Infiltrating spinal cord astrocytomas: Epidemiology, diagnosis, treatments and future directions

Management and Outcome of Recurring Low-Grade Intramedullary Astrocytomas

Intramedullary astrocytomas (IMAs) are the second most frequent intramedullary tumors in adults. Low-grade IMAs (LG-IMA, WHO grade I and II) carry a better prognosis than high-grade IMAs (HG-IMAs). However, adjuvant treatment of LG-IMAs by radiotherapy (RT) and/or chemotherapy (CT) as well as treatment of tumor recurrences remains controversial. The aim of our study was to evaluate the postoperative outcome of LG-IMAs and the management of recurring tumors. We retrospectively reviewed a series of patients operated on for IMA from 1980 to 2022 in a single neurosurgical department. We retrieved 40 patients who received surgery for intramedullary astrocytomas, including 30 LG-IMAs (22 WHO grade I; 5 WHO grade II; 3 "low-grade") and 10 HG-IMAs (4 WHO grade III; 5 WHO grade IV; 1 "high-grade"). Of the patients with LG-IMAs, the extent of surgical resection was large (gross or subtotal resection >90%) in 30% of cases. Immediate postoperative radiotherapy and/or chemotherapy was proposed only to patients who underwent biopsy (n = 5), while others were initially followed-up. Over a median follow-up of 59 months (range = 13-376), 16 LG-IMA (53.3%) recurred with a mean delay of 28.5 months after surgery (range = 3-288). These included seven biopsies, five partial resections (PR), four subtotal resections (STR) but no gross total resections (GTR). Progression-free survival for LG-IMAs was 51.9% at 3 years and 35.6% at 5 and 10 years; overall survival was 96.3% at 3 years; 90.9% at 5 years and 81.9% at 10 years. There were no significant differences in terms of OS and PFS between WHO grade I and grade II tumors. However, "large resections" (GTR or STR), as opposed to "limited resections" (PR and biopsies), were associated with both better OS (p = 0.14) and PFS (p = 0.04). The treatment of recurrences consisted of surgery alone (n = 3), surgery with RT and/or CT (n = 2), RT with CT (n = 3), RT alone (n = 2) or CT alone (n = 2). In conclusion, although LG-IMAs are infiltrating tumors, the extent of resection (GTR or STR), but not WHO grading, is the main prognostic factor. The management of recurring tumors is highly variable with no conclusive evidence for either option.

Tumor microenvironment in a minipig model of spinal cord glioma

BACKGROUND

Spinal cord glioma (SCG) is considered an orphan disease that lacks effective treatment options with margins that are surgically inaccessible and an overall paucity of literature on the topic. The tumor microenvironment is a critical factor to consider in treatment and modeling design, especially with respect to the unresectable tumor edge. Recently, our group developed a high-grade spinal cord glioma (SCG) model in Göttingen minipigs.

METHODS

Immunofluorescence and ELISA were performed to explore the microenvironmental features and inflammation cytokines in this minipig SCG model. Protein carbonyl assay and GSH/GSSG assay were analyzed in the core and edge lesions in the minipig SCG model. The primary core and edge cells proliferation rate were shown in vitro, and the xenograft model in vivo.

RESULTS

We identified an elevated Ki-67 proliferative index, vascular and pericyte markers, CD31 and desmin in the tumor edge as compared to the tumor core. In addition, we found that the tumor edge demonstrated increased pro-inflammatory and gliomagenic cytokines including TNF-α, IL-1β, and IL-6. Furthermore, the mediation of oxidative stress is upregulated in the tumor edge. Hypoxic markers had statistically significant increased staining in the tumor core, but were notably still present in the tumor edge. The edge cells cultures derived from SCG biopsy also demonstrated an increased proliferative rate compared to core cell cultures in a xenotransplantation model.

