18F-FDG PET/CT in primary brain lymphoma

Interim FDG-PET improves treatment failure prediction in primary central nervous system lymphoma: An LOC network prospective multicentric study

BACKGROUND

The purpose of our study was to assess the predictive and prognostic role of 2-18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/MRI during high-dose methotrexate-based chemotherapy (HD-MBC) in de novo primary central nervous system lymphoma (PCNSL) patients aged 60 and above.

METHODS

This prospective multicentric ancillary study included 65 immunocompetent patients who received induction HD-MBC as part of the BLOCAGE01 phase III trial. FDG-PET/MRI were acquired at baseline, post 2 cycles (PET/MRI2), and posttreatment (PET/MRI3). FDG-PET response was dichotomized with "positive" indicating persistent tumor uptake higher than the contralateral mirroring brain region. Performances of FDG-PET and International PCNSL Collaborative Group criteria in predicting induction response, progression-free survival (PFS), and overall survival (OS) were compared.

RESULTS

Of the 48 PET2 scans performed, 9 were positive and aligned with a partial response (PR) on MRI2. Among these, 8 (89%) progressed by the end of the induction phase. In contrast, 35/39 (90%) of PET2-negative patients achieved complete response (CR). Among the 18 discordant responses at interim (PETCR/MRIPR), 83% ultimately achieved CR. Eighty-seven percent of the PET2-negative patients were disease free at 6 months versus 11% of the PET2-positive patients (P < .001). The MRI2 response did not significantly differentiate patients based on their PFS, regardless of whether they were in CR or PR. Both PET2 and MRI2 independently predicted OS in multivariate analysis, with PET2 showing a stronger association.

CONCLUSIONS

Our study highlights the potential of interim FDG-PET for early management of PCNSL patients. Response-driven treatment based on PET2 may guide future clinical trials.

TRIAL

LOCALYZE, NCT03582254, ancillary of phase III clinical trial BLOCAGE01, NCT02313389 (Registered July 10, 2018-retrospectively registered) https://clinicaltrials.gov/ct2/show/NCT03582254?term=LOCALYZE&draw=2&rank=1.

Bone marrow biopsy can be omitted in the diagnostic workup of CNS lymphoma of DLBCL origin: a population-based retrospective study in the PET-CT era

Currently, bone marrow (BM) biopsy (BMB) is recommended in the initial staging of patients with the presumed primary central nervous system (CNS) lymphoma (PCNSL). However, the added value of BMB in the era of positron emission tomography (PET-CT) has been challenged in other lymphoma subtypes. We analyzed BM findings in patients with biopsy-proven CNS lymphoma and a negative PET-CT scan for disease outside CNS. A comprehensive Danish population-based registry search was performed to identify all patients with CNS lymphoma of diffuse large B cell lymphoma (DLBCL) histology with available BMB results and staging PET-CT without systemic lymphoma. A total of 300 patients fulfilled the inclusion criteria. Of them, 16% had a previous history of lymphoma, while 84% were diagnosed with PCNSL. None of the patients had DLBCL in the BM. A minority (8.3%) had discordant BMB findings, mainly low-grade histologies that did not influence treatment choice in any case. In conclusion, the risk of overlooking concordant BM infiltration in patients with CNS lymphoma of DLBCL histology and negative PET-CT scan is negligible. As we did not find any patient with DLBCL in the BMB, our results suggest that BMB can be safely omitted in the diagnostic workup in patients with CNS lymphoma and a negative PET-CT.

Dural Arteriovenous Fistula Mimicking a Brain Tumor on Methionine-positron Emission Tomography: A Case Report

In this article, we report a case wherein a brain tumor was suspected based on computed tomography and magnetic resonance imaging findings. We made an initial diagnosis of malignant brain tumor based on methionine-positron emission tomography (PET) findings, but the correct diagnosis was dural arteriovenous fistula (DAVF). The patient was a 45-year-old man with DAVF who developed headache. Methionine-PET imaging showed high methionine uptake in the lesion. Although the tumor was strongly suspected from the findings of methionine-PET, the diagnosis of DAVF could be made correctly only by interpreting digital subtraction angiography and computed tomographic angiography. The findings of methionine-PET, which is considered useful in the diagnosis and denial of brain tumors, made the diagnosis of DAVF more difficult. The increased uptake of methionine-PET in DAVF is an important finding because, to our knowledge, this study is the first to report such finding. The results of this study might be useful for differential diagnoses when the diagnosis is uncertain.

