2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography examination in patients with chronic lymphocytic leukemia may reveal Richter transformation

PET/CT in leukemia: utility and future directions

2-Deoxy-2-[ 18 F]fluoro- d -glucose PET/computed tomography ([ 18 F]FDG PET/CT) has proven to be a sensitive method for the detection and evaluation of hematologic malignancies, especially lymphoma. The increasing incidence and mortality rates of leukemia have raised significant concerns. Through the utilization of whole-body imaging, [ 18 F]FDG PET/CT provides a thorough assessment of the entire bone marrow, complementing the limited insights provided by biopsy samples. In this regard, [ 18 F]FDG PET/CT has the ability to assess diverse types of leukemia The utilization of [ 18 F]FDG PET/CT has been found to be effective in evaluating leukemia spread beyond the bone marrow, tracking disease relapse, identifying Richter's transformation, and assessing the inflammatory activity associated with acute graft versus host disease. However, its role in various clinical scenarios in leukemia remains unacknowledged. Despite their less common use, some novel PET/CT radiotracers are being researched for potential use in specific scenarios in leukemia patients. Therefore, the objectives of this review are to provide a thorough assessment of the current applications of [ 18 F]FDG PET/CT in the staging and monitoring of leukemia patients, as well as the potential for an expanding role of PET/CT in leukemia patients.

Role of Novel Quantitative Imaging Techniques in Hematological Malignancies

Hematological malignancies exhibit a widespread distribution, necessitating evaluation of disease activity over the entire body. In clinical practice, visual analysis and semiquantitative parameters are used to assess 18F-FDGPET/CT imaging, which solely represents measurements of disease activity from limited area and may not adequately reflect global disease assessment. An efficient method for assessing the global disease burden of hematological malignancies is to employ PET/computed tomography based novel quantitative parameters. In this article, we explored novel quantitative parameters on PET/CT imaging for assessing global disease burden and the potential role of artificial intelligence (AI) to determine these parameters in evaluation of hematological malignancies.

Applications of 18F-Fluorodesoxyglucose PET Imaging in Leukemia

The main finding that 18F-FDG PET imaging can reveal in patients with leukemias is the presence of bone marrow (BM) infiltration in both acute or chronic forms. This ability can influence and guide the use of BM biopsy but also assess to therapy response. Additionally 18F-FDG PET imaging has been reported as particularly useful for the diagnosis of leukemias in patients with non specific symptoms. In the case of acute leukemias it revealed also a role for the evaluation of extramedullary forms while in the case of chronic forms a role for the assessment of Richter transformation has been reported.

The Diagnostic Performance of 2-[18F]FDG PET/CT in Identifying Richter Transformation in Chronic Lymphocytic Leukemia: An Updated Systematic Review and Bivariate Meta-Analysis

Richter transformation is a rare phenomenon characterized by the transformation of cell chronic lymphocytic leukemia (CLL) into a more aggressive lymphoma variant. The early identification of CLLs with a high risk of RT is fundamental. In this field, 2-deoxy-2-[18F]-fluoro-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) has been shown to be a non-invasive and promising tool, but apparently, unclear data seem to be present in the literature. This systematic review and bivariate meta-analysis aimed to investigate the diagnostic performance of 2-[18F]FDG PET/CT and its parameters in predicting RT. Between 2006 and 2024, 15 studies were published on this topic, including 1593 CLL patients. Among semiquantitative variables, SUVmax was the most investigated, and the best threshold derived for detecting RT was five. With this cut-off value, a pooled sensitivity of 86.8% (95% CI: 78.5-93.3), a pooled specificity of 48.1% (95% CI: 27-69.9), a pooled negative predictive value of 90.5% (95% CI: 88.4-92.4), a pooled negative likelihood ratio of 0.35 (95% CI: 0.17-0.70), a pooled positive likelihood ratio of 1.8 (95% CI: 1.3-2.4), and a pooled diagnostic odds ratio of 6.7 (3.5-12.5) were obtained. With a higher cut-off (SUVmax = 10), the specificity increased while the sensitivity reduced. The other metabolic features, like metabolic tumor volume, total lesion glycolysis, and radiomic features, were only marginally investigated with controversial evidence.