CONCLUSIONS

Our study demonstrates heterogeneity in microenvironmental features in our minipig model of high-grade SCG, with a phenotype at the edge showing increased oxidative stress, proliferation, inflammatory cytokines, neovascularization, and decreased but present staining for hypoxic markers. These findings support the utility of this model as a means for investigating therapeutic approaches targeting the more aggressive and surgically unresectable tumor border.

The Role of Neuro-Inflammation and Innate Immunity in Pathophysiology of Brain and Spinal Cord Tumors

Inflammation and innate immune system play a central role in cancers, including those affecting the central nervous system (CNS). Currently, classification of neoplasms, especially regarding gliomas, is established on molecular mutations in isocitrate dehydrogenase (IDH) genes and the presence of co-deletion 1p/19q. Treatment, in most of brain and spinal cord tumors, is centered on surgery, radiotherapy and pharmacological approaches with chemotherapeutic agents. However, the results of the treatments, after several decades, are not completely satisfactory. Cytokines and angiogenic factors are closely linked to the brain cancer behavior. Moreover, recent studies suggest a link between inflammation and tumorigenesis, underlying the complex nature of this topic, especially the anti- and pro-tumoral activities of inflammation and the two-way interactions between immune and tumor cells. The current understanding of the mechanisms by which CNS cancer cells modulate the immune system, especially how bi-directional communications between immune cells and tumor cells create an immunosuppressed microenvironment, gives important information about the promotion of tumor survival and growth. Here, we have briefly reviewed the current literature on this topic, focusing on the possible role of inflammation and innate immunity involved in the origin and in the development of CNS tumors.

Primary Spinal Cord Astrocytomas: Two-Center Clinical Experience of Low- and High-Grade Lesions

OBJECTIVE

Primary spinal cord astrocytomas are rare, fatal, and poorly studied.

METHODS

This study included a 2-center, retrospective analysis of primary spinal cord astrocytoma patients from 1997 to 2020. Patients with drop metastases or without at least one follow-up were excluded.

RESULTS

Seven World Health Organization grade I, 6 grade II, 7 grade III, and 4 grade IV astrocytoma patients were included. Older patients had higher grades (median 20 years in grade I vs. 36.5 in grade IV). The median follow-up was 15 months. Thirteen patients were discharged to rehabilitation. Eight patients demonstrated radiographic progression. Adjuvant therapy was utilized more in higher grades (5 of 13 grades III vs. all 11 grades IIIIV). Six patients died (1 death in grades III vs. 5 in grades IIIIV). Ten patients had worsened symptoms at the last follow-up. The median progression-free survival in grade I, II, III, and IV tumors was 116, 36, 8, and 8.5 months, respectively. The median overall survival in grade I, II, III, and IV tumors was 142, 69, 19, and 12 months, respectively. Thrombotic complications occurred in 2 patients, one with isocitrate dehydrogenasewild type glioblastoma.

CONCLUSIONS

Outcomes worsen with higher grades and lead to difficult postoperative periods. Clinicians should be vigilant for thromboembolic complications. Further research is needed to understand these rare tumors.

Surgical approaches to intramedullary spinal cord astrocytomas in the age of genomics

Intramedullary astrocytomas represent approximately 30%–40% of all intramedullary tumors and are the most common intramedullary tumor in children. Surgical resection is considered the mainstay of treatment in symptomatic patients with neurological deficits. Gross total resection (GTR) can be difficult to achieve as astrocytomas frequently present as diffuse lesions that infiltrate the cord. Therefore, GTR carries a substantial risk of new post-operative deficits. Consequently, subtotal resection and biopsy are often the only surgical options attempted. A midline or paramedian sulcal myelotomy is frequently used for surgical resection, although a dorsal root entry zone myelotomy can be used for lateral tumors. Intra-operative neuromonitoring using D-wave integrity, somatosensory, and motor evoked potentials is critical to facilitating a safe resection. Adjuvant radiation and chemotherapy, such as temozolomide, are often administered for high-grade recurrent or progressive lesions; however, consensus is lacking on their efficacy. Biopsied tumors can be analyzed for molecular markers that inform clinicians about the tumor’s prognosis and response to conventional as well as targeted therapeutic treatments. Stratification of intramedullary tumors is increasingly based on molecular features and mutational status. The landscape of genetic and epigenetic mutations in intramedullary astrocytomas is not equivalent to their intracranial counterparts, with important difference in frequency and type of mutations. Therefore, dedicated attention is needed to cohorts of patients with intramedullary tumors. Targeted therapeutic agents can be designed and administered to patients based on their mutational status, which may be used in coordination with traditional surgical resection to improve overall survival and functional status.

