Histopathology of malignant lymphomas

Non-chemotherapy Options for Newly Diagnosed Mantle Cell Lymphoma

OPINION STATEMENT

Mantle cell lymphoma is a rare and incurable non-Hodgkin lymphoma with a heterogenous clinical presentation. Typically, treatment consists of frontline chemoimmunotherapy induction with or without autologous stem cell transplant (ASCT) as consolidation. However, this approach has the propensity to increase short- and long-term toxicities, such as secondary malignancies, without being curative. Genomic profiling of MCL will allow for greater impact of new targeted therapies in the future and may become a helpful tool to guide treatment. Based on the data discussed, use of non-chemotherapy options may become the preferred approach for frontline therapy as opposed to conventional chemotherapy and hematopoietic stem cell transplants.

Mantle cell lymphoma and its management: where are we now?

Mantle cell lymphoma is a relatively new recognized hematological malignant disease, comprising of 2.5–6% non-Hodgkin’s lymphomas. The complexity of its clinical presentations (nodular pattern, diffuse pattern, and blastoid variant), variety in disease progression, and treatment response, make this disease a research focus to both experimental oncology and clinical oncology. Overexpression of cyclin D1 and chromosome t(11,14) translocation are the known molecular biomarkers of this disease. Mantle cell international prognostic index (MIPI), ki-67 proliferation index, and TP53 mutation are emerging as the prognostic biomarkers. Epigenetic profile variance and SOX11 gene expression profile correlate with treatment response. Over the years, the treatment strategy has been gradually evolving from combination chemotherapy to combination of targeted therapy, epigenetic modulation therapy, and immunotherapy. In a surprisingly short period of time, FDA specifically approved 4 drugs for treating mantle cell lymphoma: lenalidomide, an immunomodulatory agent; Bortezomib, a proteasome inhibitor; and Ibrutinib and acalabrutinib, both Bruton kinase inhibitors. Epigenetic agents (e.g. Cladribine and Vorinostat) and mTOR inhibitors (e.g. Temsirolimus and Everolimus) have been showing promising results in several clinical trials. However, treating aggressive variants of this disease that appear to be refractory/relapse to multiple lines of treatment, even after allogeneic stem cell transplant, is still a serious challenge. Developing a personalized, precise therapeutic strategy combining targeted therapy, immunotherapy, epigenetic modulating therapy, and cellular therapy is the direction of finding a curative therapy for this subgroup of patients.

Malignant Histiocytosis: A Clinicopathologic Study of 18 Consecutive Cases

The clinical records and histologic material of 18 consecutive patients with malignant histiocytosis were reviewed. The age of the patients ranged from 20 months to 72 years (median 35 years). There were 14 males and 4 females (3.5:1). Lymph node and liver enlargement, fever, and skin nodules were the most common physical findings; and leukocytosis was frequently the most abnormal laboratory test. Seven of 18 patients died, and their survival ranged from 1 to 15 months (median 8 months) after histopathologic diagnosis. The histologic findings on lymph nodes, spleen, liver, bone marrow, and skin were investigated with special reference to both the cellular composition and the pattern of lymph node involvement. Vascular invasion of small perinodal vessels was observed in 4 fatal cases. The absence of capsular invasion and the lack of cohesiveness among atypical proliferating histiocytes of malignant histiocytosis appeared to be inconstant. Sequential lymph node biopsies revealed in later stages the extension of the histiocytic proliferation from the sinuses into the cords and the complete obliteration of the nodal structures. The radiologic investigations yielded numerous pathologic findings that were consistent with the dissemination of the disease. Complete response to initial treatment was achieved in patients that were treated with radiotherapy and/or chemotherapy. Complete response with chemotherapy was achieved only when the treatment included adriamycin. The histologic and clinical features of the present series provide further evidence for the recognition of malignant histiocytosis as a distinct clinical and pathologic entity.

Mantle cell lymphoma: 2017 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood and bone marrow with a short remission duration to standard therapies and a median overall survival (OS) of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t (11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The MCL International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median OS for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytotoxic Regimen followed by autologous stem cell transplantation should be considered. Rituximab maintenance after autologous stem cell transplantation has also improved the progression-free and overall survival. For older symptomatic MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. In addition, rituximab maintenance therapy may prolong the progression-free survival. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), lenalidamide (anti-angiogenesis) and Ibruitinib (Bruton's Tyrosine Kinase [BTK] inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients. Clinical trials with novel agents are always a consideration for MCL patients.

Mantle cell lymphoma: 2015 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood and bone marrow with a short remission duration to standard therapies and a median overall survival (OS) of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t (11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The MCL International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median OS for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytotoxic regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. In addition, rituximab maintenance therapy may prolong the progression-free survival. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), lenalidamide (anti-angiogenesis) and Ibruitinib (Bruton's Tyrosine Kinase [BTK] inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients. Clinical trials with novel agents are always a consideration for MCL patients.

Clinicopathologic features and management of blastoid variant of mantle cell lymphoma

The blastoid variant of mantle cell lymphoma (MCL), which accounts for less than one-third of MCL, may arise de novo or as a transformation from the classical form of MCL. Blastoid variant, which predominantly involves men in their sixth decade, has frequent extranodal involvement (40-60%), stage IV disease (up to 85%) and central nervous system (CNS) involvement. Diagnosis relies on morphological features and is challenging. Immunophenotyping may display CD23 and CD10 positivity and CD5 negativity in a subset. Genetic analysis demonstrates an increased number of complex genetic alterations. Blastoid variant responds poorly to conventional chemotherapy and has a short duration of response. Although the optimal therapy remains to be established, CNS prophylaxis and the use of aggressive immunochemotherapy followed by autologous stem cell transplant may prolong the remission rate and survival. Further studies are crucial to expand our understanding of this disease entity and improve the clinical outcome.

Mantle cell lymphoma: 2013 Update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The Mantle Cell Lymphoma International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor) or lenalidamide (anti-angiogenesis) are approved agents. Clinical trials with Ibruitinib (Bruton's Tyrosine Kinase inhibitor) or Idelalisib (PI3K inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

Mantle cell lymphoma: 2012 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The mantle cell lymphoma international prognostic index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 and 29 months for the high-risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), BTK inhibitors or CAL-101 (B-cell receptor inhibitors) or lenalidamide (antiangiogenesis) have clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

Outcome of deferred initial therapy in mantle-cell lymphoma

PURPOSE

Treatment of mantle-cell lymphoma (MCL) is nonstandardized, though patients are commonly treated immediately at diagnosis. Because data on observation, or "watch and wait," have not been previously reported, we analyzed the outcome of deferred initial therapy.

PATIENTS AND METHODS

Inclusion criteria in this retrospective analysis were a diagnosis of MCL between 1997 and 2007 and known date of first treatment. Hospital and research charts were reviewed for prognostic and treatment-related information. Date of death was derived from hospital records and confirmed using an online Social Security death index.

RESULTS

Of 97 patients with MCL evaluated at Weill Cornell Medical Center, 31 patients (32%) were observed for more than 3 months before initial systemic therapy, with median time to treatment for the observation group of 12 months (range, 4 to 128 months). The observation group (median follow-up, 55 months) had a median age of 58 years (range, 40 to 81 years). Prognostic factors in assessable patients included advanced stage (III/IV) in 75%, elevated lactate dehydrogenase in 25%, and intermediate- or high-risk Mantle Cell International Prognostic Index in 54%. Better performance status and lower-risk standard International Prognostic Index scores were more commonly present in those undergoing observation. Although time to treatment did not predict overall survival in a multivariate analysis, the survival profile of the observation group was statistically superior to that of the early treatment group (not reached v 64 months, P = .004).

CONCLUSION

In selected asymptomatic patients with MCL, deferred initial treatment ("watch and wait") is an acceptable management approach.

Synchronous adenocarcinoma and mantle cell lymphoma of the stomach

Synchronous occurrence of mantle cell lymphoma (MCL) and gastric cancer in the same patient has not yet been reported in the English literature. MCL comprises 2.5-7% of non-Hodgkin's lymphomas and is characterized by a poor prognosis with a median survival probability of 3-4 years in most series. A 62-year-old man was referred to our hospital for evaluation of an abnormal gastric lesion. The endoscopic finding was compatible with type IIc early gastric cancer (EGC) in the middle third of the stomach, and a biopsy of the lesion proved to be carcinoma. Radical total gastrectomy with splenectomy and Roux-en-Y esophagojejunostomy were performed. The resected specimen revealed two grossly separated lesions. Postoperative histological examination reported both adenocarcinoma and MCL. Immunohistochemical staining showed positivity for CD5, CD20, and cyclin D1 in the infiltrated lymphoid cells. MCL is an aggressive non-Hodgkin's lymphoma, and the current treatment approach is still unsatisfactory. Further advancements in the understanding of the synchronous occurrence of both diseases, and more efforts on investigations of treatment are needed.

Real-time quantitative RT-PCR of cyclin D1 mRNA in mantle cell lymphoma: comparison with FISH and immunohistochemistry

Presence of the balanced translocation t(11;14)(q13;q32) and the consequent overexpression of cyclin D1 found in mantle cell lymphoma (MCL) has been shown to be of important diagnostic value. Although many molecular and immunohistochemical approaches have been applied to analyze cyclin D1 status, correlative studies to compare different methods for the diagnosis of MCL are lacking. In this study, we examined 39 archived paraffin specimens from patients diagnosed with a variety of lymphoproliferative diseases including nine cases meeting morphologic and immunophenotypic criteria for MCL by: (1) real-time quantitative RT-PCR to evaluate cyclin D1 mRNA expression; (2) dual fluorescence in situ hybridization (FISH) to evaluate the t(11;14) translocation in interphase nuclei; and (3) tissue array immunohistochemistry to evaluate the cyclin D1 protein level. Among the nine cases of possible MCL, seven cases showed overexpression of cyclin D1 mRNA (cyclin D1 positive MCL) and two cases showed no cyclin D1 mRNA increase (cyclin D1 negative "MCL-like"). In six of seven cyclin D1 positive cases, the t(11;14) translocation was demonstrated by FISH analysis; in one case FISH was unsuccessful. Six of the seven cyclin D1 mRNA overexpressing cases showed increased cyclin D1 protein on tissue array immunohistochemistry; one was technically suboptimal. Among the two cyclin D1 negative MCL-like cases, FISH confirmed the absence of the t(11;14) translocation in both cases. All other lymphoproliferative diseases studied were found to have low or no cyclin D1 mRNA expression and were easily distinguishable from the cyclin D1 overexpressing MCLs by all three techniques. In addition, to confirming the need to assess cyclin D1 status, as well as, morphology and immunophenotyping to establish the diagnosis of MCL, this study demonstrates good correlation and comparability between measure of cyclin D1 mRNA, the 11;14 translocation and cyclin D1 protein.

Mantle cell lymphoma: a biological and therapeutic paradigm

Recent classifications of non-Hodgkin's lymphomas (NHL) have strictly individualized mantle cell lymphoma (MCL) on the basis of a combination of morphologic, immunophenotypic, and cytogenetic criteria. This clinicopathological entity now appears to be a biological and therapeutic model for the understanding and treatment of hematologic malignancies. The lymphomogenesis of MCL could be explained by a series of genetic abnormalities which occur at different steps of the disease: (1) mutation and/or loss of the ATM gene in centrocytic cells of the follicle mantle of lymph nodes, leading to the loss of ATM function, particularly involved during the V(D)J recombination process; (2) a t(11;14)(q13;q32) translocation which induces a constitutive Bcl-1/PRAD1/CCND1 expression, responsible for cell cycle activation of centrocytic cells characteristic of typical MCL; and (3) secondary additional chromosomal aberrations, such as a p53 mutation, observed in blastic transformation of MCL. Despite the evaluation of a number of treatment modalities, the optimal management of MCL has not yet been defined: (1) conventional and intensified chemotherapy and monoclonal anti-CD20 antibody therapy appear to be effective for the improvement of response rates and event-free or overall survivals; (2) combinations of different treatment modalities must be tested to modify the natural dismal outcome of the disease; and (3) innovative approaches should be developed. From this point of view, all these considerations offer a fine opportunity for extensive medical reflection.

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.

Biology and management of mantle cell lymphoma

Mantle cell lymphoma is a distinct subtype and accounts for approximately 5 to 10% of non-Hodgkin lymphomas. The malignant cells express pan B-cell markers, including CD19, CD20 and CD22, and the T-cell marker CD5, whereas CD10 and CD23 expression are usually absent. By cytogenetic analysis, the t(11;14)(q13;q32) translocation is commonly observed, resulting in overexpression of cyclin D1. This entity often combines some unfavorable clinical features of the indolent and aggressive lymphoma subtypes, as it is generally incurable and relatively aggressive. It is most commonly observed in men 50 to 70 years of age and is characterized by disseminated disease, usually involving lymph nodes, bone marrow, and spleen. Frequently, there is extranodal involvement including the gastrointestinal tract. These tumors are incurable with the currently available therapeutic options, with usual time to progression after chemotherapy of approximately 1 year. Newer chemotherapy regimens (including stem cell transplantation) and monoclonal antibody-based therapies have shown limited evidence of additional benefit. Overall, the prognosis for patients with mantle cell lymphoma remains poor, and novel strategies are needed.

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.

Mantle cell lymphoma

OBJECTIVE

This article summarizes the most useful ancillary immunohistochemical and molecular assays for use in the diagnosis of mantle cell lymphoma.

DATA SOURCES

The English language literature was surveyed, with an emphasis on recent publications, for articles presenting key advances in the molecular characterization of mantle cell lymphomas and for series of cases testing the utility of molecular diagnostic tests. The authors' series of 26 small B-cell lymphomas, analyzed for the cyclin D1 protein by paraffin immunohistochemistry and for t(11;14) by polymerase chain reaction, is included.

CONCLUSIONS

Mantle cell lymphoma, a B-cell lymphoma now recognized in the 1994 Revised European-American Classification of Lymphoid Neoplasms (REAL) classification, is a relatively aggressive lymphoma with a poor prognosis. Its characteristic t(11;14)(q13;q32) translocation has a role in oncogenesis and has been exploited for molecular diagnostic tests, but these tests vary in sensitivity, specificity, and ease of use. Improved immunohistochemical tests are sufficient to confirm the diagnosis in most cases. Conventional cytogenetics and molecular diagnostic tests for t(11;14)-Southern blot and polymerase chain reaction analysis-may be helpful in selected cases, but are laborious or of limited sensitivity. Other methods, such as fluorescence in situ hybridization, need further development to provide faster, more sensitive diagnosis.

Differential expression of cyclin D1 in mantle cell lymphoma and other non-Hodgkin's lymphomas

Mantle-cell lymphomas are associated with a characteristic chromosomal translocation, t(11;14)(q13;q32). This translocation involves rearrangement of the bcl-1 proto-oncogene from chromosome 11 to the immunoglobulin heavy chain gene on chromosome 14, resulting in an overexpression of cyclin D1 mRNA (also known as bcl-1 and PRAD1). In the current study performed on paraffin-embedded tissue, cyclin D1 mRNA could be detected in 23 of 24 mantle-cell lymphomas by reverse transcription polymerase chain reaction (RT-PCR) whereas only 9 of 24 demonstrated a t(11;14) by PCR. However, we also found that cyclin D1 mRNA could be detected in the majority (11 of 17, 65%) of non-mantle-cell lymphomas and in a minority of atypical lymphoid hyperplasias (3 of 7, 43%). Cyclin D1 mRNA expression was not observed in floridly reactive lymph nodes (0 of 9) or in unstimulated lymph nodes (0 of 20), suggesting that it is a sensitive adjunct marker for malignant lymphoproliferative processes, but not specific for mantle-cell lymphoma. A semiquantitative RT-PCR assay was developed that compared the ratio of cyclin D1 to the constitutively expressed gene beta2-microglobulin. Using this assay on a limited number of our specimens, cyclin D1 overexpression in mantle-cell lymphoma could be reliably distinguished from its expression in other non-Hodgkin's lymphomas. This assay for cyclin D1 expression, designed for formalin-fixed, paraffin-embedded tissue, was a very sensitive and specific marker for mantle-cell lymphoma.

Blastic variant of mantle-cell lymphoma: cytomorphologic, immunocytochemical, and molecular genetic features of tissue obtained by fine-needle aspiration biopsy

Mantel-cell lymphoma (MCL) is a rare type of non-Hodgkin's lymphoma that has a moderately aggressive clinical course, generally between that a low-grade and intermediate-grade lymphomas. However, a small subset of MCLs, the so-called "blastic" variant, exhibits a poor prognosis and an aggressive clinical course. We describe a case of blastic MCL that occurred in a 64-yr-old man and that was diagnosed and accurately subclassified as blastic MCL on the basis of an fine-needle aspiration (FNA) biopsy. The aspirate smears showed a monotonous population of intermediate-sized lymphocytes with irregular nuclear contours, finely dispersed nuclear chromatin, and inconspicuous nucleoli. Material was obtained by FNA for ancillary studies (immunocytochemical stains, flow cytometry, cytogenetics, image analysis, and molecular studies) that supported the diagnosis of blastic MCL. Surgical biopsy confirmed the diagnosis. These findings underscore the utility of FNA in diagnosing lymphomas, particularly when the cytomorphologic examination is combined with appropriate ancillary studies.

Bone marrow and peripheral blood involvement in mantle cell lymphoma

The peripheral blood smears, bone marrow aspirates and biopsies of 46 patients with mantle cell lymphoma were reviewed. The diagnosis of mantle cell lymphoma was established in all cases on extramedullary tissue samples using standard morphologic, phenotypic and molecular genetic criteria. 27/35 patients (77%) had circulating lymphoma cells (median 200%m of all circulating white blood cells; range 5-90%) identified by morphology at some point during the course of their disease. No statistical difference in survival was detected in patients with or without peripheral blood involvement. Lymphoma was identified in bone marrow aspirate specimens from 33/40 patients (83%) and in bone marrow biopsy specimens from 39/43 patients (91%). The pattern of marrow biopsy involvement was nodular (31 cases; 82%), interstitial (19 cases; 50%), paratrabecular (17 cases, 45%) and diffuse (12 cases; 32%). Although the median survival of patients with > or = 50% bone marrow involvement was 13 months, and the median survival of patients with < or = 50% was 49 months; no statistically significant differences between these small subgroups were observed. Mantle cell lymphoma frequently involves the peripheral blood and bone marrow. Its appearance is distinctive but variable, and immunophenotypic studies as well as morphologic confirmation by a biopsy of tissue other than bone marrow is still required for diagnosis.

Application of interphase cytogenetics for the detection of t(11;14)(q13;q32) in mantle cell lymphomas

BACKGROUND

The chromosomal translocation t(11;14)(q13;q32) is the hallmark of mantle cell lymphoma (MCL) in which it can be detected cytogenetically in about 75% of cases. The t(11;14) translocation juxtaposes the bcl-1 locus in chromosome band 11q13 next to the IgH locus in chromosome band 14q32 and, thus, leads to deregulation of the cell cycle regulatory protein cyclin D1, which is encoded by the CCND1 gene localized at the telomeric border of the bcl-1-locus. MCL has the worst prognosis of all low-grade non-Hodgkin's lymphomas (NHL). In some instances, however, histopathologic differentiation between MCL and other low-grade B-cell NHL is difficult. Therefore, detection of the t(11;14) translocation is of essential diagnostic value for the risk-adjusted management of patients with MCL. Unfortunately, chromosome analyses are frequently hampered by the low yield and quality of tumor metaphases. As the 11q13 breakpoints are scattered over a region of more than 120 kb the application of molecular genetic techniques is also limited.

PATIENTS AND METHODS

We established an interphase fluorescence in situ hybridization (FISH) approach for the detection of the t(11;14) translocation by use of a cosmid probe hybridizing to the IgH constant region and a YAC spanning the bcl-1 region. Cells containing a t(11;14) translocation show a colocalisation of the signals for IgH and bcl-1. Eight control samples and 15 MCL specimens were investigated.

RESULTS

According to our control studies, samples containing more than 10% of cells with this signal constellation can be diagnosed as carrying a clonal t(11;14) translocation. All eleven MCL found to carry the t(11;14) translocation by chromosome analysis were positive in our FISH assay. Additionally, two of four MCL lacking a clonal t(11;14) translocation by chromosome analysis were shown to carry this aberration in 14% and 37% of interphase nuclei. Southern blot data indicate that our FISH assay reliably detects the t(11;14) translocation irrespective of the location of the breakpoints within the bcl-1 region.

CONCLUSIONS

The described interphase FISH assay provides a reliable and routinely applicable tool for diagnosis of the t(11;14) translocation.

Mantle cell lymphoma: presenting features, response to therapy, and prognostic factors

BACKGROUND

The goal of this study was to analyze the presenting features, natural history, and prognostic factors in 59 patients with well characterized mantle cell lymphoma (MCL).

METHODS

Cases were classified as nodular or diffuse and as typical or blastic variants. Age, performance status (PS), histologic variants, mitotic index (MI), hematologic parameters, tumor extension data, and International Prognostic Index (IPI) were recorded and evaluated for prognosis.

RESULTS

The median age of the patients was 63 years (range, 39-83 years), and the male to female ratio was 3:1. Fifty-three patients had typical histology (3 nodular and 50 diffuse), and 6 had the blastic variant. Approximately 95% of patients presented with advanced stage disease (Ann Arbor Stage III-IV). Leukemic expression was observed in 58%. Complete and partial response rates were 19% and 46%, respectively. Parameters associated with lower response rate were Stage IV, high/intermediate or high risk IPI, and increased lactate dehydrogenase (LDH) level. In the logistic regression analysis, high LDH level and Stage IV disease were associated independently with lower response rate. Median survival was 49 months. Parameters associated with a short survival were: poor PS, splenomegaly, B-symptoms, MI > 2.5, leukocyte count > 10 x 10(9)/L, high LDH level, blastic variant, and high/intermediate or high risk IPI. In the Cox proportional hazards regression model, only poor PS (relative risk [RR] = 3.3; P = 0.002), splenomegaly (RR = 2.8; P = 0.007), and MI > 2.5 (RR = 2.4; P = 0.012) were associated with short survival.

CONCLUSIONS

In this series, patients with MCL presented with advanced stage and extranodal involvement. Only a minority of patients achieved a complete response. The median survival was 4 years, with PS, splenomegaly, and MI being the most important factors predicting survival. These results show clearly that more effective therapies for MCL are needed.

A Southwest Oncology Group perspective on the Revised European-American Lymphoma classification

In recent years several new morphologic entities and a new classification system, Revised European-American Lymphoma Classification (REAL), have been proposed which affect the nomenclature and classification of lymphoid malignancies. This article reviews some of the features of the more common new entities, places these entities in immunologic context, explores the clinical utility of these entities, and provides a working clinical organization to the names.

Mantle cell lymphomas: characteristics, natural history and prognostic factors of 45 cases

We reviewed 77 cases considered as lymphocytic lymphomas of intermediate differentiation or diffuse centrocytic lymphomas. Forty-five cases were diagnosed as mantle cell lymphoma (MCL). The architectural pattern was diffuse in 95%, 8 cases presented large blastoid cells and CD5 positivity was observed in 28/34 cases. Of 20 cases studied, 8 presented a t(11;14)(q13;q32). Patient characteristics were: median age 59 years, B symptoms in 38%, 87% stages III-IV, bone marrow involvement in 67% with peripheral leukemic cells in 24%. Forty-four patients were treated with chemotherapy and 7 received radiotherapy. The complete response (CR) rate was 58%. Of the 26 CR, 19 relapsed at a median of 15 months. Disease-free survival was 42% and overall survival was 73% at 3 years. In a univariate analysis, overall survival was related to liver and bone marrow involvement, the presence of peripheral lymphomatous cells and achieving a complete response.

Clinicopathologic study of PRAD1/cyclin D1 overexpressing lymphoma with special reference to mantle cell lymphoma. A distinct molecular pathologic entity

Mantle cell lymphomas (MCLs) are frequently associated with the overexpression of PRAD1/cyclin D1, activated by 11q13 translocation and its molecular counterpart BCL-1 gene rearrangement. We recently described the correlation of positive nuclear staining using monoclonal antibody against a PRAD1/cyclin D1 product with mRNA overexpression in MCLs. In the present study, we immunohistochemically investigated the PRAD1/cyclin D1 protein in a large series of 334 lymphoproliferative disorders, including 39 cases of MCLs on paraffin sections. Based on the cyclin D1 positivity, CD5 expression, and the morphologic features of the tumor tissue, four groups of MCL-related lesions were identified among the B-cell lymphomas examined: 36 cases with cyclin D1 overexpression, 35 (95%) of which exhibited CD5-positivity and MCL-morphology (Group 1); four cases of lymphomas with MCL morphology and CD5 expression but lacking cyclin D1 overexpression (Group II); four cases of lymphomas without cyclin D1 overexpression and surface CD5 but that fall within the morphologic boundaries of MCLs (Group III); and 11 cases of CD5-positive diffuse large cell lymphomas without cyclin D1 overexpression (Group IV). The Group I cases demonstrated quite homogeneous clinicopathologic features identical to those of MCLs. This group showed a poor prognosis (11% had 5-year survival), which is highly contrasted with that of Group II (100%). Although the four groups of MCL-related lesions sometimes overlapped in their histologic or phenotypic spectrums, each appeared to show distinct clinicopathologic and prognostic profiles. Our study provides a basis for further clarification of the nature of the neoplasms of Groups II, III, and IV. Moreover, this comprehensive study may indicate that the overexpression of PRAD1/cyclin D1 is biologically essential to defining MCLs.

Mantle cell lymphoma. A morphological, immunohistochemical and molecular genetic study

In order to identify helpful markers in the classification of mantle cell lymphoma, a morphological, immunohistochemical and molecular genetic analysis of 41 cases of NHL, originally referred to us as CC, ILL or IDL, was performed. We revised these lymphomas using the strict morphological criteria described in the updated Kiel classification and the more recently described criteria for MCL. The term MCL was used to designate the small lymphocytic B-cell NHL, previously referred to as CC or ILL/ IDL. This revision yielded 20 MCL, 8 CLL, 3 Cb/Cc, 1 CB, 6 IC and 3 MALT lymphomas. The presence of scattered histiocytes was seen in 90% of MCL and 5% of the other cases. No other morphological parameter, besides the used criteria, differentiated between MCL and similar small lymphocytic B cell lymphomas. Helpful immunohistochemical markers to distinguish MCL from similar small lymphocytic lymphomas were CD5+, CD10-, CD23- and Alkaline Phosphatase+. Large fields of dendritic reticulum cells, often in a loose and disrupted arrangement were seen in 82% of MCL and in 19% of the other lymphomas. Analysis with Southern blotting showed a rearrangement in the BCL-1 locus in 12/20 cases of MCL but not in the other 21 lymphomas. Although very specific for MCL, Southern blotting to detect BCL-1 rearrangements is, due to the large number of probes necessary, not of great help in daily practice for routine diagnostic purposes. We conclude that using strict morphological criteria, the diagnosis MCL can be made reliably and that immunophenotyping is helpful in supporting the diagnosis.