Richter's transformation: Transforming the clinical landscape

Richter transformation (RT) represents an aggressive histological transformation from chronic lymphocytic leukaemia, most often to a large B cell lymphoma. It is characterised by chemo-resistance and subsequent short survival. Drug development has struggled over recent years in light of the aggressive kinetics of the disease, lack of pivotal registrational trials and relative rarity of the phenomenon. In this review we will highlight the diagnostic and therapeutic challenges of managing patients with RT as well as taking a look to the future therapeutic landscape. Highly active therapies developed across B cell malignancies are starting to impact this field, with T-cell activation therapies (CAR-T, bispecific antibodies), antibody-drug conjugates, and novel small molecule inhibitor combinations (e.g. BTKi-BCL2i) being actively studied. We will highlight the data supporting these developments and look to the studies to come to provide hope for patients suffering from this devastating disease.

2-[18F]-FDG PET/CT Semiquantitative and Radiomics Predictive Parameters of Richter's Transformation in CLL Patients

Background and Objectives: Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in developed countries, which can evolve into aggressive lymphoma variants, a process called Richter transformation (RT). The aim of this retrospective study was to analyze the role of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (2-[18F]-FDG PET/CT) and its semiquantitative and radiomics features in detecting RT and evaluate the impact on overall survival (OS). Materials and Methods: One hundred and thirty-seven patients with histologically proven CLL were retrospectively recruited. PET/CT images were qualitatively and semiquantitatively examined by estimating the main metabolic parameters (the maximum standardized uptake value body weight (SUVbw), lean body mass (SUVlbm), body surface area (SUVbsa), lesion-to-blood-pool SUV ratio (L-BP SUV R), lesion-to-liver SUV ratio (L-L SUV R), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) and radiomics first- and second- order variables of the lesion with highest uptake. The role of these parameters in predicting RT and OS was analyzed. Results: One hundred and thirty (95%) PET/CT scans were positive, showing an increased tracer uptake at the site of disease, whereas the remaining 7 (5%) scans were negative. SUVbw, SUVlbm, SUVbsa, L-L SUV ratio, and L-BP SUV ratio were significantly higher in the RT group (p < 0.001 in all cases). Radiomics first- and second-order features were not significantly associated with RT. After a median follow-up of 44 months, 56 patients died; OS was significantly shorter in patients with RT than patients without RT (28 vs. 34 months; p = 0.002). Binet-stage, RT, and L-BP SUV R were shown to be independent prognostic features. Conclusions: Semiquantitative PET/CT parameters such as SUVbw, SUVlbm, SUVbsa, L-L SUV ratio and L-BP SUV ratio may be useful in discriminating patients with a high risk of developing RT, whereas Binet-stage, RT, and L-BP SUV R are also significant in predicting OS.

Clinical Application of 18F-FDG-PET Quantification in Hematological Malignancies: Emphasizing Multiple Myeloma, Lymphoma and Chronic Lymphocytic Leukemia

Most hematological malignancies display heightened glycolytic activity, leading to their detectability through 18F-FDG-PET imaging. PET quantification enables the extraction of metabolic information from tumors. Among various PET measurements, maximum standardized uptake value (SUVmax), which indicates the highest value of 18F-FDG uptake within the tumor, has emerged as the commonly used parameter in clinical oncology. This is because of SUVmax ease of calculation using most available commercial workstations, as well as its simplicity and independence from observer interpretation. Nonetheless, SUVmax represents the increase in activity within a specific small area, which may not fully capture the overall tumor uptake. Volumetric PET parameters have been identified as a potential solution to overcome certain limitations associated with SUVmax. However, these parameters are influenced by the low spatial resolution of PET when assessing small lesions. Another challenge is the high number of lesions observed in some patients, leading to a time-consuming process for evaluating all focal lesions. Some institutions recently have started advocating for CT-based segmentation as a method for measuring radiotracer uptake in the bone marrow and overall bone of the patients. This review article aims to provide insights into clinical application of PET quantification specifically focusing on 3 major hematologic malignancies: multiple myeloma, lymphoma, and chronic lymphocytic leukemia.