Micro-Nanocarriers Based Drug Delivery Technology for Blood-Brain Barrier Crossing and Brain Tumor Targeting Therapy

The greatest obstacle to using drugs to treat brain tumors is the blood-brain barrier (BBB), making it difficult for conventional drug molecules to enter the brain. Therefore, how to safely and effectively penetrate the BBB to achieve targeted drug delivery to brain tumors has been a challenging research problem. With the intensive research in micro- and nanotechnology in recent years, nano drug-targeted delivery technologies have shown great potential to overcome this challenge, such as inorganic nanocarriers, organic polymer-carriers, liposomes, and biobased carriers, which can be designed in different sizes, shapes, and surface functional groups to enhance their ability to penetrate the BBB and targeted drug delivery for brain tumors. In this review, the composition and overcoming patterns of the BBB are detailed, and then the hot research topics of drug delivery carriers for brain tumors in recent years are summarized, and their mechanisms of action on the BBB and the factors affecting drug delivery are described in detail, and the effectiveness of targeted therapy for brain tumors is evaluated. Finally, the challenges and dilemmas in developing brain tumor drug delivery systems are discussed, which will be promising in the future for targeted drug delivery to brain tumors based on micro-nanocarriers technology.

Role of Positron Emission Tomography in Primary Central Nervous System Lymphoma

Simple Summary

Primary central nervous system lymphoma (PCNSL) is a rare but highly aggressive lymphoma with increasing incidence in immunocompetent patients. To date, the only established biomarkers for survival are age and functional status. Currently, the magnetic resonance imaging (MRI) criteria of the International Collaborative Group on Primary Central Nervous System Lymphoma are the only ones recommended for follow-up. However, early occurrence of recurrence after treatment in patients with a complete response on MRI raises the question of its performance in assessing residual disease. While the use of ¹⁸F-fluorodeoxyglucose body positron emission tomography for identification of systemic disease has been established and can be pivotal in patient treatment decisions, the role of brain PET scan is less clear. Here we review the potential role of PET in the management of patients with PCNSL, both at diagnosis and for follow-up under treatment.

Abstract

The incidence of primary central nervous system lymphoma has increased over the past two decades in immunocompetent patients and the prognosis remains poor. A diagnosis and complete evaluation of the patient is needed without delay, but histologic evaluation is not always available and PCNSL can mimic a variety of brain lesions on MRI. In this article, we review the potential role of ¹⁸F-FDG PET for the diagnosis of PCNSL in immunocompetent and immunocompromised patients. Its contribution to systemic assessment at the time of diagnosis has been well established by expert societies over the past decade. In addition, ¹⁸F-FDG provides valuable information for differential diagnosis and outcome prediction. The literature also shows the potential role of ¹⁸F-FDG as a therapeutic evaluation tool during the treatment and the end of the treatment. Finally, we present several new radiotracers that may have a potential role in the management of PCNSL in the future.

The Role of [68Ga]Ga-Pentixafor PET/CT or PET/MRI in Lymphoma: A Systematic Review

The aim of this systematic review was to investigate published data about the role of gallium-68 Pentixafor positron emission tomography/computed tomography ([⁶⁸Ga]Ga-Pentixafor PET/CT) or PET/magnetic resonance imaging (PET/MRI) in patients affected by lymphoma. A comprehensive computer literature search of the Scopus, PubMed/MEDLINE, and Embase databases was conducted including articles indexed up to June 2022. In total, 14 studies or subsets in studies were eligible for inclusion. From the analyses of the selected studies, the following main findings have been found: (1) lymphomas can be considered [⁶⁸Ga]Ga-Pentixafor avid diseases, also in cases of fluorine-18 fluorodeoxyglucose [¹⁸F]FDG-not avid forms such as lymphoplasmacytic lymphoma (LPL), chronic lymphocytic leukemia (CLL), marginal zone lymphoma (MZL) and central nervous system lymphoma (CNSL); (2) among lymphomas, mantle cell lymphoma (MCL) and MZL are those with highest [⁶⁸Ga]Ga-Pentixafor uptake; (3) [⁶⁸Ga]Ga-Pentixafor PET/CT or PET/MRI is a useful tool for the staging and treatment response evaluation; (4) [⁶⁸Ga]Ga-Pentixafor PET seems to have a better diagnostic performance than [¹⁸F]FDG PET in evaluating lymphomas. Despite several limitations affecting this analysis, especially related to the heterogeneity of the included studies, [⁶⁸Ga]Ga-Pentixafor PET may be considered a useful imaging method for staging and treatment response evaluation of several lymphomas, especially MZL, CNSL and LPL.

