Anaplastic large cell lymphoma: update of findings

CD30 Differential Staining is Useful in Classifying Lymphomas Intermediate between Hodgkin's Disease and Anaplastic Large Cell (Ki1) Lymphoma

AIMS AND BACKGROUND

The authors analyzed the BerH2 reactivity patterns of the tumor cells in 23 Hodgkin's lymphomas (HD), in 13 CD30+ anaplastic large cell (Ki1) lymphomas (ALCL), in two HD with transition to secondary CD30+ ALCL, and in six additional lymphomas intermediate between HD and ALCL.

METHODS

Paraffin blocks of formalin-fixed biopsies were immunostained. Immunostaining was modified by pronase digestion and by microwave assistance.

RESULTS

Hodgkin-Reed-Sternberg (HRS) cells of all 23 Hodgkin's lymphomas were reactive for BerH2, but the reactivity patterns differed: after pronase digestion, HRS cells of 17/23 Hodgkin's lymphomas showed exclusively or at least predominantly cytoplasmic BerH2 reactivity, whereas only four Hodgkin's lymphomas presented with prominent membrane-bound positivity. Microwave processing in 16/23 Hodgkin's lymphomas induced membrane-bound BerH2 positivity in the HRS cells; a minority of five cases retained the distinct cytoplasmic pattern. In contrast, 10/13 ALCLs were characterized by membranous reactions, independent of whether pronase or microwave pretreatment had been applied. The CD30+ ALCLs secondary to HD also showed a tendency towards membranous positivity more than did the antecedent Hodgkin's lymphomas. In the HD/ALCL borderline group, 3/6 cases revealed cytoplasmic BerH2 patterns after pronase digestion and thus were more closely related to HD, whereas 2/6 cases reacted with membranous positivity as did the genuine ALCLs of our series.

CONCLUSIONS

We conclude from these findings that the above modifications in CD30 immunostaining can be helpful in the characterization of lymphomas that constitute a continuous histomorphological as well as phenotypical spectrum between HD and ALCL.

CD30/CD30 Ligand and CD40/CD40 Ligand in Malignant Lymphoid Disorders

CD30 and CD40 are members of the tumor necrosis factor (TNF) receptor family. These two receptors have pleiotropic biologic functions including induction of apoptosis and enhancing cell survival. This review will discuss the pattern of expression of these receptors in malignant lymphoid disorders and their prospective ligands. Understanding issues related to these two ligands and their receptors in lymphoid malignancies may help to improve the classification of these diseases and could open the doors for new treatment strategies.

Extreme neutrophil granulocytosis in a patient with anaplastic large cell lymphoma of T-cell lineage

We describe a 47-year-old male admitted with fever and extreme neutrophil granulocytosis (up to 80 x 10(9)/L). All microbiology tests and test for autoimmune disease were negative. CT scan showed pulmonary infiltrates bilaterally, mediastinal lymphadenopathy and splenomegaly. Conventional pathological examination of bone marrow and lymph node biopsies did not demonstrate malignant cells and inflammatory disease was suspected. The patient died of multiorgan failure 23 days after admission. Autopsy showed neutrophil infiltration of several organs. Immunohistochemistry and cytogenetics postmortem led to a diagnosis of anaplastic large cell lymphoma (ALCL) of T-cell lineage. Involvement of peripheral blood with leukemoid reaction is a rare manifestation of ALCL. This case emphasizes the importance of immunophenotyping in unexplained extreme granulocytosis.

Anaplastic large cell lymphomas: a study of 75 pediatric patients

In this article, we describe the morphologic and immunophenotypic features of 75 cases of pediatric anaplastic large cell lymphoma (ALCL). According to the World Health Organization classification, 49 cases were common subtype ALCL, and respectively, 3, 6, and 17 cases were small cell, lymphohistiocytic, or mixed histologic variants. Anaplastic lymphoma kinase positivity was detected in 90.7% of the tumors and, using a panel of 9 T-cell surface markers, 88% could be assigned to the T-cell lineage. A molecular analysis for the T-cell receptor gamma (TCR- gamma) and the heavy chain of the immunoglobulin H rearrangements was performed on 6/9 ALCLs with a null immunophenotype, and a TCR clonal pattern was detected in 5/6 cases. In addition, 94.1% were immunoreactive for 1 or more cytotoxic proteins (Tia1, granzyme B, or perforin), and 15% expressed CD56. Clusterin, CD83, and Pax5, respectively, expressed in 91.3%, 1.7%, and 0% of the ALCLs, were useful biomarkers for the differential diagnosis with Hodgkin's lymphomas.