Investigating and modeling positron emission tomography factors associated with large cell transformation from low-grade lymphomas

Low-grade lymphomas have a 1%-3% annual risk of transformation to a high-grade histology, and prognostic factors remain undefined. We set to investigate the role of positron emission tomography (PET) metrics in identification of transformation in a retrospective case-control series of patients matched by histology and follow-up time. We measured PET parameters including maximum standard uptake value (SUV-max) and total lesion glycolysis (TLG), and developed a PET feature and lactate dehydrogenase (LDH)-based model to identify transformation status within discovery and validation cohorts. For our discovery cohort, we identified 53 patients with transformation and 53 controls with a similar distribution of follicular lymphoma (FL). Time to transformation and control follow-up time was similar. We observed a significant incremental increase in SUV-max and TLG between control, pretransformation and post-transformation groups (P < 0.05). By multivariable analysis, we identified a significant interaction between SUV-max and TLG such that SUV-max had highest significance for low volume cases (P = 0.04). We developed a scoring model incorporating SUV-max, TLG, and serum LDH with improved identification of transformation (area under the curve [AUC] = 0.91). Our model performed similarly for our validation cohort of 23 patients (AUC = 0.90). With external and prospective validation, our scoring model may provide a specific and noninvasive tool for risk stratification for patients with low-grade lymphoma.

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.

Lipid uptake in chronic lymphocytic leukemia

Many cancers rely on glucose as an energy source, but it is becoming increasingly apparent that some cancers use alternate substrates to fuel their proliferation. Chronic lymphocytic leukaemia (CLL) is one such cancer. Through the use of flow cytometry and confocal microscopy, low levels of glucose uptake were observed in the OSU-CLL and HG3 CLL cell lines relative to highly glucose-avid Raji cells (Burkitt's lymphoma). Glucose uptake in CLL cells correlated with low expression of the GLUT1 and GLUT3 receptors. In contrast, both CLL cell lines and primary CLL cells, but not healthy B cells, were found to rapidly internalise medium- and long-chain, but not short-chain, fatty acids (FAs). Differential FA uptake was also observed in primary cells taken from patients with unmutated immunoglobulin heavy variable chain usage (IGHV) compared with patients with mutated IGHV. Delipidation of serum in the culture medium slowed the proliferation and significantly reduced the viability of OSU-CLL and HG3 cells, effects that were partially reversed by supplementation with a chemically defined lipid concentrate. These observations highlight the potential importance of FAs in the pathogenesis of CLL and raise the possibility that targeting FA utilisation may represent a novel therapeutic and prognostic approach in this disease.

The Importance of Cellular Metabolic Pathways in Pathogenesis and Selective Treatments of Hematological Malignancies

Despite recent advancements in the treatment of hematologic malignancies and the emergence of newer and more sophisticated therapeutic approaches such as immunotherapy, long-term overall survival remains unsatisfactory. Metabolic alteration, as an important hallmark of cancer cells, not only contributes to the malignant transformation of cells, but also promotes tumor progression and metastasis. As an immune-escape mechanism, the metabolic adaptation of the bone marrow microenvironment and leukemic cells is a major player in the suppression of anti-leukemia immune responses. Therefore, metabolic rewiring in leukemia would provide promising opportunities for newer therapeutic interventions. Several therapeutic agents which affect essential bioenergetic pathways in cancer cells including glycolysis, β-oxidation of fatty acids and Krebs cycle, or anabolic pathways such as lipid biosynthesis and pentose phosphate pathway, are being tested in various types of cancers. So far, numerous preclinical or clinical trial studies using such metabolic agents alone or in combination with other remedies such as immunotherapy are in progress and have demonstrated promising outcomes. In this review, we aim to argue the importance of metabolic alterations and bioenergetic pathways in different types of leukemia and their vital roles in disease development. Designing treatments based on targeting leukemic cells vulnerabilities, particularly in nonresponsive leukemia patients, should be warranted.

First case of chronic cell leukemia discovered incidentally in extra-saccular inguinal lymph node during laparoscopic bilateral inguinal hernia repair. Case report and literature review

Introduction

Chronic cell leukemia discovered incidentally in extra-saccular inguinal lymph node during laparoscopic bilateral inguinal hernia repair is extremely rare.