Rapidly progressive dementias - aetiologies, diagnosis and management

Rapidly progressive dementias (RPDs) are a group of heterogeneous disorders that include immune-mediated, infectious and metabolic encephalopathies, as well as prion diseases and atypically rapid presentations of more common neurodegenerative diseases. Some of these conditions are treatable, and some must be diagnosed promptly because of their potential infectivity. Prion disease is considered to be the prototypical RPD, but over the past two decades, epidemiological reports and the identification of various encephalitis-mediating antibodies have led to a growing recognition of other encephalopathies as potential causes of rapid cognitive decline. Knowledge of RPD aetiologies, syndromes and diagnostic work-up protocols will help clinicians to establish an early, accurate diagnosis, thereby reducing morbidity and mortality, especially in immune-mediated and other potentially reversible dementias. In this Review, we define the syndrome of RPD and shed light on its different aetiologies and on secondary factors that might contribute to rapid cognitive decline. We describe an extended diagnostic procedure in the context of important differential diagnoses, discuss the utility of biomarkers and summarize potential treatment options. In addition, we discuss treatment options such as high-dose steroid therapy in the context of therapy and diagnosis in clinically ambiguous cases.

The term ‘rapidly progressive dementia’ (RPD) describes a cognitive disorder with fast progression, leading to dementia within a relatively short time. This Review discusses the wide range of RPD aetiologies, as well as the diagnostic approach and treatment options.

Definitions of rapidly progressive dementia (RPD) vary according to the aetiological background and relate to the speed of cognitive decline, time from first symptom to dementia syndrome and/or overall survival.

RPD can occur in rapidly progressive neurodegenerative diseases, such as prion diseases, or in primarily slowly progressive diseases as a consequence of intrinsic factors or concomitant pathologies.

Besides neurodegenerative diseases, inflammatory (immune-mediated and infectious), vascular, metabolic and neoplastic CNS diseases are important and frequent causes of RPD.

To identify treatable causes of RPD, the technical diagnostic work-up must include MRI and analyses of blood and cerebrospinal fluid, and further diagnostics might be indicated in unclear cases.

Therapeutic options for many non-neurodegenerative causes of RPD are already available; disease-modifying therapies for neurodegenerative RPDs are an important focus of current research and could become a treatment option in the near future.

Prognostic value of [18F]FDG PET/CT in patients with CNS lymphoma receiving ibrutinib-based therapies

PURPOSE

Current clinical and imaging tools remain suboptimal for predicting treatment response and prognosis in CNS lymphomas. We investigated the prognostic value of baseline [18F]FDG PET in patients with CNS lymphoma receiving ibrutinib-based treatments.

METHODS

Fifty-three patients enrolled in a prospective clinical trial and underwent brain PET before receiving single-agent ibrutinib or ibrutinib in combination with methotrexate with or without rituximab. [18F]FDG uptake in these lesions was quantified by drawing PET volumes of interest around up to five [18F]FDG-avid lesions per patient (with uptake greater than surrounding brain). We measured standardized uptake values (SUVmax), metabolic tumor volumes, total lesion glycolysis (TLG), and the sum thereof in these lesions. We analyzed the relationship between PET parameters and mutation status, overall response rates, and progression-free survival (PFS).

RESULTS

Thirty-eight patients underwent single-agent therapy and 15 received combination therapy. On PET, 15/53 patients had no measurable disease. In the other 38 patients, a total of 71 lesions were identified on PET. High-intensity [18F]FDG uptake and a larger volume of [18F]FDG-avid disease were inversely related to treatment outcome (p ≤ 0.005). In univariable analysis, PFS was linearly correlated with all PET parameters, with stronger association when sum-values were used. A multivariable model showed that risk of progression increased by 9% for every 5-unit increase in sumSUVmax (hazard ratio = 1.09 [95% CI: 1.04 to 1.14]).

CONCLUSION

Higher lesional metabolic parameters are inversely related to outcome in patients undergoing ibrutinib-based therapies, and sumSUVmax emerged as a strong independent prognostic factor.

TRIAL REGISTRATION

NCT02315326; https://clinicaltrials.gov/ct2/show/NCT02315326?term=NCT02315326&draw=2&rank=1.

CXCR4-Directed PET/CT with [68Ga]Pentixafor in Central Nervous System Lymphoma: A Comparison with [18F]FDG PET/CT

PURPOSE

This study aimed to evaluate the value of [⁶⁸ Ga]Pentixafor PET/CT for the detection of lesions in central nervous system lymphoma (CNSL) patients before chemotherapy, during treatment and suspected CSNL recurrence, compared with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT).

PROCEDURES

Twenty-six patients with newly or previously diagnosed CNSL who underwent [⁶⁸ Ga]Pentixafor PET/CT were included retrospectively. Histopathological results, magnetic resonance imaging (MRI), and follow-up were used as the standard reference. The accuracy of lesion detection, maximum standardized uptake value (SUV_max) of tumors, and ratio of tumor-to-normal brain (T/N) with [⁶⁸ Ga]Pentixafor PET/CT were calculated and compared to those obtained with [¹⁸F]FDG PET/CT. CXCR4 expression was analyzed through immunohistochemistry.

