Primary macroglobulinemia with t(11;18)(q21;q21)

Disseminated Gastric MALT Lymphoma with Monoclonal Gammopathy, t(11;18)(q21;q21), and Subsequent Development of T-Large Granular Lymphocytic Leukemia: A Case Report and Review of the Literature

Background. Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a well-characterized entity that may share clinical and morphological findings with other low-grade non-Hodgkin's lymphomas. Dissemination of MALT-type lymphoma to bone marrow and peripheral blood simultaneously with the presence of T-large granular cell leukemia (T-LGL) has rarely been reported. Case Presentation. This is the case of a 42-year-old male who presented with a gastric MALT-type lymphoma, disseminated to the bone marrow and the peripheral blood with high serum IgM levels and t(11;18)(q21;q21). The morphological, immunophenotypical and, immunohistochemical studies of the successive bone marrow and peripheral blood samples had revealed the coexistence of two distinct lymphoma cell populations: a B-cell, marginal zone type population expressing CD19, CD20, CD22, CD79b, IgM, and kappa light chain, and a T-large granular cell population, developed after treatment with rituximab expressing CD3, CD8, CD5, CD7, and CD45. Conclusion. Based on the analysis of this unusual case we performed an extensive review of the literature to elucidate the relationship between T-LGL and B-cell lymphomas and to emphasize the importance of paraprotein analysis at diagnosis of gastric MALT lymphoma.

Waldenström macroglobulinemia: a review of the entity and its differential diagnosis

The definition of Waldenström macroglobulinemia (WM), originally described in 1944, has been refined substantially over time. The current fourth edition of the World Health Organization of lymphoid neoplasms, in large part, adopted criteria proposed for WM at a consensus conference in 2002. WM is defined as lymphoplasmacytic lymphoma involving the bone marrow associated with a serum immunoglobulin (Ig) M paraprotein of any concentration. Morphologically, WM is composed of a variable mixture of lymphocytes, plasmacytoid lymphocytes, and plasma cells. Immunophenotypically, the neoplastic cells express monotypic IgM and light chain: B lymphocytes express pan-B-cell antigens and surface Ig are usually negative for CD5 and CD10; and plasma cells are typically positive for CD138, CD38, CD45, cytoplasmic Ig, and CD19 (in a substantial subset of cases). The putative cell of origin of WM is a postantigen selected memory B-cell that has undergone somatic hypermutation. The most common cytogenetic abnormality in WM is del(6q), usually in the region 6q23-24.3, present in 40% to 50% of cases. IGH gene translocations are rare and recurrent chromosomal translocations or gene aberrations have not been identified in WM. Here, we provide a historical perspective of WM, review clinical and pathologic aspects of the disease as it is currently defined, and discuss some practical issues in the differential diagnosis of WM that pathologists encounter in the signout of cases.

[Chromosomal abnormalities and Waldenström macroglobulinemia]

Waldenström macroglobulinemia (WM) is now defined as an uncommon lymphoplasmocytic proliferation associated with an immunoglobulin M peak. The associated chromosomal abnormalities are not specific to the disease, and changes in the diagnostic criteria and techniques used as well as low-level abnormal cell proliferation made their analysis difficult. A literature review however, shows that if specific abnormalities were not recognized until now, it is the frequency of some chromosomal abnormalities (for instance partial deletion of the long arm of chromosome 6 and trisomy 4) that distinguishes WM from other chronic malignant B-cell proliferations. The data collected in the present review show directions for future research which will benefit from use of more recent techniques such as fluorescent in situ hybridization, comparative genomic hybridization and expression microarrays.

Waldenström macroglobulinaemia

Over time, Waldenström macroglobulinaemia (WM) has evolved conceptually from a clinical syndrome to a distinct clinicopathological entity. Progress is being made in standardization of the disease definition and treatment response criteria, although nosologic controversies persist. According to the Second International Workshop on WM, the disease is defined as a B-cell neoplasm characterized by a lymphoplasmacytic infiltrate in the bone marrow, with an associated immunoglobulin (Ig) M paraprotein. Disease symptoms are often divided into those related to tumour infiltration and those related to the rheological effects of the monoclonal IgM. As with other low-grade lymphomas, asymptomatic patients are observed only, with treatment reserved for symptomatic patients. There is no standard treatment for WM and choices include rituximab, alkylating agents, purine nucleoside analogues, alone or in combination, as well as autologous peripheral blood stem cell transplant in eligible patients. Novel treatments, such as bortezomib, oblimersen sodium, perifosine and others are being evaluated.