Presentation of case

62-year-old Romanian male presented at the outpatient general surgery clinic in April 2019 complaining of bilateral inguinal swelling that gradually increased in size mainly on right side and was diagnosed with bilateral inguinal hernia. During the laparoscopic repair of the hernia, a large lymph node in the left femoral canal was incidentally observed. Histopathologic, immunohistochemical, and flowcytometric evaluation of the excised specimen confirmed chronic lymphocytic leukemia/small lymphocytic lymphoma.

Discussion

Whole body CT showed supra and infra-diaphragmatic lymphadenopathy, and few small subsolid pulmonary nodules, possibly metastatic. Splenomegaly and pancreatomegaly were also noted, suggesting lymphomatoid infiltration.

Conclusion

There is need for cautious inspection and meticulous palpation of the inguinal area for any lymphadenopathy during routine inguinal hernia repair.

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Chronic lymphocytic leukemia (CLL) is a B-cell lymphoid neoplasm.

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CLL diagnosed incidentally in extra-saccular inguinal lymph node during inguinal hernia repair is extremely rare.

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Surgeons need inspection and meticulous palpation of inguinal area for any lymphadenopathy during inguinal hernia repair.

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No advantage of early initiation of treatment on early stages of chronic lymphocytic leukemia

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.

The Role of 2-[18F]-FDG PET/CT in Detecting Richter Transformation in Chronic Lymphocytic Leukemia: A Systematic Review

Richter transformation (RT) is a condition wherein B cell chronic lymphocytic leukemia (CLL) transforms into a more aggressive lymphoma variant. The incidence and the significance of RT detected by 2-[18F]-FDG PET/CT is a clinical challenge and it is not widely investigated in the literature. The aim of this systematic review was to analyze published data about the potential role of 2-[18F]-FDG PET/CT in detecting RT. A comprehensive computer literature search of the PubMed/MEDLINE, Embase and Cochrane library databases was conducted up to December 2020. Thirteen studies (1336 patients with CLL) were selected. The maximum standardized uptake value (SUVmax) was the most common metabolic parameter used to detect RT. An SUVmax of 5 had an average overall sensitivity of 87% (range: 71–96%), an average overall specificity of 49% (range: 4–80%), an average positive predictive value of 41% (range: 16–53%) and an average negative predictive value of 84% (range: 33–97%). Other metabolic variables were only marginally investigated, with promising results. 2-[18F]-FDG PET/CT imaging may play an important role in the detection of RT in CLL, based on the high metabolic activity of the nodal lesions that transformed into aggressive lymphomas. 2-[18F]-FDG PET/CT has high negative predictive value for evaluating RT.

The value of 18F-FDG PET/CT in the prediction of clinical outcomes of patients with acute leukemia treated with allogeneic hematopoietic stem cell transplantation

The present study aimed to determine whether ¹⁸F-FDG PET/CT performed before and/or after allogeneic hematopoietic stem cell transplantation (allo-HSCT) can predict clinical outcomes in acute leukemia (AL). A total of 79 examinations comprising 72 patients with AL who underwent ¹⁸F-FDG PET/CT before and/or after allo-HSCT were retrospectively enrolled between January 2011 and January 2019. Outcomes were assessed using overall survival (OS) and disease-free survival (DFS). A total of 63 examinations were PET-positive, while 16 examinations were PET-negative. Increased BM and splenic ¹⁸F-FDG uptake were observed in 24 (19/79) and 14% (11/79) of examinations, respectively. ¹⁸F-FDG-avid lymph nodes were observed in 38% (30/79) of examinations. E_NE_ME_S involvement was detected in 44% (35/79) of examinations. The presence of E_NE_ME_S involvement [OS hazard ratio (HR), 6.399; 95% confidence interval (CI), 1.843–22.224; P=0.003; post-HSCT OS: HR, 7.203; 95% CI, 1.510–34.369; P=0.013; DFS HR, 3.671; 95% CI, 1.145–11.768; P=0.029], post-transplantation minimal residual disease (DFS HR, 4.381; 95% CI, 1.594–12.040; P=0.004; pre-HSCT OS HR, 11.455; 95% CI, 1.336–98.179; P=0.026) and disease status (OS HR, 0.330; 95% CI, 0.128–0.848; P=0.021; post-HSCT OS HR, 0.195; 95% CI, 0.050–0.762; P=0.019; DFS: HR, 0.278; 95% CI, 0.091–0.851; P=0.025) could serve as an adverse prognostic factor in patients with AL treated with allo-HSCT. ¹⁸F-FDG PET/CT before and/or after allo-HSCT was a predictor for OS and DFS in patients with AL. E_NE_ME_S involvement detected using ¹⁸F-FDG PET/CT may help identify patients with AL who are likely to have unfavorable clinical outcomes.