Hodgkin's lymphoma: the pathologist's viewpoint

Despite its well known histological and clinical features, Hodgkin's lymphoma (HL) has recently been the object of intense research activity, leading to a better understanding of its phenotype, molecular characteristics, histogenesis, and possible mechanisms of lymphomagenesis. There is complete consensus on the B cell derivation of the tumour in most cases, and on the relevance of Epstein-Barr virus infection and defective cytokinesis in at least a proportion of patients. The REAL/WHO classification recognises a basic distinction between lymphocyte predominance HL (LP-HL) and classic HL (CHL), reflecting the differences in clinical presentation and behaviour, morphology, phenotype, and molecular features. CHL has been classified into four subtypes: lymphocyte rich, nodular sclerosing, with mixed cellularity, and lymphocyte depleted. The borders between CHL and anaplastic large cell lymphoma have become sharper, whereas those between LP-HL and T cell rich B cell lymphoma remain ill defined. Treatments adjusted to the pathobiological characteristics of the tumour in at risk patients have been proposed and are on the way to being applied.

Primary hepatic anaplastic large-cell lymphoma of T-cell phenotype in acquired immunodeficiency syndrome: a report of an autopsy case and review of the literature

Anaplastic large-cell lymphomas (ALCL) were first described by Stein et al. in 1985 as large-cell neoplasms with a pleomorphic appearance, subtotal effacement of the lymph node structure, and expression of the lymphoid activation antigen CD-30 (Ki-l). Since their first description, these tumors have been documented in a variety of extranodal sites. We report a primary hepatic anaplastic large-cell lymphoma in a patient with advanced AIDS, who presented with hepatic failure and multiple nodules in the liver. A complete autopsy showed discrete tumor nodules throughout the entire liver without gross or microscopic involvement of lymph nodes or any other organs by the neoplastic process. The tumor cells showed typical histological and immunohistochemical features of ALCL and were strongly immunoreactive with the T-cell markers CD-3 and UCHL-1. Only one previous case of primary hepatic ALCL has been reported in the literature, and this tumor occurred in an immunocompetent patient and was not immunoreactive for B- or T-cell markers. To our knowledge, this study represents the first reported case of primary hepatic anaplastic large-cell lymphoma of T-cell phenotype. Additionally, this is the first case of primary hepatic ALCL reported in an AIDS patient.

Utility of flow cytometry immunophenotyping for the diagnosis and classification of lymphoma in community hospital clinical needle aspiration/biopsies

CONTEXT

Flow cytometry immunophenotyping (FC) of needle aspiration/biopsy (NAB) samples has been reported to be useful for the diagnosis and classification of lymphoma in university and cancer center-based settings. Nevertheless, there is no agreement on the utility of these methods.

OBJECTIVE

To further define the utility of adjunctive FC of clinical NAB for the diagnosis and classification of lymphoma, and to determine if this approach is practicable in a routine clinical practice setting.

SETTING

A community-based hospital.

METHODS

Clinical NABs were submitted for adjunctive FC between June 1996 and September 1999 if initial smears were suspicious for lymphoma. Smears and cell block or needle core tissues were routinely processed and paraffin-section immunostains were performed if indicated. The final diagnosis was determined by correlating clinical and pathologic data, and the revised European-American classification criteria were used to subtype lymphomas.

RESULTS

Needle aspiration/biopsies from 60 different patients were submitted for FC. Final diagnoses were lymphoma (n = 38), other neoplasm (n = 15), benign (n = 6), or insufficient (n = 1). For 38 lymphomas (20 primary, 18 recurrent), patients ranged in age from 32 to 86 years (mean, 62 years); samples were obtained from the retroperitoneum (n = 11), lymph node (n = 9), abdomen (n = 8), mediastinum (n = 6), or other site (n = 4); and lymphoma subtypes were indolent B-cell (n = 20; 2 small lymphocytic, 14 follicle center, 4 not subtyped), aggressive B-cell (n = 14; 3 mantle cell, 10 large cell, 1 not subtyped), B-cell not further specified (n = 2), or Hodgkin disease (n = 2). For the diagnosis of these lymphomas, FC was necessary in 20 cases, useful in 14 cases, not useful in 2 cases, and misleading in 2 cases. Thirty-two of 36 lymphoma patients with follow-up data received antitumor therapy based on the results of NAB plus FC.

