Intravascular bone marrow accumulation in persistent polyclonal lymphocytosis: a misleading feature for B-cell neoplasm

[Persistent Polyclonal B-Cell Lymphocytosis (PPBL): An Entity That Is Not What it Seems]

Persistent polyclonal B-cell lymphocytosis is a rare disease with chronic lymphocytosis of polyclonal origin, which is more frequent in mostly asymptomatic middle-aged female smokers. The hallmark of this entity is the presence of bilobed/binucleated B lymphocytes, which are polyclonal as demonstrated by immunophenotyping; an elevated IgM level is common. This disease shows, in most cases, an indolent course over many years and, although controversial, it may rarely convert to malignant lymphoma. In addition to smoking, a genetic predisposition for persistent polyclonal B-cell lymphocytosis is likely. Recurrent genetic aberrations have been described. The differential diagnosis includes non-Hodgkin's lymphoma and a clear distinction between both entities is of the utmost importance because treatment is generally not indicated in the former: instead, regular follow-up is recommended. The authors describe the case of a 46-year-old female smoker, who presented with chronic lymphocytosis, elevated IgM and circulating binucleated lymphocytes. Excluding lymphoma was important considering the unusual presentation with constitutional symptoms and splenomegaly.

Reactive Intralymphovascular Immunoblastic Proliferations Mimicking Aggressive Lymphomas

Reactive intralymphovascular immunoblastic proliferations (ILVIPs) may mimic aggressive lymphomas and are rarely reported. Herein, we characterize the clinicopathologic features of 8 patients with ILVIPs. No patients had lymphadenopathy, hepatosplenomegaly, or other findings suggestive of lymphoma. The ILVIPs involved the small or large intestine (n=5) and appendix (n=3). Patients were evaluated for abdominal pain, suspected appendicitis, intestinal obstruction, diverticulitis, volvulus, or tumor resection. Histologic sections showed expanded lymphovascular spaces filled by intermediate to large immunoblasts, positive for CD38, CD43, CD45, CD79a, and MUM1/IRF4 in all cases tested. Five of 6 (83%) cases were positive for CD30. CD20 was weakly positive in a subset of cells in 2 (25%) cases, and PAX5 was weakly positive in 4 (50%) cases. The immunoblasts expressed polytypic light chains in all cases tested. In 1 case, a subset of immunoblasts expressed T-cell markers indicating the presence of a T-cell component. The immunoblasts were negative for ALK, BCL-2, BCL-6, CD10, CD56, CD138, and Epstein-Barr virus-encoded small RNA in all cases assessed. The proliferation index shown by Ki-67 was high with a median of 80%. In all 6 cases tested, the immunoblasts were shown within lymphatic channels highlighted by D2-40. In conclusion, ILVIPs can be rarely observed in patients with inflammatory or infectious conditions, especially in gastrointestinal tract surgical specimens. The immunoblasts are predominantly of B-lineage with a postgerminal center immunophenotype and are located within lymphatic channels. It is essential to distinguish reactive ILVIPs from aggressive lymphomas to avoid unnecessary therapy.

Patients with Persistent Polyclonal B-Cell Lymphocytosis Share the Symptomatic Criteria of Systemic Exertion Intolerance Disease

Introduction: Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare and still poorly understood entity, with 90% of cases occurring in female smokers. Patients often appear tired and in pain, but the clinical symptoms remain imprecise. The main risk is the development of lymphoma in some cases. To better understand the characteristics of the fatigue associated with PPBL and study its relationship with systemic exertion intolerance disease (SEID), we analyzed the symptoms in a cohort of patients with PPBL included in the French national registry. Material and methods: An anonymous questionnaire following the recommendations of the Institute of Medicine/National Academy of Medicine for screening of the new SEID criteria was created in French and mailed to 50 patients. Results: Thirty-nine (78%) contacted patients responded. The studied population was mainly constituted of women (90%) with an average age of 50 (18–59) years. Smoking was a constant factor in all patients. A total of 28/39 (72%) respondents met the SEID symptoms criteria. Severe chronic fatigue for more than 6 months was noted in 36/39 cases (92%). Unrefreshing sleep, post-exertional malaise, cognitive impairment, and orthostatic intolerance were described in 30/39 (77%), 32/39 (82%), 28/39 (72%), and 27/39 (69%) cases, respectively. Pain (arthralgia, myalgia, headache) was present in 26/39 (67%) cases. The most prominent SEID symptoms were fatigue, followed by post-exercise discomfort and cognitive difficulties. The most disabling symptom was non-restorative sleep, followed by pain. An inflammatory and/or autoimmune context was noted in 13 patients (33%), and these comorbidities could have favored the deterioration of the general condition. Three patients also presented with fibromyalgia. However, 3 patients did not mention any complaints. Conclusion: This survey indicated that patients with PPBL most often initially presented with disabling chronic fatigue, chronic pain, and other symptoms suggestive of SEID but requiring more studies to confirm it. Education of medical staff about the symptoms of PPBL should be encouraged to better assess this peculiar condition.

Issues in diagnosis of small B cell lymphoid neoplasms involving the bone marrow and peripheral blood. Report on the Bone Marrow Workshop of the XVIIth meeting of the European Association for Haematopathology and the Society for Hematopathology

Small B cell lymphoid neoplasms are the most common lymphoproliferative disorders involving peripheral blood (PB) and bone marrow (BM). The Bone Marrow Workshop (BMW) organized by the European Bone Marrow Working Group (EBMWG) of the European Association for Haematopathology (EAHP) during the XVIIth EAHP Meeting in Istanbul, October 2014, was dedicated to discussion of cases illustrating how the recent advances in immunophenotyping, molecular techniques and cytogenetics provide better understanding and classification of these entities. Submitted cases were grouped into following categories: (i) cases illustrating diagnostic difficulties in chronic lymphocytic leukaemia (CLL); (ii) cases of BM manifestations of small B cell lymphoid neoplasms other than CLL; (iii) transformation of small B cell lymphoid neoplasms in the BM; and (iv) multiclonality and composite lymphomas in the BM. This report summarizes presented cases and conclusions of the BMW and provides practical recommendations for classification of the BM manifestations of small B cell lymphoid neoplasms based on the current state of knowledge.

Persistent Polyclonal B Cell Lymphocytosis B Cells Can Be Activated through CD40-CD154 Interaction

Persistent polyclonal B cell lymphocytosis (PPBL) is a rare disorder, diagnosed primarily in adult female smokers and characterized by an expansion of CD19⁺CD27⁺IgM⁺ memory B cells, by the presence of binucleated lymphocytes, and by a moderate elevation of serum IgM. The clinical course is usually benign, but it is not known whether or not PPBL might be part of a process leading to the emergence of a malignant proliferative disorder. In this study we sought to investigate the functional response of B cells from patients with PPBL by use of an optimal memory B cell culture model based on the CD40-CD154 interaction. We found that the proliferation of PPBL B cells was almost as important as that of B cells from normal controls, resulting in high immunoglobulin secretion with in vitro isotypic switching. We conclude that the CD40-CD154 activation pathway is functional in the memory B cell population of PPBL patients, suggesting that the disorder may be due to either a dysfunction of other cells in the microenvironment or a possible defect in another B cell activation pathway.

[In situ lymphoma and other early stage malignant non-Hodgkin lymphomas]

The increasing use of immunohistochemical and molecular investigations of lymphatic tissues results in more frequent detection of early lymphoid proliferations. These show some but not all features of malignant lymphomas without fulfilling the diagnostic criteria for the diagnosis of lymphoid malignancy. In addition to well-known premalignant B-cell proliferations, such as monoclonal gammopathy of unknown significance (MGUS) and monoclonal B-cell lymphocytosis (MBL), so-called in situ lymphomas have recently been described with minimal infiltrates of clonal B-cells in morphologically reactive lymphoid tissues which show the phenotypic and genetic features of specific B-cell lymphoma subtypes and often show a characteristic topographical distribution. This article addresses a group of clonal lymphoproliferations with usually localized disease and excellent clinical prognosis, such as pediatric follicular lymphoma and nodal marginal zone lymphoma. Another group of early lesions not addressed in this review are virally induced lymphoproliferations which represent a grey zone between purely reactive lesions and malignant lymphomas and may pose significant diagnostic as well as clinical problems. In this review diagnostic criteria for early or in situ lesions and their distinction from partial infiltration by malignant lymphoma are described.

