Red Pulp Small B-cell Lymphoma Research Articles

Nouveautés sur les hémopathies lymphoïdes chroniques B matures

Summary Chronic lymphocytic leukemia (CLL) is the most common adult lymphoid malignant disease in western countries, with 3800 new incident cases in France in 2011 (1% of all cancers). The criteria for CLL diagnosis recently changed. The diagnosis is based on the combination of lymphocyte morphology, the presence of more than 5 × 109/L circulating clonal B-cells persisting for more than 3 months and a characteristic immunophenotype. In routine, it is recommended to explore patients with lymphocytosis more than 4 × 109/L. Monoclonal B-cells lymphocytosis (MBL) is defined by the presence of less than 5 × 109/L circulating B-cells. MBL is a step before CLL and can progress to CLL. The diagnosis of B-cell chronic lymphoproliferative disorders with hairy cells in the peripheral blood is a clinical challenge. Hairy cell leukemia (HCL) and splenic marginal zone lymphoma (SMZL) with villous lymphocytes in the peripheral blood are well-defined clinical entities. Inversely, splenic diffuse red pulp small B-cell lymphoma (SRPL) and hairy cell leukemia variant (HCL-v) are provisional entities in the WHO 2008 classification. We will discuss the characteristics of each entity and the ways we can use for distinguishing them: morphology, cytometry and molecular studies.

Bone Marrow Histopathology in the Diagnostic Evaluation of Splenic Marginal-zone and Splenic Diffuse Red Pulp Small B-cell Lymphoma

Primary splenic small B-cell lymphomas mostly comprise the distinct entity of splenic marginal-zone lymphoma (SMZL) and the provisional category of splenic lymphoma/leukemia unclassifiable, mainly represented by the hairy cell leukemia variant and splenic diffuse red pulp small B-cell lymphoma (SDRL). Until recently, histopathologic examination of splenectomy specimens was considered mandatory for the diagnosis of SMZL. However, nowadays, mainly because of advances in chemoimmunotherapy, splenectomy is performed much less frequently. We evaluated the diagnostic efficacy of bone marrow biopsy (BMB) histopathology in the diagnostic approach toward SMZL and SDRL and tested whether it may serve as a substitute for spleen histopathology in the differential diagnosis between these 2 entities. To this end, we conducted a paired assessment of BMB and spleen diagnostic samples from 46 cases with a diagnosis of SMZL (n=32) or SDRL (n=14) based on spleen histopathology. We demonstrate that detailed immunohistopathologic BMB evaluation offers adequate evidence for the confirmation of these entities and their differential diagnosis from other small B-cell lymphoma histotypes. Notably, the immunophenotypical profile of SMZL and SDRL was identical in both BMB and spleen specimens for 21 evaluated markers. Paired assessment of BMB and spleen specimens did not identify discriminating patterns of BMB infiltration, cytology, and/or immunohistology between SMZL and SDRL. Accordingly, bone marrow histopathology contributes significantly in confirming the diagnosis of SMZL and SDRL. However, presently it is not possible to distinguish SMZL from SDRL on the basis of BMB evaluation alone; hence, histopathologic examination of the spleen remains the "gold standard" approach.

Malignant lymphoma of the spleen in Japan: A clinicopathological analysis of 115 cases

Primary splenic lymphoma is rare, but malignant lymphoma often produces a lesion in the spleen as part of systemic disease. The frequency of splenic malignant lymphoma in Japan is unknown. We classified 184 specimens of the spleen according to the World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues, 4th edition (2008). Of the 184 specimens, 115 were determined to be lymphoid neoplasm (62.5%). The most common subtype of lymphoid neoplasm was diffuse large B-cell lymphoma (DLBCL) (46 cases), followed by splenic marginal zone lymphoma (SMZL) (28 cases), follicular lymphoma (11 cases), splenic B-cell lymphoma, unclassifiable (SBL-U) (6 cases) and peripheral T-cell lymphoma, not otherwise specified (4 cases). In the SBL-U subtype, 5 of 6 cases were splenic diffuse red pulp small B-cell lymphoma, and one case was the hairy cell leukemia variant. Analysis of clinical features revealed that patients with DLBCL had a higher age, high lactate dehydrogenase and tumor formation in the spleen. On the other hand, it was found that patients with SMZL had splenomegaly but no discrete tumor formation. Most of the patients with SBL-U presented with thrombocytopenia, bone marrow involvement, and advanced stage. Our study revealed the frequency and clinical features of splenic malignant lymphoma in Japan.

