Stereotactic Biopsy Research Articles

OS10.8.A APPLICATIONS OF NOVEL FFPE BASED TECHNOLOGIES FOR THE DIAGNOSTICS OF GLIOMAS

Abstract BACKGROUND Due to the lack of consistent tumour-cell specific markers, the diffuse brain invasion of glioblastoma (GB) presents a significant diagnostic challenge, especially for specimens with a low tumour cell fraction or scarce tissue. The only common alteration found in most GB is the gain of chromosome 7 and loss of chromosome 10. The emergence of new technologies such as spatial and single nucleus transcriptomics that allow for detection of copy number alterations (CNVs) may allow us to push the diagnostic boundaries. MATERIAL AND METHODS We performed 10x Visium spatial transcriptomic analysis of FFPE tissue from bulk resections of 14 FFPE GB and stereotactic biopsies of 6 GB, 7 IDH mutant astrocytomas, 4 oligodendrogliomas and 1 diffuse glioma NOS. Visium tissue spots were then deconvolved using data from single nucleus transcriptomic data from nuclei isolated from FFPE tissue. Fresh frozen and FFPE single nucleus transcriptomic libraries were also generated from 4 GB with matching fresh-frozen and FFPE tissue available. RESULTS The infiltration zone, the tumour core and healthy brain tissue could be differentiated using the inferred CNVs of chromosome 7 and chromosome 10. Additionally, inferred CNVs of tissue fragments smaller than 1 mm2 were in accordance with Infinium MethylationEPIC array analysis (a well-established method for CNV detection) from the same tumour tissue. Using the spatial transcriptomics approach, the loss of chromosome 1p and 19q, which is characteristic for oligodendroglioma was also detected. To overcome the low resolution of Visium, deconvolution approaches using a single cell dataset can be used to determine the tumour content of a given tissue more precisely. To test if the single nuclei data from FFPE samples is suitable for deconvolution of spatial transcriptomics, we compared fresh-frozen and FFPE single nuclei data from matching tumours. As expected, FFPE and fresh frozen nuclei clustered together according to cell types and tumours in the UMAP space. CONCLUSION Spatial transcriptomics can be useful for brain tumour diagnostic workup, especially in cases where a limited amount of tissue prevents analysis by standard molecular diagnostic METHODS . Additionally, CNVs inferred from the spatial data as well as the spatial expression of marker genes help to better distinguish tumour infiltration zones from the core tumour and healthy brain tissue in the case of GB. This analysis can be further supported by deconvolution with a reference set generated from single nucleus transcriptomic analysis of FFPE tissue.

JS09.7.A COMBINATION OF APPARENT DIFFUSION COEFFICIENT AND FET PET COMPARED WITH STANDARD IMAGING FOR QUANTITATIVE TUMOR PRESENCE IN DIFFUSE GLIOMAS

Abstract BACKGROUND Diffuse glioma local treatment is currently guided by standard MRI sequences. Yet, the combination of apparent diffusion coefficient (ADC) and O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography (FET PET) (ADC/FET) detects histopathological qualitative assessed tumor presence more accurately than standard imaging. It is unknown whether this is similar for quantitative assessed tumor presence. This study compares the diagnostic accuracy of standard imaging and ADC/FET for the detection of quantitative assessed tumor presence in diffuse glioma. MATERIAL AND METHODS Fifteen patients with newly diagnosed diffuse glioma were retrospectively included. Pre-operative standard imaging, ADC and FET PET were available. Multiregional image-guided stereotactic biopsies were acquired before craniotomy. Quantitative imaging data from regions-of-interests (ROIs) centered at the biopsy locations was obtained. For each biopsy, sample semi-automatic cellularity and proliferation index, as well as DNA methylation-based tumor purity was determined. Linear mixed models were used to evaluate which modalities were significant independent predictors for each tumor presence marker and fitness was assessed using Bayesian Information Criterium. RESULTS 125 biopsies were analyzed (75 from eight high grade and 50 from seven low grade gliomas). Cellularity was predicted by T1 weighted MRI (p = 0.033), ADC (p = 0.016) and ADC/FET (p <.001), with ADC/FET as best fit. Both proliferation index (p = 0.003) and tumor purity (p <.001) were only predicted by ADC/FET. CONCLUSION Combining ADC and FET PET predicts cellularity, proliferation index and tumor purity better than standard imaging. Further investigation into ADC/FET-guided local treatment of diffuse glioma is therefore needed.

Retrospective Evaluation of Cases Undergoing Stereotaxic Brain Biopsy.

Objective: The aim of this study is to evaluate the demographic, radiological and histopathological findings, tumoral biomarkers, and survival rates of patients who underwent a stereotactic brain biopsy and those diagnosed with glioblastoma, metastasis, and lymphoma, and the changes in the diagnosis distribution over the years. Materials and Methods: The patients who underwent stereotactic biopsy in our clinic between 2012 and 2020 were evaluated retrospectively. Metastasis, glioblastoma, and lymphoma cases were evaluated as three main groups and the others were excluded. P53 gene expression, isocitrate dehydrogenase (IDH) mutation, and Ki-67 values in glioblastoma cases and Bcl-2, Bcl-6 proteins, and Ki-67 values in lymphomas and their relationship with survival were evaluated. Results: High p53 expression was observed in 27.5% cases diagnosed with glioblastoma. IDH mutation was negative in all glioblastoma cases. Presence of Bcl-2 and Bcl-6 proteins was not associated with survival in lymphomas. Survival rate was significantly higher in cases diagnosed with lymphoma (26.9%) compared to those diagnosed with glioblastoma. A statistically significant increase was determined in patients diagnosed with lymphoma considering the distribution of diseases and incidence and in the distribution of other diagnoses over the years ( p < 0.05). Conclusion: As per the distribution of the disease in recent times, it has been observed that there is an increase in lymphoma cases. Histopathology and biomarkers have great importance in the diagnosis and treatment of cerebral lesions. We think that our findings will be supported by studies in which larger patient population and detailed biomarkers will be studied.

Accuracy Comparison between Frameless Biopsy and Frame-Based Biopsy: A Retrospective Study of a Case Series

Abstract Objective To compare the efficacy and safety of frameless and frame-based techniques for biopsies of intracranial lesions in an exclusive assistance service at a public health center in Brazil (SUS). Method A review of 65 medical records of patients with brain lesions who underwent a frame-based or frameless biopsy from September 2017 to July 2019 was performed. Results Among the 65 patients who underwent biopsy, 42 were male, and 23 were female. The mean age was 53.1 years. Most patients (49; 75.4%) presented hemispheric lesions, and, of these, 27 were in the frontal lobe (41,5%). The diagnostic rate was 78.5% (51 of 65 patients), and glial neoplasia was the most common diagnosis. In addition to glial neoplasia, a wide range of pathologies were diagnosed, such as toxoplasmosis, metastasis, lymphoma, inflammatory lesions, and abscesses. Among the 14 patients (21.5%) with inconclusive results, 8 had gliosis without neoplasia (12.3%), 4 had necrosis (6.1%), and 2 had insufficient samples (3%).The morbidity rate was 9.2%, with 4 cases of hemorrhage, 1 case of infection, and 1 case of worsening of neurological deficits. The mortality rate was 6.1% and occurred in all cases with hemorrhage.There were no significant differences in the diagnosis or complication (morbidity and mortality) rates between the frame-based and frameless groups. Conclusion The frame-based and frameless techniques for stereotactic biopsy present similar efficacy and safety.

Preoperative factors associated with underestimation of invasive breast cancer in stereotactic vacuum-assisted biopsy-diagnosed DCIS patients

Objective: To determine preoperative factors associated with underestimation of invasive breast cancer, where stereotactic vacuum-assisted biopsy (VAB) diagnosed as ductal carcinoma in situ (DCIS). Materials and Methods: Data from 95 patients diagnosed with DCIS by stereotactic VAB, including their clinical, radiological, and pathological findings between November 2010 and May 2021, were analyzed retrospectively. The clinical, radiological, and pathological features were analyzed. Results: The underestimation rate was 30.5 %. Three preoperative features were significantly associated with the underestimation of invasive breast cancer in multivariable analysis, including palpability (OR, 11.51; 95% CI: 1.817-72.897; P = 0.009), BI-RADS category (OR, 3.705; 95% CI: 1.214-11.303; P = 0.021), and visibility of a mammographically detected lesion at ultrasonography (OR, 7.115; 95% CI: 1.977-25.611; P = 0.003). The calcification morphology was statistically significant in an univariable analysis but not in a multivariable analysis. Conclusion: Preoperative variables significantly associated with underdiagnosis of invasive breast cancer, including palpability, BI-RADS category, and visibility of mammographically detected lesions at ultrasonography, could aid in assessing the risk of developing invasive breast cancer and conducting treatment selection.

Prospective Evaluation of the Cost of Performing Breast Imaging Examinations Using a Time-Driven Activity-Based Costing Method: A Single-Center Study.

Measuring the cost of performing breast imaging is difficult in healthcare systems. The purpose of our study was to evaluate this cost using time-driven activity-based costing (TDABC) and to evaluate cost drivers for different exams. An IRB-approved, single-center prospective study was performed on 80 female patients presenting for breast screening, diagnostic or biopsy exams from July 2020 to April 2021. Using TDABC, data were collected for each exam type. Included were full-field digital mammography (FFDM), digital breast tomosynthesis (DBT), contrast-enhanced mammography (CEM), US and MRI exams, and stereotactic, US-guided and MRI-guided biopsies. For each exam type, mean cost and relative contributions of equipment, personnel and supplies were calculated. Screening MRI, CEM, US, DBT, and FFDM costs were $249, $120, $83, $28, and $30. Personnel was the major contributor to cost (60.0%-87.0%) for all screening exams except MRI where equipment was the major contributor (62.2%). Diagnostic MRI, CEM, US, and FFDM costs were $241, $123, $70, and $43. Personnel was the major contributor to cost (60.5%-88.6%) for all diagnostic exams except MRI where equipment was the major contributor (61.8%). Costs of MRI-guided, stereotactic and US-guided biopsy were $1611, $826, and $356. Supplies contributed 40.5%-49.8% and personnel contributed 30.7%-55.6% to the total cost of biopsies. TDABC provides assessment of actual costs of performing breast imaging. Costs and contributors varied across screening, diagnostic and biopsy exams and modalities. Practices may consider this methodology in understanding costs and making changes directed at cost savings.

Consecutive Development of Ependymoma and Glioblastoma in a Single Patient: A Case Report

Introduction: The simultaneous occurrence of ependymoma and glioblastoma in a single patient is an exceptionally rare phenomenon, with limited documented cases in the medical literature.Case Report: This article presents a compelling case study of a 53-yearold female who sequentially developed these two distinct primary brain tumors. The patient initially underwent neurosurgery for a subependymoma in 2010 and later presented with motor and sensory symptoms, leading to the diagnosis of glioblastoma. A diagnostic stereotactic brain biopsy confirmed the presence of a high-grade oligodendroglioma. Despite postoperative complications, the patient’s recovery has been favorable with no epileptic recurrence. The discussion highlights the distinct molecular and clinical heterogeneity of ependymoma and glioblastoma and the lack of reported cases featuring their consecutive occurrence. The underlying mechanisms behind such occurrences remain poorly understood and warrant further investigation.Conclusion: This case underscores the importance of deepening our comprehension of consecutive primary brain tumors to optimize diagnosis, treatment planning, and patient outcomes.

The molecular diagnostic yield of frame-based stereotactic biopsies in the age of precision neuro-oncology: a cross-sectional study

