Hemorrhagic Presentation in Primary Central Nervous System Lymphoma: A Case Study.

BACKGROUND Primary central nervous system diffuse large B-cell lymphoma (DLBCL) is an extremely aggressive brain disease that rarely affects immunocompetent non-elderly patients, particularly with hemorrhagic presentation. Brain magnetic resonance imaging (MRI) plays an important role in the diagnosis of this entity, which typically demonstrates restricted diffusion and a T2 hypointense appearance, suggesting hypercellularity. CASE REPORT A 44-year-old man came to the emergency department with a persistent and treatment-resistant bilateral frontal headache that had been bothering him for the past 3 weeks. Upon conducting a neurological assessment, the patient displayed temporal disorientation and incoherent speech, but without any observable motor deficits. A non-contrast enhanced brain computed tomography scan was carried out, revealing a hyperattenuating, space-occupying lesion and hemorrhage in the left hemisphere of the brain. Subsequently, brain MRI demonstrated hypointense signal on T2-weighted images, restricted diffusion, and homogeneous lesional contrast enhancement, suggesting a very cellular expansive lesion with hemorrhage. To establish a definitive diagnosis, a brain biopsy was undertaken, confirming the presence of DLBCL of the primary central nervous system (germinal center phenotype). CONCLUSIONS Hemorrhagic presentation of primary central nervous system DLBCL occurs very rarely, particularly in non-elderly immunocompetent patients. Brain MRI plays an important role in the diagnosis of this entity, which allows differentiation from high-grade glial or other lesions that present more frequently with hemorrhage. Therefore, it is crucial to suspect lymphoma before surgical intervention for appropriate patient management.

BCOR::CREBBP fusion in malignant neuroepithelial tumor of CNS expands the spectrum of methylation class CNS tumor with BCOR/BCOR(L1)-fusion.

Methylation class "CNS tumor with BCOR/BCOR(L1)-fusion" was recently defined based on methylation profiling and tSNE analysis of a series of 21 neuroepithelial tumors with predominant presence of a BCOR fusion and/or characteristic CNV breakpoints at chromosome 22q12.31 and chromosome Xp11.4. Clear diagnostic criteria are still missing for this tumor type, specially that BCOR/BCOR(L1)-fusion is not a consistent finding in these tumors despite being frequent and that none of the Heidelberger classifier versions is able to clearly identify these cases, in particular tumors with alternative fusions other than those involving BCOR, BCORL1, EP300 and CREBBP. In this study, we introduce a BCOR::CREBBP fusion in an adult patient with a right temporomediobasal tumor, for the first time in association with methylation class "CNS tumor with BCOR/BCOR(L1)-fusion" in addition to 35 cases of CNS neuroepithelial tumors with molecular and histopathological characteristics compatible with "CNS tumor with BCOR/BCOR(L1)-fusion" based on a comprehensive literature review and data mining in the repository of 23 published studies on neuroepithelial brain Tumors including 7207 samples of 6761 patients. Based on our index case and the 35 cases found in the literature, we suggest the archetypical histological and molecular features of "CNS tumor with BCOR/BCOR(L1)-fusion". We also present four adult diffuse glioma cases including GBM, IDH-Wildtype and Astrocytoma, IDH-Mutant with CREBBP fusions and describe the necessity of complementary molecular analysis in "CNS tumor with BCOR/BCOR(L1)-alterations for securing a final diagnosis.

Balanced transformer: efficient classification of glioblastoma and primary central nervous system lymphoma.