Clinicoradiological characteristics of primary spinal cord H3 K27M-mutant diffuse midline glioma

OBJECTIVE

Primary spinal cord H3 K27M-mutant diffuse midline glioma (DMG) is a rare and devastating pathological entity. However, little attention has been paid to this disease. As a result, its clinicoradiological characteristics have yet to be described. The aim of this study was to describe the clinicoradiological characteristics of primary intramedullary H3 K27M-mutant DMG and to compare this tumor with the H3 K27 wild-type to explore potential features that could differentiate the two.

METHODS

A total of 59 patients with pathologically confirmed intramedullary astrocytoma were included in this study. The cohort was divided into an H3 K27M-mutant group and H3 K27 wild-type group based on the status of H3 K27M according to an immunohistochemistry method. Demographic data, MRI features, and molecular information were collected. Multivariate logistic regression was conducted to investigate variables that might have a role in differentiating an H3 K27M DMG from an H3 K27 wild-type tumor.

RESULTS

Only symptom duration showed an independent association with the H3 K27M mutation (OR 0.82, 95% CI 0.68-0.94, p = 0.016). Patients with spinal cord H3 K27M-mutant DMG had a shorter symptom duration than patients with H3 K27 wild-type glioma. No significant difference was found in terms of MRI features between the H3 K27M-mutant and H3 K27 wild-type groups. Additionally, H3 K27M-mutant DMG frequently demonstrated overexpression of p53. Survival outcome did not show a statistical difference between the H3 K27-mutant subgroup and H3 K27 wild-type subgroup in histologically high-grade astrocytoma.

CONCLUSIONS

Symptom duration was associated with an H3 K27M mutation in intramedullary astrocytoma. MRI features were heterogeneous, and no imaging feature was able to predict the H3 K27M mutation. The H3 K27M mutation did not impact survival outcome in spinal histologically high-grade astrocytoma.

Development and Validation of a Personalized Prognostic Prediction Model for Patients With Spinal Cord Astrocytoma

Background

The study aimed to investigate the prognostic factors of spinal cord astrocytoma (SCA) and establish a nomogram prognostic model for the management of patients with SCA.

Methods

Patients diagnosed with SCA between 1975 and 2016 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database and randomly divided into training and testing datasets (7:3). The primary outcomes of this study were overall survival (OS) and cancer-specific survival (CSS). Cox hazard proportional regression model was used to identify the prognostic factors of patients with SCA in the training dataset and feature importance was obtained. Based on the independent prognostic factors, nomograms were established for prognostic prediction. Calibration curves, concordance index (C-index), and time-dependent receiver operating characteristic (ROC) curves were used to evaluate the calibration and discrimination of the nomogram model, while Kaplan-Meier (KM) survival curves and decision curve analyses (DCA) were used to evaluate the clinical utility. Web-based online calculators were further developed to achieve clinical practicability.

