Among diffuse large B-cell lymphomas, T-cell-rich/histiocyte-rich BCL and CD30+ anaplastic B-cell subtypes exhibit distinct clinical features.
BACKGROUND
The EORTC clinical trial 20901, activated in 1990, was designed to treat non-Hodgkin's lymphomas (NHL) of intermediate/high-grade malignancy according to the Working Formulation. Established in 1994, the R.E.A.L. Classification on NHL has now replaced all former classifications.


METHODS
We reanalysed all cases (n = 273) documented by material available for review according to the R.E.A.L. Classification. In addition, we subdivided cases recognised as diffuse large B-cell lymphoma (DLBCL) into three morphologically distinct categories, namely, large cleaved DLBCL (LC-DLBCL), T-cell-rich/histiocyte-rich B-cell lymphoma (T-cell-rich/histiocyte-rich BCL) and CD30+ DLBCL with anaplastic cell features (CD30+ DLBCL). Finally, T/NULL anaplastic large-cell lymphoma (ALCL) cases were subdivided into ALK+ and ALK- lymphomas. Review was performed independently by two pathologists from two different centres.


RESULTS
DLBCL (61%), T/NULL ALCL (15%) and mantle-cell lymphoma (MCL, 50%) were the main NHL categories represented in the study. Fifty-seven of one hundred sixty DLBCL cases were further subclassified as LC-DLBCL (33 cases), T-cell-rich/histiocyte-rich BCL (13 cases) or CD30+ DLBCL (11 cases). The remaining cases were indicated as unspecified DLBCL. A clinico-pathological correlation confirmed the findings of previous studies suggesting that MCL, DLBCL and ALCL represent distinct entities with MCL being characterised by a short survival, in contrast with the longer survival and less frequent progression typical of ALK+ compared to ALK- ALCL. Within DLBCL, T-cell-rich/histiocyte-rich BCL showed distinctive features at presentation whereas CD30+ DLBCL showed a trend towards a more favourable prognosis, that might be comparable to that of ALK+ ALCL.


CONCLUSIONS
Our data further support the usefulness of the R.E.A.L. Classification and illustrate the feasibility of DLBCL subtyping. Moreover, our results demonstrate the distinct clinical characteristics of T-cell-rich/histiocyte-rich BCL and CD30+ DLBCL with anaplastic cell features suggesting that they may represent clinico-pathologic entities.
Maes
B
B
Department of Pathology, Catholic University of Leuven, Belgium. Brigitte.Maes@uz.kuleuven.ac.be
Anastasopoulou
A
A
Kluin-Nelemans
J C
JC
Teodorovic
I
I
Achten
R
R
Carbone
A
A
De Wolf-Peeters
C
C
D000293:Adolescent; D000328:Adult; D000077548:Anaplastic Lymphoma Kinase; D016175:B-Lymphocyte Subsets / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D017730:Ki-1 Antigen / Q000032:analysis; D008215:Lymphocytes, Null / Q000473:pathology; D016393:Lymphoma, B-Cell / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000145:classification* / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011505:Protein-Tyrosine Kinases / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases; D015996:Survival Rate; D013601:T-Lymphocytes / Q000473:pathology
D017730:Ki-1 Antigen; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases