Pathologic and clinical features of 77 Hodgkin's lymphoma patients treated in a lymphoma protocol (LNH87): a GELA study

A Rare Case of Systemic Adult Burkitt Lymphoma Presenting as Acute Acalculous Cholecystitis.ACG Case Rep J. 2019;6:e00048. [PMID: 31616732 DOI: 10.14309/crj.0000000000000048]

Acute acalculous cholecystitis (AAC) is an uncommon presentation of cholecystitis accounting for 10% of cases. AAC is caused by a localized ischemic event in the gallbladder usually in critically ill patients. Several cases of localized or systemic lymphoma have been described in the literature as causes of AAC. We present a patient with a rare case of AAC due to undiagnosed systemic Burkitt lymphoma. Pathology of the gallbladder revealed Burkitt lymphoma with analysis of his cerebral spinal fluid confirming Stage IV disease. This case report reviews acute acalculous cholecystitis, lymphomas of the gallbladder and extrahepatic duct, and adult Burkitt lymphoma.

Nodal Involvement by CD30+ Cutaneous Lymphoproliferative Disorders and Its Challenging Differentiation From Classical Hodgkin Lymphoma

Primary cutaneous lymphomas are defined as non-Hodgkin lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. Mycosis fungoides is the most common type of primary cutaneous T-cell lymphoma, representing almost 50% of primary cutaneous T-cell lymphomas, and primary cutaneous CD30+ T-cell lymphoproliferative disorders are the second most common group (30%). Transformed mycosis fungoides is usually CD30+ and can involve multiple nodal sites; other primary cutaneous CD30+ T-cell lymphoproliferative disorders can also involve draining regional nodes. Nodal involvement by CD30+ T-cell lymphoproliferative disorders can mimic classical Hodgkin lymphoma, which can aberrantly express T-cell antigens. The aim of this article is to briefly review salient clinical, histologic, immunophenotypic, and molecular features that can be used to distinguish lymph node involvement by CD30+ cutaneous T-cell lymphomas and lymphoproliferative disorders from classical Hodgkin lymphoma, a clinically important differential diagnosis that represents a challenging task for the pathologist.

CD20 Over-Expression in Hodgkin-Reed-Sternberg Cells of Classical Hodgkin Lymphoma: the Neglected Quest

We have scrutinized a previously analyzed cohort of classical Hodgkin lymphoma patients for evidence of a CD20 over-expression. This was pursued in order to determine whether all the 24 (12.6%) CD20+++ patients had clinical and/or biological profiles which would warrant a separate consideration and treatment or would carry a different outcome from our 166 CD20 (-) classical Hodgkin lymphoma patients. Except for an older age and a significantly lower expression of non-sialyl-CD15 antigen, both previously described in classical Hodgkin lymphoma, no justification to exclude these CD20+++ patients from the cohort at large is apparent. We suggest that the generally accepted view to the contrary be revised. In addition, we propose alternative interpretations for the low expression of CD20 found in a majority of Hodgkin-Reed-Sternberg cells in classical Hodgkin lymphoma.

The histological classification of diffuse large B-cell lymphomas

Diffuse large B-cell lymphomas (DLBCLs) are aggressive B-cell neoplasms with considerable clinical, biologic, and pathologic diversity, in part reflecting the functional diversity of the B-cell system and multiple pathways of transformation. In recent years, the advent of new high-throughput genomic technologies has provided new insights into the biology of DLBCL, leading to the identification of distinct molecular identities and novel pathogenetic pathways. This increasing complexity had led to an expanding number of entities in the World Health Organization classification. Using a multi-modality approach, the updated 2008 classification delineated some new subgroups, including DLBCLs associated with particular age groups or specific anatomic sites, as well as two borderline categories (tumors at the interface between classical Hodgkin lymphoma and DLBCL as well as between Burkitt lymphoma and DLBCL). This article reviews the histopathologic features of the various aggressive B-cell lymphoma subtypes included in the 2008 classification, with emphasis on some of the new entities as well as areas of diagnostic challenge.

Primary mediastinal B-cell lymphoma and mediastinal gray zone lymphoma: do they require a unique therapeutic approach?

