The morphologic spectrum of non-Hodgkin's lymphomas with BCL1/cyclin D1 gene rearrangements

Orbital marginal cell lymphoma and mantle cell lymphoma subclone in patient with monoclonal gammopathy of unknown significance

Indolent lymphomas have the potential to transform into more aggressive phenotypes. This phenomenon is best exemplified by the transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma into diffuse large B-cell lymphoma. However, it is less common to find multiple small cell lymphomas in the orbit, particularly mantle cell lymphoma. We present a case of an extranodal marginal zone lymphoma arising in the orbit that acquired a subclonal t(11;14) (q13;32) CCND1-IGH translocation, giving rise to a subclone of mantle cell lymphoma. The management of this tumor was targeted towards the more aggressive mantle cell subclone. The tumor exhibited an incomplete response to rituximab alone. To the best of the authors' knowledge, this represents the first such case to be described irrespective of site of origin.

Richter syndrome with follicular colonization of chronic lymphocytic leukemia/small lymphocytic lymphoma cells mimicking follicular lymphoma

Follicular colonization is occasionally observed in marginal zone lymphoma. In rare cases, it has also been associated with mantle cell lymphoma. Chronic lymphocytic leukemia typically involves nodal or extranodal tissues as diffuse proliferation by complete effacement of the normal architecture. The involvement of chronic lymphocytic leukemia may be less frequently limited to the interfollicular areas. Here, we report a case of Richter syndrome of the small intestine that was initially diagnosed as follicular lymphoma of the gastrointestinal tract because of a partial follicular growth pattern in addition to a mainly diffuse proliferation pattern. The follicular pattern mimicking follicular lymphoma was shown to be composed of reactive follicles with follicular colonization of the original chronic lymphocytic leukemia cells. As the prognoses of Richter syndrome and follicular lymphoma of gastrointestinal tract are quite different, clinicians must carefully diagnose these conditions to avoid a misdiagnosis.

Diffuse large B-cell lymphoma and mantle cell lymphoma of the ocular adnexal region, and lymphoma of the lacrimal gland: an investigation of clinical and histopathological features

Diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) constitute two distinct subtypes of non-Hodgkin lymphoma (NHL) associated with considerable morbidity and mortality. Marked diversities with regard to molecular biology and clinical features are recognized in different subsets of the two lymphomas. Because these differences could be related to the location of the lymphoma, it is of interest to investigate the clinical and histopathological features of DLBCL and MCL involving the ocular adnexal region (i.e. the orbit, eyelids, conjunctiva, lacrimal gland and lacrimal sac). Similarly, the lacrimal gland is the only glandular structure within the orbit. Because the lacrimal gland represents an important part of the immunological system, it is of interest to investigate lymphomas involving this location with regard to clinical and histological characteristics.

PURPOSE

  To characterize the clinical and histopathological features of Danish patients with DLBCL of the ocular adnexal region between 1980 and 2009 and of Danish ocular adnexal MCL patients from 1980 to 2005. Furthermore, the aim of this PhD was to review all specimens from patients with lymphoma of the lacrimal gland in Denmark between 1975 and 2009 to determine the distribution of lymphoma subtypes of the lacrimal gland and to describe the clinicopathological features of these patients.

RESULTS

  A total of 34 patients with DLBCL and 21 with MCL of the ocular adnexal region were identified. Twenty-seven patients had lacrimal gland lymphoma, including four DLBCLs and three MCLs from studies I and II. Elderly patients predominated in all three groups, with median ages of 78, 75 and 69 years in the DLBCL, the MCL and the lacrimal gland lymphoma groups, respectively. MCL patients had a preponderance of males, whereas females prevailed among lacrimal gland lymphoma patients. The orbit was the most common site of involvement in DLBCL and MCL. Most DLBCL patients had unilateral involvement, while MCL patients had a high frequency of bilateral involvement. Similarly, localized lymphoma was relatively frequently seen in DLBCL patients in contrast to the predominance of disseminated lymphoma in the MCL group. The majority of lacrimal gland lymphomas were low grade, and the distribution of subtypes was as follows: extranodal marginal zone lymphoma, 10 (37%); follicular lymphoma, 5 (19%); DLBCL, 4 (15%); MCL, 3 (11%); chronic lymphocytic leukaemia/small lymphatic lymphoma, 2 (7%); and unclassified B-cell lymphoma, 3 (11%). The overall survival rates at 3 and 5 years for the entire study group of DLBCL were 42% and 20%, whereas 58% and 22% of MCL patients were alive 3 and 5 years after the time of diagnosis. The 5-year overall survival rate of lacrimal gland lymphoma patients was 70%. Concordant bone marrow involvement and the International Prognostic Index score were predictive factors for the overall survival in the DLBCL group in Cox regression analysis. Rituximab-containing chemotherapy was associated with an improved survival rate in MCL patients.

CONCLUSIONS

  Diffuse large B-cell lymphoma and MCL involving the ocular adnexal region and lymphoma of the lacrimal gland are prevalent among elderly patients. The overall prognosis in DLBCL and MCL was poor, whereas the prognosis for lacrimal gland lymphoma patients was relatively good. Concordant bone marrow involvement and the International Prognostic Index score were independent predictive factors for mortality in the DLBCL group. Chemotherapy containing rituximab significantly improved survival in the MCL group.

Chronic lymphocytic leukemia/small lymphocytic lymphoma with cyclin D1 positive proliferation centers do not have CCND1 translocations or gains and lack SOX11 expression

Cyclin D1 expression, usually absent in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), has been described in the proliferation centers (PC) of some CLL/SLL. The prevalence of this finding is uncertain, as is the explanation for its occurrence and whether these cases have any other unique features. Cyclin D1 immunohistochemical staining was therefore investigated in 57 extramedullary CLL/SLL biopsies. In 6 cases, cyclin D1 immunofluorescence followed by CCND1 fluorescence in situ hybridization (FISH) and PC targeted analysis was performed using a Bioview Duet system. Excluding the prospectively selected cases that had the targeted FISH studies, cyclin D1+ PC were identified in 20% of cases. The cyclin D1+ CLL did not appear pathologically or phenotypically distinctive, though 46% had an interfollicular growth pattern. The cyclin D1+ PCs were SOX11- and lacked CCND1 translocations and gains in 5 of 5 informative cases. The recognition of cyclin D1 expression in PC of a significant minority of CLL/SLL can be a diagnostic aid and should not lead to the diagnosis of focal mantle cell lymphoma.

Mantle cell lymphoma as a component of composite lymphoma: clinicopathologic parameters and biologic implications

Composite lymphoma is a rare circumstance in which 2 or more distinct types of lymphoma occur in a single anatomical location. Although composite lymphoma has been increasingly identified with the advent of molecular genetic techniques, this topic has only rarely been a specific focus of the medical scientific literature. In this review, we focus on mantle cell lymphoma occurring as a major pathologic component of composite lymphoma and emphasize the clinicopathologic features of these tumors and associated biologic implications. To date, 26 cases of composite lymphoma including a component of mantle cell lymphoma have been previously published. Issues of clonal relatedness between the individual lymphoma components and emerging biologic implications as well as potential diagnostic pitfalls are evaluated.