Applications of PET in Diagnosis and Prognosis of Leukemia

As a malignant hematopoietic stem cell disease, leukemia remains life-threatening due to its increasing incidence rate and mortality rate. Therefore, its early diagnosis and treatment play a very important role. In the present work, we systematically reviewed the current applications and future directions of positron emission tomography (PET) in patients with leukemia, especially ¹⁸F-FDG PET/CT. As a useful imaging approach, PET significantly contributes to the diagnosis and treatment of different types of leukemia, especially in the evaluation of extramedullary infiltration, monitoring of leukemia relapse, detection of Richter’s transformation (RT), and assessment of the inflammatory activity associated with acute graft versus host disease. Future investigations should be focused on the potential of PET/CT in the prediction of clinical outcomes in patients with leukemia and the utility of novel radiotracers.

Molecular Imaging in Oncology Using Positron Emission Tomography

BACKGROUND

Anatomical and molecular data can be acquired simultaneously through the use of positron emission tomography (PET) in combination with computed tomography (CT) or magnetic resonance imaging (MRI) as a hybrid technique. A variety of radiopharmaceuticals can be used to characterize various metabolic processes or to visualize the expression of receptors, enzymes, and other molecular target structures.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, as well as on guidelines from Germany and abroad and on systematic reviews and meta-analyses.

RESULTS

Established radiopharmaceuticals for PET, such as 2-[18F]fluoro-2- deoxyglucose ([18F]FDG), enable the visualization of physiological processes on the molecular level and can provide vital information for clinical decision-making. For example, PET can be used to evaluate pulmonary nodules for malignancy with 95% sensitivity and 82% specificity. It can be used both for initial staging and for the guidance of further treatment. Alongside the PET radiopharmaceuticals that have already been well studied and evaluated, newer ones are increasingly becoming available for the noninvasive phenotyping of tumor diseases, e.g., for analyzing the expression of prostate-specific membrane antigen (PSMA), of somatostatin receptors, or of chemokine receptors on tumor cells.

CONCLUSION

PET is an important component of diagnostic algorithms in oncology. It can help make diagnosis more precise and treatment more individualized. An increasing number of PET radiopharmaceuticals are now expanding the available options for imaging. Many radiopharmaceuticals can be used not only for noninvasive analysis of the expression of therapeutically relevant target structures, but also for the ensuing, target-directed treatment with radionuclides.

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.

PET/Computed Tomography in Chronic Lymphocytic Leukemia and Richter Transformation

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the United States. In 1-10% of cases, it can undergo Richter's transformation (RT) to either diffuse large B cell lymphoma (DLBCL) or Hodgkin's lymphoma (HL). Diagnosis requires histologic confirmation by tissue biopsy. PET/CT has been studied to in several series to look at its predictive value for identifying RT in biopsies. in this review, we will discuss the role of PET/CT to identify RT in patients CLL and its utility in clinical practice.

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's syndrome of the central nervous system diagnosed concurrently with chronic lymphocytic leukaemia: A case report and literature review

RATIONALE

Central nervous system (CNS) infiltration of Richter's syndrome (RS) is rare and only a few cases were discussed. Of these published cases, either they were accompanied with lymph node involvement or with a history of chronic lymphocytic leukemia (CLL). To our knowledge, this is the first published case of RS of the brain and meninges diagnosed concurrently with CLL in the absence of any evidence of lymphoma outside of the CNS.

PATIENT CONCERNS

A 67-year-old female presented with slurred speech, headache, and left-sided hemiparesis. Magnetic resonance imaging of the brain revealed an irregular lesion 30 mm in diameter in the right parietal lobe. The mass was totally removed and pathology revealed diffuse large B-cell lymphoma (DLBCL) of non-germinal center type by Hans' classification. The patient's leukocyte count was 12.1 × 109/L (76.9% lymphocytes), and fluorescence-activated cell sorting (FACS) analysis of blood revealed a clonal B-cell population (36.75% leukocytes) corresponding to the immunological CLL profile (Matutes score of 5/5). Bone marrow (BM) aspiration and biopsy also indicated CLL. The analysis of immunoglobulin heavy chain gene (IGH) and kappa chain gene (IGK) in the patient's BM and CNS tissue indicated that the DLBCL of the brain was derived from the CLL clone.