Primary mediastinal B-cell lymphoma (PMBL) is a subtype of diffuse large B-cell lymphoma (DLBCL) that is putatively derived from a thymic B cell. Accounting for up to 10% of cases of DLBCL, this subtype predominantly affects women in the third and fourth decades of life. Its clinical and molecular characteristics are distinct from other subtypes of DLBCL and, in fact, closely resemble those of nodular sclerosing Hodgkin lymphoma (NSHL). Recently, mediastinal lymphomas with features intermediate between PMBL and NSHL, called mediastinal gray-zone lymphomas, have been described. The optimal management of PMBL is controversial, and most standard approaches include a combination of immunochemotherapy and mediastinal radiation. Recently, the recognition that mediastinal radiation is associated with significant long-term toxicities has led to the development of novel approaches for PMBL that have shown excellent efficacy and challenge the need for routine mediastinal radiation.

Gray zone lymphoma: better treated like hodgkin lymphoma or mediastinal large B-cell lymphoma?

Although primary mediastinal large B-cell lymphoma (PMBL) and classic Hodgkin lymphoma of the nodular sclerosis type (CHL-NS) are distinct diseases, they share several clinical characteristics and biologic features. Given that, it is not surprising that there exist mediastinal lymphomas that do not fit well into either category but have clinical and morphologic features overlapping and transitional between PMBL and CHL-NS. The term mediastinal gray zone lymphoma (MGZL) has been used for these tumors, which are included in the World Health Organization classification as "B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classic Hodgkin lymphoma." Although several studies have evaluated different therapeutic strategies in PMBL and CHL-NS, there is a paucity of prospective experience treating MGZL, given its rarity and relatively recent recognition. Historically, diseases that today would be categorized as MGZL were probably called "anaplastic large-cell lymphoma Hodgkin-like," and their outcome with standard approaches was poor, with short overall survivals. In this review-following a discussion of the biology and clinical features of MGZL, and how they compare to PMBL and CHL-NS-we outline how the treatment of PMBL and CHL-NS has evolved in recent years, and how we believe MGZL should be approached therapeutically.

Diagnostic Impact of Molecular Lineage Analysis on Paraffin-Embedded Tissue in Hematolymphoid Neoplasia Reclassified by Current WHO Criteria

BACKGROUND AND OBJECTIVE

By current WHO criteria, most - though not all - cases of hematolymphoid neoplasm can be diagnosed immunomorphologically, diminishing the role of molecular tests for lymphoid antigen receptor clonality in lymphoma diagnosis. Hence, our objective was to glean immunomorphological and molecular correlates from hematolymphoid neoplasms that had remained unresolvable without diagnostic molecular input.

METHODS

Thirty-five such cases were reviewed histologically and with standard immunoperoxidases. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNAs (EBER) was performed on selected cases. PCR amplification of genes encoding T-cell receptors (TcR) and immunoglobulin heavy chains (IgH) [TR and IGH genes, respectively] was performed on whole tissue in all cases, and on microdissected cells in two cases.

RESULTS

Twenty-five cases (71%) requiring diagnostic molecular genotyping had some form of peripheral T-cell lymphoma (PTCL). Twenty (80%) of these were complicated by a proliferation of B-lineage cells, either within the same tissue ('syntopic') as large B cells (LBC) or Reed-Sternberg (RS)-like cells (17 cases), florid lymphoid hyperplasia (two cases, one also with syntopic LBC) or monotypic plasma cells (one case), or at a separate ('metatopic') site as a B-cell lymphoma (two cases, one of which also had syntopic LBC) or Hodgkin lymphoma (HL; one case, also showing syntopic LBC). Fifteen (75%) of these 20 PTCLs with B-lineage proliferation yielded monoclonal TR gene rearrangements, and only two (10%) showed IGH monoclonality, which was transient in one case. Three (18%) of the PTCLs with LBC had originally been misinterpreted as some form of HL. Conversely, of the remaining cases, three of four (75%) that had been diagnosed initially as some form of large cell non-HL (NHL), including two of three that were called 'anaplastic', had to be revised to grade II/syncytial nodular sclerosing (NS) HL, yielding polyclonal TcRgamma gene (TRG) rearrangements, with one case, in addition, disclosing a biallelic clonal IGH gene rearrangement that excluded anaplastic large cell lymphoma.

DISCUSSION/CONCLUSION

Paradoxically, monoclonality of TR rather than IGH gene rearrangement may more often be detectable in a predominantly dispersed ('hodgkinoid'), large B-lineage cell proliferation, consistent with release from immune regulation in the milieu of impaired immunosurveillance within a PTCL. This is compounded by the difficulty in ascertaining clonal IGH gene rearrangements resulting from (1) poor consensus primer hybridization due to somatic hypermutations, and (2) 'dilution' in a T-cell-rich milieu. These same difficulties also account for the long-elusive identification of the RS cell lineage. Conversely, anaplastic lymphoma, which is of non-B lineage, may be mimicked by NSHL, which is of B lineage.

Primary mediastinal large B-cell lymphoma, classic Hodgkin lymphoma presenting in the mediastinum, and mediastinal gray zone lymphoma: what is the oncologist to do?

In recent years, an overlap in biologic and clinical features has been identified between classic Hodgkin lymphoma (CHL) and primary mediastinal large B-cell lymphoma (PMBL). Further strengthening this relationship is the identification of lymphomas with clinical and morphologic features transitional between the two, known as gray zone lymphomas (GZL). However, this diagnostic gray zone is not just of theoretical interest: it presents a practical problem, as the treatment approaches for CHL traditionally differ from those for aggressive B-cell lymphomas. This article reviews the treatment approach for mediastinal lymphomas, including CHL of the nodular sclerosis subtype (CHL-NS), PMBL, and mediastinal GZL. Though several trials have evaluated different regimens with or without radiation in PMBL and CHL-NS, there is a lack of prospective experience in treating GZL because of the rarity of these tumors. Historical data indicate that they have done poorly with traditional approaches developed for the treatment of either CHL or diffuse large B-cell lymphoma.

Primary mediastinal (thymic) large B-cell lymphoma: a short review with brief discussion of mediastinal gray zone lymphoma

Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL). It commonly presents as a bulky lesion in the anterior-superior mediastinum with symptoms related to local invasion or compression. Microscopic examination typically shows infiltration of medium-large cells surrounded by collagen fibrosis. The neoplastic cells express B-cell markers, and CD30 often shows heterogeneous staining. Comparative genomic hybridization has identified gains in loci of 9p24 and 2p15 as well as Xp11.4-21 and Xq24-26. Amplification of REL and BCL11A at 2p as well as elevated expression of JAK2, PDL1, and PDL2 at 9p has been demonstrated. Nodular sclerosis classic Hodgkin lymphoma needs to be differentiated from PMBCL and cases with overlapped features have been described as mediastinal gray zone lymphoma. Primary mediastinal (thymic) large B-cell lymphoma carries a favorable prognosis in comparison to conventional DLBCL.

Aggressive B-cell lymphomas: a review of new and old entities in the WHO classification

Aggressive B-cell lymphomas are clinically and pathologically diverse and reflect multiple pathways of transformation. The 2008 World Health Organization (WHO) classification reflects this complexity with the addition of several new entities and variants. Whereas MYC translocations have long been associated with Burkitt lymphoma (BL), deregulation of MYC has been shown to occur in other aggressive B-cell lymphomas, most often as a secondary event. Lymphomas with translocations of both MYC and BCL2 are highly aggressive tumors, with a high failure rate with most treatment protocols. These "double-hit" lymphomas are now separately delineated in the WHO classification as B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma (DLBCL) and BL. A MYC translocation is also found uncommonly in DLBCL, but the clinical consequences of this in the absence of a double hit are not yet fully delineated. Most recently, MYC translocations have been identified as a common secondary event in plasma cell neoplasms, seen in approximately 50% of plasmablastic lymphoma. Another area that has received recent attention is the spectrum of EBV-driven B-cell proliferations in patients without iatrogenic or congenital immunosuppression; most of these occur in patients of advanced age and include the EBV-positive large B-cell lymphomas of the elderly.

Hodgkin lymphoma: an update on its biology with new insights into classification

In the past few years, there has been a greater understanding of the spectrum and biology of Hodgkin lymphoma (HL). In standard texts, HL is classified as 2 distinct entities, namely nodular lymphocyte-predominant HL and classical HL (CHL). However, recent evidence suggests that CHL is not a single disease. Although the mixed cellularity and lymphocyte-depleted subtypes might be part of a biologic continuum, the nodular sclerosis subtype has a distinct epidemiology, clinical presentation, and histology. Nodular sclerosis HL might also be related to primary mediastinal B-cell lymphoma and mediastinal gray-zone lymphomas. We present an update on the pathobiology of HL and discuss these biologic and clinical differences in this review.