Mantle cell lymphoma with features of marginal-zone lymphoma

We present seven cases of mantle cell lymphoma with morphological features of marginal-zone lymphoma. Of particular interest, four of the patients had predominant involvement of the gastrointestinal tract. All cases displayed the translocation t(11;14)(q13;q32) and expressed cyclin D1. Cytogenetic analysis revealed trisomy 3 in one case and somatic hypermutation of immunoglobulin heavy genes could be demonstrated in two out of four cases. The latter features are reminiscent of marginal-zone lymphoma. The localization of these lymphomas mainly in the gastrointestinal tract and the higher exposure to antigens in this area may explain why this variant of mantle cell lymphoma harbours features of marginal-zone lymphoma.

Molecular characteristics of mantle cell lymphoma presenting with clonal plasma cell component

The normal counterparts of mantle cell lymphoma (MCL) are naive, quiescent B cells that have not been processed through the germinal center (GC). For this reason, although lymphomas arising from GC or post-GC B cells often exhibit plasmacytic differentiation, MCL rarely presents with plasmacytic features. Seven cases of MCL with a monotypic plasma cell (PC) population were collected from 6 centers and were studied by immunohistochemistry, fluorescence immunophenotyping and interphase cytogenetics as a tool for the investigation of neoplasms analysis, capillary gel electrophoresis, and restriction fragment length polymorphism of immunoglobulin heavy chain analysis of microdissections of each of the MCL and PC populations to assess their clonal relationship. The clinical presentation was rather unusual compared with typical MCL, with 2 cases arising from the extranodal soft tissues of the head. All MCL cases were morphologically and immunohistochemically typical, bearing the t(11;14)(q13;q32). In all cases, the PC population was clonal. In 5 of the 7 cases, the MCL and PC clones showed identical restriction fragments, indicating a common clonal origin of the neoplastic population. The 2 cases with clonal diversity denoted the coexistence of 2 different tumors in a composite lymphoma/PC neoplasm. Our findings suggest that MCL can present with a PC component that is often clonally related to the lymphoma, representing a rare but unique biological variant of this tumor.

Bortezomib resistance in mantle cell lymphoma is associated with plasmacytic differentiation

Bortezomib induces remissions in 30%-50% of patients with relapsed mantle cell lymphoma (MCL). Conversely, more than half of patients' tumors are intrinsically resistant to bortezomib. The molecular mechanism of resistance has not been defined. We generated a model of bortezomib-adapted subclones of the MCL cell lines JEKO and HBL2 that were 40- to 80-fold less sensitive to bortezomib than the parental cells. Acquisition of bortezomib resistance was gradual and reversible. Bortezomib-adapted subclones showed increased proteasome activity and tolerated lower proteasome capacity than the parental lines. Using gene expression profiling, we discovered that bortezomib resistance was associated with plasmacytic differentiation, including up-regulation of IRF4 and CD38 and expression of CD138. In contrast to plasma cells, plasmacytic MCL cells did not increase immunoglobulin secretion. Intrinsically bortezomib-resistant MCL cell lines and primary tumor cells from MCL patients with inferior clinical response to bortezomib also expressed plasmacytic features. Knockdown of IRF4 was toxic for the subset of MCL cells with plasmacytic differentiation, but only slightly sensitized cells to bortezomib. We conclude that plasmacytic differentiation in the absence of an increased secretory load can enable cells to withstand the stress of proteasome inhibition. Expression of CD38 and IRF4 could serve as markers of bortezomib resistance in MCL. This study has been registered at http://clinicaltrials.gov as NCT00131976.

Expression of sphingosine-1-phosphate receptor 1 in mantle cell lymphoma

The distribution and pathological significance of sphingosine-1-phosphate receptor 1 expression are still unclear. In this study, we evaluated sphingosine-1-phosphate receptor 1's suitability as a diagnostic marker for malignant lymphoma by immunostaining formalin-fixed paraffin-embedded sections using a well-defined commercial anti-sphingosine-1-phosphate receptor 1 antibody. Sphingosine-1-phosphate receptor 1 was strongly expressed on the surface of small lymphocytes forming primary lymphoid follicles and in the mantle zone of secondary lymphoid follicles. Microarray-based immunohistochemistry with tissue samples from 85 lymphoid malignancy cases demonstrated that sphingosine-1-phosphate receptor 1 was expressed on the surface of mantle cell lymphoma cells. Strong expression was observed in all classical mantle cell lymphoma cases involving the lymph node (19 out of 19), gastrointestinal tract (10 out of 10), bone marrow (9 out of 9), and orbita (1 out of 1). Good results were obtained even in sections where cyclin D1 signals were lost because of over-fixation and/or decalcification. One aggressive variant of mantle cell lymphoma displayed a weaker membranous staining than classical mantle cell lymphoma in the lymph node and bone marrow. In a cyclin D1-negative mantle cell lymphoma of the orbita, no conclusive result was obtained. No cases of follicular lymphoma, marginal zone lymphoma, B lymphoblastic leukemia/lymphoma, or Burkitt's lymphoma showed any significant expression, whereas 2 out of 6 chronic lymphocytic leukemia/small lymphocytic lymphomas in bone marrow, 1 out of 3 lymphoplasmacytic lymphomas in the lymph node, and 2 out of 37 diffuse large B-cell lymphomas exhibited staining. A quantitative reverse transcription polymerase chain reaction-based analysis of mantle cell lymphoma lines revealed the sphingosine-1-phosphate receptor 1 mRNA expression level to be well correlated with the results of immunocytochemistry, flow cytometry, and western blotting. Thus, sphingosine-1-phosphate receptor 1 immunohistochemistry may be useful in the histological diagnosis of mantle cell lymphoma with formalin-fixed and paraffin-embedded sections. The antigen may be particularly valuable in cases where cyclin D1 immunostaining is not successful.

Mantle cell lymphoma of the oral cavity: case series and comprehensive review of the literature

OBJECTIVE

Mantle cell lymphoma (MCL) is a rare B-cell neoplasm that has only recently been defined as a distinct entity. Because of its rarity and histologic similarities to other small cell lymphomas, the microscopic diagnosis of MCL may be challenging. This is particularly true within the oral cavity, where other lymphomas are more frequent. To date, few cases of MCL presenting within the oral cavity have been reported.

STUDY DESIGN

We present 2 new cases of MCL within the oral cavity and systematically review 7 other cases of MCL reported in the English-language literature. Historical cases were reviewed, and available data regarding morphology, special stains, demographics, clinical presentation, radiographic findings, management, and outcome were extracted. Data from our present series were then compared with the earlier published literature.

RESULTS

To the best of our knowledge, this is the largest reviewed series of MCL within the oral cavity, totaling 9 cases. The features of our cases, including histology, clinical presentation, and outcome, are consistent with the 7 earlier reported cases. The majority of oral MCLs occur in an older male population, and a high proportion occur on the palate.

CONCLUSION

We conclude that MCL of the oral cavity is an uncommon diagnosis. Most oral MCLs occur in an elderly male population and have a possible predilection for the palate. The microscopic diagnosis can be challenging, given its similar appearance to other small cell lymphomas, requiring a comprehensive immunohistochemical panel for the accurate diagnosis. Like MCL occurring in other sites in the body, the prognosis and outcome of oral MCL appears to be poor.

