Splenic marginal zone lymphoma with increased number of blasts: an aggressive variant?

Mutational landscape of marginal zone B-cell lymphomas of various origin: organotypic alterations and diagnostic potential for assignment of organ origin

This meta-analysis aims to concisely summarize the genetic landscape of splenic, nodal and extranodal marginal zone lymphomas (MZL) in the dura mater, salivary glands, thyroid, ocular adnexa, lung, stomach and skin with respect to somatic variants. A systematic PubMed search for sequencing studies of MZL was executed. All somatic mutations of the organs mentioned above were combined, uniformly annotated, and a dataset containing 25 publications comprising 6016 variants from 1663 patients was created. In splenic MZL, KLF2 (18%, 103/567) and NOTCH2 (16%, 118/725) were the most frequently mutated genes. Pulmonary and nodal MZL displayed recurrent mutations in chromatin-modifier-encoding genes, especially KMT2D (25%, 13/51, and 20%, 20/98, respectively). In contrast, ocular adnexal, gastric, and dura mater MZL had mutations in genes encoding for NF-κB pathway compounds, in particular TNFAIP3, with 39% (113/293), 15% (8/55), and 45% (5/11), respectively. Cutaneous MZL frequently had FAS mutations (63%, 24/38), while MZL of the thyroid had a higher prevalence for TET2 variants (61%, 11/18). Finally, TBL1XR1 (24%, 14/58) was the most commonly mutated gene in MZL of the salivary glands. Mutations of distinct genes show origin-preferential distribution among nodal and splenic MZL as well as extranodal MZL at/from different anatomic locations. Recognition of such mutational distribution patterns may help assigning MZL origin in difficult cases and possibly pave the way for novel more tailored treatment concepts.

CD5-Negative, CD10-Negative Low-Grade B-Cell Lymphoproliferative Disorders of the Spleen

CD5-negative, CD10-negative low-grade B-cell lymphoproliferative disorders (CD5-CD10-LPD) of the spleen comprise a fascinating group of indolent, neoplastic, mature B-cell proliferations that are essential to accurately identify but can be difficult to diagnose. They comprise the majority of B-cell LPDs primary to the spleen, commonly presenting with splenomegaly and co-involvement of peripheral blood and bone marrow, but with little to no involvement of lymph nodes. Splenic marginal zone lymphoma is one of the prototypical, best studied, and most frequently encountered CD5-CD10-LPD of the spleen and typically involves white pulp. In contrast, hairy cell leukemia, another well-studied CD5-CD10-LPD of the spleen, involves red pulp, as do the two less common entities comprising so-called splenic B-cell lymphoma/leukemia unclassifiable: splenic diffuse red pulp small B-cell lymphoma and hairy cell leukemia variant. Although not always encountered in the spleen, lymphoplasmacytic lymphoma, a B-cell lymphoproliferative disorder consisting of a dual population of both clonal B-cells and plasma cells and the frequent presence of the MYD88 L265P mutation, is another CD5-CD10-LPD that can be seen in the spleen. Distinction of these different entities is possible through careful evaluation of morphologic, immunophenotypic, cytogenetic, and molecular features, as well as peripheral blood and bone marrow specimens. A firm understanding of this group of low-grade B-cell lymphoproliferative disorders is necessary for accurate diagnosis leading to optimal patient management.

Aggressive variant of splenic marginal zone lymphoma characterized using a cancer panel test and treated with rituximab-containing chemotherapy: A case report

RATIONALE

Aggressive variant of splenic marginal zone lymphoma (AV-SMZL) is a very rare disease that is often associated with TP53 mutations and has a poor prognosis. On the other hand, recent advances in genome sequencing techniques enable us to understand the molecular characteristics of rare cancers such as AV-SMZL. Here we present a case of AV-SMZL analyzed using a genetic test.

PATIENT CONCERNS

A 66-year-old woman was admitted with splenomegaly and lymphocytosis. Computed tomography revealed marked splenomegaly without lymphadenopathy in any other areas. The serum soluble interleukin-2 receptor (sIL-2R) level was significantly elevated. Peripheral and bone marrow blood tests showed an increase in abnormal lymphocytes.