Results

A total of 818 patients with SCA were included in this study, with an average age of 30.84 ± 21.97 years and an average follow-up time of 117.57 ± 113.51 months. Cox regression indicated that primary site surgery, age, insurance, histologic type, tumor extension, WHO grade, chemotherapy, and post-operation radiotherapy (PRT) were independent prognostic factors for OS. While primary site surgery, insurance, tumor extension, PRT, histologic type, WHO grade, and chemotherapy were independent prognostic factors for CSS. For OS prediction, the calibration curves in the training and testing dataset illustrated good calibration, with C-indexes of 0.783 and 0.769. The area under the curves (AUCs) of 5-year survival prediction were 0.82 and 0.843, while 10-year survival predictions were 0.849 and 0.881, for training and testing datasets, respectively. Moreover, the DCA demonstrated good clinical net benefit. The prediction performances of nomograms were verified to be superior to that of single indicators, and the prediction performance of nomograms for CSS is also excellent.

Conclusions

Nomograms for patients with SCA prognosis prediction demonstrated good calibration, discrimination, and clinical utility. This result might benefit clinical decision-making and patient management for SCA. Before further use, more extensive external validation is required for the established web-based online calculators.

Lentiviral-Induced Spinal Cord Gliomas in Rat Model

Intramedullary spinal cord tumors are a rare and understudied cancer with poor treatment options and prognosis. Our prior study used a combination of PDGF-B, HRAS, and p53 knockdown to induce the development of high-grade glioma in the spinal cords of minipigs. In this study, we evaluate the ability of each vector alone and combinations of vectors to produce high-grade spinal cord gliomas. Eight groups of rats (n = 8/group) underwent thoracolumbar laminectomy and injection of lentiviral vector in the lateral white matter of the spinal cord. Each group received a different combination of lentiviral vectors expressing PDGF-B, a constitutively active HRAS mutant, or shRNA targeting p53, or a control vector. All animals were monitored once per week for clinical deficits for 98 days. Tissues were harvested and analyzed using hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining. Rats injected with PDGF-B+HRAS+sh-p53 (triple cocktail) exhibited statistically significant declines in all behavioral measures (Basso Beattie Bresnahan scoring, Tarlov scoring, weight, and survival rate) over time when compared to the control. Histologically, all groups except the control and those injected with sh-p53 displayed the development of tumors at the injection site, although there were differences in the rate of tumor growth and the histopathological features of the lesions between groups. Examination of immunohistochemistry revealed rats receiving triple cocktail displayed the largest and most significant increase in the Ki67 proliferation index and GFAP positivity than any other group. PDGF-B+HRAS also displayed a significant increase in the Ki67 proliferation index. Rats receiving PDGF-B alone and PDGF-B+ sh-p53 displayed more a significant increase in SOX2-positive staining than in any other group. We found that different vector combinations produced differing high-grade glioma models in rodents. The combination of all three vectors produced a model of high-grade glioma more efficiently and aggressively with respect to behavioral, physiological, and histological characteristics than the rest of the vector combinations. Thus, the present rat model of spinal cord glioma may potentially be used to evaluate therapeutic strategies in the future.

Driver Genetic Mutations in Spinal Cord Gliomas Direct the Degree of Functional Impairment in Tumor-Associated Spinal Cord Injury

Genetic analysis in glioma has been developed recently. Spinal cord glioma is less common than intracranial glioma. Thus, the clinical significance of genetic mutations in spinal cord gliomas remains unclear. Furthermore, because the spinal cord is an important communication channel between the brain and the rest of the body, increased attention should be paid to its functional prognosis. In this study, we investigated the functional prognosis and driver genetic mutations in eight patients with spinal cord gliomas (World Health Organization grade I, three cases; grade II, two cases; grade III/IV, three cases). IDH mutations were detected in all grade II cases and H3F3A mutations were detected in all grade III/IV cases. The functional status of grade I and II gliomas remained unchanged or improved 1 year after surgery, whereas grade III/IV gliomas remained unchanged or deteriorated. Spinal glioma progenitor cells with H3F3A mutations were associated with accelerated tumor-associated spinal cord injury, which led to functional impairment. Conversely, the presence of IDH mutations, which are rarely reported in spinal gliomas, indicated a relatively favorable functional prognosis.