RESULTS

Of 26 patients, 18 were newly diagnosed with a total of 23 lesions, 4 had recurrent with 4 lesions, and 4 underwent a mid-term treatment assessment after 4 cycles of chemotherapy (3 achieved complete response (CR), 1 experienced progressive disease (PD) with a total of 8 lesions). Thirty-five lesions were all clearly detected with favorable contrast by [⁶⁸ Ga]Pentixafor PET/CT (accuracy, 100%), consistent with the results of contrast-enhanced magnetic resonance imaging (CE-MRI). The SUV_max of positive lesions in [⁶⁸ Ga]Pentixafor PET/CT was correlated with tumor size (r = 0.555, P = 0.001). In 21 patients, compared with [¹⁸F]FDG PET/CT, [⁶⁸ Ga]Pentixafor PET/CT showed a remarkably higher T/N ratio (21.93 ± 10.77 vs 4.29 ± 2.16, P = 0.000) and detected 5 more lesions in the mid-term treatment assessment of patients (P = 0.026). The CXCR4 expression of CNSL lesions was correlated with SUV_max of [⁶⁸ Ga]Pentixafor PET/CT (r = 0.772, P = 0.000).

CONCLUSIONS

CXCR4-directed PET/CT using [⁶⁸ Ga]Pentixafor, with excellent tumor-to-background contrast, might be a more promising agent for the detection of lesions in CNSL patients than [¹⁸F]FDG PET/CT.

Clinical Features and Prognostic Factors for Primary Anaplastic Large Cell Lymphoma of the Central Nervous System: A Systematic Review

Simple Summary

Primary anaplastic large cell lymphoma (ALCL) of the central nervous system (CNS) is a subtype of primary central nervous system lymphoma (PCNSL). ALCL is divided into anaplastic lymphoma kinase (ALK)-positive ALCL and ALK-negative ALCL, according to ALK expression. ALK-positive cancers tend to develop at a younger age and tend to have a better prognosis. Almost all past articles on primary ALCL of the CNS have been case reports and there have been no randomized trials or cohort studies on this subject. We thus performed a systematic review of primary ALCL of the CNS. According to the author’s survey, 36 case reports have been published in English-language journals. In this paper, we have summarized the clinical features and prognostic factors for primary ALCL of the CNS based on previous studies.

Abstract

Primary anaplastic large cell lymphoma (ALCL) of the central nervous system (CNS) is a subtype of primary CNS lymphoma (PCNSL). There are very few comprehensive reports on this extremely rare tumor. Therefore, it is necessary to investigate the clinical features and prognostic factors for primary ALCL of the CNS. We performed a systematic review of the published literature. Past cases were comprehensively searched using PubMed, Cochrane Library, and Web of Science. Clinical information, such as age, sex, anaplastic lymphoma kinase (ALK) status, lesion sites, treatment methods, and survivorship were extracted. Thirty-nine cases with information on ALK status and treatment course were identified. The average observation period was 13 months, and the overall 2-year survival rate was 58%. Univariate analyses showed a statistically significantly better prognosis among patients < 40 years of age (p = 0.039, HR 0.32 (0.11–0.95)) and in relation to ALK positivity (p = 0.010, HR 0.24 (0.08–0.71) and methotrexate treatment (p = 0.003, HR 0.17 (0.05–0.56)). Because of the sparsity of cases, it is necessary to accumulate cases in order to perform more detailed analyses.

Correlation of 18F-FDG PET/CT SUVmax with clinical features, D-dimer and LDH in patients with primary intestinal lymphoma

Objective

To investigate the characteristics of fluorine-18-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) maximum standardized uptake value (SUVmax) in primary intestinal lymphoma (PIL) and its correlation with D-dimer and lactate dehydrogenase (LDH).

Methods

Fifty-two patients diagnosed with PIL from June 2016 to December 2019 were analyzed. All patients underwent 18F-FDG PET/CT. The relationships between SUVmax and different pathological subtypes, clinical stages and risk grades were analyzed. The correlations between SUVmax and Ki-67, LDH and D-dimer were determined. Additionally, PET/CT imaging results were collected from 35 patients with primary intestinal cancer (PIC) and compared with the imaging features of PIL.

Results

SUVmax was significantly different between PIL and PIC groups and various PIL pathological subgroups. Patients in the high-risk PIL group had markedly higher SUVmax values than the intermediate-risk and low-risk groups. A significant positive correlation was observed between SUVmax and Ki-67 in patients with PIL. SUVmax was significantly different between the elevated and normal D-dimer groups. D-dimer showed a positive correlation with SUVmax.

