Advances in Primary Central Nervous System Lymphoma

Progress of radiological‑pathological workflows in the differential diagnosis between primary central nervous system lymphoma and high‑grade glioma (Review)

Primary central nervous system lymphoma (PCNSL) and high‑grade glioma (HGG) are distinct entities of the CNS with completely distinct treatments. The treatment of PCNSL is chemotherapy‑based, while surgery is the first choice for HGG. However, the clinical features of the two entities often overlap, and a clear pathological diagnosis is important for subsequent management, especially for the management of PCNSL. Stereotactic biopsy is recognized as one of the minimally invasive alternatives for evaluating the involvement of the CNS. However, in the case of limited tissue materials, the differential diagnosis between the two entities is still difficult. In addition, some patients are too ill to tolerate a needle biopsy. Therefore, combining imaging, histopathology and laboratory examinations is essential in order to make a clear diagnosis as soon as possible. The present study reviews the progress of comparative research on both imaging and laboratory tests based on the pathophysiological changes of the two entities, and proposes an integrative and optimized diagnostic process, with the purpose of building a better understanding for neurologists, hematologists, radiologists and pathologists.

Decision Tree Model for Predicting the Overall Survival of Patients with Diffused Large B-Cell Lymphoma in the Central Nervous System

OBJECTIVE

To identify the significant predictors of overall survival for patients living with diffused large B-cell lymphoma (DLBCL) in the central nervous system and establish a novel decision tree model to help predict survival status at several time points.

METHODS

Patients diagnosed with DLBCL were identified from the SEER database and randomly divided into training and test samples (6:4). Dichotomous decision trees were developed for survival status at 3, 12, 24, and 60 months. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy rate, and area under the receiver operating characteristic curve were calculated to evaluate the model performance.

RESULTS

A total of 2998 patients were included, with 1799 and 1199 patients divided into the training and testing groups. Decision trees for 3, 12, 24, and 60 months survival status were generated. Chemotherapy and patient's age were of the primary importance for prognosis in the novel models. Favorable consistency between the predicted and actual survival status was presented. The accuracy rates were 0.79, 0.71, 0.68, and 0.86 for training sample at 3, 12, 24, and 60 months, respectively, and 0.75, 0.69, 0.58, and 0.84 for test sample at 3, 12, 24, and 60 months, respectively. The area under the receiver operating characteristic curve values ranged between 0.645 and 0.721 for the training sample and between 0.607 and 0.712 for the test sample.

CONCLUSIONS

Novel decision tree models were established for predicting the 3, 12, 24, and 60 months survival status of patients with DLBCL. The newly developed models were verified using training and test samples, showing favorable accuracy and predictive value on overall survival.

Evidence-based expert consensus on the management of primary central nervous system lymphoma in China

Primary central nervous system lymphoma (PCNSL) is a type of central nervous system restricted non-Hodgkin lymphoma, whose histopathological diagnosis is majorly large B cell lymphoma. To provide specific, evidence-based recommendations for medical professionals and to promote more standardized, effective and safe treatment for patients with PCNSL, a panel of experts from the Chinese Neurosurgical Society of the Chinese Medical Association and the Society of Hematological Malignancies of the Chinese Anti-Cancer Association jointly developed an evidence-based consensus. After comprehensively searching literature and conducting systematic reviews, two rounds of Delphi were conducted to reach consensus on the recommendations as follows: The histopathological specimens of PCNSL patients should be obtained as safely and comprehensively as possible by multimodal tomography-guided biopsy or minimally invasive surgery. Corticosteroids should be withdrawn from, or not be administered to, patients with suspected PCNSL before biopsy if the patient's status permits. MRI (enhanced and DWI) should be performed for diagnosing and evaluating PCNSL patients where whole-body PET-CT be used at necessary time points. Mini-mental status examination can be used to assess cognitive function in the clinical management. Newly diagnosed PCNSL patients should be treated with combined high-dose methotrexate-based regimen and can be treated with a rituximab-inclusive regimen at induction therapy. Autologous stem cell transplantation can be used as a consolidation therapy. Refractory or relapsed PCNSL patients can be treated with ibrutinib with or without high-dose chemotherapy as re-induction therapy. Stereotactic radiosurgery can be used for PCNSL patients with a limited recurrent lesion who were refractory to chemotherapy and have previously received whole-brain radiotherapy. Patients with suspected primary vitreoretinal lymphoma (PVRL) should be diagnosed by vitreous biopsy. PVRL or PCNSL patients with concurrent VRL can be treated with combined systemic and local therapy.

