How I diagnose and treat splenic lymphomas. Blood. 2011;117:2585-2595. [PMID: 21119113 DOI: 10.1182/blood-2010-09-271437]

Role of blood and bone marrow examination in the diagnosis of mature lymphoid neoplasms in patients presenting with isolated splenomegaly

OBJECTIVES

Mature lymphoid neoplasms presenting with 'prominent splenomegaly without significant lymphadenopathy' are uncommon and pose unique diagnostic challenges as compared to those associated with lymphadenopathy. Their descriptions in the literature are largely limited to a few case series. We analyzed the spectrum of these lymphomas diagnosed by peripheral blood (PB) and/or bone marrow (BM) examination.

METHODS

Over a period of 6 years, 75 patients were diagnosed with a lymphoma from PB/BM who had presented with predominant splenomegaly. Their clinical and laboratory records including PB and BM morphology; immunophenotyping using multi-parametric flow-cytometry and immunohistochemistry were reviewed. Wherever indicated, an extended panel of immunohistochemistry (IHC) was performed on BM biopsies for accurate sub-classification.

RESULTS AND DISCUSSION

The commonest lymphomas were hairy cell leukemia (HCL) (32%) and splenic marginal zone lymphoma (SMZL) (24%). Others included diffuse large B cell lymphoma (8%), chronic lymphocytic leukemia/small lymphocytic lymphoma (8%), mantle cell lymphoma (2.7%), and follicular lymphoma (1.3%), all of which usually presents with lymphadenopathy. SMZL was the commonest lymphoma among females and those with massive splenomegaly and lymphocytosis; while HCL was commonest in patients with pancytopenia. SMZL commonly presented with lymphocytosis; however, 22% of them also presented with pancytopenia.

CONCLUSION

The high diagnostic efficacy of PB and BM examination using flow-cytometry and immunohistochemistry in confirming and sub-classifying splenic lymphomas suggests that a thorough hematological evaluation should always precede a diagnostic splenectomy. Immunohistochemistry remains the best modality to identify sparse or intra-sinusoidal infiltration on BM biopsy and is particularly useful in patients with fibrotic marrows and pancytopenia.

Diagnosis of Splenic B-Cell Lymphomas in the Bone Marrow: A Review of Histopathologic, Immunophenotypic, and Genetic Findings

Splenic B-cell lymphomas are a heterogeneous group of diseases comprising several entities that exhibit overlapping features. Diagnosis of these lymphomas has been reliant on the histopathologic examination of the spleen. However, with advances in diagnostic modalities and therapy, splenectomy is not commonly performed, and diagnosis and subclassification must be rendered based on the blood and bone marrow findings. In this brief review, we summarize the morphologic, immunophenotypic, and genetic findings of splenic B-cell lymphomas in the blood and bone marrow.

Gamma-delta t-cell lymphomas

Gamma-delta T-cell lymphomas are aggressive and rare diseases originating from gamma-delta lymphocytes. These cells, which naturally play a role in the innate, non-specific immune response, develop from thymic precursor in the bone marrow, lack the major histocompatibility complex restrictions and can be divided into two subpopulations: Vdelta1, mostly represented in the intestine, and Vdelta2, prevalently located in the skin, tonsils and lymph nodes. Chronic immunosuppression such as in solid organ transplanted subjects and prolonged antigenic exposure are probably the strongest risk factors for the triggering of lymphomagenesis. Two entities are recognised by the 2008 WHO Classification: hepatosplenic gamma-delta T-cell lymphoma (HSGDTL) and primary cutaneous gamma-delta T-cell lymphoma (PCGDTL). The former is more common among young males, presenting with B symptoms, splenomegaly and thrombocytopenia, usually with the absence of nodal involvement. Natural behaviour of HSGDTL is characterised by low response rates, poor treatment tolerability, common early progression of disease and disappointing survival figures. PCGDTL accounts for <1% of all primary cutaneous lymphomas, occurring in adults with relevant comorbidities. Cutaneous lesions may vary, but its clinical behaviour is usually aggressive and long-term survival is anecdotal. Available literature on gamma-delta T-cell lymphomas is fractioned, mostly consisting of case reports or small cumulative series. Therefore, clinical suspicion and diagnosis are usually delayed, and therapeutic management remains to be established. This review critically analyses available evidence on diagnosis, staging and behaviour of gamma-delta T-cell lymphomas, provides recommendations for therapeutic management in routine practice and discusses relevant unmet clinical needs for future studies.