Analyses of DNA Methylation Profiling in the Diagnosis of Intramedullary Astrocytomas

Intramedullary astrocytomas (IMAs) consist of a heterogeneous group of rare central nervous system (CNS) tumors associated with variable outcomes. A DNA methylation-based classification approach has recently emerged as a powerful tool to further classify CNS tumors. However, no DNA methylation-related studies specifically addressing to IMAs have been performed yet. In the present study, we analyzed 16 IMA samples subjected to morphological and molecular analyses, including DNA methylation profiling. Among the 16 samples, only 3 cases were classified in a reference methylation class (MC) with the recommended calibrated score (≥0.9). The remaining cases were either considered “no-match” cases (calibrated score <0.3, n = 7) or were classified with low calibrated scores (ranging from 0.32 to 0.53, n = 6), including inconsistent classification. To obtain a more comprehensive tool for pathologists, we used different unsupervised analyses of DNA methylation profiles, including our data and those from the Heidelberg reference cohort. Even though our cohort included only 16 cases, hypotheses regarding IMA-specific classification were underlined; a potential specific MC of PA_SPINE was identified and high-grade IMAs, probably consisting of H3K27M wild-type IMAs, were mainly associated with ANA_PA MC. These hypotheses strongly suggest that a specific classification for IMAs has to be investigated.

Pilomyxoid astrocytoma of the thoracic spinal cord: Extremely rare case report of over 70-year-old patient

The Pilomyxoid is rare tumor in elderly population, in addition to the occurrence of an isolated lesion in spinal cord is extremely rare in non-pediatric population. Taking biopsy and subtotal resection is the starting point in essential approach for the treatment. After defining the histopathological nature of the tumor and specified that is Pilomyxoid, the next step is the combination of reoperation and adjuvant therapy.

Multicentric Spinal Pilocytic Astrocytoma Presenting with Syringomyelia

Pilocytic spinal cord astrocytomas make up 21% of intramedullary tumors. Only 20% of those tumors are associated with syringomyelia. To our knowledge, this is the first report of an adult presenting with multiple spinal pilocytic astrocytomas associated with syringomyelia. We report a case of a 27-year-old woman who had neck and arm pain for months. She underwent cervical magnetic resonance imaging (MRI) that demonstrated a syrinx from C2 and extending to C6. A coronal view of the MRI showed multiple mural nodules. Total excision of multicentric nodules within a cyst was performed with an uneventful intraoperative and postoperative period and the patient was discharged home with moderate right-hand numbness.

A comprehensive epidemiological review of spinal astrocytomas in the United States

OBJECTIVE

Spinal cord astrocytoma (SCA) is a rare tumor whose epidemiology has not been well defined. The authors utilized the Central Brain Tumor Registry of the United States (CBTRUS) to provide comprehensive up-to-date epidemiological data for this disease.

METHODS

The CBTRUS was queried for SCAs on ICD-O-3 (International Classification of Diseases for Oncology, 3rd edition) histological and topographical codes. The age-adjusted incidence (AAI) per 100,000 persons was calculated and stratified by race, sex, age, and ethnicity. Joinpoint was used to calculate the annual percentage change (APC) in incidence.

RESULTS

Two thousand nine hundred sixty-nine SCAs were diagnosed in the US between 1995 and 2016, resulting in an average of approximately 136 SCAs annually. The overall AAI was 0.047 (95% CI 0.045-0.049), and there was a statistically significant increase from 0.051 in 1995 to 0.043 in 2016. The peak incidence of 0.064 (95% CI 0.060-0.067) was found in the 0- to 19-year age group. The incidence in males was 0.053 (95% CI 0.050-0.055), which was significantly greater than the incidence in females (0.041, 95% CI 0.039-0.044). SCA incidence was significantly lower both in patients of Asian/Pacific Islander race (AAI = 0.034, 95% CI 0.028-0.042, p = 0.00015) and in patients of Hispanic ethnicity (AAI = 0.035, 95% CI 0.031-0.039, p < 0.001). The incidence of WHO grade I SCAs was significantly higher than those of WHO grade II, III, or IV SCAs (p < 0.001).