Conclusion

18F-FDG PET/CT SUVmax reflects the aggressiveness of lymphoma to a certain degree, is correlated with Ki-67 and determines the risk grades of PIL. Moreover, it facilitates differential diagnosis, clinical staging and treatment based on D-dimer levels.

Positron emission tomography and magnetic resonance imaging in primary central nervous system lymphoma-a narrative review

This review addresses the challenges of primary central nervous system (CNS) lymphoma diagnosis, assessment of treatment response, and detection of recurrence. Primary CNS lymphoma is a rare form of extra-nodal non-Hodgkin lymphoma that can involve brain, spinal cord, leptomeninges, and eyes. Primary CNS lymphoma lesions are most commonly confined to the white matter or deep cerebral structures such as basal ganglia and deep periventricular regions. Contrast-enhanced magnetic resonance imaging (MRI) is the standard diagnostic modality employed by neuro-oncologists. MRI often shows common morphological features such as a single or multiple uniformly well-enhancing lesions without necrosis but with moderate surrounding edema. Other brain tumors or inflammatory processes can show similar radiological patterns, making differential diagnosis difficult. [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) has selected utility in cerebral lymphoma, especially in diagnosis. Primary CNS lymphoma can sometimes present with atypical findings on MRI and FDG PET, such as disseminated disease, non-enhancing or ring-like enhancing lesions. The complementary strengths of PET and MRI have led to the development of combined PET-MR systems, which in some cases may improve lesion characterization and detection. By highlighting active developments in this field, including advanced MRI sequences, novel radiotracers, and potential imaging biomarkers, we aim to spur interest in sophisticated imaging approaches.

Differentiating between Primary Central Nervous System Lymphoma and Glioblastoma: The Diagnostic Value of Combining 18F-fluorodeoxyglucose Positron Emission Tomography with Arterial Spin Labeling

Using conventional magnetic resonance imaging (MRI) methods, the differentiation of primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM) is often difficult due to overlapping imaging characteristics. This study aimed to evaluate the diagnostic value of combining ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) with arterial spin labeling (ASL) for differentiating PCNSL from GBM. In all, 20 patients with PCNSL and 55 with GBM were retrospectively examined. From the FDG-PET data, the maximum standardized uptake values (SUVmax) and the ratio of tumor to normal contralateral gray matter (T/N_SUVmax) were calculated. From the ASL data, the T/N ratio of the maximum tumor blood flow (relative TBFmax: rTBFmax) was obtained. Diagnostic performance of each parameter was analyzed using univariate and multivariate logistic regression analyses and receiver-operating characteristic (ROC) curve analyses. A generalized linear model was applied for comparing the performance of FDG-PET and ASL individually, and in combination. In univariate analysis, SUVmax and T/N_SUVmax were statistically higher in patients with PCNSL and rTBFmax was higher in patients with GBM. In the multivariate analysis, T/N_SUVmax and rTBFmax were statistically independent. The sensitivity, specificity, and area under the curve (AUC) for discriminating PCNSL from GBM were 100%, 87.3%, and 0.950 in T/N_SUVmax; 90%, 72.7%, and 0.824 in rTBFmax; and 95%, 96.4%, and 0.991 in the combined model, respectively. The combined use of T/N_SUVmax and rTBFmax may contribute to better differentiation between PCNSL and GBM.

Diagnostic Performance of Pretreatment 18F-Fluorodeoxyglucose Positron Emission Tomography With or Without Computed Tomography in Patients With Primary Central Nervous System Lymphoma: Updated Systematic Review and Diagnostic Test Accuracy Meta-analyses

This review aimed to assess diagnostic performance of 18F-flouro-deoxy-glucose positron emission tomography (FDG-PET) with or without computed tomography (CT) scan in primary central nervous system lymphoma (PCNSL). Eligible studies reporting diagnostic accuracy of pretreatment FDG-PET(CT) scan in immunocompetent adults with PCNSL were identified through systematic literature search. Data on diagnostic performance from individual studies was summarized in a 2 × 2 table classifying patients as true positives, true negatives, false positives, and false negatives using histopathologic diagnosis as reference standard. Random-effects model was used to calculate weighted-mean pooled sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic odds ratio with 95% confidence intervals (95% CI). Twenty-nine primary studies involving 967 patients were included. Weighted-mean pooled sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic odds ratio was 87% (95% CI, 83%-90%), 85% (95% CI, 81%-88%), 84% (95% CI, 81%-88%), 87% (95% CI, 84%-90%), and 29.78 (95% CI, 18.34-48.35), respectively, demonstrating acceptably high diagnostic accuracy of pretreatment FDG-PET(CT) scan in immunocompetent patients with PCNSL.