CONCLUSIONS

Adjunctive FC of NABs is potentially practicable in a community hospital, is necessary or useful for the diagnosis and subtyping of most B-cell lymphomas, and can help direct lymphoma therapy. Repeated NAB or surgical biopsy is necessary for diagnosis or treatment in some cases.

Primary anaplastic large cell lymphoma of the lung: a clinicopathologic study of five patients

Primary anaplastic large-cell lymphoma is a rare malignancy in the lung. Anaplastic large-cell lymphoma characteristically involves the lymph nodes or skin, with few reports from other sites. We studied the clinical and pathologic features of five cases of anaplastic large-cell lymphoma limited to the lungs. The patients were three women and two men aged 27 to 66 years (mean, 44.6 y) The tumors ranged in size from 1.1 to 5 cm. All patients were CD 30 (Ki-1) positive and CD 15 (LeuM-1) negative. Epithelial membrane antigen immunoreactivity was seen in two patients. Epstein-Barr virus was not detected by immunohistochemistry (four patients tested) or by polymerase chain reaction studies (three patients tested). The immunophenotypes were T cell (n = 3) and null (n = 2). Gene rearrangement studies supported the immunophenotypic findings. One patient who had underlying HIV infection died of infectious complications. One patient died at 6 months. Two patients developed recurrent disease and are alive after 42 and 51 months of follow-up. The remaining patient is alive at 8 years of follow-up without evidence of disease. ALCL can mimic metastatic or primary carcinoma and should be considered in the differential diagnosis of large cell neoplasms of the lung.

Pathobiology of NPM-ALK and variant fusion genes in anaplastic large cell lymphoma and other lymphomas

Despite its clinical and histological heterogeneity, anaplastic large cell lymphoma (ALCL) is now a well-recognized clinicopathological entity accounting for 2% of all adult non-Hodgkin's lymphomas (NHL) and about 13% of pediatric NHL. Immunophenotypically, ALCL are of T cell (predominantly) or Null cell type; by definition, cases expressing B cell antigens are officially not included in this entity. The translocation (2;5)(p23;q35) is a recurring abnormality in ALCL; 46% of the ALCL patients bear this signature translocation. This translocation creates a fusion gene composed of nucleophosmin (NPM) and a novel receptor tyrosine kinase gene, named anaplastic lymphoma kinase (ALK). The NPM-ALK chimeric gene encodes a constitutively activated tyrosine kinase that has been shown to be a potent oncogene. The exact pathogenetic mechanisms leading to lymphomagenesis remain elusive; however, the synopsis of evidence obtained to date provides an outline of likely scenarios. Several t(2;5) variants have been described; in some instances, the breakpoints have been cloned and the genes forming a new fusion gene with ALK have been identified: ATIC-ALK, TFG-ALK and TPM3-ALK. Cloning the translocation breakpoint and identifying the ALK and NPM genes provided tools for screening material from patients with ALCL using various approaches at the chromosome, DNA, RNA, or protein level: positive signals in the reverse transcriptase-polymerase chain reaction (RT-PCR) and the immunostaining with anti-ALK monoclonal antibodies (McAb) serve as the most convenient tests for detection of the t(2;5) NPM-ALK since the fusion gene and ALK protein expression do not occur in normal or reactive lymphoid tissue. The wide range of NPM-ALK positivity reported in different series appears to be dependent on the inclusion and selection criteria of the ALCL cases studied. Overall, however, 43% of ALCL cases were NPM-ALK+ (83% of pediatric ALCL vs 31% of adult ALCL). Occasional non-ALCL B cell lymphomas (4%) with diffuse large cell and immunoblastic histology and Hodgkin's disease cases (3%) were NPM-ALK-, but these data are questionable. The aggregate results indicate that, in contrast to primary nodal (systemic) ALCL, the t(2;5) may be present in only 10-20% of primary cutaneous ALCL and rarely, if at all, in lymphomatoid papulosis, a potential precursor lesion; however, these 10-20% positive cases were not confirmed by anti-ALK McAb immunostaining and may represent an overestimate. Positivity for NPM-ALK is associated to various degrees with the following parameters: 44% and 45% of ALCL cases with T cell and Null cell immunophenotype, respectively, are positive, whereas only 8% of cases with a B cell immunoprofile are positive; the mean age of positive patients is significantly younger than that of negative patients; positive cases carry a better overall prognosis (but not in all studies). Recently, the homogenous category of ALK lymphoma ('ALKoma') has emerged as a distinct pathological entity within the heterogenous group of ALCL. The fact that patients with ALK lymphomas experience significantly better overall survival than ALK- ALCL demonstrates further that analysis of ALK expression has important prognostic implications. The term ALK lymphoma signifies a switch in the use of the diagnostic criteria: cases are selected on the basis of a genetic abnormality (the ALK rearrangement), instead of the review of morphological or immunophenotypical features which are clearly more prone to disagreement and controversy. Since its initial description in 1985 ALCL has become one of the best characterized lymphoma entities.