CONCLUSIONS

The overall AAI of SCA from 1995 to 2016 was 0.047 per 100,000. The incidence peaked early in life for both sexes, reached a nadir between 20 and 34 years of age for males and between 35 and 44 years of age for females, and then slowly increased throughout adulthood, with a greater incidence in males. Pilocytic astrocytomas were the most common SCA in the study cohort. This study presents the most comprehensive epidemiological study of SCA incidence in the US to date.

A reproduceable in situ xenograft model of spinal glioma

BACKGROUND

Spinal glioma is a nervous system tumor that tends to relapse and has no specific prognostic molecular biomarkers. Thus, a stable and reproduceable animal research model of spinal glioma is urgently needed.

NEW METHOD

We established a new in situ tumor xenograft model of spinal glioma using nude mice. In this study, we implanted tumors into the cervical spinal cord of nude mice to mimic the pathological characteristics of the original tumors.

RESULTS

Through anatomical experiments, we found that the cervical lamina of mice was thinner, the intervertebral space was much wider, and the adhesion muscles were more easily separated. According to the examination of spinal cord sections, the best puncture point we identified was located 0.9 mm lateral to the posterior median line at the level of the line between the midpoints of the scapulae and at a depth of 0.9 mm. In the nude mouse xenograft experiment, the implanted tumor tissue retained the pathological characteristics of the original tumor.

COMPARISON WITH EXISTING METHOD(S)

This model used the cervical spinal cord as the puncture site and patient-derived primary tumor cells, which has never been performed before. Tumor cells could be injected directly without damaging the lamina. Thus, we could reduce the risk of man-made spinal cord injury and infection and avoid destroying the stability and integrity of the spine.

CONCLUSIONS

This study established a stable and reliable animal model of spinal glioma for further molecular research and targeted therapy development.

Lentiviral Vector Induced Modeling of High-Grade Spinal Cord Glioma in Minipigs

BACKGROUND

Prior studies have applied driver mutations targeting the RTK/RAS/PI3K and p53 pathways to induce the formation of high-grade gliomas in rodent models. In the present study, we report the production of a high-grade spinal cord glioma model in pigs using lentiviral gene transfer.

METHODS

Six Gottingen Minipigs received thoracolumbar (T14-L1) lateral white matter injections of a combination of lentiviral vectors, expressing platelet-derived growth factor beta (PDGF-B), constitutive HRAS, and shRNA-p53 respectively. All animals received injection of control vectors into the contralateral cord. Animals underwent baseline and endpoint magnetic resonance imaging (MRI) and were evaluated daily for clinical deficits. Hematoxylin and eosin (H&E) and immunohistochemical analysis was conducted. Data are presented using descriptive statistics including relative frequencies, mean, standard deviation, and range.

RESULTS

100% of animals (n = 6/6) developed clinical motor deficits ipsilateral to the oncogenic lentiviral injections by a three-week endpoint. MRI scans at endpoint demonstrated contrast enhancing mass lesions at the site of oncogenic lentiviral injection and not at the site of control injections. Immunohistochemistry demonstrated positive staining for GFAP, Olig2, and a high Ki-67 proliferative index. Histopathologic features demonstrate consistent and reproducible growth of a high-grade glioma in all animals.

CONCLUSIONS

Lentiviral gene transfer represents a feasible pathway to glioma modeling in higher order species. The present model is the first lentiviral vector induced pig model of high-grade spinal cord glioma and may potentially be used in preclinical therapeutic development programs.

Contemporary management of pediatric spinal tumors: a single institute's experience in Taiwan in the modern era

INTRODUCTION

Pediatric spinal tumors are unique pathologies treated by pediatric neurosurgeons. Special attention is required for the preservation of neural function and bony alignment. We reported our experience in the management of these challenging lesions.