Analysis of Key Factors Associated with Response to Salvage High-Dose Methotrexate Rechallenge in Primary Central Nervous System Lymphoma with First Relapse

Background: Primary central nervous system lymphoma (PCNSL) is a rare extranodal non-Hodgkin’s lymphoma that occurs in the central nervous system. Although sensitive to chemotherapy, 35–60% of PCNSL patients still relapse within 2 years after the initial treatment. High-dose methotrexate (HD-MTX) rechallenge is generally used in recurrent PCNSL, especially for patients who have achieved a response after initial methotrexate (MTX) treatment. However, the overall remission rate (ORR) of HD-MTX rechallenge is about 70–80%. Additionally, the side effects of HD-MTX treatment endanger the health of patients and affect their quality of life. Methods: This is a retrospective study of patients with first relapse PCNSL at Huashan Hospital, Fudan University between January 2000 and November 2020. By comparing the clinical characteristics and radiological manifestations of first relapsed PCNSL patients with remission and non-remission after receiving HD-MTX rechallenge, we screened out the key factors associated with HD-MTX rechallenge treatment response, to provide some help for the selection of salvage treatment strategies for patients with recurrent PCNSL. Additionally, patients with remission after HD-MTX rechallenge were followed up to identify the factors related to progression-free survival of the second time (PFS2) (time from the first relapse to second relapse/last follow-up). The Kruskal–Wallis and Pearson chi-square tests were performed to examine the univariate association. Further, multivariable logistic regression analysis was used to study the simultaneous effect of different variables. Results: A total of 207 patients were enrolled in the study based on the inclusion criteria, including 114 patients in the remission group (RG) and 81 patients in the non-remission group (nRG), and 12 patients were judged as having a stable disease. In Kruskal–Wallis and Pearson chi-square tests, progression-free survival rates for first time (PFS1) and whether the initial treatment was combined with consolidated whole brain radiotherapy (WBRT) were related to the response to HD-MTX rechallenge treatment, which was further validated in regression analysis. Further, after univariate analysis and regression analysis, KPS was related to PFS2. Conclusions: For PCNSL patients in their first relapse, HD-MTX rechallenge may be an effective salvage treatment. PFS1 and whether initial treatment was combined with consolidation WBRT were associated with HD-MTX rechallenge treatment response. In addition, patients with higher KPS at the time of the first relapse had a longer PFS2 after HD-MTX rechallenge treatment.

Primary Pituitary Lymphoma As Rare Cause Of A Pituitary Mass And Hypopituitarism In Adulthood

OBJECTIVE

Differential diagnosis of nonadenomatous sellar masses causing hypopituitarism is still a challenge. Among these masses, growing evidence has demonstrated that primary pituitary lymphoma is a specific and emerging entity. The aim of our study was to describe our experience with a case of primary pituitary lymphoma and to perform a review of the available literature.

METHODS

We searched relevant databases up to March 2020, identifying 36 suitable articles basing on inclusion criteria (primary pituitary lymphoma in adult immunocompetent subjects). Overall, 43 cases were included in the review, adding a new case diagnosed and treated in our hospital. Epidemiologic data, clinical presentation, hormonal status, radiologic findings, pathology, treatment, and outcome were extracted.

RESULTS

Mean age at diagnosis was 58.9 years, without gender difference. Symptoms related to mass were common (52.3%), in particular cranial nerve palsy (70.5%), headache (56.8%), and alteration in visual field (40.9%). Impaired hormonal status was detected in 89.7% of patients; of them, 58.9% presented with anterior pituitary failure (partial or total), while 25.6% presented with panhypopituitarism. Overall, diabetes insipidus was present in 30.8% and hyperprolactinemia in 41.0% of patients. The majority of patients presented a radiologically invasive mass in the suprasellar region and cavernous sinus (65.9% and 40.9%, respectively) and histologic diagnosis of diffuse B-cell lymphoma (54.5%).