Use of 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography to successfully diagnose central nervous system vasculitis in systemic lupus erythematosus and antiphospholipid syndrome: a case report

A 53-year-old woman was admitted to our hospital for headache secondary to an acute subdural haematoma in the right cerebellar tentorium. She had been diagnosed with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) two years before presentation and was initiated on prednisolone (PSL) 40 mg/day as induction therapy, which was subsequently tapered to 5 mg/day. Her thrombocytopenia and renal impairment were managed by warfarin with a target prothrombin time-international normalised ratio of 2-3. Her history also included 5 instances of triggerless acute subdural haematoma in the right cerebellar tentorium in the preceding 8 months. Warfarin therapy was suspected as the cause of her bleeding; however, dose adjustment was ineffective. During the current admission, neither magnetic resonance imaging nor cerebral angiography could reveal the cause of the bleeding. However, spinal fluid IL-6 was 25.7 pg/mL, and ¹⁸F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography showed fluorodeoxyglucose accumulation in the right medial occipital lobe cortex in the proximity of the haemorrhage site. Based on these two findings, we suspected vasculitis as the cause of recurrent bleeding. After ruling out malignancy, re-induction therapy with intravenous cyclophosphamide 500 mg/m²/month and PSL 30 mg/day was initiated. PSL was tapered to 2 mg/day and no signs of relapse have developed at 2 years after discharge. Her clinical course also supported vasculitis as the cause of recurrent central nervous system (CNS) bleeding and we discuss the usefulness of ¹⁸F-Fluorodeoxyglucose-Positron Emission Tomography in the diagnosis and treatment of CNS vasculitis in SLE and/or APS.

High 18F-FDOPA PET Uptake in Primary Central Nervous System Lymphoma

We present a 42-year-old woman with primary central nervous system lymphoma (PCNSL) and strong F-FDOPA PET uptake. F-FDOPA PET has high diagnostic accuracy in gliomas and brain metastases. The L-type amino acid transporter 1, targeted by F-FDOPA and C-MET PET, is a cell-type transporter usually upregulated in malignant tumors, including PCNSL. In this line, strong uptake was already shown with C-MET in PCNSL. We report the same findings with F-FDOPA. Consequently, PCNSL is a possible differential neoplastic diagnosis of F-FDOPA uptake among neoplastic lesions.

Diagnostic Yield of Body CT and Whole-Body FDG PET/CT for Initial Systemic Staging in Patients With Suspected Primary CNS Lymphoma: A Systematic Review and Meta-Analysis

BACKGROUND. Several guidelines recommend body imaging for the initial work-up of patients with suspected primary CNS lymphoma, to exclude subclinical systemic involvement. However, to our knowledge, the diagnostic yield of body CT (contrast-enhanced CT of the chest, abdomen, and pelvis) and whole-body FDG PET/CT for the evaluation of subclinical systemic lymphoma has not yet been systematically evaluated. OBJECTIVE. The purpose of this study was to investigate and compare the diagnostic yield of body CT and whole-body FDG PET/CT in detecting subclinical systemic lymphoma in patients with suspected primary CNS lymphoma. EVIDENCE ACQUISITION. A systematic search of the MEDLINE and EMBASE databases through July 5, 2020, was conducted to identify studies evaluating the diagnostic yield of body CT or whole-body FDG PET/CT in detecting subclinical systemic lymphoma in patients with suspected primary CNS lymphoma. Pooled estimates of the diagnostic yield of both imaging modalities were calculated using the DerSimonian and Laird random-effects model. The false referral rate and the rate of incidental secondary malignancy were also pooled. EVIDENCE SYNTHESIS. Nine original articles on studies evaluating a total of 1040 patients were included. In detecting subclinical systemic lymphoma, the pooled diagnostic yields of body CT and whole-body FDG PET/CT were 2.5% (95% CI, 1.5-3.9%) and 4.9% (95% CI, 2.8-8.5%), respectively. In the subgroup analysis, the diagnostic yield of whole-body FDG PET/CT was significantly higher than that of body CT (p = .03). Four studies reported changes in the management plan: the R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone) regimen with or without radiation therapy was added if extracranial lymphoma involvement was detected by body CT or whole-body FDG PET/CT. The pooled false referral rate of whole-body FDG PET/CT was 5.3% (95% CI, 2.2-12.0%). The pooled rate of incidental secondary malignancy detected on whole-body FDG PET/CT was 3.1% (95% CI, 1.7-5.6%). CONCLUSION. Body imaging should be used in the initial workup of patients with suspected primary CNS lymphoma, to exclude systemic involvement. Whole-body FDG PET/CT may be a better alternative to body CT. CLINICAL IMPACT. Our results support current National Comprehensive Cancer Network guidelines for the use of body imaging to exclude subclinical systemic involvement in patients with suspected primary CNS lymphoma.