Clinicopathologic features of CDK6 translocation-associated B-cell lymphoproliferative disorders

Cyclin-dependent protein kinase 6 (CDK6), in cooperation with cyclin Ds, drives cell cycle progression from G1 to S phase through phosphorylation and subsequent inactivation of retinoblastoma 1 protein. Alteration of this pathway results in both nonhematologic and hematologic malignancies, which include a small subset of B-cell lymphoproliferative disorders (BLPDs). We identified 5 cases of BLPD that carried CDK6 chromosomal translocations and characterized their clinical, pathologic, immunophenotypic, and genetic features. Common clinical characteristics included marked neoplastic lymphocytosis, systemic lymphadenopathy, splenomegaly, and bone marrow involvement. Three patients were diagnosed with low-grade B-cell lymphoma and had an indolent clinical course, and 2 patients (one who transformed to large B-cell lymphoma, and the other who was initially diagnosed with a high-grade B-cell lymphoma) had an aggressive clinical course. Immunophenotypically, the neoplastic B cells expressed CD5, CDK6, and cytoplasmic retinoblastoma 1 protein in all cases, expressed phospho-RB, p27kip1, and cyclin D2 in most cases, and uniformly lacked expression of all other cyclins. In 4 cases, the CDK6 translocation partner was kappa immunoglobulin light-chain gene; and in the fifth case, the CDK6 translocation partner was unknown. These distinct clinicopathologic and cytogenetic features distinguish the CDK6 translocation-associated BLPDs (CDK6-BLPDs) from other mature B-cell lymphomas.

CD200 expression may help in differential diagnosis between mantle cell lymphoma and B-cell chronic lymphocytic leukemia

Chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL) share many features and their differential diagnosis may be challenging, especially when a leukemic picture alone is present. Monoclonal antibody panels are often useful, with CD23 being the most reliable. However, MCL diagnosis should be confirmed by immunohistochemical cyclin D1 detection, sometimes with equivocal or even negative results. Other cytofluorimetric, cytogenetics or molecular techniques are reliable but not widely available. B-CLL leukemic cells express CD200, a membrane glycoprotein belonging to the immunoglobulin superfamily. We investigated its expression on fresh neoplastic cells of 93 patients with a CD5+ lymphoproliferative disease (79 selected B-CLL and 14 MCL in leukemic phase). Although these data cannot be generalized, all B-CLL samples we examined were positive, with CD200 present on the vast majority of the cells while, in MCL patients, CD200 was expressed by a small minority of CD5+ cells in three subjects and totally absent in the remaining 11. We then examined CD200 expression on paraffin-embedded lymphoid tissues and bone marrow (BM) trephine biopsies from 23 B-CLL and 44 MCL patients. Again, all B-CLL cells were CD200+ both in lymph nodes and in BM while all MCL cells were negative. Adding CD200 in routine panels could be of diagnostic utility in excluding MCL diagnosis.

Characterization of follicular lymphoma in the small intestine using double-balloon endoscopy

Follicular lymphomas occur rarely in the gastrointestinal tract, representing only 1-3% of all gastrointestinal tract B-cell non-Hodgkin lymphomas. We describe endoscopic analysis of 3 cases of follicular lymphoma in the small intestine using double-balloon endoscopy. Double-balloon endoscopy revealed multiple nodular lesions and elevated white patches, multiple polypoid lesions, and scattered white polypoid and nodular lesions in the duodenum and small intestine. Fuji Intelligent Chromo Endoscopy demonstrated small, whitish nodules, and narrow-band imaging showed a coiled, elongated vascular pattern within the elevated lesions. These cases are the first follicular lymphomas in the small intestine evaluated using narrow-band imaging or Fuji Intelligent Chromo Endoscopy to be reported.

Focal lymphoid hyperplasia of the terminal ileum presenting mantle zone hyperplasia with clear cytoplasm. A report of three cases

We report three unusual cases of focal lymphoid hyperplasia of the ileocecal valve. The gross specimens showed thickening of the ileocecal valve. Low power magnification showed a dense lymphoid infiltrate in the mucosa and submucosa. This condition was characterized by reactive lymphoid follicles with large reactive germinal centers surrounded by a pale cuff of mantle zone lymphocytes presenting a marginal zone distribution pattern. These cells had intermediate- to- medium-sized round or slightly indented nuclei and a broad rim of clear cytoplasm. However, immunohistochemical study demonstrated that both the mantle zone lymphocytes and the pale cuff of the lymphoid cells were CD20+, sIgM+, sIgD+, CD5-, CD10-, CD23-, CD43-, Bcl-2+, Bcl-6-, CyclinD1-. The polytypic nature of these cells was demonstrated by immunohistochemistry and polymerase chain reaction. This unusual mantle cell hyperplasia with clear cytoplasm associated with focal lymphoid hyperplasia in middle-aged and elderly patients should be differentiated from the extranodal marginal zone B-cell lymphoma of mucosa associated lymphoid tissue type or mantle cell lymphoma showing a marginal zone distribution pattern. To avoid overdiagnosis and overtreatment, it is suggested that immunophenotypic and genotypic studies might be required, and careful attention should be paid to the morphologic examination.

Application of Immunohistochemistry in the Diagnosis of Non-Hodgkin and Hodgkin Lymphoma

Context.—Beginning with the immunologic classifications of Lukes and Collins and Kiel and culminating in the Revised European-American Lymphoma and World Health Organization classifications, the diagnosis of lymphoid tumors relies heavily on the determination of cell lineage, maturation, and function, based on antigen expression in addition to morphology and clinical features. Technologic advances in immunology, antibody production, genetic analysis, cloning, and the identification of new genes and proteins by microarray and proteomics have provided pathologists with many antibodies to use in routine diagnosis.

Objective.—To provide guidance to the practicing pathologist in the appropriate selection of an antibody panel for the diagnosis of lymphoma based on morphology and relevant clinical data and to avoid pitfalls in the interpretation of immunohistochemical data. Attention is given to some of the newer antibodies, particularly against transcription factors, that are diagnostically and prognostically useful.

Data Sources.—The information presented in this article is based on review of the literature using the OVID database (Ovid MEDLINE 1950 to present with daily update) and 20 years of experience in diagnostic hematopathology.

Conclusions.—Immunophenotyping is required for the diagnosis and classification of lymphoid malignancies. Many paraffin-reactive antibodies are available to the pathologist but most are not specific. To avoid diagnostic pitfalls, interpretation of marker studies must be based on a panel and knowledge of a particular antigen's expression in normal, reactive, and neoplastic conditions.

Mantle cell lymphoma presenting with unusual morphology in an adolescent female: a case report and review of the literature

We report the case of an 18-year-old female initially diagnosed with CD5-negative diffuse large B-cell lymphoma in an inguinal lymph node in 1999 who subsequently relapsed with classic-morphology mantle cell lymphoma with involvement of the bone marrow, gastrointestinal tract, and spleen in 2004. Both the 1999 and 2004 lesions were retrospectively positive for Cyclin D1 by immunohistochemistry and positive for t(11:14)(q13;q32) by fluorescence in situ hybridization, and both lesions had identical B-cell receptor gene rearrangements by polymerase chain reaction. This case of a CD5-negative large cell or pleomorphic blastoid variant of mantle cell lymphoma arising in an 18-year-old represents a very early incidence for this type of lymphoma, which is usually not seen in younger patients.