Histological and immunohistochemical features of the spleen in persistent polyclonal B-cell lymphocytosis closely mimic splenic B-cell lymphoma

Persistent polyclonal B-cell lymphocytosis (PPBL) is rare and intriguing hematological disorder predominantly reported in young to middle- aged smoking women. It is characterized by persistent moderate polyclonal B-cell lymphocytosis with circulating hallmark binucleated lymphocytes and elevated polyclonal serum IgM. Most patients have benign clinical course on long-term follow-up. Some pathologic features of PPBL may resemble malignant lymphoma, including morphology as well as frequent cytogenetic and molecular abnormalities. Significant symptomatic splenomegaly requiring splenectomy is very unusual for this disorder; therefore there is a lack of descriptions of the morphologic features of the spleen in the literature. We present here one of the first detailed descriptions of the morphologic and immunohistochemical features of the spleen from a young female with PPBL who developed massive splenomegaly during 6-year follow up. Splenectomy was performed for symptomatic relief and suspicion of malignant process. The morphological and immunohistochemical features of the spleen closely mimicked involvement by B-cell lymphoma, however there was no monotypic surface light chain restriction seen by flow cytometry and no clonal rearrangement of IgH gene was detected by molecular analysis. Evaluating a splenectomy sample in cases like this may present a diagnostic challenge to pathologists. Therefore, correlation with B cell clonality studies (by flow cytometry and molecular analysis), clinical findings and peripheral blood morphology searching for characteristic binucleated lymphocytes is essential to avoid misdiagnosing this benign process as B-cell lymphoma. We also present here a literature review on pathogenesis of PPBL.

Early lesions in lymphoid neoplasia: Conclusions based on the Workshop of the XV. Meeting of the European Association of Hematopathology and the Society of Hematopathology, in Uppsala, Sweden

The increasing use of immunophenotypic and molecular techniques on lymphoid tissue samples without obvious involvement by malignant lymphoma has resulted in the increased detection of "early" lymphoid proliferations, which show some, but not all the criteria necessary for a diagnosis of malignant lymphoma. In most instances, these are incidental findings in asymptomatic individuals, and their biological behaviour is uncertain. In order to better characterize these premalignant conditions and to establish diagnostic criteria, a joint workshop of the European Association for Haematopathology and the Society of Hematopathology was held in Uppsala, Sweden, in September 2010. The panel reviewed and discussed more than 130 submitted cases and reached consensus diagnoses. Cases representing the nodal equivalent of monoclonal B-cell lymphocytosis (MBL) were discussed, as well as the "in situ" counterparts of follicular lymphoma (FL) and mantle cell lymphoma (MCL), topics that also stimulated discussions concerning the best terminology for these lesions. The workshop also addressed the borderland between reactive hyperplasia, and clonal proliferations such as pediatric marginal zone lymphoma and pediatric FL, which may have very limited capacity for progression. Virus-driven lymphoproliferations in the grey zone between reactive lesions and manifest malignant lymphoma were covered. Finally, early manifestations of T-cell lymphoma, both nodal and extranodal, and their mimics were addressed. This workshop report summarizes the most important conclusions concerning diagnostic features, as well as proposals for terminology and classification of early lymphoproliferations and tries to give some practical guidelines for diagnosis and reporting.

[Persistent polyclonal B-cell lymphocytosis: study of 35 cases]

BACKGROUND AND OBJECTIVES

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity, presenting especially in adult smoker women. It is characterized by an increase of serum IgM, DR7-HLA haplotype, cytogenetic abnormalities and multiple IgH/BCL-2 rearrangements. To date, it has not been elucidated whether this is a benign or premalignant disorder. We analyzed the PPBL characteristics with especial attention to its evolution.

PATIENTS AND METHODS

Thirty-five PPBL patients from 5 hospitals in Catalonia were retrospectively analyzed. A simultaneous morphologic review of the blood smears was performed by members of the GCCH in a 16 multiple-observer optic microscope. Clinical and biological data were also analyzed.

RESULTS

PPBL presents in the majority of cases with persistent polyclonal B-cell lymphocytosis and affects primarily smoker women. The morphologic hallmark, in absence of viral infections, is the presence of activated lymphocytes with bilobulated and/or cleaved nuclei, and nuclear pockets in the ultrastructural study. Increased serum IgM, HLA-DR7 haplotype, chromosomal abnormalities such as i(3)(q10) and multiple IgH/BCL-2 rearrangements were detected. Thirty-four out of 35 patients are alive after a median follow up of 70.7 months. One patient died because of lung adenocarcinoma and another developed a follicular lymphoma without relation to PPBL.

CONCLUSIONS

PPBL has an asymptomatic and stable evolution, although it frequently presents genetic abnormalities. It remains unknown whether it is a premalignant entity, similar to monoclonal gammopathies of unknown significance. Hence, accurate cytologic diagnosis and follow-up are essential.