Genomics and proteomics in multiple myeloma and Waldenström macroglobulinemia

PURPOSE OF REVIEW

Multiple myeloma and Waldenström macroglobulinemia are incurable hematologic malignancies with similar clinical phenotypes characterized by over-production of monoclonal immunoglobulins. Translocations into the immunoglobulin heavy chain locus and aneuploidy are nearly universal in multiple myeloma, whereas Waldenström macroglobulinemia generally does not harbor translocations. Deletion of 6q is identified in 50% of patients with Waldenström macroglobulinemia, however. The genetic abnormalities in multiple myeloma and Waldenström macroglobulinemia have implications for disease progression, and the subsequent proteomic expression associated with each disease influences therapeutic decisions.

RECENT FINDINGS

Gene expression profiling in these hematologic malignancies demonstrated distinct differences in mRNA expression patterns. Following profiling, Waldenström macroglobulinemia samples clustered with chronic lymphocytic leukemia and normal B-cell samples. Profiling performed after separation of Waldenström macroglobulinemia samples into populations with plasma cell or B-cell morphology revealed that plasma cell Waldenström macroglobulinemia samples most closely resembled multiple myeloma samples rather than chronic lymphocytic leukemia or normal control samples.

SUMMARY

Diverse genetic abnormalities have been identified in these hematologic malignancies, although they have similar clinical features. Gene expression profiling has elucidated the impact of genetic abnormalities. Furthermore, it may be used to identify a specific pathway for therapeutic targeting, such as interleukin-6 in Waldenström macroglobulinemia.

Cytogenetics of Familial Waldenström's Macroglobulinemia: In Pursuit of an Understanding of Genetic Predisposition

Despite recent identification of a recurrent chromosome 6q21 deletion in sporadic Waldenstrom's macroglobulinemia (WM), elucidation of the molecular pathogenesis of WM remains challenging. In contrast to the growing body of cytogenetic studies in sporadic WM, there have been virtually no informative studies of familial WM. The authors therefore undertook conventional and molecular cytogenetic evaluation of 18 patients with familial WM and 3 patients with immunoglobulin (Ig) M monoclonal gammopathy (IgM-MG) from 15 families to determine the nature and extent of chromosomal abnormalities associated with familial WM. The frequency and distribution of chromosomal changes in familial WM resembled those in sporadic WM, including lack of IgH rearrangements and t(9;14); however, we detected del6q21 in only 1 patient. Occasional findings appeared to be novel; however, none were recurrent, and their significance remains unclear. Only one abnormality found in bone marrow specimens was detected in parallel peripheral blood lymphocyte studies, suggesting that most abnormalities represented somatic changes. Although they must be viewed in light of the hypoproliferative nature of WM, our results suggest that further progress in delineating the genetic determinants of WM susceptibility might be gained from alternative approaches such as candidate gene or linkage analysis.

t(1;14) and t(11;18) in the differential diagnosis of Waldenström's macroglobulinemia

Waldenström's macroglobulinemia is caused by several B-cell proliferative disorders including lymphoplasmacytic lymphoma, marginal zone B-cell lymphoma, B-cell chronic lymphocytic leukemia and multiple myeloma. Differential diagnosis between lymphoplasmacytic lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue is particularly difficult as there is a considerable overlap in histological presentation. We report a case of Waldenström's macroglobulinemia with involvement of the peripheral blood, bone marrow and stomach. Serum chemistry revealed an IgM of 5.4 g/dl, but Bence-Jones protein in urine was negative. Abnormal lymphoid cells were detected in both blood and the bone marrow. Flow cytometry of the bone marrow aspirate showed that majority of cells were CD20(+), CD38(+), expressing immunoglobulin lambda light chain, but CD5(-) and CD10(-). Gastric biopsies revealed infiltration of the gastric mucosa by small lymphoid cells showing plasmacytoid differentiation and occasional Dutcher bodies. Lymphoepithelial lesions and Helicobacter pylori were not seen. Thus, the differential diagnosis between lymphoplasmacytic lymphoma and mucosa-associated lymphoid tissue lymphoma was raised. To resolve this, we performed BCL10 immunohistochemistry and reverse transcriptional polymerase chain reaction (RT-PCR) for the API2-MALT1 fusion transcript of t(11;18)(q21;q21). Both bone marrow and gastric biopsies showed strong BCL10 nuclear staining, similar to that seen in t(1;14)(p22;q32) positive mucosa-associated lymphoid tissue lymphoma, but absence of the API2-MALT1 fusion transcript. To further ascertain whether the detection of t(1;14)(p22;q32) and t(11;18)(q21;q21) can be reliably used for the differential diagnosis between lymphoplasmacytic lymphoma and mucosa-associated lymphoid tissue lymphoma, we screened for these translocations by BCL10 immunohistochemistry in 58 lymphoplasmacytic lymphomas and RT-PCR for t(11;18)(q21;q21) in 40 lymphoplasmacytic lymphomas, respectively. None of the lymphoplasmacytic lymphomas studied harbored these translocations. Thus, detection of t(1;14)(p22;q32) and t(11;18)(q21;q21) is useful in the differential diagnosis between lymphoplasmacytic lymphoma and mucosa-associated lymphoid tissue lymphoma.