CONCLUSION

The differential diagnosis of sellar and parasellar masses causing hypopituitarism should include primary pituitary lymphoma, even in absence of systemic symptoms or posterior pituitary dysfunction. The disease has a heterogeneous pattern, so a collaboration between endocrinologists, neuroradiologists, neurosurgeons, and hematologists is desirable.

Bilateral middle cerebellar peduncle lesions: Neuroimaging features and differential diagnoses

OBJECTIVES

Lesions limited to the bilateral middle cerebellar peduncles (MCPs) are uncommon. This retrospective study investigated diseases with a proclivity for the bilateral MCPs and explored the associations between their neuroimaging features and clinical findings for the differential diagnosis of such lesions.

METHODS

We enrolled 26 patients who were admitted to our department between January 2016 and March 2019 with bilateral MCP abnormalities on magnetic resonance imaging (MRI). The demographic, clinical, and neuroimaging characteristics, and the biomarkers and diagnoses were evaluated.

RESULTS

Although all patients exhibited symmetrical bilateral MCP hypointensities on T1-weighted imaging and hyperintensities on T2-weighted and fluid-attenuated inversion recovery imaging, they were diagnosed with different conditions. Diagnoses included acute cerebral infarction (ACI) (n = 9, 34.62%), Wallerian degeneration (WD) (n = 8, 30.77%), multiple system atrophy (MSA) (n = 6, 23.08%), neuromyelitis optica (NMO) (n = 1, 3.85%), heroin-induced leukoencephalopathy (n = 1, 3.85%), and primary central nervous system lymphoma (PCNSL) (n = 1, 3.85%). Patients with ACI exhibited bilateral MCP-restricted diffusion hyperintensities on diffusion-weighted imaging and corresponding stenosis or occlusion of the vertebrobasilar system. The initial MRI of patients with WD depicted pontine infarctions, while symmetrical MCP lesions were observed on follow-up MRI. Symmetrical MCP lesions, cruciform hyperintensity, and marked atrophy in the posterior fossa were characteristic manifestations of MSA. Longitudinally extensive myelitis affecting more than three vertebral segments on cervical MRI and positive serum AQP4-IgG may be indicative of NMO. Heroin-induced leukoencephalopathy was characterized by extra-symmetrical lesions in the posterior limbs of the internal capsules, while the anterior limbs were spared. PCNSL was indicated by a significant and characteristic "fist" sign on contrast-enhanced MRI.

CONCLUSIONS

Bilateral MCP lesions were most frequently observed in cerebrovascular diseases, followed by neurodegenerative diseases, inflammatory diseases, toxic encephalopathies, and lymphomas. Our findings demonstrate that bilateral MCP signal abnormalities are more common in patients with ACI and WD, with fewer degenerative processes than previously believed. The high frequency of WD may be attributed to the specific awareness of this pathology. WD can also present with stage-related restricted diffusion and should not be mistaken for a new infarction. The symmetrical bilateral MCP hypointensities on T1-weighted imaging and hyperintensities on T2-weighted imaging often raise concern regarding a demyelinating process. Our findings emphasize that neurologists should consider the aforementioned conditions and correlate the specific neuroimaging characteristics and medical history before arriving at the final diagnosis.

Cell-Block cytology in diagnosis of primary central nervous system lymphoma: A case report

INTRODUCTION

Primary Central Nervous System Lymphoma (PCNSL) remains a diagnostic challenge due to the variable clinical manifestations. Liquid biopsies, particularly those involving cell-free DNA (cfDNA) from plasma, are rapidly emerging as important and minimally invasive adjuncts to traditional biopsies. However, conventional pathology may be still essential to obtain a diagnosis.

PATIENT CONCERNS

A 56-year-old woman presented with a progressive headache, dizziness, blurred vision, and lower limbs weakness with dysesthesia. Atypical clinical and radiological presentations, previous empirical treatment in another hospital, together with the patient's refusal to stereotactic brain biopsy made it challenging to diagnose. Her status deteriorated continuously during hospitalization.