Objective.Primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM) are malignant primary brain tumors with different biological characteristics. Great differences exist between the treatment strategies of PCNSL and GBM. Thus, accurately distinguishing between PCNSL and GBM before surgery is very important for guiding neurosurgery. At present, the spinal fluid of patients is commonly extracted to find tumor markers for diagnosis. However, this method not only causes secondary injury to patients, but also easily delays treatment. Although diagnosis using radiology images is non-invasive, the morphological features and texture features of the two in magnetic resonance imaging (MRI) are quite similar, making distinction with human eyes and image diagnosis very difficult. In order to solve the problem of insufficient number of samples and sample imbalance, we used data augmentation and balanced sample sampling methods. Conventional Transformer networks use patch segmentation operations to divide images into small patches, but the lack of communication between patches leads to unbalanced data layers.Approach.To address this problem, we propose a balanced patch embedding approach that extracts high-level semantic information by reducing the feature dimensionality and maintaining the geometric variation invariance of the features. This approach balances the interactions between the information and improves the representativeness of the data. To further address the imbalance problem, the balanced patch partition method is proposed to increase the receptive field by sampling the four corners of the sliding window and introducing a linear encoding component without increasing the computational effort, and designed a new balanced loss function.Main results.Benefiting from the overall balance design, we conducted an experiment using Balanced Transformer and obtained an accuracy of 99.89%, sensitivity of 99.74%, specificity of 99.73% and AUC of 99.19%, which is far higher than the previous results (accuracy of 89.6% ∼ 96.8%, sensitivity of 74.3% ∼ 91.3%, specificity of 88.9% ∼ 96.02% and AUC of 87.8% ∼ 94.9%).Significance.This study can accurately distinguish PCNSL and GBM before surgery. Because GBM is a common type of malignant tumor, the 1% improvement in accuracy has saved many patients and reduced treatment times considerably. Thus, it can provide doctors with a good basis for auxiliary diagnosis.

CNS Efficacy of Osimertinib With or Without Chemotherapy in Epidermal Growth Factor Receptor-Mutated Advanced Non-Small-Cell Lung Cancer.

PURPOSE: We report CNS efficacy of first-line osimertinib plus chemotherapy versus osimertinib monotherapy in patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer (NSCLC) from the phase III FLAURA2 study according to baseline CNS metastasis status. METHODS: Patients were randomly assigned to osimertinib plus platinum-pemetrexed (combination) or osimertinib monotherapy until disease progression or discontinuation. Brain scans were performed in all patients at baseline and progression and at scheduled assessments until progression for patients with baseline CNS metastases; scans were assessed by neuroradiologist CNS blinded independent central review (BICR). RESULTS: On the basis of baseline CNS BICR, 118 of 279 (combination) and 104 of 278 (monotherapy) randomly assigned patients had ≥one measurable and/or nonmeasurable CNS lesion and were included in the CNS full analysis set (cFAS); 40 of 118 and 38 of 104 had ≥one measurable target CNS lesion and were included in the post hoc CNS evaluable-for-response set (cEFR). In the cFAS, the hazard ratio (HR) for CNS progression or death was 0.58 (95% CI, 0.33 to 1.01). In patients without baseline CNS metastases, the HR for CNS progression or death was 0.67 (95% CI, 0.43 to 1.04). In the cFAS, CNS objective response rates (ORRs; 95% CI) were 73% (combination; 64 to 81) versus 69% (monotherapy; 59 to 78); 59% versus 43% had CNS complete response (CR). In the cEFR, CNS ORRs (95% CI) were 88% (73 to 96) versus 87% (72 to 96); 48% versus 16% had CNS CR. CONCLUSION: Osimertinib plus platinum-pemetrexed demonstrated improved CNS efficacy compared with osimertinib monotherapy, including delaying CNS progression, irrespective of baseline CNS metastasis status. These data support this combination as a new first-line treatment for patients with EGFR-mutated advanced NSCLC, including those with CNS metastases.

Newly Recognized Genetic Tumor Syndromes of the CNS in the 5th WHO Classification: Imaging Overview with Genetic Updates.

The nervous system is commonly involved in a wide range of genetic tumor-predisposition syndromes. The classification of genetic tumor syndromes has evolved during the past years; however, it has now become clear that these syndromes can be categorized into a relatively small number of major mechanisms, which form the basis of the new 5th edition of the World Health Organization book (beta online version) on genetic tumor syndromes. For the first time, the World Health Organization has also included a separate chapter on genetic tumor syndromes in the latest edition of all the multisystem tumor series, including the 5th edition of CNS tumors. Our understanding of these syndromes has evolved rapidly since the previous edition (4th edition, 2016) with recognition of 8 new syndromes, including the following: Elongator protein complex-medulloblastoma syndrome, BRCA1-associated protein 1 tumor-predisposition syndrome, DICER1 syndrome, familial paraganglioma syndrome, melanoma-astrocytoma syndrome, Carney complex, Fanconi anemia, and familial retinoblastoma. This review provides a description of these new CNS tumor syndromes with a focus on imaging and genetic characteristics.

Improved early outcome prediction by MRI-based 3D tumor volume assessment in patients with CNS lymphomas.