PurposeWith the increasing role of molecular genetics in the diagnostics of intracranial tumors, delivering sufficient representative tissue for such analyses is of paramount importance. This study explored the rate of successful diagnosis after frame-based stereotactic biopsies of intracranial lesions.MethodsConsecutive patients undergoing frame-based stereotactic biopsies in 2020 and 2021 were included in this retrospective analysis. Cases were classified into three groups: conclusive, diagnosis with missing molecular genetics (MG) data, and inconclusive neuropathological diagnosis.ResultsOf 145 patients, a conclusive diagnosis was possible in n = 137 cases (94.5%). For 3 cases (2.0%), diagnosis was established with missing MG data. In 5 cases (3.5%), an inconclusive (tumor) diagnosis was met. Diagnoses comprised mainly WHO 4 glioblastomas (n = 73, 56%), CNS lymphomas (n = 23, 16%), inflammatory diseases (n = 14, 10%), and metastases (n = 5, 3%). Methylomics were applied in 49% (n = 44) of tumor cases (panel sequencing in n = 28, 30% of tumors). The average number of specimens used for MG diagnostics was 5, while the average number of specimens provided was 15. In a univariate analysis, insufficient DNA was associated with an inconclusive diagnosis or a diagnosis with missing MG data (p < 0.001). Analyses of planned and implemented trajectories of cases with diagnosis with missing MG data or inconclusive diagnosis (n = 8) revealed that regions of interest were reached in almost all cases (n = 7).ConclusionAlthough stereotactic frame-based biopsies deliver a limited amount of tissue, they bear high histopathological and molecular genetic diagnostic yields. Given the proven surgical precision of the planned biopsy trajectories, optimizing surveyed lesion regions could help improve the rate of conclusive diagnoses.

Kidney Transplant Recipient With Tumefactive Demyelinating Lesions: A Case Report and Literature Review

Tumefactive demyelinating lesions (TDLs) are rare and specific types of inflammatory demyelinating lesions. Its clinical manifestations are nonspecific, and the imaging findings are similar to those of other intracranial space-occupying lesions, which are usually misdiagnosed as tumors or abscesses and require a pathologic examination to confirm the diagnosis. Tumefactive demyelinating lesions after kidney transplantation are even rarer. This article reports a case of TDLs after kidney transplantation. A 60-year-old female patient underwent kidney transplantation 15 years ago and took anti-rejection drugs such as tacrolimus, tacrolimus, and corticosteroids after surgery. The patient was admitted with headache and left limb weakness, and magnetic resonance imaging of the head showed multiple space-occupying lesions with surrounding edema. The patient underwent a stereotactic biopsy of the encephalopathy lesion, and postoperative pathology confirmed TDLs. She was treated with corticosteroids and discharged after the improvement of her symptoms. Here, to our knowledge, we report the first case of TDLs after kidney transplantation. We report this case to provide clinicians with useful information on intracranial demyelinating disease after kidney transplantation.

2-Hydroxyglutarate magnetic resonance spectroscopy in adult brainstem glioma.

Adult brainstem gliomas (BSGs) are rare tumors of the CNS that are poorly understood. Upregulation of the oncometabolite 2-hydroxyglutarate (2HG) in the tumor indicates the mutation of isocitrate dehydrogenase (IDH), which can be detected by magnetic resonance spectroscopy (MRS). Although histological examination is required for the definitive diagnosis of BSG, 2HG-optimized MRS (2HG-MRS) may be useful, considering the difficult nature of brainstem lesion biopsy. The aim of this study was to evaluate the utility of 2HG-MRS for diagnosing IDH-mutant adult BSG. Patients with a radiographically confirmed brainstem tumor underwent 3T MRS. A single voxel was set in the lesion with reference to the T2 or fluid-attenuated inversion recovery image and analyzed according to the 2HG-tailored MRS protocol (point-resolved spectroscopic sequence; echo time 35 msec). All patients underwent intraoperative navigation-guided or CT-guided stereotactic biopsy for histopathological diagnosis. The status of IDH and H3K27M mutations was confirmed by immunohistochemistry and direct DNA sequencing. In addition, the authors examined the relationship between patients' 2HG concentrations and survival time. Ten patients (7 men, 3 women; median age 33.5 years) underwent 2HG-MRS and biopsy. Four patients had an H3K27M mutation and 4 had an IDH1 mutation (1 R132H canonical IDH mutation, 2 R132S and 1 R132G noncanonical IDH mutations). Two had neither H3K27M nor IDH mutations. The H3K27M and IDH mutations were mutually exclusive. Most tumors were located in the pons. There was no significant radiological difference between mutant H3K27M and IDH on a conventional MRI sequence. A 2HG concentration ≥ 1.8 mM on MRS demonstrated 100% (95% CI 28%-100%) sensitivity and 100% (95% CI 42%-100%) specificity for IDH-mutant BSG (p = 0.0048). The median overall survival was 10 months in IDH-wild-type BSG patients (n = 6) and could not be estimated in IDH-mutant BSG patients (n = 4) due to the small number of deaths (p = 0.008). 2HG-MRS demonstrated high sensitivity and specificity for the prediction of IDH-mutant BSG. In addition, 2HG-MRS may be useful for predicting the prognosis of adult BSG patients.