Establishment and characterization of the new splenic marginal zone lymphoma-derived cell line UCH1 carrying a complex rearrangement involving t(8;14) and chromosome 3

A new cell line, designated UCH1, was established from a patient with splenic marginal zone lymphoma (SMZL). UCH1 cells feature a mature B-cell phenotype, characterized by surface IgM +, kappa+, CD5-, CD10-, CD19+ and CD20+. The BCL2 and BCL6 genes retained their germ-line configurations and overexpression of cyclin D1 was not detected. UCH1 cells carry numerical and structural aberrations in chromosome 3, but these were too complex to be analyzed with the conventional G-banding method. Spectral karyotyping (SKY) and fluorescence in situ hybridization analysis clearly demonstrated the presence of a balanced translocation between chromosomes 8 and 14 [t(8;14)(q24;q32)] in the complex aberrations involving chromosome 3. The results of Southern blot analysis supported this finding by showing rearrangement of the c-myc gene in UCH1 cells. SKY analysis also identified a translocation involving chromosome band 18q21, to which BCL2 and MALT1 genes were assigned, suggesting their implication in the development or progression of SMZL.

Mantle cell lymphoma with plasma cell differentiation

The differentiation of B lymphocytes into plasma cells (PCs) is an antigen-mediated process that largely depends on the interaction between B cells and regulatory factors in their microenvironment. Long-lived PCs are derived from activated B cells in the germinal center (GC), whereas PC differentiation from naive B cells occurs in the extrafollicular areas and the PCs are short-lived. Consequently, lymphomas arising from post-GC B cells often exhibit plasmacytic differentiation, whereas lymphomas arising from naive B cells less commonly show plasmacytic differentiation. Herein, we report 2 cases of mantle cell lymphoma (MCL) with clonal PC differentiation. Both cases presented with the typical cytologic features of MCL and were characterized by a nodular and mantle-zone growth pattern. Clusters of clonal PCs with monotypic kappa light chain expression were identified in the centers of the tumor nodules and within reactive GCs. FICTION (Fluorescence immunophenotyping and Interphase Cytogenetics as a Tool for the Investigation Of Neoplasms) analysis demonstrated the characteristic t(11;14)(q13;q32) in both the MCL cells and clonal PCs, indicating that both cell types were derived from the same B-cell clone. These findings indicate that the clonal PC differentiation may occur within GCs in some cases of MCL.

Overlapping morphologic and immunophenotypic profiles in small B-cell lymphoma. A report of two cases

We present two cases of small B-cell lymphomas of particular diagnostic interest because the histological patterns were at variance with their immunophenotype. One of these lymphomas, involving the gallbladder and duodenum, showed a marginal zone lymphoma-like (MALT type) pattern of cellular infiltration with CD5 negativity but (unexpectedly) Cyclin D1 positivity. Fluorescence in situ hybridization analysis of this case was performed because of the aberrant expression of Cyclin D1, and was clearly positive for the Cyclin D1 gene translocation. The second case, occurring in a lymph node, showed the typical growth pattern of a follicular lymphoma but it had an atypical immunophenotype, namely, expression of Cyclin D1, CD10, and Bcl2 and focally Bcl6, accompanied by a lack of CD5 and CD23. The Cyclin D1 gene translocation was detected by fluorescence in situ hybridisation (FISH), whereas c-myc and Bcl2 genes translocation were absent. Numerical chromosomal changes, which were visualized for chromosomes 8, 11, and 18 could be correlated to the aberrant immunoprofile. In this context, we discuss the diagnostic value of Cyclin D1, CD5, CD23, CD10, Bcl6 markers revealed by immunohistochemistry, as well as the significance of detection by FISH of chromosomal translocations such as t(11;14) and t(14;18). The question still remains as to whether such cases should be designated as specific lymphoma entities or reported as unclassifiable and the chromosome aberration reported.

Cyclin D1-negative mantle cell lymphoma: a clinicopathologic study based on gene expression profiling

Cyclin D1 overexpression is believed to be essential in the pathogenesis of mantle cell lymphoma (MCL). Hence, the existence of cyclin D1-negative MCL has been controversial and difficult to substantiate. Our previous gene expression profiling study identified several cases that lacked cyclin D1 expression, but had a gene expression signature typical of MCL. Herein, we report the clinical, pathologic, and genetic features of 6 cases of cyclin D1-negative MCL. All 6 cases exhibited the characteristic morphologic features and the unique gene expression signature of MCL but lacked the t(11;14)(q13; q32) by fluorescence in situ hybridization (FISH) analysis. The tumor cells also failed to express cyclin D1 protein, but instead expressed either cyclin D2 (2 cases) or cyclin D3 (4 cases). There was good correlation between cyclin D protein expression and the corresponding mRNA expression levels by gene expression analysis. Using interphase FISH, we did not detect chromosomal translocations or amplifications involving CCND2 and CCND3 loci in these cases. Patients with cyclin D1-negative MCL were similar clinically to those with cyclin D1-positive MCL. In conclusion, cases of cyclin D1-negative MCL do exist and are part of the spectrum of MCL. Up-regulation of cyclin D2 or D3 may substitute for cyclin D1 in the pathogenesis of MCL.

Growth pattern and distribution of follicular dendritic cells in mantle cell lymphoma: a clinicopathological study of 96 patients

Mantle cell lymphoma (MCL) is an aggressive lymphoma with accepted risk factors such as proliferation markers. To date, the different follicular dendritic cell (FDC) patterns have never been analyzed in comparison with the overall survival time. Lymph node biopsy specimens from 96 patients were analyzed by conventional morphology and immunohistochemistry with antibodies against cluster differentiation (CD)20, CD5, CD23, cyclin D1, and FDC (Ki-M4P). Two groups can be distinguished with different FDC patterns: a nodular pattern in 79 cases and a diffuse pattern in 17 cases. A Kaplan-Meier analysis revealed significantly better survival for the nodular group (p=0.0312). This group was subdivided into a group with a nodular FDC pattern similar to the FDC distribution in primary follicles (PF-nodular in 72 cases) and one with a nodular FDC pattern resembling the colonization of germinal centers (GCs) by tumor cells (GC-nodular in seven cases). A Kaplan-Meier analysis showed that patients with MCL with a PF-nodular FDC pattern had a significantly better clinical outcome than patients with the other two patterns (p=0.0033). If only cases with classical cytology (n=79) were analyzed (blastoid types excluded), patients with a PF-nodular FDC pattern had a better clinical outcome (p=0.0008). The distribution of FDC in MCL is a diagnostic tool for identifying patients with a better clinical prognosis.

Mantle Cell Lymphoma Disguised as Marginal Zone Lymphoma

We report a case of mantle cell lymphoma histologically indistinguishable from marginal zone lymphoma. An 83-year-old man presented with a 9.0-cm, slowly enlarging axillary mass. Microscopically, the neoplastic process was largely interfollicular, surrounding residual follicular centers, some of which had discernible small lymphocyte mantles. Overall, the morphologic pattern was highly suggestive of marginal zone lymphoma. However, flow cytometric and immunohistochemical results, including cyclin D1 positivity, revealed an immunophenotype that fit with mantle cell lymphoma. The differential diagnosis of mantle cell lymphoma is broad, and it is well known that mantle cell lymphoma can assume a number of histologic appearances, including, infrequently, that of more indolent B-cell non-Hodgkin lymphomas. Although not pathognomonic, cyclin D1 positivity is highly specific for mantle cell lymphoma and is key in distinguishing these clinically dissimilar malignant lymphomas. In recent years, detection of cyclin D1 has expanded the recognizable histologic spectrum of mantle cell lymphoma.