BACKGROUND: Central nervous system lymphomas (CNSL) display remarkable clinical heterogeneity, yet accurate prediction of outcomes remains challenging. The IPCG criteria are widely used in routine practice for the assessment of treatment response. However, the value of the IPCG criteria for ultimate outcome prediction is largely unclear, mainly due to the uncertainty in delineating complete from partial responses during and after treatment. METHODS: We explored various MRI features including semi-automated 3D tumor volume measurements at different disease milestones and their association with survival in 93 CNSL patients undergoing curative-intent treatment. RESULTS: At diagnosis, patients with more than 3 lymphoma lesions, periventricular involvement, and high 3D tumor volumes showed significantly unfavorable PFS and OS. At first interim MRI during treatment, the IPCG criteria failed to discriminate outcomes in responding patients. Therefore, we randomized these patients into training and validation cohorts to investigate whether 3D tumor volumetry could improve outcome prediction. We identified a 3D tumor volume reduction of ≥97% as the optimal threshold for risk stratification (=3D early response, 3D_ER). Applied to the validation cohort, patients achieving 3D_ER had significantly superior outcomes. In multivariate analyses, 3D_ER was independently prognostic of PFS and OS. Finally, we leveraged prognostic information from 3D MRI features and circulating biomarkers to build a composite metric that further improved outcome prediction in CNSL. CONCLUSIONS: We developed semi-automated 3D tumor volume measurements as strong and independent early predictors of clinical outcomes in CNSL patients. These radiologic features could help improve risk stratification and help guide future treatment approaches.

Intraoperative pathologic diagnosis of central nervous system lymphomas: A comparison of frozen and permanent section diagnoses, and the significance of preoperative imaging.

BACKGROUND: Central nervous system (CNS) lymphomas, either primary or secondary in origin, are rare malignant tumors affecting the brain, spinal cord, or leptomeninges. Diagnosis of CNS lymphomas is complicated by their diverse clinical presentations, radiological features, and histopathological characteristics. Although frozen section (FS) analysis is commonly employed for various CNS tumors, its role and accuracy in CNS lymphoma diagnosis are less explored. In this study, we conducted a comparative analysis to assess the impact of knowledge of preoperative imaging on enhancing the accuracy of FS diagnosis in CNS lymphomas. METHODS: Data collection involved a retrospective review of CNS lymphoma patients from January 2009 to August 2021. Patients who underwent intraoperative consultation were included, excluding those with prior cortisone treatment. The dataset incorporated patient demographics, classification as primary or secondary lymphoma, radiological preliminary diagnoses, FS diagnosis, and permanent section diagnosis. We employed various archived materials, including FSs, touch imprint slides, crush cytology slides, H&E-stained sections, and immunohistochemical stains, and re-evaluated all slides for diagnostic validation. RESULTS: Our study included 25 patients, of whom 60 % were female and had a mean age of 56.5 years. Preoperative radiology data were available for 80 % of cases, with preliminary diagnoses commonly including lymphoma and/or metastasis. Intraoperative consultation results indicated lymphoma in 18 (72 %) patients, with discordance observed in 28 % of cases when compared to permanent section diagnoses. Most permanent section diagnoses were diffuse large B-cell lymphomas (92 %), with the remainder being T-cell non-Hodgkin lymphoma (4 %) and follicular lymphoma (4 %). Intraoperative misdiagnoses were significantly associated with the absence of knowledge of preoperative imaging. CONCLUSION: Our study demonstrates the reliability of FS diagnosis for CNS lymphomas during surgery, with a favorable complete concordance rate of 72 % when compared to permanent diagnoses. Importantly, lack of knowledge of preoperative imaging significantly impaired diagnostic accuracy in FS, emphasizing the need for close collaboration between pathologists and radiologists.

Advances in diffuse glial tumors diagnosis.