Hemorrhagic complications during stereotactic biopsy of brain tumors

Relevance. Stereotactic biopsy (STB) is one of the main methods for diagnosing deep brain lesions. STB has several advantages over conventional intraoperative biopsy, as it is less traumatic and safer, especially for patients in critical condition. However, the most common complications of STB are hemorrhages, with a risk ranging from 0.9 % to 59.8 % depending on various studies. Intracranial hemorrhages are serious complications of surgical treatment of brain tumors, especially during biopsy using stereotactic techniques.Objective. To assess the risk of intracranial hemorrhages during STB of brain tumors and investigate possible factors influencing this risk, such as involvement of different brain regions in the neoplastic process, patient’s gender and age, degree of malignancy of the tumor, and use of different stereotactic devices.Materials and Methods. A retrospective study of data from 20 patients who underwent STB of brain tumors was conducted. Clinical data, examination results including coagulogram and aggregatogram, as well as data on involvement of different anatomical brain regions in the neoplastic process, degree of malignancy of the tumor, and use of a specific stereotactic device were analyzed.Results. Analysis of the frequency and structure of hemorrhagic complications of STB was performed, prognostic factors for high risk were identified, and preventive measures were proposed to reduce the number of hemorrhages.Conclusions. The introduction of the modern CRW Radionics stereotactic device into practice has reduced the frequency and severity of hemorrhagic complications after STB by two times. Lymphoproliferative processes and glioblastomas have a higher frequency of hemorrhages, but in most cases, they are clinically insignificant. There is a correlation between the degree of anaplasia of astrocytic tumors and the severity of hemorrhages. Ways to reduce the risks of intracranial hemorrhages during STB of brain tumors may include: careful preoperative planning of the biopsy trajectory; use of informative neurovisualization methods in planning the needle insertion trajectory; use of modern stereotactic systems by neurosurgeons who have undergone additional specialization and training on the specific device; use of modern biopsy needles. In addition, it is advisable to consider preoperative preventive hemostatic therapy in patients suspected of having a high degree of tumor anaplasia.

Novel application of robot-guided stereotactic technique on biopsy diagnosis of intracranial lesions.

This study was performed to examine whether there is a link between the application of three types of robot-guided stereotactic biopsy techniques and the diagnostic rate of intracranial lesion biopsy. The study involved 407 patients who underwent robot-guided stereotactic intracranial lesion biopsy at Xuanwu Hospital of Capital Medical University from January 2019 to December 2021. Age, sex, lesion characteristics, lesion distribution, surgical method, and target path depth were assessed for their impact on the biopsy diagnostic rate. The patients' mean age was 42.1 years (range, 6 months-82 years). All patients underwent robot-assisted stereotactic brain biopsy using one of three different systems: a ROSA robotic system (n=35), the CAS-R-2 (n=65), or the REMEBOT domestic robotic system (n=307). No significant difference was found in the diagnostic rate of positive histopathological findings or the mean time of surgery among the three biopsy modalities. The diagnostic rate was 93.86%. Multiple linear regression analysis showed that age, sex, and biopsy modality did not affect the diagnostic rate n>0.05), whereas enhancing lesions and smaller-volume lesions (≤l cm3) were significantly correlated with the diagnostic rate (p = 0.01). Lesions located in the suprasellar and pineal regions were significantly associated with the negative diagnostic rate (p<0.05). The presence of enhancing lesions, lesion location, and lesion volume significantly affected the diagnostic rate of brain biopsy. Age, sex, lesion depth, and biopsy modality did not significantly affect the diagnostic rate. All three procedures had high safety and effectiveness.