DIAGNOSIS

A splenectomy revealed an SMZL pattern with increased numbers of large cells and mitotic cells and a high Ki-67 positivity rate, which led to a diagnosis of AV-SMZL. Although TP53 mutation was not detected, mutations in NOTCH2, NCOA4, PTEN, EPHA3, and KMT2D were identified. Among these, the mutations in NCOA4, PTEN, and EPHA3 were novel pathogenic mutations in SMZL, which suggests they may be related to the aggressiveness and persistence of the disease.

INTERVENTIONS

The patient was administered a rituximab-containing regimen and rituximab-maintenance therapy.

OUTCOMES

The patient continues to exhibit a complete response.

LESSONS

This is a case of AV-SMZL in which a cancer panel test successfully detected genetic alterations that are potentially associated with its pathogenesis. These findings suggest that genetic analysis is useful for making diagnoses as well as for determining treatment strategies in AV-SMZL.

Clinical utility of recently identified diagnostic, prognostic, and predictive molecular biomarkers in mature B-cell neoplasms

Genomic profiling studies have provided new insights into the pathogenesis of mature B-cell neoplasms and have identified markers with prognostic impact. Recurrent mutations in tumor-suppressor genes (TP53, BIRC3, ATM), and common signaling pathways, such as the B-cell receptor (CD79A, CD79B, CARD11, TCF3, ID3), Toll-like receptor (MYD88), NOTCH (NOTCH1/2), nuclear factor-κB, and mitogen activated kinase signaling, have been identified in B-cell neoplasms. Chronic lymphocytic leukemia/small lymphocytic lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, Burkitt lymphoma, Waldenström macroglobulinemia, hairy cell leukemia, and marginal zone lymphomas of splenic, nodal, and extranodal types represent examples of B-cell neoplasms in which novel molecular biomarkers have been discovered in recent years. In addition, ongoing retrospective correlative and prospective outcome studies have resulted in an enhanced understanding of the clinical utility of novel biomarkers. This progress is reflected in the 2016 update of the World Health Organization classification of lymphoid neoplasms, which lists as many as 41 mature B-cell neoplasms (including provisional categories). Consequently, molecular genetic studies are increasingly being applied for the clinical workup of many of these neoplasms. In this review, we focus on the diagnostic, prognostic, and/or therapeutic utility of molecular biomarkers in mature B-cell neoplasms.

Splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is an indolent small B-cell lymphoma involving the spleen and bone marrow characterized by a micronodular tumoral infiltration that replaces the preexisting lymphoid follicles and shows marginal zone differentiation as a distinctive finding. SMZL cases are characterized by prominent splenomegaly and bone marrow and peripheral blood infiltration. Cells in peripheral blood show a villous cytology. Bone marrow and peripheral blood characteristic features usually allow a diagnosis of SMZL to be performed. Mutational spectrum of SMZL identifies specific findings, such as 7q loss and NOTCH2 and KLF2 mutations, both genes related with marginal zone differentiation. There is a striking clinical variability in SMZL cases, dependent of the tumoral load and performance status. Specific molecular markers such as 7q loss, p53 loss/mutation, NOTCH2 and KLF2 mutations have been found to be associated with the clinical variability. Distinction from Monoclonal B-cell lymphocytosis with marginal zone phenotype is still an open issue that requires identification of precise and specific thresholds with clinical meaning.

Splenic marginal zone lymphoma proposals for a revision of diagnostic, staging and therapeutic criteria

Since the initial description of splenic marginal zone lymphoma (SMZL) in 1992, an increasing number of publications have dealt with multiple aspects of SMZL diagnosis, molecular pathogenesis and treatment. This process has identified multiple inconsistencies in the diagnostic criteria and lack of clear guidelines for the staging and treatment. The authors of this review have held several meetings and exchanged series of cases with the objective of agreeing on the main diagnostic, staging and therapeutic guidelines for patients with this condition. Specific working groups were created for diagnostic criteria, immunophenotype, staging and treatment. As results of this work, guidelines are proposed for diagnosis, differential diagnosis, staging, prognostic factors, treatment and response criteria. The guidelines proposed here are intended to contribute to the standardization of the diagnosis and treatment of these patients, and should facilitate the future development of clinical trials that could define more precisely predictive markers for histological progression or lack of response, and evaluate new drugs or treatments.