In recent decades, there have been significant advances in the diagnosis of diffuse gliomas, driven by the integration of novel technologies. These advancements have deepened our understanding of tumor oncogenesis, enabling a more refined stratification of the biological behavior of these neoplasms. This progress culminated in the fifth edition of the WHO classification of central nervous system (CNS) tumors in 2021. This comprehensive review article aims to elucidate these advances within a multidisciplinary framework, contextualized within the backdrop of the new classification. This article will explore morphologic pathology and molecular/genetics techniques (immunohistochemistry, genetic sequencing, and methylation profiling), which are pivotal in diagnosis, besides the correlation of structural neuroimaging radiophenotypes to pathology and genetics. It briefly reviews the usefulness of tractography and functional neuroimaging in surgical planning. Additionally, the article addresses the value of other functional imaging techniques such as perfusion MRI, spectroscopy, and nuclear medicine in distinguishing tumor progression from treatment-related changes. Furthermore, it discusses the advantages of evolving diagnostic techniques in classifying these tumors, as well as their limitations in terms of availability and utilization. Moreover, the expanding domains of data processing, artificial intelligence, radiomics, and radiogenomics hold great promise and may soon exert a substantial influence on glioma diagnosis. These innovative technologies have the potential to revolutionize our approach to these tumors. Ultimately, this review underscores the fundamental importance of multidisciplinary collaboration in employing recent diagnostic advancements, thereby hoping to translate them into improved quality of life and extended survival for glioma patients.

Nas últimas décadas, houve avanços significativos no diagnóstico de gliomas difusos, impulsionados pela integração de novas tecnologias. Esses avanços aprofundaram nossa compreensão da oncogênese tumoral, permitindo uma estratificação mais refinada do comportamento biológico dessas neoplasias. Esse progresso culminou na quinta edição da classificação da OMS de tumores do sistema nervoso central (SNC) em 2021. Esta revisão abrangente tem como objetivo elucidar esses avanços de forma multidisciplinar, no contexto da nova classificação. Este artigo irá explorar a patologia morfológica e as técnicas moleculares/genéticas (imuno-histoquímica, sequenciamento genético e perfil de metilação), que são fundamentais no diagnóstico, além da correlação dos radiofenótipos da neuroimagem estrutural com a patologia e a genética. Aborda sucintamente a utilidade da tractografia e da neuroimagem funcional no planejamento cirúrgico. Destacaremos o valor de outras técnicas de imagem funcional, como ressonância magnética de perfusão, espectroscopia e medicina nuclear, na distinção entre a progressão do tumor e as alterações relacionadas ao tratamento. Discutiremos as vantagens das diferentes técnicas de diagnóstico na classificação desses tumores, bem como suas limitações em termos de disponibilidade e utilização. Além disso, os crescentes avanços no processamento de dados, inteligência artificial, radiômica e radiogenômica têm grande potencial e podem em breve exercer uma influência substancial no diagnóstico de gliomas. Essas tecnologias inovadoras têm o potencial de revolucionar nossa abordagem a esses tumores. Em última análise, esta revisão destaca a importância fundamental da colaboração multidisciplinar na utilização dos recentes avanços diagnósticos, com a esperança de traduzi-los em uma melhor qualidade de vida e uma maior sobrevida.

Lymphoma of the central nervous system originating from the septum pellucidum region: Two case reports with literature review.

RATIONALE: Non-Hodgkin lymphoma affecting the brain, eyes, and cerebrospinal fluid without systemic spread is known as primary central nervous system lymphoma (PCNSL). While intracerebroventricular PCNSL is commonly found in the lateral ventricles and the third and fourth ventricles, the occurrence of PCNSL originating from the septum pellucidum is extremely rare. PATIENT CONCERNS: Two patients presented with recent memory loss and high cranial pressure. DIAGNOSES: Magnetic resonance imaging revealed a clear enhancing lesion in the septum pellucidum region. Pathological examination confirmed that both cases were primary large B-cell lymphoma GCB (germinal center B-cell-like) subtypes located in an "immune-privileged" area. INTERVENTIONS: Both patients underwent total tumor resection, and the procedures were successfully completed without surgical complications. OUTCOMES: Over a 1-year period, treatment included four cycles of high-dose methotrexate combined with temozolomide. During the follow-up period (19-23 months), no recurrence of the lymphoma was observed. LESSONS: In cases of PCNSL in the septum pellucidum, it is crucial to consider it as a potential differential diagnosis for intraventricular tumors. Surgical interventions should focus on maximizing tumor resection while ensuring the protection of critical structures like the fornix and peripheral neural components. The role of surgery compared to biopsy, as well as the long-term complications, necessitates extended follow-up. Additionally, an individualized treatment approach, considering factors such as age, Karnofsky performance score, and organ function assessment, can lead to positive outcomes.

Tumefactive demyelinating lesions versus CNS neoplasms, a comparative study.

