBV infection |
|Epidemiology ||Double peak of increased incidence in young adults and in old age ||Unimodal peak of incidence in young adults |
|Histology ||Reed–Sternberg cells and mononuclear Hodgkin cells ||L&H cells (popcorn cells); nodular background |
|Immunophenotype of neoplastic cells ||CD30 positive; CD15 positive in most cases; CD20 expression weak or absent; CD45,CD79a, BCL6, immunoglobulin and epithelial membrane antigen not expressed; J chain negative; PAX5 positive; BOB1 negative; OCT2 variable but more often negative;MUM1 positive; EBV detectable in neoplastic cells in some cases ||CD30 and CD15 negative; CD20, CD45, CD79a and BCL6 positive; immunoglobulin usually expressed; epithelial membrane antigen is positive in about half of cases; J chain positive; PAX5 positive; BOB1 positive; OCT2 positive; MUM1 negative; EBV is not detected in neoplastic cells; L&H cells are ringed by CD3-positive and CD57-positive T cells |
|Nature of relapse ||Late relapses very rare; relapse is as classical HL ||Late relapses are more common; relapse may be as nodular lymphocyte-predominant HL or as diffuse large B-cell lymphoma |
Hodgkin lymphoma commences in a single lymphocyte in a lymph node or other organ and, in the usual case ...