Nodal aggressive B-cell lymphomas: a diagnostic approach

The diffuse aggressive B-cell lymphomas, as recognised in the 2001 WHO classification, represent a clinically and biologically heterogeneous group of neoplasms that require very different therapeutic approaches and have very different outcomes. They should be diagnosed using a multiparameter approach that emphasises morphological and immunophenotypic studies, and in at least some cases, relies on cytogenetic and/or genotypic studies. Incorporation of clinical data may be important as well. There is also current interest in going beyond the basic diagnosis and providing pathological prognostic information when possible. Whereas the diagnosis of some cases will be relatively easy, the differential diagnosis in others is very difficult, with some cases in a grey zone between two different well defined categories.

Clinicopathologic Characteristics and Outcome of Diffuse Large B-Cell Lymphomas Presenting With an Associated Low-Grade Component at Diagnosis

Purpose

Some diffuse large B-cell lymphomas (DLBCL) present at diagnosis with associated morphologic features of small B-cell non-Hodgkin's lymphoma (NHL) and may arise from the transformation of a previously unknown indolent low-grade lymphoma. The characteristics and prognosis of these particular DLBCL are not well known.

Patients and Methods

The strict morphologic review of consecutive DLBCL patients diagnosed over 12 years in our department (Hematology Department, Centre Hospitalier Lyon-Sud, Lyon, France) allowed to retrieve 60 DLBCL that could be have occurred from the transformation of marginal zone B-cell NHL (32 patients), follicular NHL (22 patients), and small lymphocytic NHL (6 patients). We compared them to 180 matched patients of de novo DLBCL.

Results

Patients median age was 55 years and presented the following clinical characteristics: poor performance status in 33%, disseminated disease in 97%, more than one extranodal site in 50%, and increased lactate dehydrogenase level in 55%. Complete remission with multidrug chemotherapy regimens was achieved in 60% of the patients, but 48% relapsed: 28% with aggressive and 20% with indolent histology, respectively. Overall survival (OS) and freedom-from-progression rates at 5 years were 57% and 33%, respectively. The matched-control analysis showed that patients with transformed NHL at diagnosis had lower complete response to chemotherapy (P = .004) and higher progression rate (P = .03), whereas no difference was observed in OS (P = .21).

Conclusion

Compared to de novo DLBCL, transformed NHL at diagnosis have similar overall survival but lower complete response to initial treatment and higher risk of indolent relapses.

Splenic Marginal Zone Lymphoma With Micronodular T-Cell Rich B-Cell Lymphoma

The types of B-cell lymphoma commonly involving the spleen include splenic marginal zone lymphoma and T-cell/histiocyte-rich large B-cell lymphoma. We describe a unique case of splenic marginal zone lymphoma associated with micronodular T cell/histiocyte-rich large B-cell lymphoma in the red pulp, a combination that has not previously reported in the literature.

Immunohistochemistry in bone marrow pathology: a useful adjunct for morphologic diagnosis

Pathomorphological examination of trephine biopsies of the bone marrow (BM) represents a standard method for the diagnosis and staging of hematologic neoplasms and other disorders involving the BM. The increasing knowledge about the genetic basis and biology of hematologic neoplasms, as well as the recently proposed WHO classification system, provide the framework for an accurate diagnosis. Although conventional morphology remains the gold standard for paraffin-embedded BM trephines, immunohistochemical stainings have become an integral part of the diagnostic workup. Antibodies suitable for paraffin sections are generally applicable to BM trephines, but modifications of staining protocols may be necessary due to the alternative fixatives and decalcification procedures used for BM biopsies. The indications for immunostainings range from confirmation and classification of lymphoma involvement, subclassification of acute leukemias, and estimating blast counts in myelodysplastic and myeloproliferative syndromes to characterization of BM involvement in nonhematologic neoplasms. Although subtyping of NHL in the BM is more difficult from the point of morphology, classification of the entities that frequently involve the BM, especially the small B-cell lymphomas, can easily be achieved with the help of immunohistochemistry. In this review, we try to summarize the current state of the art in BM immunohistochemistry for the diagnosis of hematologic disorders. Moreover, diagnostic algorithms and useful antibody panels are proposed for a rational and cost-effective approach.

Splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is an indolent B cell malignancy usually involving spleen, bone marrow and blood. The disease presents as an incidental finding or with symptoms of splenic enlargement or anaemia. Diagnosis is based on a combination of lymphocyte morphology, immunophenotype and marrow and /or splenic histology. There is no genetic abnormality specific for SMZL, but deletions of chromosome 7q are the commonest abnormality and are found in 30-50% of cases. SMZL cells may have either mutated or unmutated immunoglobulin variable region genes and probably arise from different subsets of splenic marginal zone B cells. Prognostic factors are poorly defined and only loss or mutation of the p53 gene is consistently associated with a poor outcome. Therapeutic options include splenectomy, splenic irradiation, alkylating agents, purine analogues or anti CD20 antibody. The median survival is 10-13 years and most disease-related deaths are associated with transformation to diffuse large cell lymphoma.

Patterns of bone marrow involvement in 58 patients presenting primary splenic marginal zone lymphoma with or without circulating villous lymphocytes

We studied 86 bone marrow biopsies (BMB) from 58 patients presenting with primary splenic marginal zone lymphoma (PSMZL). In 42 patients, a splenectomy was performed which enabled a histopathological diagnosis. In these patients, 44 biopsies were carried out before, and 25 after, splenectomy. In 16 recently observed patients, 17 BMB led to PSMZL diagnosis, and these patients were treated without splenectomy. Seven different patterns of infiltrates were recognized: intravascular, interstitial, nodular, massive, plasmacytic mimicking myeloma and transformation into large B-cell lymphoma (DLBCL). The association of an intravascular infiltrate and nodules with a germinal centre and/or a marginal zone favoured a diagnosis of MZL. Immunohistochemistry demonstrated the expression of B cell-associated antigens and, in 40% of the patients, a monotypic lymphoplasmacytic cell component. These patients often presented a serum M component and autoimmune disorders. In the past, such cases have been diagnosed as lymphoplasmacytic lymphoma. BM involvement was present in all patients. Successive biopsies showed progression and, after chemotherapy, a slight decrease in infiltrates. Transformation into DLBCL occurred in 11 of 34 patients. The patterns described are not specific for PSMZL and occur also in primary nodal MZL and, more rarely, in MALT-type lymphoma.

Large B-cell lymphoma presenting in the spleen: identification of different clinicopathologic conditions

Only a few series of splenic large B-cell lymphoma have been previously reported, including limited immunophenotypic studies and clinical data. Here we review the clinical data, morphology, and immunophenotype of series of 33 cases of large B-cell lymphoma presenting in the spleen. Three main groups of tumors are identified. Group A was characterized by macronodular tumors (20 cases), with predominantly stage I disease and a favorable clinical outcome. All cases were bcl6 positive. Group B was characterized by a micronodular pattern (nine cases), including a subset with T-cell-rich B-cell lymphoma features. Most of the patients in this group were diagnosed at advanced clinical stages and died of the disease. All cases were bcl6 positive. Group C was characterized by diffuse red pulp infiltration (four cases) and advanced clinical stages and showed an aggressive behavior. All but one case were bcl6 positive. The results of this series define a characteristic type of large B-cell lymphoma presenting in the spleen as a tumoral mass, associated with a relatively favorable clinical course. Additionally, they provide evidence that clinical presentation as a tumor confined to the spleen and the hilar lymph nodes is associated with lower aggressivity.

Splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is an indolent lymphoproliferative disease accounting for approximately 1% of all lymphomas. SMZL presents with marked splenomegaly, and often accompanied by circulating atypical 'villous lymphocytes' and is also known as splenic lymphoma with villous lymphocytes. Histologically, the spleen in SMZL is characterised by a nodular infiltrate based on pre-existing white pulp but also involving the red pulp. Within the white pulp, the infiltrate has a biphasic morphology comprising an inner zone of small lymphocytes and a peripheral (marginal) zone of larger lymphoid cells. Usually the splenic lymph nodes and bone marrow are also involved by a vaguely nodular infiltrate of similar nature. Immunophenotypically, the tumor cells has a mature B-cell phenotype and frequently express IgM and IgD but typically lack CD5, CD23, CD43, CD10, Bcl-6 and cyclin D1. Analysis of immunoglobulin heavy-chain gene variable regions suggest that some cases of SMZL arise form postfollicular B cells but others from naïve B cells. Genetic studies have shown abnormalities of a number of chromosomes however 7q31-32 allelic loss appears to be characteristic. Histological differential diagnosis include a number of entities such as lymphoid hyperplasias, other marginal zone lymphomas, mantle cell lymphoma, follicular lymphoma, and B-CLL.

Splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is a specific low-grade small B-cell lymphoma that is incorporated in the World Health Organization classification. Characteristic features are splenomegaly, moderate lymphocytosis with villous morphology, intrasinusoidal pattern of involvement of various organs, especially bone marrow, and relative indolent course. Tumor progression with increase of blastic forms and aggressive behavior are observed in a minority of patients. Molecular and cytogenetic studies have shown heterogeneous results probably because of the lack of standardized diagnostic criteria. To date, no definitive therapy has been established. Therapeutic options include treatment abstention, splenectomy, splenic irradiation, and chemotherapy.

Genomic abnormalities acquired in the blastic transformation of splenic marginal zone B-cell lymphoma

Among 20 cases of typical splenic marginal zone lymphoma (SMZL), two cases had blastic transformation. The genetic mechanisms underlying the morphologic transformation were investigated by comparing genetic changes in initial and blastic phases. A complex karyotype including trisomy of 3q and genomic gain of 17q22-q24 was seen in both cases at diagnosis. However, the extra copy of 3q was lost during the transformation process in both tumors. Additionally, the Karpas 1718 cell line, which was derived from a patient with transformed SMZL and carried a trisomy of 3q, also evidenced the spontaneous loss of the extra 3q during the culturing process. Other acquired abnormalities observed exclusively in the transformation phase included amplification and/or translocation of bands 7p22-q22 and 19p13. These findings suggest that the loss of + 3q and the acquisition of other genomic imbalances may represent unique markers for the transformation process of SMZL. We hypothesize that the trisomy of 3q may correlate with the indolent nature of SMZL, and that the loss of this acquired abnormality leads to or accompanies the development of blastic tumors.

Burkitt lymphoma following splenic marginal zone lymphoma. evidence for two independent B-cell clones

We report the progression of splenic marginal zone lymphoma (SMZL) with circulating villous lymphocytes to Burkitt lymphoma with the presence of a t(8;14)(q24;q32) followed by a highly aggressive course. While the initial indolent lymphoma had an IgM lambda immunophenotype the Burkitt lymphoma was IgM kappa-positive. Immunoglobulin heavy chain gene (IGH) sequence analysis showed no identity between the two clones. We conclude that Burkitt lymphoma can occur in patients with SMZL, although not necessarily of identical clonal origin.

Splenic marginal-zone lymphoma: a distinct clinical and pathological entity

In the World Health Organization classification system, splenic marginal-zone lymphoma (splenic MZL) is described as an indolent B-cell lymphoma, which generally presents as splenomegaly with involvement of the bone marrow and peripheral blood. Presence of disease in peripheral lymph nodes and extranodal locations is uncommon. Splenic MZL is characterised by micronodular infiltration of the spleen with marginal-zone differentiation; the immunophenotype is usually IgM+ IgD+/- cytoplasmic-Ig-/+ pan B antigens+ CD5- CD10- CD23- CD43-/+ cyclin D1-; and the most common genetic abnormalities are deletions at 7q22-7q32. Most patients with splenic MZL live for a long time but classic prognostic factors cannot distinguish between patients who are likely to have good and poor outcomes. However, immunological events, such as haemolytic anaemia and immune thrombocytopenia, or the presence of a monoclonal component, are significantly associated with shorter survival. Splenectomy is considered the first-line treatment of choice for splenic MZL; it results in only partial remission, but responses are generally sufficient for correcting cytopenia, improving quality of life, and increasing survival.

Analysis of the IgV(H) somatic mutations in splenic marginal zone lymphoma defines a group of unmutated cases with frequent 7q deletion and adverse clinical course

This study aimed to correlate the frequency of somatic mutations in the IgV(H) gene and the use of specific segments in the V(H) repertoire with the clinical and characteristic features of a series of 35 cases of splenic marginal zone lymphoma (SMZL). The cases were studied by seminested polymerase chain reaction by using primers from the FR1 and J(H) region. The results showed unexpected molecular heterogeneity in this entity, with 49% unmutated cases (less than 2% somatic mutations). The 7q31 deletions and a shorter overall survival were more frequent in this group. Additionally a high percentage (18 of 40 sequences) of SMZL cases showed usage of the V(H)1-2 segment, thereby emphasizing the singularity of this neoplasia, suggesting that this tumor derives from a highly selected B-cell population and encouraging the search for specific antigens that are pathogenically relevant in the genesis or progression of this tumor.