Lack of PAX5 rearrangements in lymphoplasmacytic lymphomas: reassessing the reported association with t(9;14)1 1These studies were performed in the University of Pittsburgh Cancer Institute Cytogenetics Facility

A t(9;14)(p13;q32) involving the PAX5 and IGH genes has been described in association with lymphoplasmacytic lymphoma. Although often described as common, the incidence of this translocation in nodal lymphoplasmacytic lymphoma has never been investigated. Recent studies of patients with Waldenström's macroglobulinemia (often corresponding to marrow-based lymphoplasmacytic lymphoma) have failed to identify the t(9;14). These studies have suggested that either nodal and marrow-based lymphoplasmacytic lymphomas have distinct pathogenetic mechanisms or that the t(9;14) is less frequent in lymphoplasmacytic lymphoma than was believed previously. We therefore analyzed a series of nodal or other extramedullary lymphoplasmacytic lymphomas for the presence of the t(9;14) with paraffin section interphase fluorescence in situ hybridization. We developed a BAC contig probe spanning all previously described PAX5 breakpoints and validated this assay with the KIS-1 cell line that expresses a t(9;14). Analysis with the PAX5 probe showed a lack of PAX5 rearrangements in all cases that were analyzed successfully. Similarly, analysis by an IGH fluorescence in situ hybridization probe showed no evidence of translocations involving the IGH locus. These findings indicate that the t(9;14) is at least uncommon in lymphoplasmacytic lymphoma and should no longer be considered a characteristic finding in this type of lymphoma as defined by World Health Organization criteria.

Detection of Two Cell Populations Corresponding to Distinct Maturation Stages in API-2/MLT-Positive Mucosa-Associated Lymphoid Tissue Lymphoma Cells Proliferating in Pleural Effusion

A 66-year-old man was admitted to our hospital because of an intra-abdominal tumor and pleural effusion (PE). Immunoelectrophoresis of the serum showed immunoglobulin M (IgM) kappa paraprotein (7330 mg/dL). Abnormal plasmacytoid cells were seen in both the peripheral blood (PB) and the bone marrow (BM). Computed tomography scans showed extensive thickening of the gastric wall and bilateral massive PE without lymph node or pulmonary involvement. A histologic examination of the gastric mucosa showed a diffuse infiltration of small- to medium-sized lymphoid CD20-bearing cells, some of which showed a plasmacytoid morphology. Lymphoepithelial lesions were demonstrated with an immunohistochemical stain. The diagnosis was gastric mucosa-associated lymphoid tissue (MALT) lymphoma infiltrating to the PE, PB, and BM. The PE contained numerous lymphoid cells with plasmacytoid morphology that Southern blotting analysis showed to have a monoclonal IgH gene rearrangement pattern. The cells seemed to be divided into two populations according to their surface markers: mature B-cells (CD19+CD20+CD22+CD21+CD38-) and secretory B-cells (CD19+CD20(dim)CD22-CD21-CD38+). The reverse transcriptase-polymerase chain reaction technique detected the API-2/MLT transcript in the PE and PB. The patient had a good response to fludarabine treatment, which was followed with rituximab therapy. In general, gastric MALT lymphoma cells have a tendency to differentiate into plasma cells. In this article, we show that the cell character of API-2/MLT-positive MALT lymphoma is preserved even when the cells are disseminated. This is the first published case, to our knowledge, in which two differentiation stages of MALT lymphoma cells infiltrating into PE have been confirmed by flow cytometric analysis.