Lymphoid variant of hyaline vascular Castleman's disease containing numerous mantle zone lymphocytes with clear cytoplasm

We report two unusual cases of hyaline vascular type Castleman's disease showing a pale clear cuff of mantle zone lymphocytes presenting a marginal zone distribution pattern. These cells had medium-sized round or slightly indented nuclei and a moderate amount of clear cytoplasm. The histopathologic findings in our cases were similar to those of nodal marginal zone B-cell lymphoma. However, immunohistochemistry demonstrated that both the mantle zone lymphocytes and the pale cuff of the lymphoid cells were CD20+, CD79a+, sIgM+, sIgD+, CD5-, CD10-, CD43-, CD45RO-, Bcl-2+, Bcl-6- and cyclin D1-. The polytypic nature of these cells was demonstrated by immunohistochemistry and polymerase chain reaction. Reactive lymph node lesions only rarely show mantle cell hyperplasia with clear cytoplasm. This unusual mantle cell hyperplasia with clear cytoplasm associated with a hyaline vascular type of Castleman's disease should be differentiated from nodal marginal zone B-cell lymphoma, mantle cell lymphoma and follicular lymphoma. To avoid overdiagnosis and overtreatment, it is suggested that immunophenotypic and genotypic studies might be required, and furthermore careful attention should be paid to the morphologic examination.

Aggressive B-cell lymphomas: a review based on the workshop of the XI Meeting of the European Association for Haematopathology

The generic term aggressive B-cell lymphoma includes a variety of entities, each with particular diagnostic and therapeutic issues. To define these entities better and to help confront such issues, a workshop was organized by the European Association of Haematopathology (EAHP) and the Society of Haematology during the XI Meeting of the EAHP, held in Italy in May 2002. Participants were asked to submit cases under various categories and all cases submitted were examined and reviewed by the panel members. The panel's diagnoses formed the basis for discussion at the workshop and a limited number of cases were selected to be presented in more detail and discussed during the workshop. After the workshop the panel met again to discuss the outcome, summarized in this report, which describes the panel's proposals regarding diagnostic criteria, terminology, the definition of new entities and evaluation of biological differential and new prognostic parameters.

The Value of Fluorescence In Situ Hybridization and Polymerase Chain Reaction in the Diagnosis of B-Cell Non-Hodgkin Lymphoma by Fine-Needle Aspiration

Context.—Molecular genetic analyses have been predicted to improve the diagnostic accuracy of fine-needle aspiration of B-cell non-Hodgkin lymphoma.

Objective.—To determine the value of routine molecular genetic assays, polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH), in the diagnosis of B-cell non-Hodgkin lymphoma by fine-needle aspiration (FNA).

Design.—A multiparametric method, including cytology, flow cytometry, PCR, and FISH, was prospectively evaluated in the diagnosis of B-cell non-Hodgkin lymphoma by FNA. Aspirates from 30 consecutive patients with suspected hematolymphoid malignancies were collected. All aspirates were triaged through a uniform program including cell-size analysis, B- and T-cell clonality studies, flow cytometric immunophenotyping, and bcl-1 and bcl-2 gene rearrangements by PCR and FISH. After completion of FNA evaluations, FNA results were compared with diagnoses from prior or subsequent surgical biopsies.

Results.—Monoclonal B-cell populations were detected in 18 of 20 B-cell non-Hodgkin lymphomas by flow cytometry and PCR. bcl-1 gene rearrangement was detected in 2 of 2 cases of mantle cell lymphoma. bcl-2 rearrangement was detected in 5 cases including 4 of 4 low-grade follicular lymphomas and 1 transformed follicular lymphoma. By incorporating the results of molecular genetic and ancillary diagnostics, a definitive classification was reached in 12 cases of B-cell non-Hodgkin lymphoma by FNA, including all cases of low-grade follicular lymphoma (4/4) and mantle cell lymphoma (2/2) and approximately 50% of small lymphocytic lymphoma (2/4) and large B-cell lymphoma (4/8). Ten of the 12 cases with a final classification reached by FNA had either prior or follow-up surgical biopsies, and all 10 cases showed agreement between the diagnoses rendered on FNA and surgical biopsies.

Conclusions.—With proper handling and management of specimens, FNA can routinely provide samples adequate for molecular genetic studies, in addition to cytomorphology and flow cytometry, making it possible to consistently render accurate and definitive diagnoses in a subset of B-cell non-Hodgkin lymphomas. By incorporating FISH and PCR methods, FNA may assume an expanded role for the primary diagnosis of B-cell non-Hodgkin lymphoma.

Massive hyperplasia of marginal zone B-cells with clear cytoplasm in the lymph node: a case report

An enlarged axillary lymph node from a 63-year-old woman showed proliferating marginal zone B-cells arranged in a vague nodular pattern or in band-forming aggregates throughout the cortex. Marginal zone B-cells, which also infiltrated the adjacent fatty tissue, had round or slightly indented nuclei of medium size and a moderate amount of clear cytoplasm. Immunohistochemically, these cells were CD20+, CD79a+, Bcl-2+, sIgD-, CD5-, CD10-, CD21-, CD23-, CD45RO-, Bcl-6-, and cyclin D-. A portion of the cells were sIgM- and CD43-positive. The polytypic nature of these cells was demonstrated by immunohistochemistry and polymerase chain reaction. Systemic bacterial infection appears to be the cause of marginal zone B-cell hyperplasia. This unusual marginal zone B-cell hyperplasia should be differentiated from low-grade B cell lymphomas, and particularly from nodal marginal zone B-cell lymphomas.

Prognostic impact of p27KIP1 expression in cyclin D1 positive lymphoproliferative disorders

Nodal mantle cell lymphoma (MCL) is a well-defined entity, but non-nodal leukemic cyclin D1 positive lymphoproliferative disorders have been reported and their relationship with MCL remains controversial and their prognosis heterogeneous. We prospectively studied the expression of cyclin D1 in CD5 positive leukemic B lymphoproliferative disorders at diagnosis and identified 65 cases overexpressing cyclin D1. We did not distinguish any clinical or biological criteria allowing one to identify a non-MCL group. Multivariate analysis identified age, anemia and p27kip1 expression as independent prognostic factors of survival. By univariate analysis, p27kip1 high expression proved to be the strongest predictor of prolonged survival. The median survival of p27 low expressors was 30 months, while it was not reached for p27 high expressors. A high level of p27 expression was often found associated with the absence of nodal involvement and the presence of somatic mutations, but neither of them was restricted to the p27 high expression group. In conclusion, we hypothesize that MCL and these cyclin D1 positive leukemic lymphoproliferative disorders represent a continuous spectrum of diseases. Determination of p27 expression level appears as a routine applicable test allowing identification of a subset of patients who could be considered for different therapeutic approaches.