Selective X-ray contrast enhancement of the spleen of living mice mediated by gold nanorods

Gold nanomaterials (AuNPs) represent a promising new class of contrast agents for X-ray computed tomographic (CT) imaging in both research and clinical settings. These materials exhibit superior X-ray absorption properties compared with other iodinated agents, and thus require lower injection doses. Gold is nonimmunogenic and therefore contributes to safety profile in living specimens. Unfortunately, most reports on the use of AuNPs as X-ray CT enhancers only demonstrate marginal enhancement of the intended anatomical structure. In this study, we demonstrate the dramatic properties of gold nanorods (GNR) to serve as robust X-ray CT contrast-enhancing agent for selective imaging of the spleen. These organ-specific uptake properties were delineated by performing longitudinal CT imaging of living mice that were dosed with GNR at 2 day intervals. Rapid uptake in spleen was noted within 12 h of first systemic administration with a change in contrast enhancement of 90 Hounsfield units (ΔHU = 90) and with two subsequent injections a total contrast enhancement of over 200 HU was observed. The resulting images provide excellent contrast that will enable the detailed anatomical visualization and study of a range of pre-clinical models of spleen disease including infection and cancer.

Bone marrow stroma CD40 expression correlates with inflammatory mast cell infiltration and disease progression in splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is a mature B-cell neoplasm characterized by rather indolent clinical course. However, nearly one third of patients experience a rapidly progressive disease with a dismal outcome. Despite the characterization of clone genetics and the recognition of deregulated immunologic stimulation in the pathogenesis of SMZL, little is known about microenvironment dynamics and their potential biological influence on disease outcome. Here we investigate the effect of stroma-intrinsic features on SMZL disease progression by focusing on the microenvironment of the bone marrow (BM), which represents an elective disease localization endorsing diagnostic and prognostic relevance. We show that the quality of the BM stromal meshwork of SMZL infiltrates correlates with time to progression. In particular, we describe the unfavorable prognostic influence of dense CD40 expression by BM stromal cells, which involves the contribution of CD40 ligand (CD40L)-expressing bystander mast cells infiltrating SMZL BM aggregates. The CD40/CD40L-assisted crosstalk between mesenchymal stromal cells and mast cells populating the SMZL microenvironment finds correlation in p53(-/-) mice developing SMZL and contributes to the engendering of detrimental proinflammatory conditions. Our study highlights a dynamic interaction, playing between nonneoplastic elements within the SMZL niche, toward disease progression.

Challenges and new prospects in hepatosplenic γδ T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphoid neoplasms characterized by aggressive clinical behavior and dismal prognosis. Hepatosplenic γδ T-cell lymphoma (γδ-HSTL) is a particular form of PTCL that arises from a small subset of γ/δ T-cell receptor-expressing lymphocytes. γδ-HSTL has a rapidly progressive course and poor outcome due also to its refractoriness to conventional chemotherapy regimens. The very low incidence of γδ-HSTL, along with its propensity to mimic different pathological entities, makes this lymphoma a true diagnostic challenge. In this review, we highlight the biological and clinical features of γδ-HSTL that contribute to making this lymphoma a mostly incurable disease. Moreover, we provide a new insight into the crosstalk between HSTL clones and the bone marrow, liver and spleen vascular microenvironment, in which neoplastic cells reside and proliferate. We further discuss γδ-HSTL associated molecules that might be proposed as potential targets for novel therapeutic approaches.

Primary splenic lymphoma: a case report

Primary splenic lymphomas (PSL) constitute a rare variety of splenic neoplasms. As a secondary lymphoid organ, the spleen is usually involved by lymphomas as part of the systemic illness. However, rarely it can be the exclusive site of disease burden. An elderly lady presented with symptoms and signs of splenomegaly. After evaluation she was found to have a splenic tumor. Splenectomy was done which revealed primary splenic lymphoma. This case report highlights the evaluation and management of this illness.

