Hodgkin transformation of chronic lymphocytic leukemia

Lymphocytic Lymphoma Transforming into Hodgkin Lymphoma in Sub-Saharan Africa: Case Report and Literature Review

The Hodgkin variant Richter syndrome (HvRS) is an infrequent complication occurring in 1% of lymphocytic lymphoma/chronic lymphocytic leukemia patients. We report a case of HvRS diagnosed in Sub-Saharan Africa. A 63-year-old patient was consulted for the investigation of an abdominal mass that had been evolving for 5 years prior to admission. His history revealed night sweats, 13% weight loss in 3 months and persistent pruritis. Examination revealed bilateral cervical axillary and inguinal macroadenopathies, painless abdominal distension, pruritic lesions and WHO 2 PS. The blood count showed anemia at 9.5 g/dL. Histology revealed a lymphomatous proliferation of diffuse architecture, nodular in places, with Hodgkin and Sternberg cells associated with small lymphocytes, histiocytes and eosinophilic polymorphs. Immunohistochemistry showed CD20, PAX5, BCL2, CD5, CD23 and MYC positivity; Ki67 at 10% and cyclin D1, BCL6 and CD10 negativity; CD30 positivity on Hodgkin and Sternberg cells that remained CD20 negative; difficulty interpreting CD15; EBV positivity (EBERs); and CD3 and CD5 positivity on reactive T cells. CD138 and kappa and lambda light chains were non-contributory. The extension work-up classified the patient as Ann Arbor stage III B with a Hasenclever score of 3/7. This case illustrates the difficulties in diagnosing HvRS in our countries, where the number of haematopathologists is insufficient and the technical facilities are limited.

A + AVD for Treatment of Hodgkin Lymphoma Variant of Richter's Transformation

Hodgkin lymphoma variant of Richter's transformation (HvRT) is a rare complication for patients with chronic lymphocytic leukemia (CLL), with an overall poor prognosis. We present the first known case series of patients with HvRT treated with the combination of brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine (A + AVD). In our series of 4 patients, two patients treated with A + AVD for HvRT had durable remissions of 40 and 42 months, while two patients had disease progression and ultimately died. Continued investigation into the optimal management for patients with HvRT is still needed.

A case of Hodgkin lymphoma-type Richter syndrome presenting as small-intestinal perforation

Hodgkin lymphoma type of Richter syndrome (HL-type RS) is a rare disease that arises in patients with chronic lymphocytic leukemia (CLL). HL-type RS lesions can manifest in various sites and are often accompanied by related symptoms. This is the first case report to describe diagnosis of HL-type RS after emergency surgery for gastrointestinal perforation caused by the development of a HL-type RS lesion. A 47-year-old man diagnosed with CLL three years prior began treatment with ibrutinib due to worsening anemia and splenomegaly two months prior to the emergency department presentation. Although splenomegaly improved, lymphocytopenia, anemia, and a newly arising mesenteric lymphadenopathy continued to worsen. He presented to the emergency department with abdominal pain, and subsequent surgery revealed small intestinal perforation and mesenteric lymphadenopathy with HL-type RS confirmed by histopathological examination of the resected small intestine. He subsequently received brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine (A + AVD), which effectively managed the HL-type RS. If CLL clinical presentation deviates from the typical course, an early tissue biopsy should be considered to evaluate for HL-type RS. Given the adoption of the A + AVD regimen as the standard treatment for Hodgkin lymphoma, further research is needed to evaluate its efficacy in HL-type RS.

From genetics to therapy: Unraveling the complexities of Richter transformation in chronic lymphocytic leukemia

Richter transformation (RT) refers to the progression of chronic lymphocytic leukemia, the most prevalent leukemia among adults, into a highly aggressive lymphoproliferative disorder, primarily a diffuse large B-cell lymphoma. This is a severe complication that continues to be a therapeutic challenge and remains an unmet medical need. Over the last five years, significant advances have occurred in uncovering the biological processes leading to the RT, refining criteria for properly diagnose RT from other entities, and exploring new therapeutic options beyond the ineffective chemotherapy. This review summarizes current knowledge in RT, including recent advances in the understanding of the pathogenesis of RT, in the classification of RT, and in the development of novel therapeutic strategies for this grave complication.

Transformations of marginal zone lymphomas and lymphoplasmacytic lymphomas: Report from the 2021 SH/EAHP Workshop

OBJECTIVES

To summarize the conclusions of the 2021 Society for Hematopathology/European Association for Haematopathology workshop regarding transformations of marginal zone lymphoma (MZL) and lymphoplasmacytic lymphoma (LPL).

METHODS

Nineteen cases were submitted to this portion of the workshop. Additional studies were performed in cases with sufficient material.