Anaplastic large-cell lymphomas of B-cell phenotype are anaplastic lymphoma kinase (ALK) negative and belong to the spectrum of diffuse large B-cell lymphomas

There is controversy in the literature as to whether anaplastic large-cell lymphoma of B-cell phenotype is related to the t(2;5)-positive T- or 'null' cell lymphoma of the same morphology. We report a study of 24 lymphomas with morphological features of anaplastic large-cell lymphoma which expressed one or more B-cell markers and lacked T-lineage markers. Clinical features were more in keeping with large B-cell lymphoma than with classical t(2;5)-positive anaplastic large-cell lymphoma, and immunostaining for anaplastic lymphoma kinase (ALK) protein provided no evidence for the (2;5) translocation (or one of its variants). The staining patterns for CD20 and CD79 were typical of diffuse large B-cell lymphoma, CD30 expression was variable, and most cases (15/22) lacked epithelial membrane antigen (EMA). These findings support the view that 'B-cell anaplastic large-cell lymphoma' is unrelated to t(2;5)-positive (ALK-positive) lymphoma, and that it represents a morphological pattern occasionally encountered among diffuse large B-cell lymphomas. By the same reasoning, most tumours diagnosed as 'ALK-negative anaplastic large-cell lymphoma of T-cell or null phenotype' probably belong to the spectrum of peripheral T-cell lymphomas.

Primary anaplastic large cell lymphoma of the adrenal gland

Primary adrenal lymphomas are rare. Most reported cases are of B-cell phenotype and follow an aggressive clinical course. We report a case of primary anaplastic large cell, CD30+ adrenal lymphoma developing in a 62-year-old woman. The patient presented with fatigue and vague right upper quadrant pressure. Computed tomography revealed bilateral adrenal masses. A right adrenalectomy was performed. Histologic evaluation showed islands of large atypical cells surrounded by eosinophilic acellular material. The tumor cells stained positive for CD45, CD45RO, CD43, and CD30. Epstein-Barr virus genome was identified in tumor cells using in situ hybridization. The patient was treated with chemotherapy and a 23-month follow-up examination showed no change in the size of the opposite adrenal gland and no other evidence of lymphoma.