DIAGNOSES

RS of the CNS diagnosed concurrently with CLL.

INTERVENTIONS

The patient received intravenous chemotherapy (6.0 g methotrexate) and intrathecal chemotherapy (10 mg methotrexate, 50 mg cytarabine, 5 mg dexamethasone).

OUTCOMES

The patient returned to our department with left-sided hemiparesis and headache 2 weeks after the chemotherapy. Repeat MRI showed progression of the brain lesion. Her general condition deteriorated significantly with confusion and high fever, and she died within a few days at only 10 weeks after the onset of symptoms.

LESSONS

The survival of CNS-RS patients is very poor and and is always complicated with multiple and different genetic alterations. Because of chemotherapy insensitivity, a multidisciplinary treatment including surgery and radiotherapy together with novel agents may be an option to improving patient outcomes.

Peripheral T-Cell Lymphoma of the Submandibular Salivary Gland as an Unusual Manifestation of Richter's Syndrome: A Case Report and Literature Review

Richter's syndrome is the development of high-grade non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). In most patients with Richter's syndrome, the high-grade NHL is diffuse large B-cell lymphoma. Only a small minority of CLL/SLL patients develop T-cell malignancies. Herein, we describe a 40-year-old male patient presenting with peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) in the submandibular salivary gland, two years after the diagnosis of CLL/SLL. The PTCL-NOS consisted of small lymphocytes, which complicated diagnosis. Immunohistochemical, cytological, and molecular studies allowed the correct diagnosis of composite lymphoma (SLL/PTCL-NOS) of the submandibular salivary gland. The PTCL-NOS had a cytotoxic phenotype and aberrant expression of CD79a. There was no evidence to suggest that the PTCL-NOS of the submandibular salivary gland developed from an intimately associated submandibular lymph node or by PTCL-NOS dissemination. A review of the literature and presented case suppose that the PTCLs developed following CLL/SLL have the cytotoxic phenotype and can clinically mimic typical Richter's syndrome.

Richter Transformation of Chronic Lymphocytic Leukemia: A Review of Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography and Molecular Diagnostics

Chronic lymphocytic leukemia (CLL) is a low-grade B-cell proliferative disease with a generally indolent course. In a few cases, it undergoes transformation and becomes a more aggressive malignancy, such as diffuse large B-cell lymphoma (DLBCL). This process, which is called Richter transformation (RT), is often detected too late and is associated with a poor prognosis. There are multiple molecular diagnostic approaches to detect RT in preexisting CLL. Metabolic imaging using 18-fluorine fluorodeoxyglucose positron emission tomography–computed tomography (18F-FDG PET/CT) can be a very useful tool for early detection of RT and which can hence allow for timely intervention, thereby improving the patient’s chances of survival.

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.

NCRI phase II study of CHOP in combination with ofatumumab in induction and maintenance in newly diagnosed Richter syndrome

Richter syndrome (RS) is associated with chemotherapy resistance and a poor historical median overall survival (OS) of 8-10 months. We conducted a phase II trial of standard CHOP-21 (cyclophosphamide, doxorubicin, vincristine, prednisolone every 21 d) with ofatumumab induction (Cycle 1: 300 mg day 1, 1000 mg day 8, 1000 mg day 15; Cycles 2-6: 1000 mg day 1) (CHOP-O) followed by 12 months ofatumumab maintenance (1000 mg given 8-weekly for up to six cycles). Forty-three patients were recruited of whom 37 were evaluable. Seventy-three per cent were aged >60 years. Over half of the patients received a fludarabine and cyclophosphamide-based regimen as prior CLL treatment. The overall response rate was 46% (complete response 27%, partial response 19%) at six cycles. The median progression-free survival was 6·2 months (95% confidence interval [CI] 4·9-14·0 months) and median OS was 11·4 months (95% CI 6·4-25·6 months). Treatment-naïve and TP53-intact patients had improved outcomes. Fifteen episodes of neutropenic fever and 46 non-neutropenic infections were observed. There were no treatment-related deaths. Seven patients received platinum-containing salvage at progression, with only one patient obtaining an adequate response to proceed to allogeneic transplantation. CHOP-O with ofatumumab maintenance provides minimal benefit beyond CHOP plus rutuximab. Standard immunochemotherapy for RS remains wholly inadequate for unselected RS. Multinational trials incorporating novel agents are urgently needed.