Diffuse aggressive B-cell lymphomas

Diffuse aggressive B-cell lymphomas comprise a relatively common and increasingly diverse group of neoplasms. Newer modalities including gene expression profiling and an increasing panel of immunohistochemical markers have contributed to greater accuracy in defining these entities. Attention is paid not only to the neoplastic cells but also to the cellular and stromal milieu in which they proliferate. These distinctions may have therapeutic implications as well, with improved outcome related to newer and sometimes targeted therapies. At the same time there is increasing understanding of the overlap, which occurs in the grey zone between diffuse large B-cell lymphoma and Burkitt lymphoma as well as between diffuse large B-cell lymphoma and Hodgkin lymphoma. This review aims to provide practical insights in the correct identification and differential diagnosis of these lymphomas, with emphasis on the changes that have occurred with the publication of the 2008 World Health Organization updated classification.

Hodgkin-like anaplastic large cell lymphoma (previously designated in the REAL classification) has same immunophenotypic features to classical Hodgkin lymphoma

In the WHO classification, the majority of Hodgkin-like ALCL cases as defined by the REAL classification are considered to be CHL. However, establishing a histological diagnosis for the gray zone between CHL and ALCL is often confusing. In this study, we re-evaluated such cases by performing immunohistochemistry with antibodies against PAX-5/BSAP, Oct.2, and BOB.1/OBF.1. Expression of PAX-5/BSAP was observed in 88% (76/87) of CHL specimens and none (0/11) of ALK-positive ALCL specimens. Among specimens of Hodgkin-like ALCL and ALK-negative ALCL, expression of PAX-5/BSAP was observed in 77% (20/26) and 18% (3/17), respectively. Most of the PAX-5/BSAP-positive specimens were negative for Oct.2 and/or BOB.1/OBF.1 except for four CHL specimens. Our results may support the WHO classification in which most cases of Hodgkin-like ALCL are classified as CHL. However, the patients with Hodgkin-like ALCL with CHL-immunophenotype (PAX-5/BSAP-positive and negative for Oct.2 and/or BOB.1) did not have a favorable outcome, with a 5-year OS rate of 58%.

Mediastinal gray zone lymphoma: the missing link between classic Hodgkin's lymphoma and mediastinal large B-cell lymphoma

In recent years, overlap in biologic and morphologic features has been identified between classic Hodgkin lymphoma (cHL) and B-cell non-Hodgkin lymphoma. Nevertheless, the therapeutic approaches for these diseases remain different. We undertook a study of "mediastinal gray zone lymphomas" (MGZL), with features transitional between cHL nodular sclerosis (NS) and primary mediastinal large B-cell lymphoma (MLBCL) to better understand the morphologic and immunophenotypic spectrum of such cases. Twenty-one MGZL cases were identified over a 20-year period. We also studied 6 cases of composite or synchronous lymphoma with two distinct components at the same time (cHL-NS and MLBCL) and 9 sequential cases with MLBCL and cHL-NS at different times. All patients had a large mediastinal mass. Immunohistochemical studies focused on markers known to discriminate between cHL and MLBCL, including B-cell transcription factors. VJ-PCR was performed in 8 cases to look at clonality of the immunoglobulin heavy chain gene (IgH). Of the gray zone cases, 11 had morphology reminiscent of cHL-NS, but with unusual features, including a large number of mononuclear variants, diminished inflammatory background, absence of classic Hodgkin phenotype, and strong CD20 expression (11 of 11). Ten cases had morphology of MLBCL, but with admixed Hodgkin/Reed-Sternberg and lacunar cells, absent (3 of 10) or weak (7 of 10) CD20 expression, and positivity for CD15 in 7 cases. B-cell transcription factor expression in the gray zone cases more closely resembled MLBCL than cHL with expression of Pax5, Oct2, and BOB.1 in all but 1 case studied (14 of 15). MAL staining was found in 7 of 10 MGZL, and in at least one component of 6 of 7 evaluable composite or sequential MLBCL/cHL cases. Two cases of sequential lymphoma showed rearrangements of the IgH gene of identical size: one in which MLBCL was the first diagnosis and one in which MLBCL was diagnosed at relapse, indicating clonal identity for the two components of cHL and MLBCL. There is accumulating evidence that MLBCL and cHL are related entities. Further support for a relationship between MLBCL and cHL-NS is provided by composite and metachronous lymphomas in the same patient, as well as the existence of MGZL with transitional morphology and phenotype.

