Diagnostic Yield of Extensive Systemic Staging Including Whole-body 18F-fluoro-deoxy-glucose Positron Emission Tomography With or Without Computed Tomography in Patients With Primary Central Nervous System Lymphoma: Systematic Review and Meta-analysis

Extranodal lymphoma: pathogenesis, diagnosis and treatment

Approximately 30% of lymphomas occur outside the lymph nodes, spleen, or bone marrow, and the incidence of extranodal lymphoma has been rising in the past decade. While traditional chemotherapy and radiation therapy can improve survival outcomes for certain patients, the prognosis for extranodal lymphoma patients remains unsatisfactory. Extranodal lymphomas in different anatomical sites often have distinct cellular origins, pathogenic mechanisms, and clinical manifestations, significantly influencing their diagnosis and treatment. Therefore, it is necessary to provide a comprehensive summary of the pathogenesis, diagnosis, and treatment progress of extranodal lymphoma overall and specifically for different anatomical sites. This review summarizes the current progress in the common key signaling pathways in the development of extranodal lymphomas and intervention therapy. Furthermore, it provides insights into the pathogenesis, diagnosis, and treatment strategies of common extranodal lymphomas, including gastric mucosa-associated lymphoid tissue (MALT) lymphoma, mycosis fungoides (MF), natural killer/T-cell lymphoma (nasal type, NKTCL-NT), and primary central nervous system lymphoma (PCNSL). Additionally, as PCNSL is one of the extranodal lymphomas with the worst prognosis, this review specifically summarizes prognostic indicators and discusses the challenges and opportunities related to its clinical applications. The aim of this review is to assist clinical physicians and researchers in understanding the current status of extranodal lymphomas, enabling them to make informed clinical decisions that contribute to improving patient prognosis.

Systemic inflammatory biomarkers in primary central nervous system lymphoma versus high-grade glioma: exploratory, comparative and correlative analysis

Aim:

To assess systemic inflammatory biomarkers in non invasive differential diagnosis of primary central nervous system lymphoma (PCNSL) from high-grade glioma (HGG).

Materials & methods:

Patients with similar morphology (PCNSL or HGG) on conventional neuro-imaging were included. Systemic inflammatory indices were calculated from pretreatment complete blood counts and liver function tests and compared against histopathology as reference standard.

Results:

Mean values of absolute lymphocyte count and prognostic nutritional index were significantly different between PCNSL (n = 42) versus HGG (n = 16). Area under receiver operating characteristics curve for absolute lymphocyte count and prognostic nutritional index in the diagnosis of PCNSL was 0.70 and 0.72 respectively suggesting fair and acceptable diagnostic accuracy.

Conclusion:

Systemic inflammatory biomarkers complement established clinico-radiological features and aid in the differential diagnosis of PCNSL from HGG.

There exists a complex interplay between cancer and inflammation that can manifest as increased inflammatory biomarkers in blood. However, utility of systemic inflammatory biomarkers in the non invasive differential diagnosis of primary brain lymphoma from high-grade glioma is generally lacking. Two simple serum biomarkers, absolute lymphocyte count and prognostic nutritional index, easily derived from routine pretreatment blood tests have fair correlation and acceptable diagnostic accuracy in differentiating brain lymphoma from glioma in patients with similar morphology on MRI.

EANM procedure guidelines for brain PET imaging using [18F]FDG, version 3

The present procedural guidelines summarize the current views of the EANM Neuro-Imaging Committee (NIC). The purpose of these guidelines is to assist nuclear medicine practitioners in making recommendations, performing, interpreting, and reporting results of [¹⁸F]FDG-PET imaging of the brain. The aim is to help achieve a high-quality standard of [¹⁸F]FDG brain imaging and to further increase the diagnostic impact of this technique in neurological, neurosurgical, and psychiatric practice. The present document replaces a former version of the guidelines that have been published in 2009. These new guidelines include an update in the light of advances in PET technology such as the introduction of digital PET and hybrid PET/MR systems, advances in individual PET semiquantitative analysis, and current broadening clinical indications (e.g., for encephalitis and brain lymphoma). Further insight has also become available about hyperglycemia effects in patients who undergo brain [¹⁸F]FDG-PET. Accordingly, the patient preparation procedure has been updated. Finally, most typical brain patterns of metabolic changes are summarized for neurodegenerative diseases. The present guidelines are specifically intended to present information related to the European practice. The information provided should be taken in the context of local conditions and regulations.

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.