PRAD1/Cyclin D1 gene overexpression in mantle cell lymphoma

The t(11;14) (q13;q32) translocation and its molecular counterpart Bcl-1 rearrangement are consistent features of mantle cell lymphoma (MCL). This translocation activates the PRAD1/cyclin D1 gene that is considered to be the Bcl-1 oncogene. PRAD1/cyclin D1 gene overexpression is closely associated with MCL. The PRAD1/cyclin D1 protein is localized to the nucleus, and the strong correlation between PRAD1/cyclin D1 and MCL is also found in the protein level. This finding indicates that PRAD1/cyclin D1 expression is a highly specific and sensitive molecular marker for MCL. This gene may function as an oncogene in the malignant transformation of cells.

Translocation t(8;16)(p11;p13) in acute non-lymphocytic leukemia: report on two new cases and review of the literature

Two new cases of t(8;16)(p11;p13) in acute nonlymphocytic leukemia (ANLL) are described. These two patients in addition to the 34 previously described, showed a striking association with myelomonocytic (M4) or monocytic (M5) leukemia, extramedullary infiltration, erythrophagocytosis and disseminated intravascular coagulation. One of our patients showed a TCRbeta gene rearrangement. Alltogether 36 cases of t(8;16) ANLL have been documented until today. We here review their clinical and cytogenetic features.

New classification of low-grade lymphoma

The problem of morphologic classification of the indolent non-Hodgkin's lymphomas has been addressed by the National Cancer Institute Working Formulation, the International Lymphoma Study Group, and other groups. The criteria for classification have expanded to include biologic and laboratory parameters. Clinical aspects are important, because diagnostic categories that obscure discrete entities, such as mucosa-associated B-cell lymphoma could adversely affect therapy. This and other indolent non-Hodgkin's lymphomas and mantle-cell lymphoma, which has been provisionally included among them, are reviewed. Variations in nomenclature, immunohistochemical and molecular characteristics, and whenever possible, prognosis and clinical outcome are described. The need for further correlation with clinical outcome of these entities is noted.

Mantle-cell lymphoma: classification and therapeutic implications

Mantle-cell lymphomas have been recognized in the new Revised European-American Lymphoma Classification as a peripheral B-cell neoplasm that has a distinct morphologic, immunologic, and genetic phenotype. Mantle-cell lymphomas have been subtyped into four categories, termed 'mantle zone', 'nodular', 'diffuse', or 'blastoid'. The incidence of the 'mantle-zone' pattern remains controversial. The fact that patients with the nodular, diffuse, or blastoid subtypes of mantle-cell lymphoma have a high proliferative rate resulting from overexpression of the cyclin D1 and a very short median survival demonstrates conclusively that these patients should be categorized as having an aggressive lymphoma. Most authorities believe that the 'mantle zone' variant pursues a more benign clinical course than the other subtypes. Trials of the new purine analogs are of great interest in these mantle-zone lymphoma patients.

Mantle cell lymphomas

MCLs are thought to arise from a subset of B cells that normally express the CD5 antigen and that reside in the mantle zone of secondary lymphoid follicles. Although expression of the CD5 antigen is also seen in small lymphocytic lymphoma and chronic lymphocytic leukemia, MCL differs from SLL/ CLL in several ways. Whereas trisomy of chromosome 12 is the hallmark cytogenetic abnormality of SLL/CLL, the translocation (11;14) (q13q32) is the most frequent karyotypic abnormality in MCL. The histologic pattern of MCL is most frequently diffuse. However, this lymphoma can grow in a unique pattern called 'mantle zone MCL,' indicating that the malignant cells expand the mantle of the follicle and grow around a normal germinal center. If the germinal center is also replaced by the malignant cells, but the follicular architecture remains, the pattern appears nodular. The clinical presentation of MCL is usually only seen with advanced disease stage, particularly in patients with diffuse MCL. The bone marrow is the most frequently affected extranodal site, followed by the gastrointestinal tract. The histologic pattern of disease in the lymph nodes correlates with clinical outcome. Patients with diffuse MCL have poor response to frontline combination chemotherapy including doxorubicin, whereas patients with mantle zone MCL have excellent complete remission rates. The therapeutic response correlates in turn with worse survival outcome for patients with diffuse MCL compared to mantle zone MCL. The few patients with nodular MCL had clinical behavior similar to diffuse MCL. The chemotherapeutic response of diffuse and nodular MCL, however, is quite poor, and we would propose that new investigational approaches be considered in the front-line therapy of these disorders.

Scanning and transmission electron microscopy of clonal peripheral blood lymphocytes in low grade non-Hodgkin's B-cell lymphomas with predominant splenomegaly

Peripheral blood mononuclear cells (PBLs) from 14 patients with low grade non-Hodgkin's B-cell lymphomas with predominant splenomegaly were studied by means of scanning (SEM) and transmission electron microscopy (TEM). All patients had peripheral blood and bone marrow involvement, the absence of lymphoadenopathy, and, except in one case, immunophenotypic features of a malignant proliferation of mature spleen B-cells arising from outside the germinal center, but not consistent with CLL or HCL. Several distinctive cytological features were observed in PBLs of the different subgroups. The SEM surface features of PBLs in patients with intermediate differentiation lymphocytic lymphoma (IDL) (five cases), lymphoplasmacytoid immunocytoma (LP-IC) (two cases), and mixed small and large cells malignant lymphoma (one case) were characterized by the presence of numerous well-developed microvilli. Some distinctive TEM ultrastructural features were also seen in the different cases. In the two cases of splenic lymphoma with villous lymphocytes (SLVL), SEM revealed large and elongated surface microvilli generally arising from two or three poles of the cells. This surface morphology, confirmed by TEM analysis, may be pathognomonic of this disease. Four additional cases, tentatively classified as small lymphocytic lymphoma on the basis of immunophenotypic data, were extremely heterogeneous at both SEM and TEM analysis. The ultrastructural features revealed by SEM and TEM may be useful for the more precise characterization of this heterogeneous group of diseases, which is generally difficult to define even when immunophenotypic and molecular approaches are used.