Anaplastic large-cell lymphoma associated with acquired ichthyosis

Anaplastic, CD30(+), large-cell lymphoma (ALCL) is a subtype of non-Hodgkin's lymphoma that accounts for 2% to 8% of all lymphomas. Its most common form is a classical systemic type, which involves multiple nodal and extranodal sites, including the skin. Malignant lymphoproliferative disorders, especially Hodgkin's disease, are known rarely to be associated with acquired ichthyosis, whereas only 1 case of ALCL has been reported to be associated with acquired ichthyosis. We describe a 74-year-old Japanese man with ALCL, involving lymph nodes and the skin, who exhibited acquired ichthyosis. The clinical and histopathologic findings were recorded, and immunophenotyping, T-cell receptor (TCR), and immunoglobulin gene rearrangement were determined. Clinically, right axillary and bilateral inguinal lymph nodes were palpable. The cutaneous eruptions were multiple pinkish and yellow colored, up to thumb-sized nodules, some of which were ulcerated. Histologically, the right axillary lymph node showed proliferation of anaplastic large cells in the paracortical and sinusoidal areas. Both the lymph node and skin showed pleomorphic proliferation of lymphoid cells with a mixture of mononuclear cells having oval, embryo-shaped, reniform, and lobulated nuclei, binucleated Reed-Sternberg-like cells, and multinucleated cells, with giant anaplastic and wreath-shaped nuclei. Immunophenotyping of the neoplastic cells revealed that they were positive for CD30 (Ber-H2), CD15 (Leu-M1), CD45 (LCA), and CD45RO (UCHL-1). Southern blot analysis demonstrated clonal rearrangement of the TCR beta region. In contrast, no novel bands were detected with the immunoglobulin heavy chain JH probe. Several months after the detection of the axillary nodes, an ichthyosiform, scaly eruption developed over almost the entire body of the patient. Histologically, it showed orthokeratotic, slight hyperkeratosis of the epidermis without a granular layer or with only a single layer of cells in the granular layer. Several kinds of lymphoproliferative diseases are associated with acquired ichthyosis, including Hodgkin's disease, multiple myeloma, and lymphomatoid papulosis. This is the second case report of acquired ichthyosis associated with ALCL. Although a common pathomechanism is suspected of underlying the development of acquired ichthyosis in these diseases, it is still unexplained.

Anaplastic large cell lymphoma: a clinicopathologic analysis

The clinicopathologic features of anaplastic large cell lymphoma (ALCL) are reviewed. ALCL is a heterogeneous group of tumours, and histologic examination alone is not adequate in providing useful prognostic information. However, using a combination of clinical, phenotypic, and genotypic features, several distinct clinicopathologic entities have been identified. A subset of ALCL as presently defined is characterized by a balanced translocation, t(2;5)(p23;q35), resulting in a novel fusion protein (NPM-ALK) that can be readily detected by immunohistochemical methods using antibodies against the ALK protein. Detection of ALK protein, along with other methods for demonstrating the t(2;5), has assisted in identifying a distinct biologic entity within the heterogeneous group of ALCL with significant prognostic implications. It is important to separate these from cases of ALK-negative ALCL, which have a poorer prognosis, and cases of primary cutaneous ALCL, which have an excellent prognosis.

T-cell and T/natural killer-cell lymphomas involving ocular and ocular adnexal tissues: a clinicopathologic, immunohistochemical, and molecular study of seven cases

OBJECTIVE

Lymphomas of the eye and its adnexa are frequently of B lineage. This study aims to characterize the clinical and histopathologic features of the rare non-B-cell non-Hodgkin lymphomas (NHL) of these locations.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Seven cases of T- and T/NK-cell lymphomas involving the ocular and ocular adnexal tissues.

METHODS

A morphologic, immunohistochemical, and molecular analysis (polymerase chain reaction) of each of the tumors was undertaken. The lesions were classified according to the Revised European-American Lymphoma (REAL) classification. The clinical and follow-up data were collected.

RESULTS

The patients included four women and three men ranging in age from 32 to 88 years (mean, 63 years). The presenting ophthalmic symptoms varied from a small nodule on the upper eyelid and conjunctival swellings to dramatic loss of vision associated with gross protrusion of the globe. Five of the cases presented were secondary manifestations of a systemic lymphoma in ocular tissues; two cases represented primary disease. Three cases were "peripheral T-cell lymphomas (PTCL), unspecified" with positivity for CD3, CD8, and betaF1 and negativity for CD56. Two cases were CD3+, CD30+, and CD56- and were classified as "anaplastic large-cell lymphomas of T-cell type" (T-ALCL). The remaining two cases showed an immunophenotype of CD3+, CD56+, and betaF1- and proved to contain Epstein-Barr virus (EBV) by in situ hybridization, consistent with "T/natural killer (NK)-cell lymphoma of nasal type." Clonal T-cell populations were shown in all three of the PTCLs by Southern blot (n = 1) and polymerase chain reaction (n = 2) for the T-cell receptor gamma and beta genes in one case of ALCL but not in the T/NK-cell lymphomas. Five patients died within 2 years; only two patients (one primary PTCL and one cutaneous T-ALCL) were disease free at 4 and 5 years' follow-up, respectively.