Polyclonal B-cell lymphocytosis with binucleated lymphocytes (PPBL)

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare and recently described entity. The review of the literature show PPBL is diagnosed predominantly but not exclusively in women, usually smokers. PPBL is recognized by a moderate, chronic and absolute lymphocytosis (>4 × 10(9)/l) in the peripheral blood. In 10% of cases without lymphocytosis, the PPBL diagnosis has to be suggested by peripheral blood examination showing in all cases atypical binucleated lymphocytes. A polyclonal serum IgM is also associated and HLA-DR7 expression is present in most cases. Contrary to B-cell chronic lymphoproliferative disorders (B-CLPD), peripheral B cells are polyclonal with kappa and lambda light-chain expression and no clonal rearrangement of immunoglobulin heavy chain genes is usually demonstrated. The detection of an extra isochromosome for the long arm of chromosome 3 +i(3)(q10) has to be considered as a specific marker of PPBL. We performed conventional cytogenetic analysis (CCA) in 111 patients with typical PPBL we followed-up more than 4 years. +i(3q) was detected in 34% (33/98), PCC in 8% (8/98) and both abnormalities in 31% (30/98). CCA showed neither +i(3q) nor PCC in 28% (27/98). Fluorescence in situ hybridization (FISH) was also performed in 84 cases and +i(3q) was detected in 71% (60/84). When combining both procedures in 84 patients, +i(3q) was detected in 17 patients with negative CCA and was confirmed in 43 patients with positive CCA. CCA and FISH were both negative in 24 cases. Whether patients with PPBL are at increased risk of hematological malignancy remains unclear. After a median follow-up of 4.4 years, most PPBL patients presented a stable clinical and biological course. Six patients died from pulmonary cancer, myocardial infarction, cerebral aneurysm rupture or diffuse large B-cell lymphoma. Two patients had IgM monoclonal gammopathy of undetermined significance (MGUS) at the time of PPBL diagnosis and two other patients developed IgM MGUS respectively 12 and 22 years after PPBL diagnosis. A malignant non Hodgkin's lymphoma (NHL) appeared in 3 additional patients: two patients presented diffuse large B cell lymphoma and 1 patient a splenic marginal zone lymphoma. In conclusion, the possibility of PPBL to evolve toward a clonal proliferation, malignant lymphoma or secondary solid cancer lead us to consider PPBL not as a benign pathology. We recommend a careful and continued clinical and biological long-term follow-up in all PPBL patients.

Combined automated cell and flow cytometric analysis enables recognition of persistent polyclonal B-cell lymphocytosis (PPBL), a study of 25 patients

Persistent polyclonal B-cell lymphocytosis (PPBL) is an extremely rare disorder, which occurs almost exclusively in smoking women and is characterized by a lymphocytosis with circulating binucleated lymphocytes. We analyzed 25 PPBL patients with respect to immunophenotype and by adaptive cluster analysis system (ACAS). Furthermore, HLA type, presence of Epstein-Barr virus (EBV) DNA in B cells, and clinical data were evaluated. Overall, the median percentages of B cells in PPBL patients with expression of CD5(dim), CD23(dim), CD25, CD27, and FMC7 were 21%, 38%, 16%, 74%, and 93%. Compared to normal controls, ACAS revealed a subset of nucleic-acid-rich lymphocytes located between the regular lymphocyte and regular monocyte region. Sixteen (64%) of 25 patients carried a HLA DR7 phenotype. Quantitative real-time polymerase chain reaction analysis did not detect relevant amounts of EBV DNA in circulating B cells of any patient. During a median follow-up of 5 years, a single patient developed lymphoplasmacytic lymphoma. The abnormal morphology and frequent, albeit dim, expression of CD5 and CD23 in PPBL may result in erratic diagnostic assignment of this benign disorder. However, incorporation of immunophenotyping and ACAS into the diagnostic algorithm allows recognition of PPBL in routine analysis and its differentiation from malignant B cell lymphoproliferative diseases. We found that an infection of a significant percentage of PPBL cells by EBV is unlikely. The observation of malignant lymphoma in a single patient implicates that evolution into a clonal malignant transformation may occasionally occur in PPBL.