BACKGROUND: Differentiating tumefactive demyelinating lesions (TDL) from neoplasms of the central nervous system continues to be a diagnostic dilemma in many cases. OBJECTIVE: Our study aimed to examine and contrast the clinical and radiological characteristics of TDL, high-grade gliomas (HGG) and primary CNS lymphoma (CNSL). METHOD: This was a retrospective review of 66 patients (23 TDL, 31 HGG and 12 CNSL). Clinical and laboratory data were obtained. MRI brain at presentation were analyzed by two independent, blinded neuroradiologists. RESULTS: Patients with TDLs were younger and predominantly female. Sensorimotor deficits and ataxia were more common amongst TDL whereas headaches and altered mental status were associated with HGG and CNSL. Compared to HGG and CNSL, MRI characteristics supporting TDL included relatively smaller size, lack of or mild mass effect, incomplete peripheral rim enhancement, absence of central enhancement or restricted diffusion, lack of cortical involvement, and presence of remote white matter lesions on the index scan. Paradoxically, some TDLs may present atypically or radiologically mimic CNS lymphomas. CONCLUSION: Careful evaluation of clinical and radiological features helps in differentiating TDLs at first presentation from CNS neoplasms.

Amphiphysin-IgG autoimmune sciatic neuropathy and facial neuropathy related to primary central nervous system lymphoma: A case report.

We reported a 61-year-old man presented with 10-month progressing left sciatic neuropathy and 10-day right facial neuropathy. Serum amphiphysin-IgG was positive. 18F-FDG PET/CT of the whole body showed no signs of malignancy. Treatment with plasma exchange and oral prednisone relieved the symptoms. Nine months later, right hemiparesis and seizure of right limbs developed. 18F-FDG and 18F-PBR06 (18 kDa translocator protein, TSPO) radioligand PET/MRI of the whole body revealed intense uptake in the intracranial lesions. Intracranial lymphoma was diagnosed by stereotactic needle brain biopsy. Mononeuropathies could be paraneoplastic syndromes. TSPO shows high uptake in intracranial lymphoma on 18F-PBR06 PET images.

Study on primary central nervous system lymphoma in pediatric patients.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) in pediatric patients presents diagnostic and treatment challenges, leading to delays and suboptimal strategies. Moreover, PCNSL in immunocompetent pediatric patients is rarely reported. This retrospective study aimed to describe the demographic and clinical features, as well as outcomes, of pediatric PCNSL cases. METHODS: A retrospective review was conducted on 11 immunocompetent pediatric patients diagnosed with PCNSL between January 2012 and April 2020. Data regarding age, gender, initial presenting symptoms, tumor location, and radiological characteristics were collected. Treatment strategies and analyzed prognosis were documented. Survival curves were generated using the Kaplan-Meir method, and data were analyzed using SPSS (version 23.0, IBM Corp.). RESULTS: The study cohort comprised 11 patients, including 10 males and 1 female. The age at diagnosis ranged from 4 to 15 years, with a median age of 10.6 years. Headache was the most common presenting symptom, observed in 81.8% (9/11) of patients. Tumor locations in the supratentorial and infratentorial regions exhibited a similar occurrence rate. All tumors showed strong contrast enhancement on T1-weighted images. The average survival time for the 11 patients was 44.4 months. Among them, 5 patients died by the last follow-up visit, with a mean survival time of 8.8 months (one patient died in a car accident). CONCLUSION: Headache is the predominant manifestation of PCNSL in pediatric patients. PCNSL demonstrates imaging characteristics resembling various intracranial tumors and is associated with a poor prognosis. Therefore, pediatric neurosurgeons should exercise caution in diagnosing and treating intracranial lymphoma.

Lymphomas of Central Nervous System.

Central nervous system (CNS) lymphoma consists of primary central nervous system lymphoma (PCNSL) and secondary CNS involvement by systemic lymphoma. This chapter focuses on the former. PCNSL is a relative rare disease, accounting for approximately 2.4-4.9% of all primary CNS tumors. It is an extra-nodal variant of non-Hodgkin's lymphoma (NHL), confined to the brain, leptomeninges, spinal cord, and eyes, with no systemic involvement. Recently, elderly patients (≥ 60 years) are increasing. Histologically, B cell blasts, which originate from late germinal center exit B cell, are growing and homing in CNS. Immunohistochemically, these cells are positive for PAX5, CD19, CD20, CD22, and CD79a. PCNSL shows relatively characteristic appearances on CT, MR imaging, and PET. Treatment first line of PCNSL is HD-MTX-based chemotherapy with or without rituximab and irradiation. Severe side-effect of this treatment is delayed onset neurotoxicity, which cause of cognitive impairment. Therefore, combined chemotherapy alone or chemotherapy with reduced-dose irradiation is more recommended for elderly patients. There is no established standard care for relapse of the PCNSLs. Temsirolimus, lenalidomide, temozolomide, and Bruton's tyrosine kinase (BTK) inhibitor ibrutinib are candidates for refractory patients. The prognosis of PCNSL has significantly improved over the last decades (median OS: 26 months, 5-year survival: 31%). Younger than 60 age and WHO performance status less than < or = 1 are associated with a significantly better overall survival.