RESULTS

Cases included splenic MZL (n = 4), splenic diffuse red pulp small B-cell lymphoma (n = 2), nodal MZL (n = 4), extranodal MZL (n = 1), and LPL (n = 8). The most common transformation was to diffuse large B-cell lymphoma (DLBCL), but others included classic Hodgkin lymphoma, high-grade B-cell lymphomas with MYC and BCL6 rearrangements, plasmablastic lymphoma, and plasma cell leukemia. Two splenic MZLs with transformation to DLBCL contained t(14;19)(q32;q13.3) IGH::BCL3 rearrangements in both samples. Paired sequencing studies in 5 MZLs with transformation to clonally related DLBCL identified a variety of mutations and gene fusions at the time of transformation, including CARD11, IGH::MYC, NOTCH2, P2RY8, TBLX1X1, and IGH::CD274.

CONCLUSIONS

Marginal zone lymphoma and LPL may undergo a variety of transformation events, most commonly to DLBCL, which is usually, although not always, directly clonally related to the underlying low-grade lymphoma. Multiparameter analysis including broad-based sequencing studies can assist in the diagnosis and classification of these uncommon cases.

Immunological Aspects of Richter Syndrome: From Immune Dysfunction to Immunotherapy

Richter Syndrome (RS) is defined as the development of an aggressive lymphoma in patients with a previous or simultaneous diagnosis of chronic lymphocytic leukemia (CLL). Two pathological variants of RS are recognized: diffuse large B-cell lymphoma (DLBCL)-type and Hodgkin lymphoma (HL)-type RS. Different molecular mechanisms may explain the pathogenesis of DLBCL-type RS, including genetic lesions, modifications of immune regulators, and B cell receptor (BCR) pathway hyperactivation. Limited data are available for HL-type RS, and its development has been reported to be similar to de novo HL. In this review, we focus on the immune-related pathogenesis and immune system dysfunction of RS, which are linked to BCR over-reactivity, altered function of the immune system due to the underlying CLL, and specific features of the RS tumor microenvironment. The standard of care of this disease consists in chemoimmunotherapy, eventually followed by stem cell transplantation, but limited possibilities are offered to chemo-resistant patients, who represent the majority of RS cases. In order to address this unmet clinical need, several immunotherapeutic approaches have been developed, namely T cell engagement obtained with bispecific antibodies, PD-1/PD-L1 immune checkpoint blockade by the use of monoclonal antibodies, selective drug delivery with antibody-drug conjugates, and targeting malignant cells with anti-CD19 chimeric antigen receptor-T cells.

Hodgkin's variant of Richter transformation during ibrutinib therapy: A case report and review of the literature

Hodgkin's variant of Richter transformation is a rare complication of chronic lymphocytic leukemia and is associated with inferior outcomes compared to de novo Hodgkin lymphoma. Further data concerning prognosis and treatment of Hodgkin's variant of Richter transformation occurring in the setting of novel targeted therapies are needed.

Richter Syndrome: From Molecular Pathogenesis to Druggable Targets

Richter syndrome (RS) represents the occurrence of an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL), in patients with chronic lymphocytic leukemia (CLL). Most cases of RS originate from the direct transformation of CLL, whereas 20% are de novo DLBCL arising as secondary malignancies. Multiple molecular mechanisms contribute to RS pathogenesis. B-cell receptor (BCR) overreactivity to multiple autoantigens is due to frequent stereotyped BCR configuration. Genetic lesions of TP53, CDKN2A, NOTCH1 and c-MYC deregulate DNA damage response, tumor suppression, apoptosis, cell cycle and proliferation. Hyperactivation of Akt and NOTCH1 signaling also plays a role. Altered expression of PD-1/PD-L1 and of other immune checkpoints leads to RS resistance to cytotoxicity exerted by T-cells. The molecular features of RS provide vulnerabilities for therapy. Targeting BCR signaling with noncovalent BTK inhibitors shows encouraging results, as does the combination of BCL2 inhibitors with chemoimmunotherapy. The association of immune checkpoint inhibitors with BCL2 inhibitors and anti-CD20 monoclonal antibodies is explored in early phase clinical trials with promising results. The development of patient-derived xenograft mice models reveals new molecular targets for RS, exemplified by ROR1. Although RS still represents an unmet medical need, understanding its biology is opening new avenues for precision medicine therapy.

Hodgkin Lymphoma and Hairy Cell Leukemia Arising from Chronic Lymphocytic Leukemia: Case Reports and Literature Review

Richter’s syndrome represents the progression of chronic lymphocytic leukemia (CLL) to more aggressive diseases, most frequently diffuse large B-cell lymphoma, while Hodgkin’s lymphoma (HL) and hairy cell leukemia (HCL) are rarely described. The first case involved a 67-year-old man with a diagnosis of a high-risk stage-II CLL treated with rituximab and ibrutinib, developed a HL nodular sclerosis variant after three months of therapy for CLL. After achieving a complete remission for HL and ibrutinib cessation because of drug-related cardiotoxicity, the patient relapsed after five months off-therapy and died due to disease progression after two cycles of brentuximab-vedotin. The second case involved an 83-year-old female with a diagnosis of stage-IV CLL treated with rituximab plus bendamustine who developed a HCL eight years later. Pentostatin was unsuccessfully employed as upfront HCL therapy, and the patient was then switched to rituximab while in remission for CLL. In conclusion, Richter’s transformation risk rate might be higher in patients treated with novel targeted therapies, and multiparametric flow cytometry and lymph node biopsy at relapse could help in early identifying small clones. The treatment of predominant neoplasia is mandatory, and disease-specific drugs are administered; however, clinical efficacy might be lower in these patients.

Outcomes of Hodgkin variant Richter transformation in chronic lymphocytic leukaemia and small lymphocytic lymphoma in British Columbia

Hodgkin variant Richter transformation (HvRT) is a rare and challenging complication of chronic lymphocytic leukaemia (CLL) for which information on prognostic factors and treatment approaches remain limited. We analysed characteristics and survival outcomes of a population-based cohort of 32 patients with HvRT identified in British Columbia over a 40-year period. Median interval from CLL diagnosis to HvRT was 5.6 years (range, 0-33.6), with five cases diagnosed concurrently. Most patients (80%) had treatment for CLL prior to HvRT. Median age at HvRT was 71 years (range, 51-86) and the majority of patients had high-risk disease, including stage 3-4 in 87% and International Prognostic Score (IPS) ≥ 4 in 65%. Two-year progression-free (PFS) and overall survival (OS) from HvRT were 47% (95% CI: 29%-64%) and 57% (95% CI: 38%-72%), respectively. OS from HvRT was significantly worse in those with anaemia (p = 0.02), elevated lactate dehydrogenase (p = 0.04), high IPS (p = 0.04), and worse performance status (p = 0.001). For those treated with curative-intent ABVD/ABVD-like therapy, 2-year PFS and OS were 70% (95% CI: 45%-85%) and 74% (95% CI: 49%-89%), respectively. In this real-world population-based cohort, HvRT was associated with poor clinical outcomes overall; however, those able to tolerate curative-intent therapy had similar survival to older patients with de novo HL.

Biology and Treatment of Richter Transformation

Richter transformation (RT), defined as the development of an aggressive lymphoma on a background of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), represents a clinical unmet need because of its dismal prognosis. An increasing body of knowledge in the field of RT is arising from the recent development of preclinical models depicting the biology underlying this aggressive disease. Consistently, new therapeutic strategies based on a genetic rationale are exploring actionable pathogenic pathways to improve the outcome of patients in this setting. In this review, we summarize the current understandings on RT biology and the available treatment options.

Hodgkin lymphoma arising in patients with chronic lymphocytic leukemia: outcomes from a large multi-center collaboration

Chronic lymphocytic leukemia (CLL) patients who develop Hodgkin lymphoma (HL) have limited survival. No current therapeutic standard of care exists. We conducted a multi-center retrospective study of patients with Hodgkin Transformation (HT) of CLL. Clinicobiologic characteristics, treatment type, and survival outcomes were analyzed and compared with historic case series. Ninety-four patients were identified. Median age at HT was 67 years (range, 38-85). Median time from CLL diagnosis to HT was 5.5 years (range, 0-20.2). Prior to HT, patients received a median of 2 therapies for CLL (range, 0-12). As initial therapy for HT, 61% (n=62) received ABVD-based regimens (adriamycin, bleomycin, vinblastine, and dacarbazine). Seven (7%) patients received hematopoietic cell transplantation (HCT) while in first complete remission (CR1). The median number of treatments for HT per patient was 1 (range, 0-5) with 59 (61%) patients only receiving one line of therapy. After HT, patients had a median follow-up of 1.6 years (range, 0-15.1). Two-year overall survival (OS) after HT diagnosis was 72% (95%CI 62-83%). The patients who received standard ABVD-based therapy had a median OS of 13.2 years. Although limited by small sample size, the patients who underwent HCT for HT in CR1 had a similar 2-year OS (n=7; 67%) compared to patients who did not undergo HCT for HT in CR1 (n=87; 72%; p=0.46). In this multi-center study, HT patients treated with ABVD-based regimens had prolonged survival supporting the use of these regimens as standard of care for these patients.

Early Transformation to Classic Hodgkin Lymphoma in a Chemotherapy-naïve Chronic Lymphocytic Leukemia Patient upon Initial Treatment with Ibrutinib

A 71-year-old woman with a four-year history of chronic lymphocytic leukemia (CLL) received ibrutinib as initial treatment due to progressive anemia and thrombocytopenia. Eleven months after the start of the treatments, although her cytopenia had ameliorated, she developed classic Hodgkin lymphoma, a rare form of Richter's transformation. She was successfully treated with two courses of adriamycin, vinblastin, bleomycin and dacarbazine followed by radiotherapy. In general, several clinical, genetic and molecular factors are associated with Richter's transformation. In addition, our present case suggested that ibrutinib could be a potential risk factor for Richter's transformation in CLL patients.

Hodgkin Variant of Richter's Transformation in Chronic Lymphocytic Leukemia (CLL): An Illustrative Case Report and Literature Review

Hodgkin lymphoma variant of Richter's transformation (HL-RT) is a rare event, occurring in < 1% chronic lymphocytic leukemia (CLL) cases, of which, in < 10% cases, HL is the first finding leading to a diagnosis of CLL that co-exists simultaneously. Here we report a 60 years old male patient who presented with an outside diagnosis of lymphocyte-rich classical HL. On evaluation, he had only B-symptoms in the form of low-grade fever and weight loss. Peripheral smear revealed mild leukocytosis with an absolute lymphocytosis and a few smudge cells. Bone marrow (BM) aspirate and biopsy exhibited diffuse infiltration by a small cell, low grade, Non-Hodgkin's lymphoma with no immunohistochemical evidence of HL. Flow cytometry performed on BM was consistent with classical immunoprofile of CLL. Meanwhile the lymph node received for review revealed diffuse effacement of nodal architecture by small mature lymphocytes with immunoprofile of CLL expressing CD20, CD5, and CD23. Interspersed between these cells, were a few eosinophils along with classical Reed Sternberg cells, expressing CD30, MUM-1, CD15, and dim PAX-5, with a surrounding rosette of T-Cells highlighted by CD3 and PD-1 and negative for CD45, CD20, and EBV immunohistochemistry. Fluorodeoxyglucose positron emission tomography (FDG-PET) scan revealed hepatosplenomegaly with multiple supra/infra diaphragmatic lymph nodes. So, a final diagnosis of HL-RT in CLL was considered. The patient is currently doing well after the first cycle of ABVD chemotherapy. HL-RT occurring in CLL is a rare event with heterogeneous clinical presentation, morphology, clonal origin, disease course, prognostic features, and survival.

Morphologic and molecular analysis of Richter syndrome in chronic lymphocytic leukaemia patients treated with ibrutinib or venetoclax

Richter syndrome (RS) represents the development of high-grade lymphoma in patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma (SLL) and presents a diagnostic and therapeutic challenge with an adverse prognosis. The genetic background and morphology of RS in CLL patients treated with chemoimmunotherapy is extensively characterised; however, our knowledge about RS in patients treated with targeted oral therapies should be extended. To understand the morphologic and molecular changes leading to RS in CLL patients treated with the Bruton's tyrosine kinase inhibitor, ibrutinib, and the BCL2 inhibitor, venetoclax, sequential samples from six CLL/SLL patients undergoing RS were collected in both the CLL and RS phases. A detailed immunophenotypic analysis of formalin-fixed, paraffin-embedded tissue specimens of RS phase was performed, followed by extensive molecular characterisation of CLL and RS samples, including the immunoglobulin heavy chain gene (IGH) rearrangement, TP53 mutations, drug-induced resistance mutations in BTK and BCL2 genes and various copy number changes and point mutations detectable with multiplex ligation-dependent probe amplification (MLPA). Rare, non-diffuse large B-cell lymphoma phenotypes of RS were observed in 3/6 cases, including plasmablastic lymphoma and a transitory entity between diffuse large B-cell lymphoma and classical Hodgkin lymphoma. The majority of cases were clonally related and harboured an unmutated variable region of the immunoglobulin heavy chain gene. Abnormalities affecting the TP53 gene occurred in all patients, and every patient carried at least one genetic abnormality conferring susceptibility to RS. In the background of RS, 2/5 patients treated with ibrutinib showed a BTK C481S resistance mutation. One patient developed a BCL2 G101V mutation leading to venetoclax resistance and RS. In conclusion, our findings contribute to better understanding of RS pathogenesis in the era of targeted oral therapies. Rare phenotypic variants of RS do occur under the treatment of ibrutinib or venetoclax, and genetic factors leading to RS are similar to those identified in patients treated with chemoimmunotherapy. To our best knowledge, we have reported the first BCL2 G101V mutation in an RS patient treated with venetoclax.

Revisiting Richter transformation in the era of novel CLL agents

Richter transformation (RT) is the development of aggressive lymphoma - most frequently diffuse large B-cell lymphoma (DLBCL) and rarely Hodgkin lymphoma (HL) - arising on the background of chronic lymphocytic leukaemia (CLL). Despite recent advances in CLL treatment, RT also develops in patients on novel agents, usually occurring as an early event. RT incidence is lower in CLL patients treated with novel agents in the front line compared to relapsed/refractory cases, with a higher incidence in patients with TP53 disruption. The genetic heterogeneity and complexity are higher in RT-DLBCL than CLL; the genetics of RT-HL are largely unknown. In addition to TP53, aberrations in CDKN2A, MYC, and NOTCH1 are common in RT-DLBCL; however, no distinct RT-specific genetic aberration is recognised yet. RT-DLBCL on ibrutinib is frequently associated with BTK and PLCG2 mutations. Here, we update on genetic analysis, diagnostics and treatment options in RT in the era of novel agents.

Richter Syndrome

PURPOSE OF REVIEW

Richter syndrome (RS) is an uncommon but aggressive evolution of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). RS is an unmet clinical need in the field of CLL. Recent advances in understanding the biology of this condition provide the rationale for testing new therapeutic concepts in order to improve the outcome of patients developing RS, which is so far poor. In this review, we summarize disease characteristics and available therapeutic options for RS.

RECENT FINDINGS

Current regimens with novel agents in monotherapy have shown little impact on survival. Nevertheless, the better reported outcome for RS has been achieved with the combination of chemo-immunotherapy with a novel agent, confirming the synergistic effect of the approaches. Still, the frailty of this population may impose a less toxic management leaving most patients with no reasonable therapeutic option. Treatment options for RS need to be further expanded. Preclinical models in current development may allow to explore actionable pathways and identify new drug targeted combinations.

Richter's transformation in patients with chronic lymphocytic leukaemia: a Nationwide Epidemiological Study

Richter's transformation (RT) refers to the development of an aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL). Approximately, 2-10% of patients with CLL develop RT, most often as diffuse large B-cell lymphoma. To assess the incidence of RT, we examined risk factors for RT and death among patients with RT in a nationwide CLL cohort (from 2008 to 2016). Among 3772 patients, 113 had biopsy-proven RT. With a median follow-up of 4.3 years, the 5-year cumulative incidence of RT was 2.8%. Advanced Binet stage (B/C) (p<.001), unmutated IGHV (p<.001), and del(17p) (p<.001) were independently associated with risk of developing RT. Half of the patients with RT (49%) were treatment-naïve prior to transformation and demonstrated longer survival after RT compared to patients previously treated for CLL (6.1 vs. 2.8 years, p=.03). Whether this finding could be explained by a higher proportion of clonally unrelated RT among treatment-naïve patients, remain to be addressed.

Computed tomography textural analysis for the differentiation of chronic lymphocytic leukemia and diffuse large B cell lymphoma of Richter syndrome

OBJECTIVE

To test the hypothesis that both indolent and aggressive chronic lymphocytic leukemia (CLL) can be differentiated from diffuse large B cell lymphoma (DLBCL) of Richter syndrome (RS) by CT texture analysis (CTTA) of involved lymph nodes.

MATERIAL AND METHODS

We retrospectively included 52 patients with indolent CLL (26/52), aggressive CLL (8/52), and DLBCL of RS (18/52), who underwent standardized contrast-enhanced CT. In main lymphoma tissue, VOIs were generated from which CTTA features including first-, second-, and higher-order textural features were extracted. CTTA features were compared between the entire CLL group, the indolent CLL subtype, the aggressive CLL subtype, and DLBCL using a Kruskal-Wallis test. All p values were adjusted after the Bonferroni correction. ROC analyses for significant CTTA features were performed to determine cut-off values for differentiation between the groups.

RESULTS

Compared with DLBCL of RS, CTTA of the entire CLL group showed significant differences of entropy heterogeneity (p < 0.001), mean intensity (p < 0.001), mean average (p = 0.02), and number non-uniformity gray-level dependence matrix (NGLDM) (p = 0.03). Indolent CLL significantly differed for entropy (p < 0.001), uniformity of heterogeneity (p = 0.02), mean intensity (p < 0.001), and mean average (p = 0.01). Aggressive CLL showed significant differences in mean intensity (p = 0.04). For differentiation between CLL and DLBCL of RS, cut-off values for mean intensity and entropy of heterogeneity were defined (e.g., 6.63 for entropy heterogeneity [aggressive CLL vs. DLBCL]; sensitivity 0.78; specificity 0.63).

CONCLUSIONS

CTTA features of ultrastructure and vascularization significantly differ in CLL compared with that in DLBCL of Richter syndrome, allowing complementary to visual features for noninvasive differentiation by contrast-enhanced CT.

KEY POINTS

• Richter transformation of CLL into DLBCL results in structural changes in lymph node architecture and vascularization that can be detected by CTTA. • First-order CT textural features including intensity and heterogeneity significantly differ between both indolent CLL and aggressive CLL and DLBCL of Richter syndrome. • CT texture analysis allows for noninvasive detection of Richter syndrome which is of prognostic value.

Immunochemotherapy for Richter syndrome: current insights

Richter syndrome (RS) is recognized as the development of a secondary and aggressive lymphoma during the clinical course of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Most of such histological transformations are from RS to diffuse large B-cell lymphoma (DLBCL-RS, 90%) and Hodgkin’s lymphoma (HL-RS, 10%). Histopathological examination is a prerequisite for diagnosis. It is crucial to assess the relationship between the RS clone and the underlying CLL/SLL because clonally related DLBCL-RS has a poor outcome, while clonally unrelated cases have a prognosis similar to de novo DLBCL. An anti-CD20 antibody-based immunochemotherapy is hitherto the frontline treatment of choice for DLBCL-RS; nonetheless, the results are unsatisfactory. Allogeneic stem cell transplantation should be offered to younger and fit patients as a consolidative treatment; however, the majority of the patients may not be qualified for this procedure. The HL-RS transformation has better outcomes than those of DLBCL-RS and can effectively be treated by the adriamycin, bleomycin, vinblastine, and dacarbazine regimen. Although novel agents are currently being investigated for RS, immunochemotherapy nevertheless remains a standard treatment for DLBCL-RS.

Richter transformation in the era of novel agents

Recent approvals of several oral targeted agents have revolutionized chronic lymphocytic leukemia (CLL) therapy. However, CLL patients continue to progress; particularly, 4% to 20% of previously treated CLL patients undergo transformation into high-grade lymphoma. Richter transformation is defined as a transformation of CLL into aggressive lymphoma, most commonly diffuse large B-cell lymphoma. These patients typically have poor response to traditional chemotherapy used to treat de novo diffuse large B-cell lymphoma and similar or shorter overall survival (median 3-11 months) in the era of novel agents. Here, I review the contemporary literature on Richter transformation, particularly in the context of novel agents used in CLL, and discuss the management approach for these patients.

Classic Hodgkin Lymphoproliferative Diseases Clonally Unrelated to B-Chronic Lymphocytic Leukemia Successfully Treated with Bendamustine Plus Rituximab

A 62-year-old male was diagnosed with chronic lymphocytic leukemia (CLL) and treated with a fludarabine-containing regimen which maintained the disease in a partial response. Nine years after diagnosis, a rapidly growing systemic lymphadenopathy was observed, and a biopsy specimen revealed the presence of typical Hodgkin/Reed-Sternberg (HRS) cells, surrounded by T-lymphocytes and CLL cells. Sequencing analysis of the germline complementary determining region 3 (CDR3) region of the immunoglobulin heavy chain (IGH) gene showed that the Hodgkin/Reed-Sternberg cells were clonally unrelated to the preexisting CLL cells and the HRS cells were composed of five different clones, leading to the molecular diagnosis of de novo lymphocyte-rich classic Hodgkin lymphoproliferative diseases (LPDs) with small lymphocytic lymphoma (SLL). As the initial treatment was neither effective for classic Hodgkin LPDs nor for SLL, Bendamustine, Rituximab (BR) was started and complete remission was achieved, which has continued for more than one year so far. BR may be a good therapeutic option for both entities without causing hematological toxicity.

Biology and treatment of Richter syndrome

Richter syndrome (RS) is the development of an aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL). Two pathologic variants of RS are recognized: namely, the diffuse large B-cell lymphoma (DLBCL) variant and the rare Hodgkin lymphoma (HL) variant. Histologic documentation is mandatory to diagnose RS. The clinical suspicion of RS should be based on clinical signs and symptoms. Differential diagnosis between CLL progression and RS and choice of the biopsy site may take advantage of positron emission tomography/computed tomography. Molecular lesions of regulators of proliferation (CDKN2A, NOTCH1, MYC) and apoptosis (TP53) overall associate with ∼90% of DLBCL-type RS, whereas the biology of the HL-type RS is largely unknown. The prognosis of the DLBCL-type RS is unfavorable; the outcome of HL-type RS appears to be better. The most important RS prognostic factor is the clonal relationship between the CLL and the aggressive lymphoma clones, with clonally unrelated RS having a better prognosis. Rituximab-containing combination chemotherapy for DLBCL is the most widely used treatment in DLBCL-type RS. Fit patients who respond to induction therapy should be offered stem cell transplantation (SCT) to prolong survival. Adriamycin, bleomycin, vinblastine, and dacarbazine is the preferred regimen for the HL-type RS, and SCT consolidation is less used in this condition.

Central nervous involvement by chronic lymphocytic leukaemia

Inclusion of the central nervous system (CNS) in the course of chronic lymphocytic leukaemia (CLL) is rare. At the moment no risk factors or proven treatment methods are known. The disease is described both in its early phase and during its acceleration period, thus it has been suggested that there might be independent mechanisms influencing the development of this condition. As there are no unified diagnostic procedure algorithms each patient needs to be assessed individually. CLL can manifest mostly in elderly people, for whom a possibility of development of neurological disorders with their aetiology different from leukaemia, should also be taken into consideration. The thesis presents a group of seven patients with CLL with CNS infiltration. Patients with prolymphocytic leukaemia, Richter's transformation and the original location of leukemic infiltration within the eye socket constitute an especially interesting case.