Splenic marginal zone lymphoma: a case report and review of the literature

Splenic marginal zone lymphoma is a recently described primary splenic lymphoproliferative disorder that mainly affects older individuals. We report the case of a 22-year-old woman with morphologic and immunophenotypic findings consistent with splenic marginal zone lymphoma. This woman is one of the youngest patients ever described with this disease. The patient presented with complaints of left-sided abdominal fullness and was noted to have splenomegaly on physical examination. Laboratory evaluation revealed pancytopenia and a serum M component. The spleen was removed and weighed 1550 g. Histology showed prominent white pulp with an expanded marginal zone. The neoplastic cells were marginal zone-type cells with small to intermediate-sized nuclei with occasional conspicuous nucleoli and moderate amounts of pale to amphophilic cytoplasm. Immunophenotypic analysis revealed a B-cell population (CD20 positive) with kappa-light-chain restriction. The patient was treated with adjuvant therapy, but developed progressive disease less than 2 years after initial diagnosis.

Progression to large B-cell lymphoma in splenic marginal zone lymphoma: a description of a series of 12 cases

Splenic marginal zone lymphoma (SMZL) is considered to be an indolent extranodal B-cell lymphoma. Despite its low aggressivity, histologic progression has been described in sporadic reports, although the frequency, characteristics, and underlying molecular abnormalities of this phenomenon are largely unknown. We review here the clinical, morphologic, immunohistochemical, and molecular features of a series of 12 SMZL cases that showed progression to large B-cell lymphoma (LBCL). The most frequent location of secondary LBCL was in peripheral lymph node. This occurred between 12 and 85 months after diagnosis of SMZL. However, in two cases LBCL was diagnosed at the initial stage of the disease (one spleen tumoral nodule and one hilar lymph node). The histologic and immunophenotypic features of these cases were similar to those of transformed LBCL at other sites. In four cases the immunoglobulin heavy chain gene polymerase chain study revealed the same rearrangement pattern in both primary and secondary tumors, thereby confirming their identity and excluding the possibility of a second malignancy. As is the case with other low-grade lymphoproliferative disorders, SMZL may undergo high-grade transformation. These 12 cases represent 13% of our series of SMZL with adequate follow-up. The incidence of large cell transformation in SMZL seems to be lower than in follicular lymphoma (25-60%) and mantle cell lymphoma (11-39%), although it is similar to the frequency of transformation in B-chronic lymphocytic lymphoma/small lymphocytic lymphoma (1-10%). The mean proliferative index (MIB1 staining) in initial SMZL specimens of cases with LBCL transformation was 28.6%, higher than that of MIB1 staining in the overall SMZL series (21.8%), although not statistically significantly so. p53 or p16INK4a inactivation in this series was observed in only one case, in contrast with the situation observed in chronic lymphocytic leukemia, follicular lymphoma, and mantle cell lymphoma. It seems that progression in SMZL is mainly independent of p53 or p16INK4a inactivation. The frequency of the 7q deletion in this series was 3 of 7 (42%). 7q loss may play an alternative role in the inactivation of the p53 and p16INK4a pathway, thereby favoring tumoral progression.

p53 abnormalities in splenic lymphoma with villous lymphocytes

The incidence and role of p53 abnormalities have not been reported in splenic lymphoma with villous lymphocytes (SLVL), the leukemic counterpart of splenic marginal zone lymphoma. Because p53 abnormalities correlate with progressive and refractory disease in cancer and isochromosome 17q has been described in SLVL, a low-grade lymphoma that behaves aggressively in a minority of patients, this study investigated p53 changes by molecular and immunophenotypic methods in samples from 59 patients. The p53 deletion was analyzed by fluorescence in situ hybridization, and p53 protein expression was assessed by immunocytochemistry in 35 of 59 cases and by flow cytometry in 20 of 35 patients. Ten patients (17%) had a monoallelic p53 loss, 3 (9%) of 35 nuclear protein expression by immunocytochemistry, and 2 (10%) of 20 by flow cytometry. Two patients had both deletion and protein expression. Direct sequencing of all p53 exons was used to delineate mutations in 9 of 11 patients with an identified abnormality. Mutations, both compromising p53 DNA binding, were identified in the 2 patients with deletion and protein accumulation. Kaplan-Meier analysis revealed a significantly worse survival for patients with p53 abnormalities. Although p53 abnormalities are infrequent in SLVL, they underlie a more aggressive disease course and poor prognosis. (Blood. 2001;97:3552-3558)