DIAGNOSIS

Lumber punctual was performed, and CSF cytological analysis revealed malignancy cells with a high nuclear-cytoplasmic ratio. However, these cells were too loose to perform immunohistochemical stains. Genetic aberrations detections with CSF and peripheral blood sample were also inconclusive. We made a "cell-block" using the sedimentary cells collected from CSF collected through multiple aspirations via an Omaya reservoir. We further performed cytopathological and immunohistochemical analysis using this "cell-block," which finally confirmed the diagnosis of diffuse large-B cell PCNSL.

INTERVENTIONS

Intracranial chemotherapy began afterwards (MTX 15 mg and dexamethasone 5 mg, twice per weeks).

OUTCOMES

Unfortunately, this patient was dead 2 weeks later due to severe myelosuppression and secondary septic shock.

CONCLUSION

We provided "cell-block" method, which collects cell components from large amount of CSF for cytology and immunohistochemical analysis. "Cell-block" cytology can be an alternative diagnostic method in diagnosis of PCNSL.

Real-World Impact of Surgical Excision on Overall Survival in Primary Central Nervous System Lymphoma

Substantial controversy still exists regarding the use of surgical excision in the treatment of primary central nervous system lymphoma (PCNSL). This study was aimed to evaluate the survival benefit of surgical excision in PCNSL patients based on a US population. Using the Surveillance, Epidemiology, and End Results (SEER) Program database, a total of 3,543 PCNSL patients were identified from 2000 to 2014 for analysis. Surgical excision was accessed via Kaplan–Meier and multivariate Cox regression survival analyses. Coarsened exact matching (CEM) analysis was additionally employed to intensify our findings. Finally, we found that surgical excision was significantly associated with increased survival over no surgery/biopsy (P < 0.001), and its survival benefit was also independent of baseline prognostic factors. The survival benefit of surgery was also validated in clinically important subsets. CEM analysis further validated the survival advantage of surgery (P < 0.001). Moreover, a novel prediction model with excellent performance was established to estimate the potential benefit from surgical excision of the lesion with respect to the end point of overall survival. The current study supports the favorable impact of surgical excision on clinical outcome in patients with PCNSL. Although further randomized controlled trials are warranted, currently available evidence should be considered in the clinical management of this disease.

Curative effect of methotrexate combined with teniposide in the treatment of primary central nervous system lymphoma

The present study aimed to investigate the curative effect of high-dose methotrexate (HD-MTX) combined with teniposide (Vm26) vs. HD-MTX alone in the treatment of primary central nervous system lymphoma (PCNSL), in order to provide data for assisting decisions associated with clinical treatment. Data from 56 patients with PCNSL admitted in Shanghai Huashan Hospital (Shanghai, China) from January 2009 to December 2014 were included into the present study. Clinical data, curative effects and prognosis of patients in these two groups were retrospectively analyzed using SPSS 20 statistical software. In the HD-MTX+Vm26 group, 12 patients (42.85%) achieved complete remission (CR) and 10 patients (35.71%) achieved partial remission (PR), while in the HD-MTX group 7 patients (25%) achieved CR and 11 patients (39.29%) achieved PR (P=0.158). The median progression-free survival (PFS) time was 22 months in the HD-MTX+Vm26 group and 12 months in the HD-MTX group (P=0.019). The median overall survival time was 57 months in the HD-MTX+Vm26 group, and 28 months in the HD-MTX group (P=0.013). Compared with HD-MTX alone, the combined treatment of HD-MTX+Vm26 had an improved curative effect in the treatment of PCNSL, effectively controlled tumor progression in patients, prolonged survival time and improved prognosis. Age was an independent prognostic factor in patients with PCNSL. Patients with an age of ≤60 years exhibited longer PFS compared with patients with an age of >60 years.