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.

The role of comorbidity indices and histochemical markers in surgically resected and non-resected primary central nervous system lymphoma.

The role of surgical resection in primary central nervous system lymphoma (PCNSL) was not recognized until recently. However, prognostic factors for surgically treated PCNSL remain unclear. In the present study, we aimed to identify and compare the prognostic value of comorbidity indices and immunohistochemical markers in patients with surgically and non-surgically treated PCNSL. This retrospective single-center study analyzed patients who underwent either surgical resection or stereotactic biopsy for newly diagnosed PCNSL between January 2012 and December 2021. Clinical demographics, comorbidity indices, and immunohistochemical markers were analyzed. We included 23 and 18 patients who underwent stereotactic biopsy and surgical resection, respectively. The median overall survival (OS) was 11.05months. Using multivariate Cox regression, we identified pretreatment prognostic nutritional index (PNI) (p = 0.009), positive BCL2 staining (p = 0.026), and infratentorial involvement (p = 0.004) as independent prognostic factors of OS. Predictors of progression-free survival (PFS) included PNI (p = 0.040), infratentorial involvement (p = 0.021), and surgical resection for PCNSL (p = 0.048). Subgroup analyses revealed that positive BCL2 (p = 0.048) and PD-L1 (p = 0.037) staining were associated with worse OS in the biopsy group. PNI and infratentorial involvement could significantly impact both OS and PFS in patients with PCNSL. Surgical resection could predict favorable PFS but not OS. Moreover, BCL2 and PD-L1 expression can be employed as prognostic markers in these patients.

Life expectancy in glioblastoma patients who had undergone stereotactic biopsy: a retrospective single-center study.

The best results in glioblastoma (GBM) are obtained through aggressive treatment comprising maximally radical but safe resection followed by chemoradiotherapy. However, certain patients will undergo only stereotactic biopsy. This paper aims to evaluate life expectancy in GBM patients who underwent only stereotactic biopsy, including the effect of subsequent oncological treatment. Patients with confirmed GBM histology who had undergone stereotactic biopsy between June 2006 and December 2016 were retrospectively selected. Each patient had received a CT scan, followed by an MRI scan with a contrast agent. None of the patients were amenable to microsurgical resection. Of the 60 patients, 41 (69%) received no subsequent oncological treatment, while 14 (23%) underwent isolated radiotherapy. Mean survival time of all patients was 2.8 months. Those who received no additional treatment had an average survival time of 2.3 months; patients who received any type of oncological treatment was 3.7 months. Of these, those receiving radiotherapy alone had a mean survival of 3.1 months. Patients who received oncological treatment with the Stupp protocol had a survival time of 6.6 months. Diagnostic and surgical advances related to GBM treatment mean that radical resections can be performed even in eloquent brain areas. However, patients not indicated for resection will experience a major reduction in life expectancy. Patients who underwent stereotactic biopsy and received some form of oncological treatment experienced slightly increased overall survival relative to patients with a natural disease course. Patients with favorable clinical factors reacted better to treatment.

Surgical Site Infections in Glioblastoma Patients-A Retrospective Analysis.