Primary mediastinal large B-cell lymphoma: optimal therapy and prognostic factor analysis in 141 consecutive patients treated at memorial Sloan Kettering from 1980 to 1999

Primary mediastinal large B-cell lymphoma (PMLBL) is a distinct clinicopathological entity with unclear prognostic factors and optimal treatment approach. To elucidate an optimal treatment and identify predictive factors, a retrospective analysis of 141 consecutive patients was undertaken. Patients received cyclophosphamide, hydroxydaunomycin, Oncovin, prednisone (CHOP)-like therapy, the non-Hodgkin lymphoma (NHL)-15 regimen or upfront autologous stem cell transplantation (ASCT) on Institutional Review Board approved trials or according to the institutional guidelines. Evaluation included lactate dehydrogenase, International Prognostic Index (IPI) assessment, computed tomography scan and gallium imaging. With a median follow-up of 10.9 years, event-free survival (EFS) and overall survival (OS) was 50% and 66% respectively. EFS/OS for CHOP/CHOP-like, NHL-15 and upfront ASCT was 34/51%, 60/84% and 60/78% respectively. CHOP/CHOP-like regimens had inferior EFS and OS versus NHL-15 or upfront ASCT (P < 0.001). A total of 23% of patients received radiotherapy. Multivariate analysis revealed the following outcome predictors: for EFS, greater than or equal to two extranodal sites and initial therapy received (NHL-15 or upfront ASCT); for OS, only initial therapy with NHL-15. We conclude: (i) dose-dense chemotherapy with NHL-15 may be superior to CHOP for PMLBL; (ii) The impact of consolidative radiotherapy requires randomised controlled trials; (iii) The age-adjusted IPI did not predict survival in this analysis; (iv) high-dose chemotherapy/ASCT should be reserved for upfront anthracycline-based therapy failure or in clinical trials for high-risk patients.

Multi-lineage interrogation of the performance characteristics of a split-signal fluorescence in situ hybridization probe for anaplastic lymphoma kinase gene rearrangements: a study of 101 cases characterized by immunohistomorphology on fixed archival tissue

BACKGROUND

Fluorescence in situ hybridization (FISH) can identify chromosomal translocations on fixed archival tissue, but studies cross-validating the utility of FISH on lesions of different cell lineages that harbor similar translocations (e.g. those involving anaplastic lymphoma kinase [ALK]) have not been published.

AIM

Our objective was to define the diagnostic utility, performance characteristics, and limitations of a commercially available, split-signal, FISH probe for ALK gene rearrangements on fixed, archived tissue from lesions of diverse cell lineage.

STUDY DESIGN

The sensitivity, specificity, and positive and negative predictive values of the Vysis ALK FISH probe were compared with those of the ALK-1 antibody (Dako) in a series of 101 cases, comprising 43 hematolymphoid neoplasms, 4 reactive lymphoid controls, 50 non-hematolymphoid (including neuroectodermal, epithelial, myofibroblastic, and germ cell) lesions, and 4 early-trimester aborted fetuses that served as neuroblastic controls.

METHODS

The study involved a predominantly (72%) Singaporean Chinese population aged between 9 months and 88 years (excluding the aborted fetal controls). All cases were reviewed both histologically and immunohistochemically with a wide panel of antibodies using the standard protocols in order to diagnose them according to the latest WHO classification systems. A positive cut-off value was determined, both by comparison with diagnostic categories with and without ALK translocations, as well as with negative controls.

RESULTS

The ALK FISH probe suffered a 33% non-informative rate, but in informative cases it showed 94% concordance with the ALK-1 immunostain. A minimum cut-off value of 5 in 200 informative cells was adopted to make a positive call in each case. Of the ALK-1 immunoreactive lesions, nine lymphomas were concordantly ALK translocation-positive but one vesical inflammatory myofibroblastic tumor was discordantly FISH-negative. Among the ALK-1-immunonegative lesions, one case each of anaplastic lymphoma and pulmonary mycobacterial spindle cell pseudotumor were discordantly ALK FISH-positive, while a case each of intestinal myeloblastic tumor and ganglioglioma showed initial--but not reproducible--positive FISH readings. The remaining cases were concordantly negative.