METHODS

A total of 75 pediatric patients with spinal tumors treated at the National Taiwan University Hospital from 1998 to 2018 were identified retrospectively. Clinical data, radiographic image, and pathological report were reviewed for analysis.

RESULTS

There were 37 females and 38 males. The median age was 9 years. Thirty-eight tumors (50.6%) were extradural, 20 (26.7%) intradural extramedullary, and 17 (22.6%) intramedullary. The most common pathologies were glioma, ependymoma, and neuroblastoma. The rate of total and subtotal resection was 45.3% and 21.3%. Thirty-four patients (45.3%) required post-operative adjuvant therapy. Eight patients (10.6%) with spinal deformity had simultaneous tumor excision and spinal fusion surgery. Additional six (8%) patients had subsequent spinal fixation and fusion for deformity after primary tumor operation. Eighty-four percent of patients were ambulatory 3 years after operation. For patients with intradural extramedullary and intramedullary tumors, worse survival outcome was associated with tumor derived from CSF seeding and cranial involvement of spinal tumor, while poorer functional outcome was correlated with cranial involvement and adjuvant therapy with chemotherapy or radiotherapy.

CONCLUSIONS

Pediatric spinal tumor surgery carries low surgical morbidity and mortality under current standard of neurosurgical practice. Post-operative adjuvant therapy is required for nearly half of the cases. Spinal deformity requires special attention and sometimes surgical correction. Contemporary management of pediatric spinal tumors enables effective ablation of the lesion and delivers favorable outcome for the majority of patients.

Primary Spinal Astrocytomas: A Literature Review

Primary spinal astrocytoma is a subtype of glioma, the most common spinal cord tumor found in the intradural intramedullary compartment. Spinal astrocytomas account for 6-8% of all spinal cord tumors and are primarily low grade (World Health Organization grade I (WHO I) or WHO II). They are seen in both the adult and pediatric population with the most common presenting symptoms being back pain, sensory dysfunction, or motor dysfunction. Magnetic Resonance Imaging (MRI) with and without gadolinium is the imaging of choice, which usually reveals a hypointense T1 weighted and hyperintense T2 weighted lesion with a heterogeneous pattern of contrast enhancement. Further imaging which may aid in surgical planning includes computerized tomography, diffusion tensor imaging, and tractography. Median survival in spinal cord astrocytomas ranges widely. The factors most significantly associated with poor prognosis and shorter median survival are older age at initial diagnosis, higher grade lesion based on histology, and extent of resection. The mainstay of treatment for primary spinal cord astrocytomas is surgical resection, with the goal of preservation of neurologic function, guided by intraoperative neuromonitoring. Adjunctive radiation has been shown beneficial and may increase overall survival. The role of adjunctive chemotherapy is employed, however, its benefit has not been clearly defined. Primary spinal cord astrocytomas are rare and challenging to treat. The gold standard treatment is surgical resection. Second-line treatments include radiation and chemotherapy, although, the optimal regimen for adjunctive therapy has not yet been clearly defined.

Case Report of Spinal Cord Astrocytoma Presenting with Extensive Spinal Vertebral Body Destruction

Background

Spinal cord astrocytomas are rare lesions in adults.

Case Description

In this report, we present the case of a 28-year-old female patient who presented with a 2-year history of back pain and 3-month history of leg weakness. Magnetic resonance imaging of the patient showed an intrinsic expansive spinal cord lesion with extensive vertebral body destruction. Open biopsy from the tumor with limited debulking confirmed World Health Organization grade II astrocytoma. Postoperatively, the patient had mild improvement in neurologic status.

Conclusions

This case represents a rare presentation of a spinal cord astrocytoma with extensive erosion of the vertebral body.