Waldenstrom macroglobulinemia involving extramedullary sites: morphologic and immunophenotypic findings in 44 patients

Waldenstrom macroglobulinemia (WM) is a clinicopathologic syndrome in which a B-cell neoplasm involving the bone marrow, usually lymphoplasmacytic lymphoma (LPL), is associated with immunoglobulin M paraprotein in the serum. Extramedullary involvement occurs in a subset of patients and is infrequently examined histologically. The files of M.D. Anderson Cancer Center were searched for patients with WM who underwent biopsy of one or more extramedullary sites during the course of disease. Each biopsy specimen was classified using the criteria of the World Health Organization classification. The study group consisted of 44 patients (26 men and 18 women), with a total of 51 specimens obtained from lymph nodes (n = 36), soft tissue (n = 4), spleen (n = 3), skin (n = 2), lung (n = 2), tonsils (n = 1), colon (n = 1), liver (n = 1), and gallbladder (n = 1). Lymphoplasmacytic lymphoma was the most common histologic type, in 40 (78%) samples. This category was morphologically heterogeneous and was further subclassified as lymphoplasmacytic (n = 21), lymphoplasmacytoid (n = 18), and polymorphous (n = 1). Four of these LPL cases morphologically resembled marginal zone B-cell lymphoma. Four additional samples were involved by diffuse large B-cell lymphoma, probably transformed from LPL. Three more samples were involved by LPL with unusual features: two were CD5-positive and one was a composite tumor with classical Hodgkin's disease. Other categories of lymphoma in this group of patients with WM included small lymphocytic lymphoma/chronic lymphocytic leukemia (n = 2), mantle cell lymphoma (n = 1), and follicular lymphoma (n = 1). Waldenstrom macroglobulinemia is most commonly associated with LPL but can rarely occur with other types of B-cell lymphoma. Lymphoplasmacytic lymphoma in patients with WM is morphologically heterogeneous and can be indistinguishable from marginal zone B-cell lymphoma. CD5+ B-cell lymphomas with features otherwise typical of LPL are rare, and we think these tumors are part of the spectrum of LPL.

Genetics and cytogenetics of Waldenstrom's macroglobulinemia

Waldenstrom's macroglobulinemia (WM) is a clonal B-cell disorder characterized by the production of a monoclonal paraprotein and lymphoplasmacytic clonal expansion. The genetic basis of this disorder is poorly understood. We have recently found that the genetic makeup of WM cells is different from that commonly reported for multiple myeloma (MM), follicular lymphoma, and B-cell chronic lymphocytic leukemia. Translocations involving the immunoglobulin heavy chain locus (IgH) translocations could not be detected in any case, and a molecular analysis showed that the IgH locus switch mu retained its germline configuration. Aneuploidy was not detected using chromosome enumeration probes. The only recurrent chromosome abnormality found was deletion of 6q21. The lack of legitimate of illegitimate rearrangements at the IgH locus suggests that other mechanisms are involved in the pathogenesis of the disorder. Given the clear evidence of a familial form of WM and the currently presumed genomic stability of the clonal cells, it is likely that a single gene defect may be responsible for disease pathogenesis. Having found deletions of the long arm of chromosome 6 as the only recurrent aberration, we speculate that a gene involved in B-cell maturation or survival at this locus may be inactivated as a cause of WM.

Dysregulation of apoptosis in Waldenstrom's macroglobulinemia does not involve nuclear factor kappa B activation

Indolent lymphoproliferative disorders such as Waldenstrom's macroglobulinemia (WM) are characterized by defective apoptosis, which leads to progressive accumulation of slowly dividing neoplastic lymphocytes. Activation of nuclear factor kappa B (NFkappaB) is considered to have a central pathogenic role in some hematological malignancies, including multiple myeloma, Hodgkin's disease, and extranodal marginal zone lymphoma (ENMZL). NFkappaB activation may inhibit apoptosis through the transactivation of genes such as Bcl-2 and may therefore be an important mechanism in indolent lymphoproliferative disorders, including WM. In order to assess this potential mechanism, we used immunohistochemistry to determine the presence and subcellular localisation of the major NFkappaB subunits p50 and p65. Nuclear staining of NFkappaB subunits (indicative of activation) was not seen in any of the 40 cases examined. Thirty-seven (95%) cases showed cytoplasmic positivity for both p50 and p65 and one case demonstrated cytoplasmic staining for p65 alone, while the two remaining cases showed complete absence of staining. We would therefore conclude that NFkappaB activation is not a feature of WM and that alternative mechanisms of apoptosis inhibition should be investigated in this disorder.

Waldenström macroglobulinemia with a novel der(8;17)(q10;q10)

We report the occurrence of an unbalanced whole-arm translocation of der(8;17)(q10;q10) in an 80-year-old female patient with Waldenström macroglobulinemia. To our knowledge, der(8;17)(q10;q10) has not been described in Waldenström macroglobulinemia. Although this cytogenetic abnormality has been reported in a number of solid tumors, a literature review suggests also a possible association with B-cell chronic lymphoproliferative disorders.