[Successful treatment with rituximab in a patient with splenic marginal zone B-cell lymphoma accompanied by cold agglutinin disease]

An 81-year-old man was admitted to our hospital due to dyspnea in July 2008. A physical examination revealed marked splenomegaly, and the results of laboratory tests were as follows: hemoglobin (Hb)=7.0 g/dL, Ret=6.4%, WBC=24,100/μL (Ly: 20,003/μL), indirect bilirubin=3.6 mg/dL, LDH=232 IU/L. The cold agglutinin titer was 1 : 8,192, and a direct antiglobulin test was positive. A PET scan showed abnormal accumulation in the spleen and bone marrow. A bone marrow aspirate examination and biopsy demonstrated diffuse involvement of abnormal lymphocytes that were found to be positive for CD20 and negative for CD5, CD10, and cyclin D1. The immunoglobulin genes were clonally rearranged. Based on these findings, splenic marginal zone B-cell lymphoma (SMZL) associated with cold agglutinin disease (CAD) was diagnosed. Because the patient refused splenectomy, he was treated with four cycles of rituximab therapy (375 mg/kg, once a week). The Hb level and lymphocyte count subsequently normalized and the splenomegaly resolved. One year later, he relapsed and was again treated with rituximab therapy with complete remission. CAD accompanied by SMZL is very rare. Rituximab may be chosen as an alternative and effective therapeutic option in patients with SMZL-particularly those with autoimmune hemolytic anemia.

Cladribine with immediate rituximab for the treatment of patients with variant hairy cell leukemia

PURPOSE

In contrast with the classic form, variant hairy cell leukemia (HCLv) responds poorly to single-agent purine analogs, expresses unmutated BRAF, has shorter overall survival, and lacks effective standard therapy. No treatment has achieved a high complete remission (CR) rate even in small series, and of 39 reported cases from six studies, overall response rate after cladribine was 44% with 8% CRs. Rituximab has been found to increase the sensitivity of malignant cells to cladribine, suggesting that combination with cladribine might improve response in HCLv. To test this hypothesis, patients with HCLv were treated with simultaneous cladribine and rituximab.

EXPERIMENTAL DESIGN

Patients with HCLv with 0 to 1 prior courses of cladribine received cladribine 0.15 mg/kg for days 1 to 5, with eight weekly doses of rituximab 375 mg/m(2) beginning day 1. Restaging was performed, and minimal residual disease (MRD) in blood and marrow was quantified using PCR, immunohistochemistry, and flow cytometry.

RESULTS

By 6 months, 9 (90%) of 10 patients achieved CR, compared with 3 (8%) of 39 reported cases treated with cladribine alone (P < 0.0001). Of the 9 CRs, 8 remain free of MRD at 12 to 48 (median 27) months of follow-up. No dose-limiting toxicities were observed when beginning cladribine and rituximab on the same day, although most patients required short-term steroids to prevent and treat rituximab infusion reactions. Cytopenias in CRs resolved in 7 to 211 (median 34) days without major infections.

CONCLUSION

Although cladribine alone lacks effectiveness for early or relapsed HCLv, cladribine with immediate rituximab achieves CRs without MRD and is feasible to administer.

Splenic marginal zone lymphoma: disease features and management

Splenic marginal zone lymphoma (SMZL) is a lymphoma recognized as a distinct entity in the WHO classification of the lymphoid tumors. SMZL probably results from the expansion of a marginal zone B-cell driven by persistent antigen stimulation. SMZL is clinically and biologically heterogeneous. The SMZL Working Group has published guidelines for the diagnosis, workup and treatment of SMZL. There are no standard criteria to initiate treatment. A policy of watch and wait in asymptomatic patients is recommended. In symptomatic patients, data from retrospective studies suggest that rituximab with or without chemotherapy is the best strategy for SMZL. It is uncertain which is the optimal type of chemotherapy and whether patients may benefit from splenectomy prior chemoimmunotherapy. In the future, we may see progress with agents targeting known molecular lesions in SMZL.

Comparative outcomes of rituximab-based systemic therapy and splenectomy in splenic marginal zone lymphoma