Surgical site infections (SSIs) after craniotomy lead to additional morbidity and mortality for patients, which are related to higher costs for the healthcare system. Furthermore, SSIs are associated with a longer hospital stay for the patient, which is particularly detrimental in glioblastoma patients due to their limited life expectancy. Risk factors for SSIs have already been described for craniotomies in general. However, there is limited data available for glioblastoma patients. As postoperative radiation influences wound healing, very early radiation is suspected to be a risk factor for SSI. Nevertheless, there are no data on the optimal timing of radiotherapy. To define risk factors for these patients, we analyzed our collective. We performed a retrospective analysis of all operations with histological evidence of a glioblastoma between 2012 and 2021. Open biopsy and tumor removal (gross total resection, subtotal resection) were included. Stereotactic biopsies were excluded. Demographic data such as age and gender, as well as duration of surgery, diameter of the trepanation, postoperative radiation with interval, postoperative chemotherapy, highest blood glucose level, previous surgery, ASA score, foreign material introduced, subgaleal suction drainage, ventricle opening and length of hospital stay, were recorded. The need for surgical revision due to infection was registered as an SSI. A total of 177 patients were included, of which 14 patients (7.9%) suffered an SSI. These occurred after a median of 45 days. The group with SSIs tended to include more men (57.1%, p = 0.163) and more pre-operated patients (50%, p = 0.125). In addition, foreign material and subgaleal suction drains had been implanted more frequently and the ventricles had been opened more frequently, without reaching statistical significance. Surprisingly, significantly more patients without SSIs had been irradiated (80.3%, p = 0.03). The results enable a better risk assessment of SSIs in glioblastoma patients. Patients with previous surgery, introduced foreign material, subgaleal suction drain and opening of the ventricle may have a slightly higher for SSIs. However, because none of these factors were significant, we should not call them risk factors. A less radical approach to surgery potentially involving these factors is not justified. The postulated negative role of irradiation was not confirmed, hence a rapid chemoradiation should be induced to achieve the best possible oncologic outcome.

Feasibility of probe washing after stereotactic needle biopsy as a novel technique for developing cell lines and xenografts of H3 K27-altered diffuse midline gliomas.

H3 K27-altered diffuse midline gliomas (DMGs) are frequently biopsied to obtain tissue diagnosis, inform clinical decision-making, and determine clinical trial eligibility. Tissue yield from biopsies is typically low, leaving little material available for research. To advance understanding of disease biology and promote preclinical testing of novel therapeutics, collecting viable cellular material from treatment-naive tumors is of paramount importance. Here, the authors report the feasibility of a practicable technique for creating DMG cell lines and patient-derived xenografts (PDXs) without the need for additional biopsy specimens. Tumor cells are obtained by probe washing immediately after completion of biopsy. Wash fluid is collected, and viable cells are expanded in vitro. Cultured cells are used to establish PDX rodent models. A total of 5 patient samples were collected by this technique. Viable tumor cells were obtained from 3 of the 5 samples, and cell lines suitable for experiments were obtained within 6-8 months. Orthotopic implantation and flank engraftment was successful in 1 of the 3 established cell lines. Animals harboring intracranial tumors were euthanized due to disease burden 6-7 months after stereotactic injection. Flank tumors formed within 4-5 months and were serially passaged. Molecular and tissue analyses confirmed retention of H3 K27M expression and loss of H3 K27me3 in all cell lines and PDXs.

Stepwise Implementation of 2D Synthesized Screening Mammography and Its Effect on Stereotactic Biopsy of Microcalcifications.

Information evaluating the efficacy of 2D synthesized mammography (2Ds) reconstructions in microcalcification detection is limited. This study used stereotactic biopsy data for microcalcifications to evaluate the stepwise implementation of 2Ds in screening mammography. The study aim was to identify whether 2Ds + digital breast tomosynthesis (DBT) is non-inferior to 2D digital mammography (2DM) + 2Ds + DBT, 2DM + DBT, and 2DM in identifying microcalcifications undergoing further diagnostic imaging and stereotactic biopsy. Retrospective stereotactic biopsy data were extracted following 151,736 screening mammograms of healthy women (average age, 56.3 years; range, 30-89 years), performed between 2012 and 2019. The stereotactic biopsy data were separated into 2DM, 2DM + DBT, 2DM + 2Ds + DBT, and 2Ds + DBT arms and examined using Fisher's exact test to compare the detection rates of all cancers, invasive cancers, DCIS, and ADH between modalities for patients undergoing stereotactic biopsy of microcalcifications. No statistical significance in cancer detection was seen for 2Ds + DBT among those calcifications that underwent stereotactic biopsy when comparing the 2Ds + DBT to 2DM, 2DM + DBT, and 2DM + 2Ds + DBT imaging combinations. These data suggest that 2Ds + DBT is non-inferior to 2DM + DBT in detecting microcalcifications that will undergo stereotactic biopsy.