Waldenström macroglobulinemia neoplastic cells lack immunoglobulin heavy chain locus translocations but have frequent 6q deletions

Lymphoplasmacytic lymphoma (LPL) is characterized by t(9;14)(p13;q32) in 50% of patients who lack paraproteinemia. Waldenström macroglobulinemia (WM), which has an immunoglobulin M (IgM) paraproteinemia, is classified as an LPL. Rare reports have suggested that WM sometimes is associated with 14q23 translocations, deletions of 6q, and t(11;18)(q21;q21). We tested for these abnormalities in the clonal cells of WM patients. We selected patients with clinicopathologic diagnosis of WM (all had IgM levels greater than 1.5 g/dL). Southern blot assay was used to detect legitimate and illegitimate IgH switch rearrangements. In addition to conventional cytogenetic (CC) and multicolor metaphase fluorescence in situ hybridization (M-FISH) analyses, we used interphase FISH to screen for t(9;14)(p13;q32) and other IgH translocations, t(11;18)(q21;q21), and 6q21 deletions. Genomic stability was also assessed using chromosome enumeration probes for chromosomes 7, 9, 11, 12, 15, and 17 in 15 patients. There was no evidence of either legitimate or illegitimate IgH rearrangements by Southern blot assay (n = 12). CC (n = 37), M-FISH (n = 5), and interphase FISH (n = 42) failed to identify IgH or t(11;18) translocations. Although tumor cells from most patients were diploid for the chromosomes studied, deletions of 6q21 were observed in 42% of patients. In contrast to LPL tumors that are not associated with paraproteinemia and that have frequent t(9;14)(p13;q32) translocations, IgH translocations are not found in WM, a form of LPL tumor distinguished by IgM paraproteinemia. However, WM tumor cells, which appear to be diploid or near diploid, often have deletions of 6q21.

Autopsy case of lymphoplasmacytic lymphoma with a large submucosal tumor in the stomach

An autopsy case of lymphoplasmacytic lymphoma with a large submucosal tumor in the stomach is presented. The patient was a 77-year-old woman with gastric lymphoma associated with Waldenstrom's macroglobulinemia of IgM-lambda type. Diagnosis was initially mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach, because gastric biopsy specimens showed epitheliotropic proliferation (lymphoepithelial lesion) of the lymphoma cells. Postmortem examination revealed a large gastric lymphoma with metastatic foci in the esophagus, larynx, trachea, lungs, spleen and lymph nodes. The bone marrow was also involved. Lymphoma cells consisted of small lymphocytoid cells occasionally admixed with blast-like large cells and a large number of plasmacytoid or plasma cells. Centrocyte-like cells were not found. Lymphoepithelial lesions were not conspicuous in autopsy specimens. Immunohistochemically, lymphoma cells reacted with CD20, CD45, CD79a, anti-IgM, anti-lambda protein and anti-BCL-2, but not with CD5, CD10, CD23 or CD38. Based on these findings, the revised diagnosis of the present case was lymphoplasmacytic lymphoma, and it highlighted the differential diagnostic problem from marginal zone B-cell lymphoma of MALT type.

Cytogenetic findings in lymphoplasmacytic lymphoma/Waldenström macroglobulinemia. Chromosomal abnormalities are associated with the polymorphous subtype and an aggressive clinical course

We correlated bone marrow cytogenetic findings with morphologic and immunophenotypic data in 37 patients with lymphoplasmacytic lymphoma (LPL)/Waldenström macroglobulinemia (WM). Each LPL/WM case was classified as lymphoplasmacytoid (n = 18), lymphoplasmacytic (n = 10), or polymorphous (n = 9) using the Kiel criteria. Of 12 cases with chromosomal abnormalities, a single numeric abnormality was present in 4 and a complex karyotype in 8. The most common numeric abnormalities were and -8 in 3 cases each; the most common structural abnormality was del(6q) in 6 cases. Cytogenetic abnormalities were significantly less common in the lymphoplasmacytic and lymphoplasmacytoid groups (5/28 [18%]) compared with the polymorphous group (7/9 [78%]). Clinical follow-up was available for 28 patients for a median of 36 months. Six (67%) of 9 patients with aneuploid tumors, including 4 with polymorphous subtype, subsequently had clinical progression or developed high-grade lymphoma. In contrast, 4 (21%) of 19 patients with diploid tumors, including 1 of polymorphous type, developed clinical progression or high-grade lymphoma. We conclude that abnormal cytogenetic findings in LPL/WM correlate with the polymorphous subtype and poor prognosis.