Primary central nervous system lymphoma in China: a single-center retrospective analysis of 167 cases

Primary central nervous system lymphoma (PCNSL) is a rare form of extranodal non-Hodgkin's lymphoma and a limited number of cases have been reported from China. This study aimed to investigate the clinicopathological features of newly diagnosed PCNSLs from a single center in eastern China and to identify the potential prognostic factors for overall survival (OS) and progression-free survival (PFS). All consecutive patients with histopathologically diagnosed PCNSLs at our center between January 2003 and October 2017 were recruited. Demographic and clinicopathological data were collected and reviewed retrospectively. The potential risk factors for OS and PFS were identified using the log-rank test and Cox regression analysis. A total of 167 immunocompetent cases were enrolled. The median age was 58 years (range 17-96 years), and the male:female ratio was 3:2. Headache (n = 65; 39%) and cerebral hemisphere (n = 96; 57%) were the most common presenting complaint and location, respectively. Out of 167 cases, 150 cases were diffuse large B cell lymphomas. With a median follow-up of 25 months (range 1-152 ), the median OS and PFS were 37 months (95% CI, 25-49) and 17 months (95% CI, 13-20), respectively. Residual tumor after operation, chemotherapy without HD-MTX and palliative treatment was revealed as independent prognostic markers. Moreover, ECOG > 3, multifocal lesions, and palliative treatment were revealed as unfavorable independent prognostic markers for PFS. In conclusion, Chinese patients with PCNSL have distinct characteristics. Further studies are warranted to confirm the prognostic value of these factors and to optimize treatments for these patients.

Clinical neuro-oncology for the neurologist

Purpose of review

Neuro-oncologic patients are routinely encountered in clinical practice. Neuro-oncology is a rapidly evolving field, so understanding the most classic paradigms and contemporary advances will optimize patient care.

Recent findings

We discuss the recent reclassification of tumors via molecular characteristics as it applies to direct clinical practice and review the contemporary standard of care for infiltrating gliomas, meningiomas, brain metastases, and CNS lymphoma.

Summary

We provide a straightforward primer on neuro-oncology with a focus on the brain tumors most commonly encountered by the adult neurologist and a clear emphasis on clinically relevant points including those which have recently become incorporated into our standard management. We cite key reviews to allow interested readers an opportunity to gain a more comprehensive understanding of specific topics.

Analysis of Genomic Alteration in Primary Central Nervous System Lymphoma and the Expression of Some Related Genes

Primary central nervous system lymphoma (PCNSL) is a rare and special type of non-Hodgkin lymphoma. The treatment of PCNSL is comprehensive, combining surgery, radiotherapy, and chemotherapy. However, the outcome is poor because of its high invasiveness and rate of recurrence. We analyzed 22 cases of PCNSL using next-generation sequencing (NGS) to detect 64 candidate genes. We used immunohistochemical methods to analyze gene expression in 57 PCNSL samples. NGS showed that recurrent mutations in KMT2D and CD79B, components of the NF-κB pathway, accounted for 65% of total mutations in PCNSL samples. The most frequent mutated gene was PIM1 (77.27%, 17/22), followed by MYD88 (63.64%, 14/22), CD79B (69.09%, 13/22), and KMT2D (50.00%, 11/22). Mutations of the CD79B gene were associated with an inferior progression-free survival (PFS), and GNA13 gene mutations were associated with a shorter PFS and overall survival (OS) in PCNSL patients (P < .05). PIM1 and MYD88 were highly expressed in PCNSL patients and were related to their OS time. MYD88 overexpression might be an independent and poor prognostic predictor of OS time. In summary, we identified highly recurrent genetic lesions in CD79B and KMT2D, components of the NF-κB pathway, in PCNSL and validated the expression of PIM1 and MYD88 related to poor survival, thereby providing novel insights into the pathogenesis and precision medicine of PCNSL.

Primary CNS Lymphomas: Challenges in Diagnosis and Monitoring

Primary Central Nervous System Lymphoma (PCNSL) is a rare neoplasm that can involve brain, eye, leptomeninges, and rarely spinal cord. PCNSL lesions most typically enhance homogeneously on T1-weighted magnetic resonance imaging (MRI) and appear T2-hypointense, but high variability in MRI features is commonly encountered. Neurological symptoms and MRI findings may mimic high grade gliomas (HGGs), tumefactive demyelinating lesions (TDLs), or infectious and granulomatous diseases. Advanced MRI techniques (MR diffusion, spectroscopy, and perfusion) and metabolic imaging, such as Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) or amino acid PET (usually employing methionine), may be useful in distinguishing these different entities and monitoring the disease course. Moreover, emerging data suggest a role for cerebrospinal fluid (CSF) markers in predicting prognosis and response to treatments. In this review, we will address the challenges in PCNSL diagnosis, assessment of response to treatments, and evaluation of potential neurotoxicity related to chemotherapy and radiotherapy.