Diagnosis and Classification of Malignant Lymphoma and Related Entities in the Bone Marrow Trephine Biopsy

The trephine bone marrow (BM) biopsy is an important diagnostic tool in patients with malignant lymphoma. BM examination can serve to establish or confirm a primary diagnosis of lymphoma or to determine the extent of disease dissemination for staging purposes. BM histology renders information which cannot be gained equally from aspirate material, such as spacial distribution and extent of infiltrates, BM cellularity and fibrosis. Furthermore, cytology including flow cytometric immunophenotyping can give false-negative results in BM involvement by lymphoma due to intralesional fibrosis. In addition to morphological examination, the availability of a broad panel of antibodies suitable for paraffin-embedded tissues, in conjunction with less damaging decalcification procedures, nowadays enables us to perform complete immunophenotyping on BM trephines and allows for classification of lymphoma infiltrates according to established algorithms. Molecular determination of clonality and interphase fluorescent in situ hybridization can be employed selectively to resolve difficult cases. This review describes important diagnostic features of malignant lymphoma in the BM, relevant differential diagnoses, and the proper use of ancillary techniques.

[Asymptomatic 32 year old female smoker with persistent polyclonal lymphocytosis]

A 32 year old female smoker (20 pack years) presented with an asymptomatic lymphocytosis of 13,000/nl and splenomegaly. The patient's blood smear showed an absolute lymphocytosis with 65% atypical lymphocytes. A total of 1% of the lymphocytes were bilobulated. Bone marrow histology and immunphenotyping of blood and bone marrow excluded leukemia and non-Hodgkin's lymphoma. IgH-CDR-3 PCR analysis revealed a polyclonal pattern. In summary, a persistent polyclonal B-cell-lymphocytosis (PPBL) was diagnosed. The exact etiology of PPBL is still unclear, however, it is associated with a polyclonal raise in the lymphocyte count of CD27+IgD+-memory-B-lymphocytes due to a defect in apoptosis signaling and leukocyte homing to secondary lymphoid tissues. An association with cigarette smoking is obvious since all patients are smokers. From all published cases, only two developed a malignancy with an uncertain association with PPBL. We have been monitoring our patient for 6.5 years without any evidence of the development of a lymphoma.

Intravascular lymphoma: a neoplasm of 'homeless' lymphocytes?

Intravascular lymphoma (IVL) is an extremely rare form of non-Hodgkin lymphoma characterized by almost exclusive growth of neoplastic lymphocytes within blood vessel lumen. IVL is morphologically characterized in most instances by large cells with B-cell lineage. IVL is an aggressive and usually disseminated disease that predominantly affects elderly patients, resulting in poor PS, B-symptoms, anemia, and high lactate dehydrogenase serum level. The brain and skin are the most commonly involved sites; nodal disease is rare. Survival after conventional chemotherapy is disappointing, with a relevant impact of diagnostic delay and lethal complications. Notwithstanding these results, IVL limited to the skin (cutaneous variant) is a favorable presentation with distinctive clinical characteristics. Moreover, differences in clinical presentation with Eastern Countries IVL cases, mostly associated with hemophagocytic syndrome, do exist. Intensive combinations containing drugs with higher central nervous system bioavailability are needed in cases with brain involvement; the role of high-dose chemotherapy with autologous stem cell transplantation should be investigated in younger patients with unfavorable features. The present review will discuss the most recent acquisitions related either to diagnosis and immunophenotypic/biologic characteristics as well as clinical/therapeutic issues of IVL.

Immunohistochemistry in bone marrow pathology: a useful adjunct for morphologic diagnosis

Pathomorphological examination of trephine biopsies of the bone marrow (BM) represents a standard method for the diagnosis and staging of hematologic neoplasms and other disorders involving the BM. The increasing knowledge about the genetic basis and biology of hematologic neoplasms, as well as the recently proposed WHO classification system, provide the framework for an accurate diagnosis. Although conventional morphology remains the gold standard for paraffin-embedded BM trephines, immunohistochemical stainings have become an integral part of the diagnostic workup. Antibodies suitable for paraffin sections are generally applicable to BM trephines, but modifications of staining protocols may be necessary due to the alternative fixatives and decalcification procedures used for BM biopsies. The indications for immunostainings range from confirmation and classification of lymphoma involvement, subclassification of acute leukemias, and estimating blast counts in myelodysplastic and myeloproliferative syndromes to characterization of BM involvement in nonhematologic neoplasms. Although subtyping of NHL in the BM is more difficult from the point of morphology, classification of the entities that frequently involve the BM, especially the small B-cell lymphomas, can easily be achieved with the help of immunohistochemistry. In this review, we try to summarize the current state of the art in BM immunohistochemistry for the diagnosis of hematologic disorders. Moreover, diagnostic algorithms and useful antibody panels are proposed for a rational and cost-effective approach.