Use of FDG-PET/CT for systemic assessment of suspected primary central nervous system lymphoma: a LOC study

INTRODUCTION

Primary Central Nervous System Lymphoma (PCNSL) is a rare disease with different therapeutic implications than systemic lymphoma. In this study, we evaluated whole-body ¹⁸FDG-PET/CT for pre-chemotherapy imaging of suspected PCNSL.

METHODS

One hundred and thirty consecutive immunocompetent patients were retrospectively included. The results of initial ¹⁸FDG-PET/CT, contrast-enhanced CT (CeCT) and bone marrow biopsy (BMB) when available were compared to a gold standard based on pathological diagnosis or follow-up.

RESULTS

CNS lesion pathology showed large B-cell lymphoma in 95% of patients, including 11 patients with primary vitro-retinal lymphoma. Ten patients (8%) where ultimately diagnosed with systemic lymphoma involvement, including five pathologically confirmed cases, all of which were detected by ¹⁸FDG-PET/CT. ¹⁸FDG-PET/CT showed incidental systemic findings unrelated to lymphoma in 14% of patients. An SUVmax threshold of nine enabled good discrimination between systemic lymphoma and other lesions (sensitivity 92% and specificity 89%). CeCT and BMB performed in 108 and 77 patients respectively revealed systemic lesions in only three patients.

CONCLUSION

¹⁸FDG-PET/CT detected concomitant occult systemic involvement in a non-negligible proportion of suspected PCNSL cases (8%). In this setting its sensitivity is higher than that of CeCT. All of our patients ultimately diagnosed with concomitant systemic involvement had positive ¹⁸FDG-PET/CT. We believe it constitutes a safe one-stop shop evaluation for the systemic pre-treatment imaging of suspected PCNSL.

Small Cell Variant of Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma of the Dura Mimicking Tentorial Meningioma

BACKGROUND

Primary central nervous system (CNS) anaplastic large cell lymphoma (ALCL) is an uncommon type of brain tumor, usually treated with a regimen that includes high-dose methotrexate (MTX). Only a few cases of primary CNS anaplastic lymphoma kinase (ALK)-positive ALCL have been reported so far, with no reported cases of a small cell variant.

CASE DESCRIPTION

A 26-year-old man presenting with headache and visual field impairment was found to have a supratentorial mass mimicking meningioma. Craniotomy was performed for tumor resection, and postoperative histologic examination revealed atypical cells that were nonenlarged lymphocytes with irregularly shaped and enlarged nuclei; these cells were cluster of differentiation 30 and ALK-positive, leading to the diagnosis of a small cell variant of ALK-positive ALCL. In this case, the tumor exhibited an aggressive behavior with MTX resistance with metastases in the pelvis but responded well to cytarabine and etoposide (CYVE).

CONCLUSIONS

In general, CNS ALK-positive ALCL responds well to MTX, but small cell variants show aggressive behavior and may be resistant to MTX. For small cell variants of ALCL that are resistant to MTX therapy, as in this case, CYVE therapy may be an effective treatment.

Atypical radiological findings of primary central nervous system lymphoma

PURPOSE

Primary central nervous system lymphoma (PCNSL) presenting with atypical radiological findings often leads to delayed diagnosis. We aim to characterize the radiological features and apparent diffusion coefficient (ADC) values of PCNSL with atypical neuroimaging presentation in our local population.

METHODS

We retrospectively reviewed all patients with histological diagnosis of CNS lymphoma at our tertiary center from 2005 to 2016. We screened all initial pre-treatment MRIs and excluded cases with typical imaging findings of contrast-enhancing lesions without intra-lesional susceptibility and central non-enhancement. Additional exclusion criteria included (i) relapsed PCNSL, (ii) secondary CNS lymphoma, and (iii) positive HIV status. Two independent raters scored MRI and CT scans at presentation. We computed ADC values in the tumors by 2 methods: single region of interest (ROI1) and multiple ROI (ROI2).

RESULTS

Sixteen (25.4%) of 63 patients with CNS lymphoma met inclusion criteria. There were 8 men; median age was 61 (range 22-81) years. Histological diagnoses were diffuse large B cell lymphoma (n = 14) and intravascular lymphoma (n = 2). Fifteen (93%) patients had enhancing lesions (5 solitary; 10 multifocal); most enhancing lesions had T1 hypointense (67%) and T2 mixed (53%) signals, and 6 (40%) had central non-enhancing regions. Nine (56%) patients had lesions with susceptibility. Using the ROI methods, median values for minimum ADC and mean ADC ranged 0.65-0.71 × 10^-3 mm²/s and 0.79-0.84 × 10^-3 mm²/s respectively.