Mantle-cell lymphoma

Histological subtyping of non-Hodgkin's lymphomas is of prognostic significance. Current classification systems subdivide them into low-, intermediate-, and high-grade malignancies. These subgroups are largely supported by clinical findings, but immunophenotyping and genotyping have shown that several of these histologically defined subcategories are heterogeneous. This is exemplified by the 'diffuse small cleaved-cell lymphoma' which comprises B-cell and T-cell lymphomas. Moreover, within the B-cell lymphomas, several entities have been included, which recapitulate the different compartments present in the reactive B follicle, e.g., the follicle centre, the mantle, and the marginal zone. Mantle-cell lymphomas have been identified in the United States as mantle-zone lymphomas and as intermediate differentiated lymphomas and in Europe as centrocytic lymphomas. Morphology, immunophenotyping, and cytogenetics of these three lymphomas support their similarity and underline their distinction from follicle centre-cell lymphomas as well as from small lymphocytic lymphomas. All three are composed of a mixture of small round and small cleaved cells, expressing several B-cell markers, surface immunoglobulins, and CD5, but lacking CD10 expression. They often carry the translocation t(11;14) with rearrangement of bcl-1/PRAD1 gene. The behaviour and responsiveness to therapy of mantle-cell lymphomas has not been fully documented yet. In order to obtain these data, precise subtyping of non-Hodgkin's lymphomas--not only based on morphology, but supported by immunophenotyping and cytogenetic analysis--is now mandatory.

Cyclin D and oncogenesis

The D-type cyclins are among the candidate 'G1 cyclins' in higher eukaryotes that may regulate G1-S-phase progression. The human cyclin D1 gene, also known as PRAD1 (and previously as D11S287), is a putative proto-oncogene strongly implicated in several types of human tumors, including parathyroid adenomas, B-cell neoplasms (as the 'BCL-1 oncogene'), and breast and squamous cell cancers. The mechanism by which deregulated production of cyclin D1/PRAD1, and perhaps other D-type cyclins, contributes to tumor development is only beginning to be deciphered.

Leukaemic intermediate lymphocytic lymphomas: analysis of twelve cases diagnosed by morphology

Twelve cases of leukaemic intermediate diffuse lymphocytic lymphoma (ILL), diagnosed by morphology, were analysed. The morphology of the ILL cells was so typical that it allowed ready distinction from chronic lymphocytic leukaemia (CLL) and other related B cell disorders. All cases were of B derivation, had strong mu and chi or lambda immunoglobulin (Ig) staining, were CD5 and FMC7 positive and CD10 negative. Cytogenetic abnormalities were found in 8 patients all having t(11;14)(q13;q32). DNA analysis revealed a relatively high incidence of hypoploidy. At diagnosis all the patients (9 males, 5 females; median age 68) had a low degree of absolute lymphocytosis but the disease was advanced and mostly widespread. The course of the disease appears to be aggressive and incurable with conventional combination chemotherapy.

Mantle cell lymphoma: an update

Mantle cell lymphoma is a distinctive pathologic entity that incorporates the previous histopathologic categories of centrocytic lymphoma and lymphocytic lymphoma of intermediate differentiation. These lymphomas are characterized by common histologic and immunologic characteristics that suggest derivation from the follicular mantle zone. Mantle cell lymphomas are characterized by the t(11;14) (q13;q32) translocation and its molecular counterpart bcl-1 rearrangement. This translocation activates a gene called BCL-1/PRAD-1. The identification of the BCL-1 gene product as a cyclin has added a new dimension to our understanding of the variety of mechanisms involved in lymphomagenesis.

Multicentre randomized therapeutic trial for advanced centrocytic lymphoma: anthracycline does not improve the prognosis

Within a multicentre observation study on non-Hodgkin lymphomas (NHL) diagnosed according to the Kiel classification advanced stages III and IV of centrocytic (CC) lymphoma exhibited the worst prognosis among lymphomas of low-grade malignancy with a 5-year survival probability of less than 10 per cent. Treatment had been solely expectative and palliative with treatment results showing a prognostic superiority of patients achieving partial and complete remissions over non-responders. Therefore, a randomized multicentre study was initiated to compare the remission-inducing potential of the COP regimen (Bagley et al., 1972) with that of the more intensive adriamycin-containing CHOP regimen (McKelvey et al., 1976). From 91 newly diagnosed CC lymphomas 63 fulfilled randomization criteria with 37 patients assigned to the COP regimen and 26 patients to the CHOP regimen. Between the COP- and CHOP-treated patients no significant differences could be demonstrated with respect to initial clinical parameters, rate of complete (41 per cent versus 58 per cent) or partial remissions (43 per cent versus 31 per cent), median overall survival probability (32 versus 37 months), relapse-free survival (10 versus 7 months) and rates of relapse (73 per cent versus 67 per cent) and death (57 per cent versus 50 per cent). It can be concluded that CC lymphoma is a typical lymphoma of low-grade malignancy with its inability to reach stable remissions while the demonstration of identical survival probabilities for patients with complete and partial remissions constitutes a unique feature of this lymphoma entity. These observations prove advanced CC lymphoma to represent an incurable neoplastic disease under conventional therapeutic approaches.