Clinical and diagnostic observation of primary lymphoma of the central nervous system

Background. Lymphoma of the central nervous system (CNS), both primary and secondary, is a rare but very aggressive type of non-Hodgkin’s lymphoma. Primary CNS lymphoma (PCNSL) refers to cases confined to the CNS parenchyma, dura mater, leptomeninges, cranial nerves, and spinal cord or intraocular region. The prognosis of PCNSL has been very dismal with an overall survival of 1.5 months without treatment and a 5-year survival rate of 30%. Due to the introduction of high-dose methotrexatebased chemotherapy regimens, there has been substantial progress in treating patients with lymphomas of the CNS, leading to improved survival. Diagnosis and differential diagnosis of PCNSL can often cause complications because it may have similar clinical and radiological signs with some other tumors, primarily with high-grade gliomas and metastatic lesion of the CNS. Stereotactic biopsy remains the main diagnostic method.&#x0D; Purpose – to investigate the complexity of the diagnostic and therapeutic process in PCNSL on the example of a clinical case.&#x0D; Materials and methods. Clinical observation of patient K., 59 years old, who underwent examination and inpatient treatment at the Department of Radiation Pathology and Palliative Care of the State Organization «Grigoriev Institute for Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine» regarding multifocal lesions of the brain (volumetric formations of the white matter of the left hemisphere of the brain).&#x0D; Results and discussion. In this clinical case, the presence of multiple volumetric white matter formations of the left hemisphere of the brain in the frontal and temporal lobes of the brain with pronounced perifocal edema, mass effect and signal amplification from the described formations after the administration of a contrast agent in the patient in magnetic resonance imaging allowed us to assume metastatic lesion of the central nervous system. However, a comprehensive examination made it possible to exclude the presence of primary cancer, as well as an infectious lesion of the brain. The diagnosis of primary non-Hodgkin’s diffuse large B-cell lymphoma with damage to the central nervous system was established only after the neurosurgical removal of one of the neoplasms with the conduction of pathohistological and immunohistochemical studies.&#x0D; Conclusion. Multifocal brain injury often causes difficulties in diagnosis. Magnetic resonance imaging using T1, T2 and Flair imaging, although very important for the diagnosis of PCNSL, is not always specific. Timely cerebral biopsy with immunohistochemical examination remains the method of choice for verification of the pathological process, which is necessary for the correct treatment.

BIOL-24. USING NEEDLE WASH SPECIMEN AFTER STEREOTACTIC BIOPSY TO DEVELOP PDOX MODELS OF DIPG AND DIFFUSE MIDLINE GLIOMAS

Abstract Obtaining viable tissue remains a major barrier for lab-based studies, especially in brain tumors deemed surgically unresectable such as diffuse midline gliomas. Surgical biopsy is performed for those tumors invested in deep and vital brain structures however, biopsied specimens are usually of small volume without additional tissue for research after clinical testing. To overcome the barrier of limited surgical specimen volume, we partnered with neurosurgeons to develop a protocol which procures viable cells from discarded biopsy needle after stereotactic biopsies to develop patient-derived orthotopic xenograft (PDOX) models. After procurement of surgical specimen and prior to disposal of biopsy needle, each stereotactic biopsy needle was washed with FBS media twice. Wash solution was collected and immediately transported on ice to the research lab. Cell number was counted for in vitro culture and for orthotropic in vivo tumor implantation. To date, 29 samples of biopsy needle washes have been obtained including 12 diffuse midline gliomas of the brain stem, 8 supratentorial diffuse midline gliomas, and 3 pineal region tumors with harvested cell number from no visible cells to 5.3 million cells (median 1 million). 14 tumors have been orthotopically implanted into matched locations of immunodeficient mouse brains. Tumor formation was confirmed in 4 out of 15 (28.5%), including 2 brain stem tumors, 1 infiltrating astrocytoma, and 1 midline glioma, after implantation of cell numbers as low as 12,500. 3 models were successfully sub-transplanted to passages II and III. Histological examination confirmed the replication of key pathological features of the originating patient tumors. In conclusion, we have developed a novel protocol to procure clinical specimen by using wash solution of stereotactic brain tumor biopsy needles for surgically unresectable tumors. Our work demonstrates a new possibility for clinical sample acquisition and tumor modeling, opening new frontiers in the field of pediatric brain tumor research.