Mantle cell lymphoma of the hard palate: a case report and review of the differential diagnosis based on the histomorphology and immunophenotyping pattern

To our knowledge, mantle cell lymphoma (MCL) has never been reported in the hard palate, but it is commonly observed in the nasopharynx and Waldeyer's tonsillar ring. MCL is characterized by a diffuse infiltrate of small lymphocytes with the expression of CD5, CD20, and cyclin D1 (Bcl-1), but not CD10. MCL presenting in the hard palate must be accurately distinguished from other forms of so-called small B-cell lymphomas-such as small lymphocytic lymphoma, follicular lymphoma, and extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue-because MCL possesses a worse prognosis. Awareness of MCL of the hard palate will prompt pathologists to perform adequate immunohistochemical analysis to aid in confirming the diagnosis.

Mantle cell lymphoma: improved diagnostics using a combined approach of immunohistochemistry and identification of t(11;14)(q13;q32) by polymerase chain reaction and fluorescence in situ hybridization

INTRODUCTION

Mantle cell lymphoma (MCL) is a clinicopathological entity characterized by an aggressive clinical course, morphological features, and overexpression of cyclin D1 due to juxtaposition of the bcl-1 locus (and CCND1 gene coding for the cyclin D1) to the IgH gene. This phenomenon is caused by t(11;14)(q13;q32). The morphological diagnosis of MCL may pose difficulties. Ancillary methods are available to support the diagnosis.

PATIENTS AND METHODS

We studied a group of 32 patients with MCL; 24 men and 8 women. The median age at the diagnosis was 64 years. We characterized the investigated group by histology, and to analyze the immunohistochemical (IHC) profile we used a panel of antibodies including anti-cyclin D1. Polymerase chain reaction (PCR) was used to detect the rearrangement of bcl-1/IgH in 26 cases (in 11 patients, the DNA was isolated from frozen tissues or from nucleated cells of bone-marrow aspirate or peripheral blood, in 15 patients we utilized paraffin-embedded material). Dual color fluorescence in situ hybridization (FISH) on interphase nuclei detecting the t(11;14)(q13;q32) was applied in all 32 cases.

RESULTS

Cyclin D1 IHC was positive in 29 of 30 cases tested (97%). In six, the result was weak and difficult to rely on to support the diagnosis. PCR revealed the fusion gene in 14 of the 26 cases (54%). The best yield was obtained from fresh and frozen samples (8 of 11 positive). Using FISH, we identified the translocation in all 32 patients, the findings being easily interpretable in 29 patients. In three cases, the intensity of red and green signals was weaker and difficult to read though the co-hybridized signals were identified. The classical pattern of the translocation was observed in 26 patients, while in 3 we found variant patterns suggesting a loss of the V segment of the IgH gene (2x) and a shift in the breakpoint region at chromosome 11 (1x).

CONCLUSION

The diagnosis of MCL should be supported by a complex laboratory approach. Interphase FISH seems a useful complementary method to morphology and IHC. It is applicable to various tissues and cells prepared as tissue imprints or histological sections.

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.

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.

Follicular hyperplasia presenting with a marginal zone pattern in a reactive lymph node lesion

Histologically, the marginal zone pattern of the lymph node is characterized by lymphoid follicles with three distinct layers. The inner layer is composed of follicular center zones, the middle layer of darkly stained mantle zones, and the outer layer of marginal zones. However, the marginal zone pattern is rarely seen in reactive lymph nodes except for mesenteric lymph nodes. We describe the clinicopathologic, immunohistochemical and genotypic findings of six cases of reactive follicular hyperplasia exhibiting the marginal zone pattern. The patients comprised three males and three females (age range 24 to 63 years; medium 56 years). Follow-up data were obtained from five patients. None of them developed malignant lymphomas during the follow-up period of from 5 to 204 months (median 68 months). Histologically, the lesion was characterized by numerous lymphoid follicles and partial distortion of lymph node structure. Varying degrees of progressive transformation of the germinal center (PTGC) were noted in the four cases. The marginal zone pattern was observed in some or most of the lymphoid follicles including PTGC. The marginal zone B cells were small to medium-sized lymphocytes with round or slightly indented nuclei and a broad rim of pale cytoplasm. Some of them had a monocytoid appearance. They were CD20+, CD79a+, sIgM+/-, sIgD-, CD5-, CD10-, CD21-, CD23-, CD43-, CD45RO-, Bcl-6-, cyclin D1-, EMA- and p53-. A portion of them were Bcl-2 positive. Occasional large lymphoid cells with round or indented nuclei and moderate amounts of cytoplasm were observed in the marginal zone in four cases. These large lymphoid cells were usually CD20 positive, but Bcl-6 negative. A small number of them contained polytypic intracytoplasmic immunoglobulins. The polytypic nature of B lymphocytes was demonstrated by immunohistochemistry and polymerase chain reaction. Recognition of unusual marginal zone hyperplasia in reactive lymph node lesions is important to avoid confusion with nodal involvement in various low-grade B cell lymphomas presenting a marginal zone distribution pattern.

The clinical and diagnostic relevance of CD23 expression in the chronic lymphoproliferative disease

BACKGROUND

CD23 antigen is a cell surface protein considered important in the differentiation of chronic lymphocytic leukemia (CLL) from other lymphoid leukemias.

METHODS

To better clarify CD23 role as a diagnostic tool, the authors retrospectively evaluated clinical and laboratory features of 372 patients who were referred to M.D. Anderson Cancer Center with a diagnosis of CLL or B-cell chronic lymphoproliferative disease.

RESULTS

Most of the patients (91%) were CD19+/CD5+. Only 6% of these CD19+/CD5+ patients were CD23-. Overall, CD23- patients had the worse prognostic features compared with CD23+ cases, including anemia (P = 0.03), massive splenomegaly (P = 0.000), high lactate dehydrogenase (P = 0.007), high beta2-microglobulin (P = 0.006), older age (P = 0.001), and male gender (P = 0.02). Surface immunoglobulin expression was moderate/strong in 19 (82%) patients, and FMC-7 was positive in 22 (96%) patients. None of the 13 patients tested for CD10 expressed the antigen. Based on morphology, of the CD23, 16 (70%) were diagnosed with mantle cell leukemia (MCL) was diagnosed in 16 (70%) CD23- patients, 3 (13%) with splenic marginal-zone leukemia, 3 (13%) with prolymphocytic leukemia (PLL) or PLL/CLL, and 1 (4%) with CLL. No cyclin D1 protein expression was noted by Western blot analysis in the one case that showed typical CLL morphology, and this patient did not require therapy. On the whole, the survival rate of CD23- patients was significantly worse than that of patients with CD23+. In contrast, 15 of 32 (49%) CD19+/CD5- patients were CD23-. CD23 negativity in this group was not associated with distinct clinical features or outcome. Eleven (73%) of these patients were classified as having splenic marginal-zone lymphoma and 4 as having follicular lymphoma.

CONCLUSIONS

These data indicate that CD23 negativity is rare in typical B-cell CLL, and CD23 negativity in patients with CD19+/CD5+ is suggestive of mantle cell leukemia a more aggressive disease with poor response to conventional therapy in which newer chemotherapy regimens such as hyper-CVAD may be more effective.