CONCLUSION

This study shows that a heterogeneous group of T-cell lymphomas can involve the eye and its adnexal tissue. Most T-cell neoplasms are secondary manifestations of systemic disease and carry a poor prognosis. These findings, in conjunction with published data on ocular B-NHL, also indicate that immunophenotypic differentiation between T- and B-NHL in these locations is of clinical importance.

Recent advances in the molecular pathogenesis of lymphomas

Most human lymphomas remain heterogeneous biologic entities in spite of recent advances in the description of their clinical presentation, cellular morphology, immunophenotype, and genotype. Elucidation of genetic alterations causing malignant transformation may explain pathogenesis, refine differential diagnosis, clarify prognosis, and provide rational basis for new therapy. During the last year the expression of anaplastic lymphoma kinase clarified presentation and provided clues toward the outcome of anaplastic large cell lymphoma; the breakpoints of t(2;5) were mapped; constitutive activation of anaplastic lymphoma kinase by a chromosomal inversion was described; transformation was shown to be independent of nuclear localization of anaplastic lymphoma kinase; and phospholipase C-gamma was identified as a molecular target for the kinase activity of anaplastic lymphoma kinase. Molecular characterization of recurrent chromosome abnormalities has identified new candidate oncogenes: bcl-9, bcl-10, PAX-5, MMSET, and c-maf. Their precise role in malignant transformation, and the frequency of their alteration in lymphoma and myeloma, is not yet defined. The expression of the antiapoptotic protein bcl-2 on aggressive lymphomas was shown to be associated with inferior disease-free survival by several investigators. This may be a target of pharmacologic reduction of bcl-2 levels. Can these advances in molecular pathogenesis improve cure rates for lymphoma? The spectacularly successful molecular modeling of inhibitors for HIV protease suggests that this may be an attainable objective.

The many faces of Hodgkin's disease around the world: what have we learned from its pathology?

In the past decade there have been many advances in our understanding of Hodgkin's disease. Among the most important is the discovery that the Reed-Sternberg cell is a lymphoid cell, in most cases a B cell, and that it is clonal, and thus a true lymphoma, deserving of a name change, to 'Hodgkin's lymphoma' (HL). Based on a combination of immunophenotype and morphology, the R.E.A.L. Classification recognizes two main types of HL: classical types (nodular sclerosis, mixed cellularity, lymphocyte-rich classical HL, and lymphocyte depletion) and nodular lymphocyte predominance type (NLPHL), which probably represent distinct biological entities. The immunophenotype and genetic features of both classical HL and NLPHL have been defined. These are useful in the subclassification of HL and in distinguishing HL from two recently-described, aggressive lymphomas that were in the past often diagnosed as HL: anaplastic large-cell lymphoma, T-cell type (ALCL), and T-cell/histiocyte-rich large B-cell lymphoma (T/HRBCL). Epstein-Barr virus has been detected in approximately 40% of the cases of classical HL, and is clonal, suggesting that this virus may play a role in the pathogenesis of at least some types of HL. The frequency of HL varies in different populations, and the frequency of EBV-positive HL appears to be inversely related to the overall frequency of HL in a given population. Thus, it is possible that its presence may simply reflect the prevalence of EBV-infected B cells in the individual. Despite the advances of the past ten years, many questions remain to be answered, and these will provide the challenges of the next decade.

Anaplastic large cell lymphoma of the spleen

A case is presented of CD30+ anaplastic large cell lymphoma of the spleen. The patient, a 61 year old woman with a history of chronic lymphocytic leukemia (CLL) was seen for the sudden development of splenomegaly with thrombocytopenia. A splenectomy was performed which showed massive replacement of the spleen by a population of large atypical lymphoid cells showing bizarre nuclear forms and multinucleated tumor cells reminiscent of Reed-Sternberg cells. Immunohistochemical studies showed strong membrane and dot-like paranuclear positivity in the majority of the atypical cells for CD30, with coexpression in many of the cells for CD15. Additionally, the cells also strongly reacted with CD3, UCHL-1, EMA and LCA. The present case illustrates an unusual variant of anaplastic (CD30+) large cell lymphoma sharing histologic and immunophenotypic features that overlap with those of Hodgkin's disease. The history in this patient of CLL with sudden development of splenomegaly raises the possibility of transformation of CLL into a high-grade lymphoma (Richter's syndrome). The possible pathogenetic implications of this phenomenon are discussed.