Splenic B-cell lymphomas with more than 55% prolymphocytes in blood: evidence for prolymphocytoid transformation

We describe 4 patients aged 62 to 79 years with splenomegaly and bone marrow involvement by splenic B-cell lymphoma who developed more than 55% prolymphocytes in blood. The diagnosis of B-cell prolymphocytic leukemia was considered clinically based on a markedly elevated leukocyte (up to 131.5×10(9)/L) or prolymphocyte (up to 86%) count. Splenectomy was performed in all patients, and spleen weight ranged from 1500 to 2380 g. In 3 patients, the neoplasms were classified as splenic marginal zone lymphoma, and in 1 patient, the neoplasm was classified as splenic diffuse red pulp small B-cell lymphoma. In 2 patients, splenectomy preceded a B-cell prolymphocytic leukemia-like picture, and the spleen showed splenic marginal zone lymphoma or splenic diffuse red pulp small B-cell lymphoma with increased (10%-20%) nucleolated cells consistent with prolymphocytes. In the other 2 patients, a B-cell prolymphocytic leukemia-like picture prompted splenectomy. Initial examination of bone marrow in these patients suggested splenic marginal zone lymphoma. The spleen specimens showed extensive involvement by splenic marginal zone lymphoma with numerous prolymphocytes. Flow cytometry immunophenotyping in all cases showed lymphocytes positive for monotypic surface immunoglobulin (bright), pan-B-cell antigens, CD11c, CD22, and FMC7. Immunohistochemical analysis in all patients showed moderate to bright p53 expression in the spleen (n=3) or bone marrow (n=2). Annexin A1 and cyclin D1 were negative in all cases. Conventional cytogenetic analysis showed del(7q) in 3 patients. We conclude that splenic B-cell lymphoma of various types can undergo prolymphocytoid transformation with more than 55% prolymphocytes in the blood mimicking B-cell prolymphocytic leukemia.

Grey zone lymphoid neoplasms with features overlapping between splenic marginal zone lymphoma and hairy cell leukaemia: splenic B-cell lymphoma/leukaemia, unclassifiable

The best characterized primary splenic B-cell lymphoma/leukaemias include splenic marginal zone lymphoma (SMZL) and hairy cell leukaemia (HCL). However, there are other primary splenic B-cell neoplasms that do not have the characteristic features of SMZL or HCL. The WHO classification has proposed a provision entity—splenic B-cell lymphoma/leukaemia, unclassifiable (SBLLu) to include the better-defined small B-cell clonal lymphoproliferations involving spleen that do not fall into any of the other types of B-cell lymphoid neoplasms. The recognized provisional entities among SBLLu include splenic diffuse red pulp small B-cell lymphoma (SDRPSBL) and hairy cell leukaemia variant (HCLv). The possibility of SBLLu arises when the spleen shows diffuse red pulp involvement, or when the bone marrow trephine biopsy shows extensive intra-sinusoidal involvement by a small B-cell lymphoma with marked splenomegaly, or when a patient with marked splenomegaly presents with a high white cell count in the peripheral blood without monocytopenia, and with presence of atypical lymphocytes with villous or hairy projections and with prominent nucleoli, and the cells are CD25 negative. These clonal B cells lack IgD and frequently express IgG with or without IgM. They are consistently negative for CD25, Annexin A1, cyclin D1, CD38 and cytoplasmic Ig, and are variably positive for CD76, tartrate-resistant acid phosphatase, CD11c, CD103 and CD123. Distinguishing SDRPSBL and HCLv can pose diagnostic problems. Features favouring SDRPSBL include relatively low lymphocytosis along with leucopenia and thrombocytopenia, lack of a paraprotein and a relatively monomorphic cytology with only a proportion of cells being nucleolated. Features that favour HCLv include high white cell count (average ∼35 × 109/L) and presence of monocytes, prominent and obvious intra-sinusoidal infiltrates in spleen and bone marrow and prominence of cells with nucleoli resembling prolymphocytes.

Relevance of a scoring system including CD11c expression in the identification of splenic diffuse red pulp small B‐cell lymphoma (SRPL)

'Splenic red pulp lymphoma with numerous basophilic villous lymphocytes' (SRPL), recently described, is characterized by clinical, morphologic, immunologic, cytogenetic and molecular features distinct from SMZL/SLVL and HCL. In particular, the intensity of CD11c staining (expressed as fluorescence intensity -RFI-) in SRPL is significantly different from the RFI in SMZL/SLVL and HCL. Moreover the use of a scoring system based on the expression of CD11c, CD22, CD76, CD38 and CD27 appears to improve the differential diagnosis between SRPL and SMZL/SLVL and emphasizes that SRPL is an entity closed to but distinct from SMZL/SLVL.