Despite diagnostic and therapeutic advances, the majority of patients with splenic marginal zone lymphoma (SMZL) are still treated with splenectomy. We analyzed survival outcomes after surgery or rituximab-based systemic therapy in the Surveillance Epidemiology and End Results-Medicare database, using inverse probability of treatment weighting to minimize treatment selection bias. From the 657 recorded cases diagnosed between 2000 and 2007, with a median age of 77 years, we selected 227 eligible patients treated with splenectomy (68 %), rituximab alone (23 %), or in combination with chemotherapy (9 %) within 2 years from diagnosis. No significant difference between the groups was observed in the cumulative incidence of lymphoma-related death (LRD) at 3 years (19.6 % with systemic therapy and 17.3 % with splenectomy; hazard ratio [HR], 1.04; 95 % confidence interval [CI], 0.56-1.92; P = 0.90) or in the overall survival (HR, 1.01; 95 % CI, 0.66-1.55; P = 0.95). The 90-day mortality after splenectomy was 7.1 %. The rates of hospitalizations, infections, transfusions, and cardiovascular or thromboembolic events were higher after combination chemoimmunotherapy than after splenectomy. Conversely, there was no significant difference in most complications between groups treated with splenectomy or rituximab alone. The cumulative incidence of LRD after single-agent rituximab at 3 years was 18.7 % (95 % CI, 8.6-31.7). In conclusion, in SMZL patients over the age of 65 years, the risk of LRD and overall survival are similar with systemic therapy or splenectomy as initial therapy. Single-agent rituximab may offer the most favorable risk/benefit ratio in this population.

Hepatosplenic gamma-delta T-cell lymphoma

Hepatosplenic T-cell lymphoma (HSTL) is a rare and aggressive extranodal lymphoma derived mostly from cytotoxic γδ T-cells. The peak incidence is in adolescents and young adults, and is more common in males. Up to 20% of HSTL arise in the setting of chronic immune suppression, most commonly solid organ transplantation or prolonged antigenic stimulation. Patients present with systemic symptoms (fever), abdominal pain, weakness, and marked hepatosplenomegaly in the absence of lymphadenopathy. Patients usually manifest marked thrombocytopenia, often with anaemia and leucopenia, a leukemic phase, and bone marrow involvement in 80% of cases. Lactate dehydrogenase levels are usually markedly elevated. HSTL exhibits a marked chemoresistance to currently used regimens, a rapidly progressive behavior, and dismal prognosis. Patients with post-transplant HSTL exhibit an especially poor outcome. Standard treatment has yet to be established. Anthracycline-based chemotherapy is associated with a satisfactory response in two thirds of patients, but poor long-term results. Complete remission is extremely uncommon, and most patients die from lymphoma within two years of diagnosis. A prognostic correlation between outcome and degree of thrombocytopenia has been reported. Relapsing disease is usually chemorefractory and fast growing, and patients' performance status and clinical conditions are poor. These aspects, as well as the lack of drugs with proven activity against HSTL, render salvage treatment almost impossible. A few cases of HSTL successfully treated with autologous or allogeneic stem-cell transplantation have been reported. The use of 2'-deoxycoformycin and other targeted therapies, such as alemtuzumab, anti-γδ TCR monoclonal antibodies, and anti-CD44 therapy, have shown promising results in anecdotal reports.

DOSim: an R package for similarity between diseases based on Disease Ontology

Background

The construction of the Disease Ontology (DO) has helped promote the investigation of diseases and disease risk factors. DO enables researchers to analyse disease similarity by adopting semantic similarity measures, and has expanded our understanding of the relationships between different diseases and to classify them. Simultaneously, similarities between genes can also be analysed by their associations with similar diseases. As a result, disease heterogeneity is better understood and insights into the molecular pathogenesis of similar diseases have been gained. However, bioinformatics tools that provide easy and straight forward ways to use DO to study disease and gene similarity simultaneously are required.

Results

We have developed an R-based software package (DOSim) to compute the similarity between diseases and to measure the similarity between human genes in terms of diseases. DOSim incorporates a DO-based enrichment analysis function that can be used to explore the disease feature of an independent gene set. A multilayered enrichment analysis (GO and KEGG annotation) annotation function that helps users explore the biological meaning implied in a newly detected gene module is also part of the DOSim package. We used the disease similarity application to demonstrate the relationship between 128 different DO cancer terms. The hierarchical clustering of these 128 different cancers showed modular characteristics. In another case study, we used the gene similarity application on 361 obesity-related genes. The results revealed the complex pathogenesis of obesity. In addition, the gene module detection and gene module multilayered annotation functions in DOSim when applied on these 361 obesity-related genes helped extend our understanding of the complex pathogenesis of obesity risk phenotypes and the heterogeneity of obesity-related diseases.

Conclusions

DOSim can be used to detect disease-driven gene modules, and to annotate the modules for functions and pathways. The DOSim package can also be used to visualise DO structure. DOSim can reflect the modular characteristic of disease related genes and promote our understanding of the complex pathogenesis of diseases. DOSim is available on the Comprehensive R Archive Network (CRAN) or http://bioinfo.hrbmu.edu.cn/dosim.