FDG-PET imaging in hematological malignancies

The majority of aggressive lymphomas is characterized by an up regulated glycolytic activity, which enables the visualization by F-18 FDG-PET/CT. One-stop hybrid FDG-PET/CT combines the functional and morphologic information, outperforming both, CT and FDG-PET as separate imaging modalities. This has resulted in several recommendations using FDG-PET/CT for staging, restaging, monitoring during therapy, and assessment of treatment response as well as identification of malignant transformation. FDG-PET/CT may obviate the need for a bone marrow biopsy in patients with Hodgkin's lymphoma and diffuse large B cell lymphoma. FDG-PET/CT response assessment is recommended for FDG-avid lymphomas, whereas CT-based response evaluation remains important in lymphomas with low or variable FDG avidity. The treatment induced change in metabolic activity allows for assessment of response after completion of therapy as well as prediction of outcome early during therapy. The five-point scale Deauville Criteria allows the assessment of treatment response based on visual FDG-PET analysis. Although the use of FDG-PET/CT for prediction of therapeutic response is promising it should only be conducted in the context of clinical trials. Surveillance FDG-PET/CT after complete remission is discouraged due to the relative high number of false-positive findings, which in turn may result in further unnecessary investigations. Future directions include the use of new PET tracers such as F-18 fluorothymidine (FLT), a surrogate biomarker of cellular proliferation and Ga-68 CXCR4, a chemokine receptor imaging biomarker as well as innovative digital PET/CT and PET/MRI techniques.

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.

Metabolism pathways in chronic lymphocytic leukemia

Alterations in chronic lymphocytic leukemia (CLL) cell metabolism have been studied by several investigators. Unlike normal B lymphocytes or other leukemia cells, CLL cells, like adipocytes, store lipids and utilize free fatty acids (FFA) to produce chemical energy. None of the recently identified mutations in CLL directly affects metabolic pathways, suggesting that genetic alterations do not directly contribute to CLL cells' metabolic reprogramming. Conversely, recent data suggest that activation of STAT3 or downregulation of microRNA-125 levels plays a crucial role in the utilization of FFA to meet the CLL cells' metabolic needs. STAT3, known to be constitutively activated in CLL, increases the levels of lipoprotein lipase (LPL) that mediates lipoprotein uptake and shifts the CLL cells' metabolism towards utilization of FFA. Herein, we review the evidence for altered lipid metabolism, increased mitochondrial activity and formation of reactive oxygen species (ROS) in CLL cells, and discuss the possible therapeutic strategies to inhibit lipid metabolism pathways in patient with CLL.

Imaging of non-Hodgkin lymphomas: diagnosis and response-adapted strategies

Optimal lymphoma management requires accurate pretreatment staging and reliable assessment of response, both during and after therapy. Positron emission tomography with computerized tomography (PET/CT) combines functional and anatomical imaging and provides the most sensitive and accurate methods for lymphoma imaging. New guidelines for lymphoma imaging and recently revised criteria for lymphoma staging and response assessment recommend PET/CT staging, treatment monitoring, and response evaluation in all FDG-avid lymphomas, while CT remains the method of choice for non-FDG-avid histologies. Since interim PET imaging has high prognostic value in lymphoma, a number of trials investigate PET-based, response-adapted therapy for non-Hodgkin lymphomas (NHL). PET response is the main determinant of response according to the new response criteria, but PET/CT has little or no role in routine surveillance imaging, the value which is itself questionable. This review presents from a clinical point of view the evidence for the use of imaging and primarily PET/CT in NHL before, during, and after therapy. The reader is given an overview of the current PET-based interventional NHL trials and an insight into possible future developments in the field, including new PET tracers.