CONCLUSION

PCNSL with atypical radiological features represented one-fourth of our histologically diagnosed lymphoma cases; low ADC values in atypical lesions should prompt clinicians to consider early biopsy for definitive diagnosis.

Posttransplant Lymphoproliferative Disorder in Children: A 360-degree Perspective

An earlier incorrect version of this article appeared online. This article was corrected on December 17, 2019.

Utility of flouro-deoxy-glucose positron emission tomography/computed tomography in the diagnostic and staging evaluation of patients with primary CNS lymphoma

Aim: To prospectively assess the clinical utility of pretreatment flouro-deoxy-glucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in patients with primary central nervous system (CNS) lymphoma (PCNSL). Materials & methods: Patients with suspected/proven PCNSL underwent baseline whole-body 18F-FDG-PET/CT. Maximum standardized uptake value and tumor/normal tissue ratios were compared between CNS lymphoma and other histological diagnoses. Results: The mean maximum standardized uptake value (27.5 vs 18.2; p = 0.001) and mean tumor/normal tissue ratio (2.34 vs 1.53; p < 0.001) of CNS lymphoma was significantly higher than other histologic diagnoses. Five of 50 (10%) patients with biopsy-proven CNS lymphomas had pathologically increased FDG-uptake at extraneuraxial sites uncovering systemic lymphoma. Conclusion: Pretreatment whole-body 18F-FDG-PET/CT provides valuable complementary information in the diagnostic and staging evaluation of patients with PCNSL to guide therapeutic decision-making.

13N-NH3 PET/CT in oncological disease

¹³N-Ammonia (¹³N-NH₃) is widely used positron emission tomography/computed tomography (PET/CT) radiotracer for the measurement of myocardial blood perfusion; the possible role of ¹³N-NH₃ PET or PET/CT in oncological disease is not yet clear. Aim of this review is to evaluate the diagnostic performances of ¹³N-NH₃ PET in this field. A comprehensive computer literature search of the PubMed/MEDLINE, Scopus, and Embase databases was conducted including articles up to June 2019. Eighteen articles were finally included in the review. From the analyses of the selected studies, the following main findings could be drawn: (1) ¹³N-NH₃ PET is useful in discriminating between gliomas and non-neoplastic brain lesions, and among gliomas between high-grade and low-grade gliomas; (2) ¹³N-NH₃ PET have better diagnostic performance than ¹⁸F-FDG in studying gliomas; (3) a combination of ¹³N-NH₃ PET and ¹⁸F-FDG PET may be useful to differentiate between several cerebral lesions (gliomas, cerebral lymphoma, meningioma); (4) only preliminary results about the positive impact in liver and prostate cancer.

Prognostic role of pretreatment 18F-FDG PET/CT in primary brain lymphoma

OBJECTIVE

Primary brain lymphoma is an aggressive extranodal non-Hodgkin lymphoma with poor prognosis. Many possible prognostic factors are investigated with controversial results, but possible prognostic role of 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features remains unclear. Our aim was to study the metabolic behavior of brain lymphoma at 18F-FDG PET/CT and the prognostic impact of qualitative and semiquantitative PET/CT parameters.

METHODS

Between 2006 and 2018, 52 patients (26 females and 26 males; mean age: 61 years) with histologically confirmed diagnosis of brain lymphoma who underwent 18F-FDG PET/CT for staging before any treatment were included. PET images were qualitatively and semiquantitatively analyzed by measuring the maximum standardized uptake value body weight (SUVbw), lean body mass (SUVlbm), body surface area (SUVbsa), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The Kaplan-Meier method was used to estimate the progression-free survival (PFS) and overall survival (OS) times. Cox regression models were performed to determinate the relation between qualitative and semiquantitative PET/CT features and OS and PFS.

RESULTS

Thirty-nine patients had positive 18F-FDG PET/CT showing 18F-FDG uptake (mean SUVbw of 18.2; SUVlbm of 13.9; SUVbsa of 5; MTV of 14.8; TLG of 153) at the corresponding cerebral lesion; the remaining 13 were not 18F-FDG avid. Relapse or progression of disease occurred in 22 patients with an average time of 9.7 months; death occurred in 18 patients with an average of 7.9 months. There was no difference in PFS and OS between baseline PET/CT positive and negative groups or considering SUVbw, SUVlbm, and SUVbsa. PFS and OS was significantly shorter in patients with MTV ≥ 9.8 cm³ (p = 0.037 and p = 0.022, respectively) and TLG ≥ 94 (p = 0.045 and p = 0.0430, respectively).

CONCLUSIONS

18F-FDG avidity was noted in 75% of cases. Only metabolic tumor parameters (MTV and TLG) were independently correlated with PFS and OS.