Emergence of Bruton's tyrosine kinase-negative Hodgkin lymphoma during ibrutinib treatment of chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is a chronic B-cell lympho-proliferative disorder in which lymphomatous transformations occur in 5%-15% of patients. Histologically these cases resemble diffuse large B-cell lymphoma, or Richter's transformation, in over 80% of cases. Rare cases of transformation to Hodgkin lymphoma (HL) have been reported in the literature with an estimated prevalence of 0.4%. We report a case of a 67-year-old female with CLL treated with the novel Bruton's tyrosine kinase (Btk) inhibitor, ibrutinib, who subsequently presented with intractable fevers. Bone marrow trephine, and lymph node biopsy revealed classical HL with negative immuno-histochemistry for Btk in HL cells, on a backdrop of CLL. The patient commenced treatment with Adriamycin, Vinblastine and Dacarbazine (AVD), which resulted in an excellent response. Hodgkin transformation of CLL is rare with a single retrospective study of 4121 CLL patients reporting only 18 cases. Btk expression in HL cells is recently recognised in classical HL; however, the majority of HLs are Btk negative. Given that Btk inhibitors have recently been shown to induce genomic instability in B cells, in the context of their widespread use, such emerging cases are increasingly relevant.

Transformation in Low-grade B-cell Neoplasms

Low-grade B-cell leukemias/lymphomas are a diverse group of indolent lymphoproliferative disorders that are typically characterized by good patient outcomes and long life expectancies. A subset of cases, however, undergo histologic transformation to a higher-grade neoplasm, a transition associated with a more aggressive clinical course and poor survival. Transformation of follicular lymphoma to diffuse large B-cell lymphoma and Richter transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma are best characterized in the literature. This article reviews clinical and pathologic characteristics of these most common forms of transformation, with an emphasis on salient histologic, immunophenotypic, and genetic features.

Richter Syndrome in Chronic Lymphocytic Leukemia

The term Richter syndrome (RS) indicates the transformation of chronic lymphocytic leukemia (CLL) into an aggressive lymphoma. RS is a rare complication with an aggressive clinical course, bearing an unfavorable prognosis. In the majority of cases, CLL transforms into RS as diffuse large B cell lymphoma (DLBCL), and a clonal relation between the two processes can be found. However, clonally unrelated RS can occur and transformations to other histologies beside DLBCL have been described. Recent data have shed some light on genetic characteristics that can influence and drive the transformation from CLL to RS. This molecular information has not been translated yet into significant treatment advances, and currently the therapy regimens for RS continue to rely on intensive chemotherapy combinations followed by stem cell transplant in suitable candidates. Based on the rapid pace of discoveries in the field of hematological malignancies and on the recent revolution in the therapeutic landscape for CLL and B cell lymphomas, new therapeutic options for RS might be available in the upcoming years.

Herpes simplex infection simulating Richter transformation: a series of four cases and review of the literature

AIMS

Richter transformation (RT) occurs in 5-10% of patients with chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL), and is associated with a poor outcome. The histological manifestations of RT are variable, and include an increase in the proportion of prolymphocytes, immunoblasts, and other pleomorphic cells, along with an increased proliferation rate and often necrosis. Rarely, superimposed herpes simplex virus (HSV) infection involving lymph nodes in patients with CLL/SLL may mimic RT clinically and histologically. In this study, we describe four cases of CLL/SLL with superimposed HSV lymphadenitis, and we review the literature.

METHODS AND RESULTS

We describe the clinicopathological and immunophenotypic findings of four cases of CLL/SLL with superimposed HSV infection. The patients presented with B-type symptoms, and laboratory and imaging findings suggested progression of lymphoma. Histologically, there were geographical areas of necrosis and increased numbers of prolymphocytes and immunoblasts, in some areas forming sheets, with increased mitotic figures and a high proliferation (Ki67) rate. However, the necrotic regions were associated with acute inflammatory cells and larger cells, mostly necrotic, showing viral cytopathic effects. Therapy with antiviral agents resulted in improvement of clinical symptoms and laboratory and imaging findings. Additionally, we identified 11 cases of CLL/SLL with superimposed HSV infection described in the English-language literature, and integrated the cases that we report here into this wider context.

CONCLUSIONS

Herpes simplex virus infection of lymph nodes in patients with CLL/SLL results in clinicopathological and radiological findings that may mimic RT. It is essential to refrain from misclassifying these cases as RT, as patients can respond remarkably well to antiviral therapy.

Transformation of marginal zone lymphoma (and association with other lymphomas)

Marginal zone lymphomas (MZL) are a diverse group of indolent lymphoproliferative disorders that comprise three subtypes: nodal, splenic and mucosal associated marginal zone lymphomas (MALT). Histologic transformation (HT) to an aggressive lymphoma is a rare event that can occur in any subtype, and at lower frequency compared to other indolent non Hodgkin lymphomas (NHL) like follicular lymphoma. There are few data directly associated with risk and prognosis of transformation in MZL. However, recent advances in the understanding of molecular and genetic features of MALT have contributed to an evolving appreciation of HT in this disease. Optimal treatment of HT of MZL remains unknown. Much of the approach to managing transformed MZL is extrapolated from other indolent NHLs.