Central Nervous System Tumor With BCL6 Corepressor Internal Tandem Duplication: Treatment Course of a Long-term Survivor.

Central nervous system (CNS) tumor with BCL6 corepressor (BCOR) internal tandem duplication (ITD) is a newly described CNS tumor, characterized by in-frame ITDs of the BCOR gene. There is no standard practice regarding the management of this tumor. We report the clinical course of a 6-year-old boy who presented to the hospital with worsening headaches. Computed tomography scan showed a large right-sided parietal supratentorial mass and brain magnetic resonance imaging confirmed a 6×8×6.7 cm lobulated, solid but heterogeneous mass in the right parieto-occipital region. While initial pathology suggested a WHO grade 3 anaplastic meningioma, additional investigation with molecular analysis confirmed the diagnosis of high-grade neuroepithelial tumor with BCOR exon 15 ITD. This diagnosis was renamed CNS tumor with BCOR ITD in the 2021 WHO CNS tumor classification. The patient received 54 Gy of focal radiation and has no evidence of disease recurrence after 48 months from the end of treatment. As this is a newly discovered entity with only a few previous reports in the scientific literature, this report presents a unique treatment for this CNS tumor compared with those previously described.

MRI manifestations of central nervous system leukaemia and cytological analysis of the cerebrospinal fluid.

AIM: To investigate the magnetic resonance imaging (MRI) features and explore the value of MRI in the diagnosis of central nervous system leukaemia (CNSL). MATERIALS AND METHODS: A retrospective study was performed in 68 patients with leukaemia who underwent cranial MRI between January 2020 and June 2022 at Institute of Hematology and Blood Diseases Hospital. RESULTS: A total of 33 patients fulfilled the requirements for inclusion. The findings showed that 87.9% patients exhibited neurological symptoms, and 23 patients showed abnormal MRI findings. No differences were observed between the MRI+ and MRI- groups in terms of age, sex, neurological symptoms, glucose in the cerebrospinal fluid (CSF), chloride in the CSF, abnormal cells detected using conventional cytology (CC), bone marrow status at the diagnosis of CNSL, signal intensity ratio, and mortality, except for protein concentration and the number of leukaemic cells detected using flow cytometry (FCM) in the CSF. Kaplan-Meier survival analysis in patients with leukaemia revealed no statistical differences in the median survival times between the MRI+ group and MRI- group. Cox regression analysis and multivariate analysis showed no significant difference in survival rate between the MRI+ and MRI- groups. Kappa consistency test shows weak diagnostic consistency between MRI and CC, and weak diagnostic inconsistency between MRI and FCM. CONCLUSION: MRI could serve as an important complementary tool to CC and FCM in the diagnosis of CNSL, especially in patients without leptomeningeal involvement.

A Radiologist's Guide to the 2021 WHO Central Nervous System Tumor Classification: Part 2-Newly Described and Revised Tumor Types.

The fifth edition of the World Health Organization classification of tumors of the central nervous system (CNS), published in 2021, introduces major shifts in the classification of brain and spine tumors. These changes were necessitated by rapidly increasing knowledge of CNS tumor biology and therapies, much of which is based on molecular methods in tumor diagnosis. The growing complexity of CNS tumor genetics has required reorganization of tumor groups and acknowledgment of new tumor entities. For radiologists interpreting neuroimaging studies, proficiency with these updates is critical in providing excellent patient care. This review will focus on new or revised CNS tumor types and subtypes, beyond infiltrating glioma (described in part 1 of this series), with an emphasis on imaging features.