Genomic DNA amplification and the detection of t(2;5)(p23;q35) in lymphoid neoplasms

Anaplastic large cell lymphoma (ALCL) is an intermediate grade Non-Hodgkin's lymphoma (NHL) characterized by the frequent presence of the t(2;5)(p23;q35). This translocation fuses the nucleophosmin (NPM) gene on chromosome 5q35 to a protein kinase gene (Anaplastic Lymphoma Kinase, ALK) on chromosome 2p23. In order to determine the frequency of t(2;5) we used a DNA polymerase chain reaction (PCR) amplification using genomic DNA, 5'-primers derived from the NPM gene, and 3'-primers derived from the ALK gene. The presence of amplifiable DNA in the samples was established with PCR and oligonucleotide primers designed to amplify a 3,016 bp fragment from the beta-globin locus. The t(2;5) PCR assay was established using DNA isolated from three t(2;5)-positive ALCL cell lines. Its ability to amplify genomic DNA prepared for routine molecular diagnostic use was validated using archival DNA from four ALCL tumors known to be t(2;5)-positive. Its sensitivity was established by serially diluting t(2;5)-positive DNA in normal DNA: amplicons were generated in 100% of reactions diluted 10(4)-fold (6-8 cells per tube) and in 30% of those diluted 10(5)-fold (0.6-0.8 cells per tube.) We subsequently analyzed archival genomic DNA extracted from 38 ALCL, 77 NHLs, 37 Hodgkin's lymphomas, and 9 lymphomatoid papuloses. The t(2;5) was detected in 6 ALCLs (16%, 95% confidence intervals 6%-31%), but not in any other lymphoma, or in lymphomatoid papulosis. By using the published sequence of the fourth NPM intron that is involved in t(2;5) and by sequencing the individual tumor amplicons and also the normal ALK intron that is involved in t(2;5), we established that all breakpoints involve the same introns in the ALK and NPM loci. Detailed analysis demonstrated that each translocation generates a unique breakpoint sequence, and suggested that sequence homology between the ALK and NPM intron sequences may be involved in the translocation. We conclude that genomic DNA-PCR is useful for the detection of t(2;5) that in our patient population is restricted to ALCL and is not detectable in other NHL, Hodgkin's disease, or lymphomatoid papulosis. More work is needed to determine the prognostic significance of t(2;5), and to establish the utility of the genomic DNA PCR in monitoring minimal residual disease.

A new variant chromosomal translocation t(2;2)(p23;q23) in CD30+/Ki-1+ anaplastic large cell lymphoma

A case with a complex chromosome abnormality with a t(2;2)(p23;q23) in CD30+/Ki-1+ anaplastic large cell lymphoma (ALCL) is described. This chromosome aberration has not been reported previously in neoplastic diseases and was associated with T-cell phenotype and involvement of the nasopharynx by the tumour.

t(2;5) positive lymphoma with peripheral blood involvement

We report two cases of CD30 and t(2;5) positive lymphomas with peripheral blood (PB) involvement. Case one demonstrated the histological appearance of a diffuse large cell lymphoma with disease in the bone marrow (BM) and PB. Immunoperoxidase stains of the BM for CD30 proved to be of value in detecting disease. RT-PCR for the t(2;5) translocation product was positive in the PB, BM and lymph node. Case two had a typical anaplastic large cell lymphoma (ALCL) morphology, with a suboptimal BM biopsy, but abnormal circulating cells in the PB showing the presence of the NPM/ALK fusion product demonstrated by RT-PCR. The first case demonstrates that not all CD30 positive and t(2;5)-associated lymphomas have an anaplastic appearance. Routine staining for CD30 and EMA in BM biopsies is useful for pathological staging. The significance of the t(2;5) in defining a specific histological subtype is unclear. RT-PCR for the t(2;5) is a more sensitive test to detect disease in PB and BM as compared with light microscopy. The clinical significance of molecular staging for patients with ALCL using RT-PCR needs to be evaluated.