Analysis of cyclin D1 expression by quantitative real-time reverse transcription-polymerase chain reaction in the diagnosis of mantle cell lymphoma

Mantle cell lymphoma (MCL) is characterized by typical morphologic features and the CD5+, CD23-immunophenotype. However, some morphologically typical MCLs are CD23+. A t(11;14)(q13;q32) translocation is frequently found in MCL, leading to overexpression of cyclin D1. We studied the expression of cyclin D1 in 50 small cell non-Hodgkin lymphomas by real-time reverse transcription-polymerase chain reaction. Most cases with typical MCL morphologic features and immunophenotype gave a strong signalfor cyclin D1, whereas most typical chronic lymphocytic leukemias/small lymphocytic lymphomas (CLLs/SLLs) gave weak or no signals. Based on these results, we determined a threshold value for the diagnosis of cyclin D1-overexpressing MCL. Cyclin D1 expression in 17 lymphomas with conflicting data from morphologic examination and immunophenotyping was variable. The concordance of cyclin D1 measurements with morphologic features and immunophenotype in typical cases proves the usefulness of the method. Unexpectedly high values were found in few CLL/SLL cases and in many CD23+ lymphomas with MCL morphologic features.

From centrocytic to mantle cell lymphoma: a clinicopathologic and molecular review of 3 decades

Mantle cell lymphoma (MCL), described almost 3 decades ago as centrocytic lymphoma and by a variety of other names, was initially recognized morphologically. MCL is a classic illustration of how the field of hematopathology and our basic understanding of neoplasia have evolved. The advent of immunophenotypic and increasingly sophisticated genotypic and cytogenetic studies, together with clinical investigations, have led to a better practical and biologic understanding of MCL and have broader implications as well. MCL is now recognized as an aggressive, difficult to treat, B-cell lymphoma with a broader morphologic spectrum than was initially appreciated and a characteristic phenotype (CD5+, CD10-, CD23-, FMC7+). Virtually all MCLs carry the translocation t(11;14)(q13;q32) with overexpression of the involved CCND1 (cyclin D1) gene. Additional cytogenetic and molecular abnormalities have been identified, including some that are early events (such as ATM gene deletion and mutation) and others that appear to be late events (such as deletions and mutations in the negative cell cycle regulatory elements p53, p16, and p18). The latter are often associated with a blastoid morphology and more aggressive clinical course. Ongoing clinical and basic investigations including microarray analysis will undoubtedly provide additional insights into MCL and perhaps more effective and specific therapeutic modalities.

Morphological spectrum of cyclin D1-positive mantle cell lymphoma: study of 168 cases

Immunostaining for cyclin D1 is essential for reliable diagnosis of mantle cell lymphoma (MCL). However, a small number of cyclin D1-positive lymphomas other than MCL have been encountered. Our goal was to investigate the morphological spectrum of MCL as a disease entity, based on cyclin D1 overexpression. We reviewed 181 biopsy specimens obtained from 168 cases of cyclin D1-positive MCL. Typical findings were the presence of nodular (53.9% of cases) or diffuse (46.1%) histological patterns, containing mantle zone patterns (16.8%), naked germinal centers (33.5%) and perivascular hyaline deposition (83.2%). Unusual findings of residual germinal centers with a mantle cuff (four cases) and follicular colonization (two cases) were seen. High magnification showed a monotonous proliferation of tumor cells with cytological diversity including small (3.0%), intermediate (43.1%), medium (34.1%), medium-large (13.2%) and large (6.6%) cells. Pleomorphic and blastic/blastoid variants were encountered in 9.6 and 7.2% of cases, respectively. Three cases had foci of cells of considerable size, with a moderately abundant pale cytoplasm resembling marginal zone B cells. Two cases showed an admixture of cells which appeared transformed and mimicked the histology of chronic lymphocytic leukemia/small lymphocytic leukemia. In one, neoplastic mantle zones were surrounded by sheets of mature plasma cells, resembling the plasma cell type of Castleman's disease. An admixture of areas characteristic of MCL and of other larger cells, indicating histological progression or a composite lymphoma, were observed in seven cases. In high-grade lesions of five cases, nuclear staining of cyclin D1 was rarely detected. In our experience, cyclin D1 expression was also found in nine lymphomas other than MCL (five plasma cell myelomas, three Hodgkin's disease and one anaplastic large cell lymphoma). The application of cyclin D1 staining prompted us to recognize the broad morphological spectrum of MCL. MCL can be diagnosed with the application of cyclin D1 immunostaining, if careful attention is given to architectural and cytological features.

Cyclin D1 as an aid in the diagnosis of mantle cell lymphoma in skin biopsies: a case report

Mantle cell lymphoma (MCL), an uncommon and aggressive form of non-Hodgkin lymphoma, typically involves lymph nodes. It usually only secondarily involves extranodal sites. We describe an unusual case of a MCL that presented and relapsed in the earlobes. Light microscopic findings were initially regarded as suggestive of small lymphocytic lymphoma, although subsequent analysis of fresh tissue by flow cytometry led to the diagnosis of MCL. Retrospective application of a broad panel of recently developed markers suitable for analysis of routinely processed tissue yielded results that also permitted a diagnosis of MCL. If these results had been available at the time of initial presentation, they would have obviated the need for rebiopsy. Greater awareness not only of the phenotypic criteria by which lymphomas are classified but of the lymphoma markers available for evaluation of routinely processed tissue should facilitate the accurate diagnosis of diseases like MCL and minimize the risk of misdiagnosis as an indolent disorder.

Hyperplasia of mantle/marginal zone B cells with clear cytoplasm in peripheral lymph nodes. A clinicopathologic study of 35 cases

We describe 35 peripheral lymph nodes classified as mantle cell/marginal zone B-cell hyperplasia with clear cells using morphologic and immunologic findings. For the purpose of this study, we obtained clinical follow-up information and performed immunoglobulin gene rearrangement studies on paraffin sections by polymerase chain reaction. Architecturally, the nodes were suggestive of a benign process: no pericapsular infiltration, sinuses readily identified, scattered reactive follicles present, and paracortical nodular hyperplasia present. No monocytoid B cells were present. Focally, small lymphoid cells with round nuclei and clear cytoplasm (clear cells) formed monomorphic nodular, inverse follicular, and/or marginal zone patterns. Flow cytometry and immunohistochemical analysis revealed neither light chain restriction nor an aberrant B-cell phenotype. Immunoglobulin gene rearrangement studies showed a clonal band in 1 of 26 cases in which DNA was amplified. To ascertain the clinical relevance of this positive case, follow-up information was obtained 30 months after the initial biopsy; the 83-year-old woman was alive without treatment but had splenomegaly and bone marrow involvement by marginal zone B-cell lymphoma. The morphologic and immunologic criteria used for diagnosis of mantle cell/marginal zone B-cell hyperplasia with clear cytoplasm are valid; however, to rule out the possibility of occult lymphoma, immunoglobulin gene rearrangement studies and clinical follow-up are necessary.