Application value of CT and MRI in diagnosis of primary brain lymphoma

This study explored the correlation between computed tomography (CT) and magnetic resonance imaging (MRI) manifestations and pathological features of primary brain lymphoma to improve the diagnostic accuracy. A total of 230 patients with primary brain lymphoma admitted to People's Hospital of Rizhao from July, 2005 to December, 2016 were selected into the study and their clinical data were analyzed retrospectively. Among them, 87 patients were examined by CT, 74 patients by MRI, 69 patients by both MRI and CT. Features of MRI and CT scanning figures were observed with a focus on the density, number and margins of the lesions, and the diagnostic accuracy was analyzed. A total of 353 lesions were identified from 230 primary brain lymphoma patients, of which 224 were single lesions, and 129 were multiple lesions. Most lesions were on the upper curtain (81.3%, 187 cases) and 43 cases (18.7%) were on the lower curtain. Lesion signal of CT and MRI plain scan showed uniform state, and enhanced scan showed significantly enhanced signal. Diagnostic accuracy of CT was 82.8%, and sensitivity and specificity was 75.5 and 67.4%, respectively. Diagnostic accuracy of MRI was 83.8%, and sensitivity and specificity was 79.3 and 64.9%, respectively. Diagnostic accuracy of MRI combined with CT was 89.9%, and sensitivity and specificity was 86.3 and 75.8%, respectively. CT combined with MRI can provide better diagnosis for primary brain lymphoma compared with CT or MRI alone, but pathological test is still needed.

Neuroradiological features of lymphomatosis cerebri: A systematic review of the English literature with a new case report

Lymphomatosis cerebri is a rare form of diffusely infiltrating primary central nervous system (CNS) lymphoma (PCNSL). The neuroradiological findings of lymphomatosis cerebri have not been adequately characterized, as the relevant literature consists only of case reports and small case series. The present study describes an unusual presentation of lymphomatosis cerebri in a 56-year-old immunocompetent woman who presented with diffusely infiltrating lesions with perivascular curvilinear enhancement on initial magnetic resonance imaging (MRI) and multiple nodules on the later follow-up computed tomography (CT) scan. A systematic review of the literature is also performed searching PubMed between January 1996 and December 2016 to collect all pertinent case reports and series written in the English language with pathologically confirmed lymphomatosis cerebri and diffuse infiltrative PCNSL without cohesive masses on initial MRI. A total of 45 cases were identified from 39 articles and the present case report. The patient ages ranged from 28 to 85 years (mean, 57.3 years). Only 3 patients (6.7%) were immunosuppressed (acquired immune deficiency syndrome patients). The most common clinical presentation was cognitive changes or dementia (46.7%). Cerebrospinal fluid analysis in all cases was non-specific. Diffuse and asymmetric abnormal T2-hyperintensity in deep and subcortical white matter was observed in all cases. Gray matter involvement (17.8%), spreading along the corticospinal tract (35.6%) and a slight mass effect (51.1%) also were observed. Contrast-enhanced patterns on MRI could be divided into three forms of non-enhancement (64.4%) and non-mass-like enhancement (35.6%) on initial MRI, as well as nodular or mass-like enhancement on the later follow-up MRI (15.6%). There were non-specific findings on magnetic resonance spectroscopy for 4 patients, on positron emission tomography/CT for 12 patients and on single-photon emission CT for 1 patient. Diagnosis was established by brain biopsy in 35 cases (77.8%) and autopsy in 9 cases (20%), involving B-cell lymphoma in 40 cases (88.9%) and T-cell lymphoma in 4 cases (8.9%). In conclusion, lymphomatosis cerebri, namely diffuse PCNSL or diffuse lymphoma of the CNS, is characterized by rapidly progressive dementia in the elderly, diffusely infiltrated CNS white matter along the corticospinal tract, possible involvement of the gray matter, a slight mass effect and varied contrast-enhancement patterns on MRI. Non-enhancement or non-mass-like enhancement on MRI may be a special form of diffuse PCNL during disease development and progression.

