Recent advances in Hodgkin's disease: an overview and review of the literature

Pathobiology of hodgkin lymphoma

Despite its well-known histological and clinical features, Hodgkin's lymphoma (HL) has recently been the object of intense research activity, leading to a better understanding of its phenotype, molecular characteristics, histogenesis, and possible mechanisms of lymphomagenesis. There is complete consensus on the B-cell derivation of the tumor in most cases, and on the relevance of Epstein-Barr virus infection and defective cytokinesis in at least a proportion of patients. The REAL/WHO classification recognizes a basic distinction between lymphocyte predominance HL (LP-HL) and classic HL (cHL), reflecting the differences in clinical presentation and behavior, morphology, phenotype, and molecular features. cHL has been classified into four subtypes: lymphocyte rich, nodular sclerosing, with mixed cellularity, and lymphocyte depleted. The borders between cHL and anaplastic large-cell lymphoma have become sharper, whereas those between LP-HL and T-cell-rich B-cell lymphoma remain ill defined. Treatments adjusted to the pathobiological characteristics of the tumor in at-risk patients have been proposed and are on the way to being applied.

[Classical Hodgkin's lymphoma: biology and grey zones]

Advances in the biology of Hodgkin's lymphoma have lead to the distinction between two entities, "classical" Hodgkin's lymphoma and nodular lymphocyte predominance Hodgkin's lymphoma, previously called nodular paragranuloma, which share distinct clinical aspects. The definition of diagnostic criteria has also been helpful to separate Hodgkin's lymphoma from other lymphomas which can mimick Hodgkin's disease such as anaplastic large cell lymphomas, T-cell/histiocyte rich diffuse large B-cell lymphoma, and some peripheral T-cell lymphomas, mainly angioimmunoblastic-type. Reed-Sternberg cell, the neoplastic cell of "classical" Hodgkin's lymphoma, still retains some secrets. Despite some controversies, there is more and more evidence for a lymphoid B cell origin. The involvement of Epstein-Barr virus, cytokines and/or oncogenes expression in the pathogeny can be suggested, although the precise mechanisms leading to transformation and/or accounting for tumour progression are still elusive. Recently, the roles of the pathway implicating the activation of NFkappaB as well as the autocrine secretion of interleukin-13 have been demonstrated.

Pathologic and clinical features of 77 Hodgkin's lymphoma patients treated in a lymphoma protocol (LNH87): a GELA study

Between 1987 and 1993, 77 of 2855 lymphomas included in the LNH87 protocol of the GELA as non-Hodgkin lymphoma (NHL) and reviewed by a panel of pathologists had a diagnosis changed to Hodgkin lymphoma (HL). Some of these lymphomas had been initially interpreted as anaplastic large-cell lymphoma Hodgkin-like (ALCL-HL subtype). The purpose of this study was to analyze the histologic pitfalls initially encountered, to define more clearly the diagnostic criteria of lymphomas placed in the gray zone around HL, and to follow the survival of these 77 patients affected with HL and initially treated with NHL regimens. The 77 cases of HL were reviewed by three hematopathologists and immunostained with a large panel of antibodies, including CD30, CD15, CD3, CD20, CD45, CD43, LMP-1, EMA, BNH-9, TiA1, and ALK1. Each case was classified according to the Lukes-Rye system and the British National Lymphoma Investigation (BNLI) grading. The initial clinical presentation of patients was analyzed, and the overall and event-free survival rates of the 77 patients were estimated. Among the 77 HLs, 46 were misinterpreted as NHL by primary individual pathologists (12 as ALCL, 8 as ALCL-HL, 12 as peripheral T-cell lymphoma (PTCL), 6 as B-cell lymphoma, and 8 as unclassifiable NHL). The other 31 cases had been first considered by the panel as consistent with ALCL-HL (n = 18) or with PTCL (n = 13) and were changed later in view of an immunophenotype concordant with HL. Fifty-five percent of the patients completed the full NHL treatment. The 5-year event-free and overall survival rates were 54% and 77%, respectively. The current results indicate that lymphomas initially called ALCL-HL should not be regarded as a variant of ALCL, but as HL. The clinical consequences of misdiagnoses seem to be a lower event-free survival rate compared with that of classical HL, probably because of more relapses of initially inappropriately treated HL.