DISCUSSION

The discrepancies between ALK FISH results and well-established immunomorphological parameters indicate that interpretation is not always straightforward. Notably, the derivation of threshold cut-off values for positive calls on FISH assays has seldom been addressed in the literature, and has raised issues in interpreting cases with borderline positivity in this study. The factors that may influence such cut-off values are extensively reviewed.

CONCLUSIONS

We propose the term 'conditional threshold positivity' to encourage the adoption of different cut-off values for making positive calls in lesions of different origin.

[Classical Hodgkin's lymphoma: biology and grey zones]

Advances in the biology of Hodgkin's lymphoma have lead to the distinction between two entities, "classical" Hodgkin's lymphoma and nodular lymphocyte predominance Hodgkin's lymphoma, previously called nodular paragranuloma, which share distinct clinical aspects. The definition of diagnostic criteria has also been helpful to separate Hodgkin's lymphoma from other lymphomas which can mimick Hodgkin's disease such as anaplastic large cell lymphomas, T-cell/histiocyte rich diffuse large B-cell lymphoma, and some peripheral T-cell lymphomas, mainly angioimmunoblastic-type. Reed-Sternberg cell, the neoplastic cell of "classical" Hodgkin's lymphoma, still retains some secrets. Despite some controversies, there is more and more evidence for a lymphoid B cell origin. The involvement of Epstein-Barr virus, cytokines and/or oncogenes expression in the pathogeny can be suggested, although the precise mechanisms leading to transformation and/or accounting for tumour progression are still elusive. Recently, the roles of the pathway implicating the activation of NFkappaB as well as the autocrine secretion of interleukin-13 have been demonstrated.

Nodular lymphocyte-predominant Hodgkin lymphoma with nodules resembling T-cell/histiocyte-rich B-cell lymphoma: differential diagnosis between nodular lymphocyte-predominant Hodgkin lymphoma and T-cell/histiocyte-rich B-cell lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and T-cell/histiocyte-rich B-cell lymphoma (T/HRBCL) are distinct tumors and are treated differently. They are linked by a morphologic and probably a biologic continuum, which renders the differential diagnosis difficult. To develop criteria to distinguish the entities along the morphologic continuum, we correlated the lymph node architecture and immunophenotype of both tumor cells and reactive components of 235 neoplasms in the spectrum of NLPHL and T/HRBCL with clinical data. Two hundred and eighteen cases fitted the World Health Organization (WHO) criteria of NLPHL (139) or T/HRBCL (79). While tumor cells in both entities were immunophenotypically similar, background composition differed: in NLPHL small B cells and CD3+CD4+CD57+ T cells were common, whereas in T/HRBCL, CD8+ cytotoxic T cells and histiocytes dominated. Follicular dendritic cells (FDCs) formed expanded meshworks in NLPHL, whereas they were absent in T/HRBCL. Seventeen cases represented a gray zone: within FDC meshworks, neoplastic B cells resided in a background depleted of small B cells but rich in T cells and histiocytes. Tumor cells either were loosely scattered or formed clusters, thus resembling areas of either T/HRBCL or inflammatory diffuse large BCL (DLBCL) within the nodules. Patients with these NLPHLs with T-cell/histiocyte-rich nodules presented at a high stage and with B symptoms, as in T/HRBCL, but had an excellent survival, as in NLPHL. This morphologic pattern suggests a biologic continuum between NLPHL and T/HRBCL.

The clinical impact of expert pathological review on lymphoma management: a regional experience

The All Wales Lymphoma Panel (AWLP) was established in January 1998 to provide a central expert pathological review service for district general hospital pathologists. A discordance rate of 20% between the submitted and reviewed diagnosis has previously been identified. It has not been known whether this change in diagnosis affects clinical management. Ninety-nine patients whose diagnosis was changed as a result of central pathological review are presented. Between January 1998 and August 2000, 125 of 745 (17%) specimens submitted for AWLP review had a consequent change in pathological diagnosis. Of these 125 specimens, 99 (79%) complete case notes were recovered. In all 99 cases, a hypothetical management plan was generated using collected data, clinical protocols and the submitted pathological diagnosis. These plans were compared with the actual management patients received based on the reviewed diagnosis proffered by the AWLP. Forty-six of 99 (46%) cases had a change in management as a result of central pathological review. Overall, management was changed in 8% of cases referred for central pathological review. In conclusion, expert central pathological review has a direct effect on patient management.