Splenic diffuse red pulp small B-cell lymphoma: revision of a series of cases reveals characteristic clinico-pathological features

Splenic diffuse red pulp small B-cell lymphoma is an uncommon B-cell lymphoma, now recognized as a provisional entity in the 2008 update of the WHO Classification. Additional work is required to review this entity and establish its diagnostic features. We have retrospectively analyzed the disease features in a highly selected series of 17 patients diagnosed as splenic diffuse red pulp small B-cell lymphoma. The median age was 65.5 years (range 40-79 years) and there was a predominance of males (male/female ratio: 2.4). Clinical manifestations were mainly derived from splenomegaly. Splenectomy was the front-line treatment in 11 symptomatic patients; the remaining 6 received chemotherapy initially followed by splenectomy. After a mean follow-up of 72 months, the five-year overall survival was 93%. All cases showed a purely diffuse pattern of splenic infiltration by monomorphous small cells with small round nuclei and pale cytoplasm. All bone marrow biopsies showed tumoral infiltration, with intrasinusoidal infiltration. Peripheral blood cells were small to medium-sized, with clumped chromatin and round nuclear outline and villous cytoplasm. Neoplastic cells had a CD20(+), CD23(-), bcl6(-), Annexin A1- phenotype, with frequent expression of DBA44+ (15/17) and IgG (10/15). FCM data had a B-cell phenotype (CD19(+), CD20(+), CD22(+)) with FMC7 (10/11) and CD11c (5/8) expression. Clonal IgH rearrangement studies in 4 cases showed IgVH mutations in all cases, without VH1.2 usage. Our data suggest that splenic diffuse red pulp small B-cell lymphoma is a distinct entity with morphological and immunophenotypical features that differ from those of other splenic lymphomas.

Gene Expression Profiling Classifies Splenic Marginal Zone Lymphoma and Hairy Cell Leukemia-Variant as Related Diseases That Are Distinct From Typical Hairy Cell Leukemia.

Abstract 3467Poster Board III-355Hairy cell leukemia (HCL) is an uncommon B-cell malignancy that shares some features with a variant form, HCL-variant, and splenic marginal zone lymphoma (SMZL). The distinction between these disorders can be difficult, but correct diagnosis is important for patient management and clinical outcome. The recent WHO classification has recognized SMZL as a distinct entity and HCL-variant was included in a provisional category of unclassifiable splenic lymphomas involving the splenic red pulp that also includes splenic diffuse red pulp small B-cell lymphoma (SDSL). The molecular features of these disorders are still largely uncharacterized and genomic studies have been limited due to their rarity. We have used Affymetrix gene expression microarrays to compare the transcription profiles of 31 HCL, 24 HCL-variant, 44 SMZL and 5 cases of SDSL with the aim of elucidating the relationships between these disorders and to identify novel potential therapeutic and disease-specific diagnostic targets. Total RNA was extracted from PBMC samples enriched for tumor cells (median 89%, range 70-98%) and the expression of approximately 18,000 genes was interrogated using the Affymetrix Human Exon 1.0 ST Array. Data were normalized and analyzed using Partek Genomics Suite® and differentially expressed transcripts between the disorders were identified by ANOVA. Unsupervised hierarchical clustering revealed disease-related patterns within the transcription profiles. Strikingly, the HCL-variant, SMZL and SDSL profiles clustered together and separately from those of typical HCL. Using a false discovery rate threshold of <0.001 and an expression fold-change >2 we identified 366 transcripts that distinguished HCL from HCL-variant, SMZL and SDSL. Using these same criteria, and even those less stringent, we could not identify a gene expression signature that could distinguish between HCL-variant, SMZL and SDSL. Biological interpretation of the data revealed many of the differentially expressed transcripts linked to immune response and signal transduction processes, including key oncogenes and tumor suppressor genes. Transcripts with higher expression in HCL-variant, SMZL and SDSL relative to HCL were associated with lymphocyte activation and proliferation, NFκB signaling and integrin signaling. Conversely, transcripts with higher expression in HCL relative to HCL-variant, SMZL and SDSL, comprised amongst others, pathways of antigen processing, MAP kinase signaling, JAK-STAT signaling, and FLT3 signaling. Comparison of the transcription signatures of HCL, HCL-variant and SMZL provides insight into their relationships and for the first time provides strong evidence that HCL-variant and SDSL may be variant forms of SMZL and that HCL remains as a distinct disease entity characterized by different signaling pathways. These data further strengthen our previous observation that showed that the immunoglobulin heavy chain gene (IGH) repertoire of HCL-variant is more similar to SMZL than to HCL and that, in contrast to HCL, both HCL-variant and SMZL contain subsets of cases with unmutated IGHV. Interestingly, the expression profiles of both HCL-variant and SMZL could not be discriminated based on their IGHV mutation status. We are currently performing further analyses of these data, including comparison with the expression profiles of normal B cells, with the aim of gaining further insight into the clonal history and the normal B-cell counterpart of these disorders. DisclosuresNo relevant conflicts of interest to declare.