Histologic transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma

Although generally considered a clinically indolent neoplasm, CLL/SLL may undergo transformation to a clinically aggressive lymphoma. The most common form of transformation, to DLBCL, is also known as Richter syndrome. Transformation determines the course of the disease and is associated with unfavorable patient outcome. Precise detection of transformation and identification of predictive biomarkers and specific molecular pathways implicated in the pathobiology of transformation in CLL/SLL will enable personalized therapeutic approach and provide potential avenues for improving the clinical outcome of patients. In this review, we present an overview of the pathologic features, risk factors, and pathogenic mechanisms of CLL/SLL transformation. Am. J. Hematol. 91:1036-1043, 2016. © 2016 Wiley Periodicals, Inc.

Richter's Transformation in the Era of Kinase Inhibitor Therapy: A Review

Richter's transformation (RT) is the transformation of chronic lymphocytic leukemia (CLL) into rapidly progressive B-cell lymphoma. This disease has long been recognized as a difficult-to-treat illness with poor survival outcomes. Although the incidence of RT has been well documented in previous studies, less is understood in the era of novel therapeutics, such as kinase inhibitors (KIs). The present review discusses the current risk factors, incidence, and outcomes of patients with RT in the modern era of KI therapy. Although the outcomes remain poor for RT patients after KI therapy, the most up-to-date studies have shown no increased incidence of RT in this patient population. Additionally, the present review reports the outcomes from the most recent data on novel therapies under investigation for patients with RT.

Epstein-Barr virus DNA load in chronic lymphocytic leukemia is an independent predictor of clinical course and survival

The relation between Epstein-Barr virus (EBV) DNA load and clinical course of patients with chronic lymphocytic leukemia (CLL) is unknown. We assessed EBV DNA load by quantitative PCR at CLL presentation in mononuclear cells (MNC) of 220 prospective patients that were enrolled and followed-up in two major Institutions. In 20 patients EBV DNA load was also assessed on plasma samples. Forty-one age-matched healthy subjects were tested for EBV DNA load on MNC. Findings were validated in an independent retrospective cohort of 112 patients with CLL. EBV DNA load was detectable in 59%, and high (≥2000 copies/µg DNA) in 19% of patients, but it was negative in plasma samples. EBV DNA load was significantly higher in CLL patients than in healthy subjects (P < .0001). No relation was found between high EBV load and clinical stage or biological variables, except for 11q deletion (P = .004), CD38 expression (P = .003), and NOTCH1 mutations (P = .05). High EBV load led to a 3.14-fold increase in the hazard ratio of death and to a shorter overall survival (OS; P = .001). Poor OS was attributable, at least in part, to shorter time-to-first-treatment (P = .0008), with no higher risk of Richter's transformation or second cancer. Multivariate analysis selected high levels of EBV load as independent predictor of OS after controlling for confounding clinical and biological variables. EBV DNA load at presentation is an independent predictor of OS in patients with CLL.

High-grade Transformation of Low-grade B-cell Lymphoma: Pathology and Molecular Pathogenesis

Patients with low-grade (clinically indolent) lymphomas are at risk to undergo transformation to high-grade (clinically aggressive) lymphoma, although transformation only occurs in a subset of patients. When transformation occurs it is a critical event that determines the course of disease and is associated with unfavorable patient outcomes. Accurate detection of transformation, predictive biomarkers, and identification of specific molecular pathways implicated in the pathobiology of transformation will facilitate personalized therapeutic approaches and underpin advances in clinical outcomes. In this article, we present an update of the clinical and pathologic diagnostic criteria for low-grade B-cell lymphoma transformation and discuss the molecular alterations involved in the pathogenesis of this biological phenomenon.

Richter syndrome: pathogenesis and management

Richter syndrome (RS) is the development of an aggressive lymphoma in patients with a previous or concomitant diagnosis of chronic lymphocytic leukemia (CLL). The incidence rate RS is ~0.5% per year of observation. Two biomarkers (NOTCH1 mutations and subset 8 configuration of the B-cell receptor) may help identifying CLL patients at risk of RS to be considered for close monitoring and a careful biopsy policy. In the presence of clinical features suspicious of RS, diagnosis of transformation and choice of the site of biopsy may take advantage of fluorine 18 fluorodeoxyglucose ((18)FDG) positron emission tomography (PET)/computed tomography (CT). Molecular lesions of regulators of tumor suppression (TP53), cell cycle (CDKN2A), and cell proliferation (NOTCH1, MYC) overall account for ~90% of RS and may be responsible for the aggressive clinical phenotype observed in this disease because of the combined effect of chemoresistance and rapid disease kinetics. The prognosis of RS is generally highly unfavorable. However, the pattern of survival is not homogeneous and the most important prognostic factor is the clonal relationship between the CLL and the aggressive lymphoma clones. Rituximab-containing polychemotherapy represents the backbone for induction treatment in RS. Younger patients who respond to induction therapy should be offered stem cell transplant (SCT) to prolong survival.