T‐cell‐rich B‐cell lymphoma – diagnostic and therapeutic aspects

Background. Morphologically, T‐cell‐rich B‐cell lymphoma (TCRB‐NHL) may be indistinguishable from Hodgkin's disease (HD). Immunophenotyping may be helpful in the separation of these entities. TCRB‐NHL is occasionally misdiagnosed and treated as HD. However, information is limited regarding clinical characteristics and outcome of this patient population. Furthermore, knowledge concerning any association with Epstein‐Barr virus (EBV) in TCRB‐NHL, as well as the immunophenotype of reactive T‐cells and the expression of T‐cell intracellular antigen‐1 (TIA‐1), granzyme B (GrB) and the CD3‐ζ‐chain is limited. Patients and methods. We have re‐evaluated 251 tumour biopsies from patients aged ≥15 years with HD diagnosed 1985–1994. Reclassification from HD to TCRB‐NHL was done in 12 cases (5%). Six TCRB‐NHL patients initially diagnosed and treated as B‐NHL were also included. All TCRB‐NHL biopsies were analysed for latent membrane protein 1 (LMP‐1), CD4, CD8, CD56, CD57, TIA‐1, GrB and CD3‐ζ‐chain. Results. Twelve cases of TCRB‐NHL were initially subclassified as HD (lymphocyte predominance 5, nodular sclerosis 3, and mixed cellularity 4). Of these 12 TCRB‐NHL patients, 6 were given radiotherapy alone, 5 MOPP/ABVD or similar combination chemotherapy, and one patient combined modality treatment. Male sex (p<0.05) and inguinal involvement (p<0.001) were significantly more frequent when TCRB‐NHL patients receiving HD treatment (n=12) were compared with the remaining patients with confirmed (conf) HD, while no significant differences were seen with regard to stage, bone marrow infiltration, splenomegaly or cause‐specific survival. Similar results were achieved when all TCRB‐NHL patients (n=18) were compared to conf HD patients. Lymphoma cells in three samples stained positively for LMP‐1. A decreased expression of CD3‐ζ‐chain was seen in 9/14 tumour biopsies. Conclusion. Immunohistochemistry makes it possible to identify cases of TCRB‐NHL that are morphologically difficult to distinguish from HD. The outcome of TCRB‐NHL patients treated as having HD was comparable with that of the remaining HD population.