Leukaemic phase of mantle zone (intermediate) lymphoma: its characterisation in 11 cases

Sixteen patients presented with B cell leukaemia (white cell count 26-269 x 10(9)/l) which could not be classified as chronic lymphocytic (CLL), prolymphocytic leukaemia, or follicular lymphoma in leukaemic phase. Eleven patients (10 men, one woman) corresponded histologically to intermediate (INT) or mantle zone lymphoma, and five, with less well defined features, were designated small lymphocytic lymphoma with cleaved cells. The blood films showed a pleomorphic picture with lymphoid cells of predominantly medium size with nuclear irregularities and clefts. The membrane phenotype of the circulating cells showed strong immunoglobulin staining and reactivity with CD5 and FMC7 in all cases tested; CD10 was positive in six out of nine cases. The membrane phenotype of two of the five cases of small lymphocytic lymphoma was close to those of B-CLL and three resembled INT lymphoma. Bone marrow trephine biopsy specimens showed a diffuse pattern of infiltration in INT lymphoma. The median survival of these patients was less than two years, suggesting that a leukaemic presentation is associated with poor prognosis. By combining data from histology, membrane markers, and peripheral blood morphology, the leukaemic phase of typical INT lymphoma can be defined in most cases.

Placental-like alkaline phosphatase reactivity in human tumors: an immunohistochemical study of 520 cases

Placental-like alkaline phosphatase (PLAP) activity has been reported in various human neoplasms of both somatic and germ cell types. The expression of PLAP was examined with a polyclonal antibody and the immunoperoxidase technique in formalin-fixed, paraffin-embedded sections of 37 germ cell neoplasms and 483 somatic tumors. The expression of keratin and epithelial membrane antigen (EMA) was concurrently assessed to determine whether these stains were helpful in distinguishing germ cell neoplasms from somatic tumors that might mimic them microscopically. All germ cell lesions were reactive for PLAP, but so were 62 somatic carcinomas, usually in female müllerian, intestinal, and lung cancers and less often in carcinomas of the breast and kidney. PLAP-reactive somatic tumors exhibited EMA and keratin positivity in the absence of prior protease digestion, whereas germ cell neoplasms failed to do so. Malignant mesotheliomas were nonreactive for PLAP, as were carcinomas of the nasopharynx, adrenals, liver, pancreas, stomach, prostate, and urinary bladder. PLAP is a highly sensitive but nonspecific immunohistologic marker of germ cell differentiation. However, non-protease-enhanced stains for keratin and EMA allow separation of germ cell and somatic carcinomas, despite their shared capacity for PLAP expression. In somatic neoplasms, PLAP immunoreactivity might be of potential use in predicting possible primary sources for metastatic tumors of unknown origin.

Small noncleaved follicular center cell lymphoma: Burkitt's and non-Burkitt's variants in the US. II. Pathologic and immunologic features

The morphologic criteria for the two variants of small noncleaved follicular center cell (SNC FCC) lymphoma in the Lukes-Collins classification, Burkitt's (BL) and non-Burkitt's variants (NBL), were evaluated and related to the results of multiparameter laboratory and clinical studies. Forty-two patients were studied: 25 cases were classified as BL according to World Health Organization (WHO) criteria. Seventeen cases were classified as NBL on the basis of greater variability in nuclear size and shape, more prominent nucleoli, and greater variation in the amount of cytoplasm. Neoplastic follicles were present in three cases of BL and two of NBL, indicating an FCC origin for this lymphoma. Electron microscopic examination confirmed the light microscopic features. Immunoglobulin (Ig) monoclonality, as demonstrated by immunofluorescence (surface Ig) and/or immunoperoxidase staining for cytoplasmic immunoglobulin (CIg), was demonstrated in 21 of 24 (87.5%) of BL and 13 of 16 (71%) of NBL. Clinically, BL presented more frequently in extranodal sites and with gastrointestinal involvement than NBL. Bone marrow involvement was more common in NBL patients. Both groups had advanced stage disease at diagnosis. The median survival was 10.5 months in BL and 7.7 months in NBL. The results of this study indicate that BL and NBL are biologically related variants of SNC FCC lymphoma but have different presentations, which may be clinically significant.

Agreement rates and American-Japanese pathologists' comparability of a modified Working Formulation for non-Hodgkin's lymphomas. An analysis of the cases collected for the Fifth International Workshop on Chromosomes in Leukemia-Lymphoma

Histopathologic slides of 368 cases collected from 16 institutions around the world for the Fifth International Chromosome Workshop were independently reviewed by a group of five hematopathologists consisting of two Americans and three Japanese. Agreement rates of their diagnoses using the Working Formulation (WF) for non-Hodgkin's lymphomas were studied. A modified classification scheme of the WF was used in order to define cytologic subtypes more specifically, enabling 65 possible diagnostic choices. Data analyses by computer revealed that at least four out of five diagnostic agreements were observed in 290 cases (78.9%). Similar agreements were observed in more than 80% of the cases for most of the categories of the WF, excepting diffuse small cleaved (73.3%), diffuse mixed (64.2%), diffuse large cell (76.5%), and immunoblastic lymphoma (70.2%). Agreement rates between American and Japanese pathologists did not demonstrate statistically significant differences against expected values. It was concluded that the WF was a reliable and useful classification system for multi-institutional as well as international projects, although refinements may be necessary in some categories for better diagnostic agreement.