From the ER to the OR: Initial Evaluation of Primary Central Nervous System Lymphoma.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a rare, often curable neoplasm, often initially presenting in acute care settings by nonneuroscience specialized physicians. Delays in the recognition of specific imaging findings, lack of appropriate specialist consultation, and urgent incorrect medication administration can delay necessary diagnosis and treatment. REVIEW SUMMARY: In this paper, the reader is moved quickly from the initial presentation to the diagnostic surgical intervention for PCNSL in a manner analogous to the experience of clinicians in the frontline setting. We review the clinical presentation of PCNSL, its radiographic features, the effect of prebiopsy steroids, and the role of a biopsy in the diagnosis. In addition, this paper revisits the role of surgical resection for PCNSL and investigational diagnostic studies for PCNSL. CONCLUSION: PCNSL is a rare tumor that is associated with high morbidity and mortality. However, with appropriate identification of clinical signs, symptoms, and key radiographic findings, the early suspicion of PCNSL can lead to steroid avoidance and timely biopsy for rapid administration of the potentially curative chemoimmunotherapy. Surgical resection presents the potential for improving outcomes for patients with PCNSL, however, this remains controversial. Further research into PCNSL presents the opportunity for better outcomes and longer livelihoods for patients.

Deep learning-based overall survival prediction model in patients with rare cancer: a case study for primary central nervous system lymphoma.

PURPOSE: Primary central nervous system lymphoma (PCNSL) is a rare, aggressive form of extranodal non-Hodgkin lymphoma. To predict the overall survival (OS) in advance is of utmost importance as it has the potential to aid clinical decision-making. Though radiomics-based machine learning (ML) has demonstrated the promising performance in PCNSL, it demands large amounts of manual feature extraction efforts from magnetic resonance images beforehand. deep learning (DL) overcomes this limitation. METHODS: In this paper, we tailored the 3D ResNet to predict the OS of patients with PCNSL. To overcome the limitation of data sparsity, we introduced data augmentation and transfer learning, and we evaluated the results using r stratified k-fold cross-validation. To explain the results of our model, gradient-weighted class activation mapping was applied. RESULTS: We obtained the best performance (the standard error) on post-contrast T1-weighted (T1Gd)-area under curve [Formula: see text], accuracy [Formula: see text], precision [Formula: see text], recall [Formula: see text] and F1-score [Formula: see text], while compared with ML-based models on clinical data and radiomics data, respectively, further confirming the stability of our model. Also, we observed that PCNSL is a whole-brain disease and in the cases where the OS is less than 1 year, it is more difficult to distinguish the tumor boundary from the normal part of the brain, which is consistent with the clinical outcome. CONCLUSIONS: All these findings indicate that T1Gd can improve prognosis predictions of patients with PCNSL. To the best of our knowledge, this is the first time to use DL to explain model patterns in OS classification of patients with PCNSL. Future work would involve collecting more data of patients with PCNSL, or additional retrospective studies on different patient populations with rare diseases, to further promote the clinical role of our model.

Neuroimaging to diagnose central nervous system tumours in children.

QUESTION: Headache, vomiting, lethargy, and seizures are common symptoms in healthy children with benign viral illnesses, but they are also signs that could represent a central nervous system (CNS) tumour. Primary care providers and guardians are hesitant to expose children to radiation associated with computed tomography scans or take on risks associated with the sedation frequently needed for magnetic resonance imaging. When should primary care providers order radiologic head imaging for children with common symptoms to identify those with a CNS tumour? ANSWER: Central nervous system tumours have no pathognomonic features, which often results in delays in diagnosis. Owing to the high prevalence of infratentorial tumours, children commonly present with symptoms of increased intracranial pressure, making a detailed history and a comprehensive physical examination, including ophthalmoscopy for papilledema, especially important. Magnetic resonance imaging is the criterion standard test but it may take time to access, and young children may need sedation. Hence, computed tomography may be a preferable first option.The HeadSmart initiative in the United Kingdom provides guidance to obtain brain imaging within 4 weeks of onset of persistent symptoms that are associated with CNS tumours. We advocate applying the same criteria in Canada in order to reduce delay in diagnosis of CNS tumours in children.

Newly Recognized CNS Tumors in the 2021 World Health Organization Classification: Imaging Overview with Histopathologic and Genetic Correlation.

In 2021, the World Health Organization released an updated classification of CNS tumors. This update reflects the growing understanding of the importance of genetic alterations related to tumor pathogenesis, prognosis, and potential targeted treatments and introduces 22 newly recognized tumor types. Herein, we review these 22 newly recognized entities and emphasize their imaging appearance with correlation to histologic and genetic features.