Large B-cell lymphoma of thyroid. Two cases with a marginal zone distribution of the neoplastic cells

Diagnostic Impact of Molecular Lineage Analysis on Paraffin-Embedded Tissue in Hematolymphoid Neoplasia Reclassified by Current WHO Criteria

BACKGROUND AND OBJECTIVE

By current WHO criteria, most - though not all - cases of hematolymphoid neoplasm can be diagnosed immunomorphologically, diminishing the role of molecular tests for lymphoid antigen receptor clonality in lymphoma diagnosis. Hence, our objective was to glean immunomorphological and molecular correlates from hematolymphoid neoplasms that had remained unresolvable without diagnostic molecular input.

METHODS

Thirty-five such cases were reviewed histologically and with standard immunoperoxidases. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNAs (EBER) was performed on selected cases. PCR amplification of genes encoding T-cell receptors (TcR) and immunoglobulin heavy chains (IgH) [TR and IGH genes, respectively] was performed on whole tissue in all cases, and on microdissected cells in two cases.

RESULTS

Twenty-five cases (71%) requiring diagnostic molecular genotyping had some form of peripheral T-cell lymphoma (PTCL). Twenty (80%) of these were complicated by a proliferation of B-lineage cells, either within the same tissue ('syntopic') as large B cells (LBC) or Reed-Sternberg (RS)-like cells (17 cases), florid lymphoid hyperplasia (two cases, one also with syntopic LBC) or monotypic plasma cells (one case), or at a separate ('metatopic') site as a B-cell lymphoma (two cases, one of which also had syntopic LBC) or Hodgkin lymphoma (HL; one case, also showing syntopic LBC). Fifteen (75%) of these 20 PTCLs with B-lineage proliferation yielded monoclonal TR gene rearrangements, and only two (10%) showed IGH monoclonality, which was transient in one case. Three (18%) of the PTCLs with LBC had originally been misinterpreted as some form of HL. Conversely, of the remaining cases, three of four (75%) that had been diagnosed initially as some form of large cell non-HL (NHL), including two of three that were called 'anaplastic', had to be revised to grade II/syncytial nodular sclerosing (NS) HL, yielding polyclonal TcRgamma gene (TRG) rearrangements, with one case, in addition, disclosing a biallelic clonal IGH gene rearrangement that excluded anaplastic large cell lymphoma.

DISCUSSION/CONCLUSION

Paradoxically, monoclonality of TR rather than IGH gene rearrangement may more often be detectable in a predominantly dispersed ('hodgkinoid'), large B-lineage cell proliferation, consistent with release from immune regulation in the milieu of impaired immunosurveillance within a PTCL. This is compounded by the difficulty in ascertaining clonal IGH gene rearrangements resulting from (1) poor consensus primer hybridization due to somatic hypermutations, and (2) 'dilution' in a T-cell-rich milieu. These same difficulties also account for the long-elusive identification of the RS cell lineage. Conversely, anaplastic lymphoma, which is of non-B lineage, may be mimicked by NSHL, which is of B lineage.

Senile EBV-associated B-cell lymphoproliferative disorder of indolent clinical phenotype with recurrence as aggressive lymphoma

Senile EBV-associated B-cell lymphoproliferative disorder (LPD) was proposed as a new disease entity in 2003. This condition has a high incidence in elderly people without underlying immunodeficiencies, and is characterized by EBV-positive B-cell proliferation with a polymorphic composition. Histologically, the disease has two subtypes. The polymorphic LPD (PLPD) subtype has a preferable prognosis, whereas the large cell lymphoma (LCL) subtype involves aggressive disease progression. Reported herein is a case of senile EBV-BLPD with indolent clinical features and PLPD subtype in the initial phase that recurred as an aggressive lymphoma 3 years after the initial diagnosis. In the recurrent phase, Southern blotting confirmed monoclonal proliferation of large lymphoid B-cells. In both the initial and recurrent phases, polymerase chain reaction (PCR) yielded a single discrete band of a similar size due to an immunoglobulin heavy-chain gene rearrangement, indicating that the large lymphoid B-cells retained identical monoclonality throughout the histological progression and over the whole clinical course. These results suggest that the PLPD subtype is a histological finding in early phase senile EBV-BLPD and that the LCL subtype reflects the progressive phase of the disease.

Composite EBV negative peripheral T-cell lymphoma and diffuse large B-cell lymphoma involving the ileum: a case report and a systematic review of the literature

We report a case of an intestinal peripheral T-cell lymphoma (PTCL) with a concurrent diffuse large B-cell lymphoma (DLBL) involving the ileum and a regional lymph node. The patient presented with an abdominal mass. The terminal ileum showed a diffuse and monotonous population of small CD3-positive T cells. The T-cell receptor gamma (TCRgamma) gene was rearranged by PCR while the immunoglobulin heavy chain (IgH) gene was not. A separate section of the ileum showed a colliding large B-cell proliferation. The regional lymph node showed a diffuse proliferation of large centroblasts positive for CD20 and CD79a admixed with small T cells and showed a rearranged IgH receptor gene without evidence of a clonally rearranged TCRgamma gene. Both the PTCL and DLBL components were negative for EBV. A review and analysis of the pertinent literature describing composite T- and B-cell lymphomas is performed and reported.

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-zeta-chain is limited.

PATIENTS AND METHODS

We have re-evaluated 251 tumour biopsies from patients aged > or =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-zeta-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-zeta-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.