Anaplastic large cell lymphoma: a distinct molecular pathologic entity: a reappraisal with special reference to p80(NPM/ALK) expression

The p80(NPM/ALK) expression activated by the t(2;5) (p23;q35) translocation recently has been shown to play an important role in the pathogenesis of anaplastic large cell lymphoma (ALCL). However, the clinicopathologic significance of identification of p80 among ALCL cases has not been completely resolved. Difficulties also exist in the histologic and immunophenotypic identification of ALCL and Hodgkin's disease (HD) as separate processes, often complicating the clinicopathologic evaluation of and therapeutic approach to these entities. In order to clarify these issues, 67 specimens of ALCL and 63 specimens of HD (31 of the nodular-sclerosing type [NS-HD] and 32 of the mixed-cellularity type [MC-HD]) were immunostained using anti-p80 antibody and other relevant markers on paraffin sections. The clinicopathologic and immunophenotypic features were reviewed on the basis of p80 reactivity. The expression of p80 was detected in 43 of 67 cases of ALCL (64%), but none of HD. The p80+ ALCL cases constituted a very homogeneous group of tumors, characterized by the occurrence in a much younger group and relatively more favorable clinical course than the p80- ALCL, which were in keeping with the data previously reported. They showed virtually the identical immunophenotypic findings of p80+, CD30+, EMA+, CD15-, bcl-2-, and Epstein-Barr virus (EBV) with T- and null-cell phenotype, and showed the distinct morphologic features, including three cases of lymphohistiocytic/small-cell variant, as follows: the indented nuclei, often termed as reniform, embryolike, and horseshoelike; multiple, irregular, but indistinct nucleoli; and few reactive cells of eosinophils and epithelioid cells. Conversely, the 24 p80- ALCL cases, in which epithelial membrane antigen (EMA) and bcl-2 positivities were 33% and 55%, respectively, were heterogeneous and could be subdivided into five different categories, namely (a) 11 cases of HD-like ALCLs, (b) six cases of p80 common ALCL, (c) three cases of secondary ALCL, (d) two cases of primary cutaneous ALCL, and (e) two cases of primary classical ALCL that lacked p80 expression. This study clearly demonstrated that the immunohistochemical detection of p80 is of a crucial importance in delineating the biologically distinct entity of "primary classical ALCL" from various diseases that show morphologic and immunohistologic overlap, including HD and HD-like ALCL.

Treatment considerations in the elderly patient with lymphoma

One half of all non-Hodgkin's lymphomas occur in the elderly, a growing segment of the population in North America. Significantly, the incidence of lymphoma in general, and especially in the elderly, is rising rapidly. These trends will combine to double the number of cases of lymphoma in the elderly in the next 2 to 3 decades. Certain lymphomas can be treated as effectively in the elderly as in the young, and others are treatable but with only half the expectation of cure. Further improvements will be made as future clinical investigation focuses on the elderly with lymphoma as a special group.

Spontaneous anaplastic large cell lymphoma in a chimpanzee: a clinicopathological and immunohistochemical study

An anaplastic large cell lymphoma with disseminated abdominal metastases was diagnosed in a 35-year-old male chimpanzee. Clinically, the animal displayed lethargy, weight loss, ascites, and abdominal distention. Imaging studies showed several large abdominal masses. At necropsy, variably sized masses of neoplastic mesenteric lymph nodes that encompassed several intestinal loops were present throughout the abdomen. The largest mass measured 9 x 5 cm and had cauliflower-like protrusions into the jejunal lumen. The entire abdominal cavity was covered by a sheet of neoplastic tissue. Histopathologically, the tumor consisted of solid sheets of proliferating lymphoid cells forming a cohesive growth that filled the lymph node sinuses. The tumor had invaded the intestinal wall. Anaplastic large cell lymphoma was diagnosed from immunohistochemistry findings on the basis of positive reaction to the CD3 and CD30 markers and negative reaction to the CD20 marker. Serologic analysis revealed positive titers for Epstein-Barr, cytomegalo-, and varicella-zoster viruses. Both serologic and virologic studies showed no evidence of detectable retroviral infection. This type of tumor has not been reported before in the chimpanzee.