Pathology of lymphoma progression

Reflecting the stepwise process of oncogenesis, lymphomas may cumulatively develop a more aggressive phenotype during the course of disease, a process referred to as lymphoma progression. Although morphological, clinical and biological aspects of lymphoma progression do not always overlap, changes in lymphoma morphology frequently indicate alterations in the clinical and biological behaviour of the disease. Indolent and aggressive lymphomas in disease progression can either be clonally related or represent clonally unrelated neoplasms. We propose to use the term 'lymphoma progression' in a biological sense denoting only clonal development of and within a lymphoma entity. The term 'composite lymphoma' should be used as a merely descriptive morphological designation for different lymphoma entities in one individual irrespective of clonal relationship. Many types of aggressive B-cell non-Hodgkin's lymphomas and Hodgkin's lymphomas are reported to secondarily develop in lymphoma progression. Genetic changes associated with lymphoma progression frequently abrogate the differentiating effects of alterations occurring in indolent lymphomas, leading to increased cell proliferation. Within different lymphoma entities, high-risk disease variants mimicking lymphoma progression exist.

Splenectomy influences bone marrow infiltration in patients with splenic marginal zone cell lymphoma with or without villous lymphocytes

BACKGROUND

Splenic marginal zone cell lymphoma (SMZL) is a low grade B-cell lymphoma in which patients can have circulating villous lymphocytes and can show a peculiar intrasinusoidal bone marrow (BM) infiltration. Splenectomy is the reported treatment of choice for these patients. The objective of this study was to evaluate the effects of splenectomy on patients with BM lymphomatous infiltration.

METHODS

BM biopsies of 16 patients with SMZL were studied morphologically and immunohistochemically. In 12 patients, BM biopsies were taken before and after splenectomy. Four patients did not undergo splenectomy, and their BM biopsies were performed with an approximately 1 year interval.

RESULTS

BM infiltration ranged from 10% to 40% of overall cellularity and was mostly of the intrasinusoidal type. After splenectomy, BM infiltration tended to become frankly nodular and showed an increase in tumor burden. Nonsplenectomized patients showed an unmodified picture.

CONCLUSIONS

Splenectomy seems to induce important changes in patients with BM infiltration, probably through the lack of microenvironmental factors on circulating cells. These effects suggest reconsidering the role of splenectomy in the treatment of patients with SMZL.

Abnormalities of the p53 Tumour Suppressor Gene in Mature B-cell Neoplasms

The p53 gene, located on the short arm of human chromosome 17 at 17p13, codes for a 393 aminoacid phosphoprotein, which acts as a transcription factor and is involved in the control of many different cellular processes. It is the most frequently mutated gene in neoplasia and mutations have been observed in 231 of the 393 codons, including all but one codon of the DNA binding domain. p53 abnormalities in mature B-cell lymphoproliferative disorders (B-LPDs) occur in up to 75% of cases and are mostly detected in patients with advanced clinical stages. B-LPDs encompass a heterogeneous group of clinically important lymphoid malignancies with a complex biology, varying natural history and prognosis that makes their classification and treatment difficult. Despite many publications concerning the role of p53 abnormalities in the development of B-LPDs and the prognostic implications of detecting aberrant p53 function, it is difficult to draw firm conclusions as studies have varied with respect to patient selection and classification and techniques used. This review focuses on the available data pertaining to p53 abnormalities in the different mature B-cell neoplasms and summarises the incidences of abnormalities, the mutation patterns encountered and their clinical significance.

Simultaneous presence of t(2;8)(p12;q24) and t(14;18)(q32;q21) in a B-cell lymphoproliferative disorder with features suggestive of an aggressive variant of splenic marginal-zone lymphoma

We report a case of an aggressive variant of splenic marginal-zone lymphona (SMZL) with circulating villous lymphocytes. The karyotype of all examined cells had multiple structural and numerical abnormalities, including two lymphoma characteristic translocations, t(2;8)(p12;q24) and t(14;18)(q32;q21). Based on a literature review of cytogenetic aberrations of splenic lymphoma with villous lymphocytes (SLVL) and SMZL, this is apparently the first documentation of these two translocations in a case of SMZL, and could reflect the heterogeneity of the disorder.