Richter syndrome in chronic lymphocytic leukemia: updates on biology, clinical features and therapy

Richter syndrome (RS) or Richter transformation is the development of secondary aggressive lymphoma in the setting of underlying chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Most frequently CLL transforms into diffuse large B-cell lymphoma (DLBCL) (90%) and rarely (10%) into Hodgkin lymphoma, termed Hodgkin variant of Richter syndrome (HvRS). RS is generally characterized by an aggressive clinical course and poor prognosis. In recent years, major advances have been made in understanding genetic events which relate to the progression of CLL or transformation into RS. Better understanding of the molecular pathways has revealed that RS is not a single homogeneous entity. The majority of cases are clonally related to the original CLL clone, while a minority develop from an unrelated clone. This review summarizes new data relating to the molecular biology and the genetic/epigenetic changes occurring during Richter transformation, and also considers the clinical features and therapy for both DLBCL-RS and Hodgkin variant-RS.

FDG/PET in CLL today

In this issue of Blood, Falchi et al present their experience with 2-deoxy-2-[18F] fluoroglucose/positron emission tomography (FDG/PET) in the management of patients with chronic lymphocytic leukemia (CLL) or Richter syndrome (RS) over a 10-year period at a referral center. The results of this study shed light on the potential role of FDG/PET in CLL.

How we treat Richter syndrome

Richter syndrome (RS) is defined as the transformation of chronic lymphocytic leukemia (CLL) into an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). RS occurs in approximately 2% to 10% of CLL patients during the course of their disease, with a transformation rate of 0.5% to 1% per year. A combination of germline genetic characteristics, clinical features (eg, advanced Rai stage), biologic (ζ-associated protein-70(+), CD38(+), CD49d(+)) and somatic genetic (del17p13.1 or del11q23.1) characteristics of CLL B cells, and certain CLL therapies are associated with higher risk of RS. Recent studies have also identified the crucial role of CDKN2A loss, TP53 disruption, C-MYC activation, and NOTCH1 mutations in the transformation from CLL to RS. An excisional lymph node biopsy is considered the gold standard for diagnosis of RS; a (18)F-fluorodeoxyglucose positron emission tomography scan can help inform the optimal site for biopsy. Approximately 80% of DLBCL cases in patients with CLL are clonally related to the underlying CLL, and the median survival for these patients is approximately 1 year. In contrast, the remaining 20% of patients have a clonally unrelated DLBCL and have a prognosis similar to that of de novo DLBCL. For patients with clonally related DLBCL, induction therapy with either an anthracycline- or platinum-based regimen is the standard approach. Postremission stem cell transplantation should be considered for appropriate patients. This article summarizes our approach to the clinical management of CLL patients who develop RS.

Use of positron emission tomography-computed tomography in the management of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) cells typically have low 2-deoxy-2-[(18)F]fluoro-d-glucose (FDG) avidity, and patients with CLL have an increased risk of developing FDG-avid aggressive lymphomas, second malignancies and infections. We hypothesized that FDG positron emission tomography-computed tomography (PET-CT) of the trunk is a sensitive method of detecting these complications in patients with CLL. Of the of 2299 patients with CLL seen in the Division of Hematology at Mayo Clinic Rochester between 1 January 2006 and 31 December 2011, 272 (11.8%) had 526 PET-CT scans and 472 (89.7%) of these were reported as abnormal. Among the 293 (55.7%) PET-CT scans used for routine evaluation of CLL, the PET component was of clinical value in only one instance. In contrast, in 83 (30.5%) patients, PET-CT scans used to evaluate new clinical complications localized high FDG-avidity lesions for biopsies. This resulted in clinically relevant new diagnoses in 32 patients, including those with more aggressive lymphoma (n = 16), non-hematological malignancies (n = 8) and opportunistic infections (n = 3). Twenty-seven patients had high FDG-avidity CLL, which was associated with prominent lymph node proliferation centers, an increased frequency of poor prognostic factors (17p13 deletion, unmutated immunoglobulin heavy chain variable gene [IGHV], expression of ZAP-70 and CD38) and a shorter overall survival. We conclude that FDG PET scans should not be used for routine surveillance of patients with CLL. However PET-CT scans are sensitive, but not specific, for detection of aggressive lymphomas, other cancers and systemic infections in patients with CLL.