Molecular analysis of mucosa-associated lymphoid tissue (MALT) lymphoma of ocular adnexa

Lymphomas of mucosa-associated lymphoid tissue (MALT) are a distinct subgroup of extranodal B-cell non-Hodgkin's lymphomas. Most studies have failed to demonstrate the clonal rearrangement of BCL-1, BCL-2 or c-MYC genes for MALT lymphomas. Further, alteration of the p53 gene is rarely demonstrated in low-grade MALT lymphomas, but can be detected in high-grade disease. Lymphomas of the ocular adnexa represent approximately eight percent of all extranodal lymphomas, most of which are MALT lymphomas, but few studies had explored the alterations of BCL-1, BCL-2, c-MYC and p53 genes specifically for ocular MALT lymphomas. We investigated the changes to BCL-1, BCL-2, c-MYC and p53 genes in these lymphomas for Taiwanese patients. Clonal rearrangement for immunoglobulin heavy-chain (IgH), BCL-1, BCL-2, c-MYC and p53 genes was examined for 16 cases of ocular MALT lymphoma. Restriction-length polymorphism and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) of the DNA, corresponding to exons 5 through 9, followed by DNA sequencing, were utilized to analyze the possible mutations of the p53 gene for these tumors. Thirteen of the cases revealed rearranged IgH genes using Southern blotting or PCR. No rearrangement of BCL-1, BCL-2, c-MYC or p53 genes was discovered, with point mutation of the p53 gene in one case. As for other types of MALT lymphomas, BCL-1, BCL-2 and c-MYC genes are not implicated in the pathogenesis of the ocular sub-group. Although alteration of the p53 gene is rare for low-grade ocular MALT lymphoma, its role in disease progression merits further research.

Pathologic diagnosis of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a clinicopathologic entity with distinctive morphologic and immunophenotypic features and a characteristic cytogenetic abnormality, the t(11;14)(q13;q32). Although MCL was recognized over 30 years ago, a lack of consensus regarding its morphologic features precluded its inclusion into non-Hodgkin's lymphoma (NHL) classification schemes until relatively recently. An accurate diagnosis of MCL is of great importance, since this tumor generally carries a poor prognosis and requires more aggressive and novel treatment regimens. In this article, we briefly overview the clinical features of MCL and then focus on the pathologic diagnosis of MCL, emphasizing morphologic findings and various ancillary techniques useful in the diagnostic workup. Involvement of lymph nodes and other sites, such as the spleen, liver, gastrointestinal tract, Waldeyer's ring, bone marrow, peripheral blood, and cerebrospinal fluid are reviewed. The diagnosis of high-grade variants of MCL is a particular challenge, as these tumors exhibit a broad spectrum of morphologic findings that can be misinterpreted as other types of NHL. The molecular basis of MCL is also briefly reviewed to highlight the biologic role of the t(11;14) and cyclin D1 overexpression in this tumor and the value of immunophenotypic and molecular methods for their detection as diagnostic aids.

Histological and immunoglobulin VH gene analysis of interfollicular small lymphocytic lymphoma provides evidence for two types

Interfollicular small lymphocytic lymphoma (I-SLL) has not been well characterized and its relationship to small lymphocytic lymphoma (SLL) or chronic lymphocytic leukemia (CLL) is uncertain. Moreover, two different proliferation center growth patterns have been described with respect to reactive germinal centers. In this study, we evaluate the histological and immunophenotypic features of 13 cases of I-SLL and immunoglobulin heavy chain variable (VH) gene sequences from 10 cases. Immunophenotypic analyses indicate that cases showing either growth pattern have the same CD5-positive B cell phenotype typical of SLL or CLL. Sequence analysis revealed the use of VH, D, and J gene segments often found in CLL, although there may be more frequent use of J6. Similar to recent studies of CLL, there were approximately equal numbers of cases with either mutated or unmutated VH genes without evidence of ongoing mutation, consistent with I-SLL having either a naïve or memory B cell origin. Interestingly, the mutational status of the I-SLL VH genes seemed to correlate with the two different histological growth patterns. These studies support the proposal that I-SLL represents SLL/CLL and suggest the recently proposed two types of CLL originating from either memory or naïve B cells may have different histological patterns of growth in lymph nodes that show architectural preservation.

Classification of small B-cell lymphoid neoplasms using a paraffin section immunohistochemical panel

Immunophenotypic analysis is critical in categorizing small B-cell neoplasms; however, many recommended antibody panels have required fresh or frozen tissue. Many paraffin-reactive antibodies are now available but have been studied mostly in isolation. Therefore, the utility of a panel of paraffin-reactive antibodies in differentiating small B-cell neoplasms was investigated. Paraffin-embedded sections of small lymphocytic lymphoma/B-chronic lymphocytic leukemia (SLL/B-CLL; 12), mantle cell (MCL; 15), follicular (FL; 11), and marginal zone B-cell (MZL; eight) lymphomas were stained with CD20/L26, CD3, CD43/DF-T1 or Leu22, CD5/4C7, CD23/BU38, cyclin D1/H295, and CD10/56C6 antibodies. For select antibodies, results were compared to flow cytometric data (FC). Formalin and B5 fixation were also compared. Seven of 11 SLL/B-CLL were CD43+ CD5+ CD23+ cyclin D1- CD10-; seven of 11 MCL were CD43+ CD5+ CD23- cyclin D1+ CD10-; nine of 10 FL were CD43- CD5- CD23- cyclin D1- CD10+; and five of six MZL were CD43+ CD5- CD23- cyclin D1- CD10-. CD5, CD23, and CD10 stains showed sensitivities of 81, 88, and 100%, respectively, compared to FC. With B5 fixation, cyclin D1 was more often negative and CD5 more often equivocal. A panel of paraffin-reactive antibodies aids in classification of small B-cell neoplasms, although a small number of cases have indeterminate phenotypes and MZL have no defining features. CD5 separates most SLL/B-CLL and MCL from FL and MZL. CD23 separates SLL/B-CLL from most MCL, but cyclin D1 is most important for identifying MCL. CD10 positivity distinguishes most FL from other small B-cell lymphoid neoplasms.

Increased proteasome degradation of cyclin-dependent kinase inhibitor p27 is associated with a decreased overall survival in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive neoplasm characterized by the deregulated expression of cyclin D1 by t(11;14). The molecular mechanisms responsible for MCL's clinical behavior remain unclear. The authors have investigated the expression of p53, E2F-1, and the CDK inhibitors p27 and p21 in 110 MCLs, relating their expression to proliferative activity (Ki-67). For comparison, they have similarly analyzed low-grade (12 MALT, 16 CLL/SLL) and high-grade (19 DLCL) lymphomas. p53 was detected more frequently in large-cell MCL (l-MCL; 5 of 7) than in classical MCL (s-MCL; 13 of 103) and DLCL (8 of 19). In MCL and DLCL, the percentage of E2F-1+ nuclei was high, correlating with high Ki-67 expression. Most MCLs (91 of 112) and DLCLs (12 of 19) showed a loss of p27; MALT and CLL/SLL, however, were p27 positive. Reverse transcription–polymerase chain reaction and in vitro protein degradation assays demonstrated that MCLs have normal p27 mRNA expression but increased p27 protein degradation activity via the proteasome pathway. Correlation of MCL p53 and p27 expression with clinical data showed an association between reduced overall survival rates and the overexpression of p53 (P = .001), the loss of p27 (P = .002), or both. Loss of p27 identified patients with a worse clinical outcome among p53 negative cases (P = .002). These findings demonstrated that MCL has a distinct cell cycle protein expression similar to that of high-grade lymphoma. The loss of p27 and the overexpression of p53 in MCL are prognostic markers that identify patients at high risk. The demonstration that low levels of p27 in MCL result from enhanced proteasome-mediated degradation should encourage additional clinical trials. (Blood. 2000;95:619-626)