Diagnostic value of using 18F-FDG PET and PET/CT in immunocompetent patients with primary central nervous system lymphoma: A systematic review and meta-analysis

BACKGROUND

18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and PET/CT have become two of the most powerful tools for malignant lymphoma exploration, but their diagnostic role in primary central nervous system lymphoma (PCNSL) is still disputed. The purpose of our study is to identify the usefulness of 18F-FDG PET and PET/CT for detecting PCNSL.

RESULTS

A total of 129 patients, obtained from eight eligible studies, were included for this systematic review and meta-analysis. The performance of 18F-FDG PET and PET/CT for diagnosing PCNSL were as follows: the pooled sensitivity was 0.88 (95% CI: 0.80-0.94), specificity was 0.86 (95% CI: 0.73-0.94), positive likelihood ratio (PLR) was 3.99 (95% CI: 2.31-6.90), negative likelihood ratio (NLR) was 0.11 (95% CI: 0.04-0.32), and diagnostic odds ratio (DOR) was 33.40 (95% CI: 10.40-107.3). In addition, the area under the curve (AUC) and Q index were 0.9192 and 0.8525, respectively.

MATERIALS AND METHODS

PubMed/MEDLINE, Embase and Cochrane Library were systematically searched for potential publications (last updated on July 16th, 2016). Reference lists of included articles were also checked. Original articles that reported data on patients who were suspected of having PCNSL were considered suitable for inclusion. The sensitivities and specificities of 18F-FDG PET and PET/CT in each study were evaluated. The Stata software and Meta-Disc software were employed in the process of data analysis.

CONCLUSIONS

18F-FDG PET and PET/CT showed considerable accuracy in identifying PCNSL in immunocompetent patients and could be a valuable radiological diagnostic tool for PCNSL.

Expression of OCT4 and SALL4 in Diffuse Large B-cell Lymphoma: An Analysis of 145 Consecutive Cases and Testicular Lymphomas

OCT4 and SALL4 are transcription factors within a complex network that functions to maintain pluripotency in primitive stem cells and germ cells. Nuclear expression of OCT4 is widely cited as sensitive and specific for primary and metastatic germ cell tumors and is commonly used in the diagnosis of central nervous system (CNS) germinomas. Studies have failed to systematically examine the expression of OCT4 or SALL4 in diffuse large B-cell lymphoma (DLBCL), although this entity enters the morphologic differential diagnosis of some germ cell tumors. A retrospective review was conducted on 145 consecutive cases of DLBCL and testicular lymphoma to evaluate the prevalence of OCT4 and SALL4 expression. Nuclear OCT4 expression was present in 2/11 (18%) testicular DLBCLs and 6/134 (4.5%) nontesticular DLBCLs. Most OCT4 cases demonstrated moderate to strong expression in >50% of neoplastic cells. Rare, weak nuclear SALL4 expression was detected in only 3 nontesticular DLBCLs. Within the extratesticular DLBCL group, 2/6 (33%) primary CNS DLBCLs expressed nuclear OCT4. In addition, OCT4 DLBCL showed an overall predilection toward non-germinal center B-cell phenotype (7/8; 88%) and had a higher than expected rate of CD5 coexpression (4/8, 50%). These results are cautionary against using OCT4 as a sole marker of germ cell differentiation in testicular and extratesticular sites, especially in the CNS. The apparent associations of OCT4 expression with primary CNS DLBCL, non-germinal center B-cell phenotype, and CD5 coexpression raise the question of whether OCT4 expression in DLBCL may reflect more aggressive biology.

Cytologic perspectives on neoteric B-cell lymphoproliferative disorders

The 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tissues has been recently revised, and publication of the updated 2016 version is expected soon. Given that cytopathologists are often involved in the diagnosis of primary, recurrent, and transformed lymphoproliferative disorders, knowledge of updates to the WHO lymphoma classification, including terminology, pathogenesis, ancillary techniques, and targeted therapies is necessary. Herein, we reference the last decade of cytology specific literature for seven newer B-cell disorders and provide illustrative examples of each entity from our files.