Recent advances in intradural spinal tumors

Intradural spinal tumors are rare tumors of the central nervous system. Due to the eloquence of the spinal cord and its tracts, the compact architecture of the cord and nerves, and the infiltrative nature of some of these tumors, surgical resection is difficult to achieve without causing neurological deficits. Likewise, chemotherapy and radiotherapy are utilized more cautiously in the treatment of intradural spinal tumors than their cranial counterparts. Targeted therapies aimed at the genetic alterations and molecular biology tailored to these tumors would be helpful but are lacking.Here, we review the major types of intradural spinal tumors, with an emphasis on genetic alterations, molecular biology, and experimental therapies for these difficult to treat neoplasms.

MR imaging features of spinal pilocytic astrocytoma

Background

The purpose of this retrospective review is to determine the MR imaging features of pilocytic astrocytoma (PA) in the spinal cord to help neuroradiologists preoperatively differentiate PA from other intramedullary tumors.

Methods

Neuro-oncology database review revealed 13 consecutive patients with a pathological spinal PA diagnosis and availability of preoperative MR imaging. Three patients had preoperative diffusion-weighted MR imaging. Demographics and conventional and diffusion MR imaging records were retrospectively evaluated.

Results

Among 13 cases of spinal PA, six PAs were located in the cervical region, 4 in the cervical-thoracic region, and 3 in the thoracic region. The average length of vertebral segments involved for the tumors were 4.7 ± 4.6 segments. Six tumors had associated syringomyelia. Eight PAs were located eccentrically in the spinal cord, and eleven had well-defined margins. Eight tumors (61.5%) were intermixed cystic and solid. All were contrast-enhanced, and 53.8% of all PAs showed focal nodule enhancement of the solid components. Two PAs showed intratumoral hemorrhages, and only one demonstrated cap sign. The ADC values (n = 3) of the tumors were 1.40 ± 0.28 × 10^− 3 mm²/s (min–max: 1.17–1.71 × 10^− 3 mm²/s).

Conclusions

PA should be considered in the differential diagnosis of intramedullary tumors that occur in the cervical and thoracic regions. Eccentric growth pattern, well-defined margin, intermixed cystic and solid appearance, focal nodular enhancement of solid components and syringomyelia are relatively frequent features. Relatively high ADC values compared with normal-appearing spinal cord parenchyma are common in spinal PA.

Spinal cord astrocytomas: progresses in experimental and clinical investigations for developing recovery neurobiology-based novel therapies

Spinal cord astrocytomas (SCAs) have discernibly unique signatures in regards to epidemiology, clinical oncological features, genetic markers, pathophysiology, and research and therapeutic challenges. Overall, there are presently very limited clinical management options for high grade SCAs despite progresses made in validating key molecular markers and standardizing tumor classification. The endeavors were aimed to improve diagnosis, therapy design and prognosis assessment, as well as to define more effective oncolytic targets. Efficacious treatment for high grade SCAs still remains an unmet medical demand. This review is therefore focused on research state updates that have been made upon analyzing clinical characteristics, diagnostic classification, genetic and molecular features, tumor initiation cell biology, and current management options for SCAs. Particular emphasis was given to basic and translational research endeavors targeting SCAs, including establishment of experimental models, exploration of unique profiles of SCA stem cell-like tumor survival cells, characterization of special requirements for effective therapeutic delivery into the spinal cord, and development of donor stem cell-based gene-directed enzyme prodrug therapy. We concluded that precise understanding of molecular oncology, tumor survival mechanisms (e.g., drug resistance, metastasis, and cancer stem cells/tumor survival cells), and principles of Recovery Neurobiology can help to create clinically meaningful experimental models of SCAs. Establishment of such systems will expedite the discovery of efficacious therapies that not only kill tumor cells but simultaneously preserve and improve residual neural function.

A reproducible model of intramedullary spinal cord tumor in rats bearing RG2 cells

Intramedullary spinal cord tumors (IMSCTs) are lethal diseases to many patients. The lack of adequate animal model has hampered the development of novel treatments. In the current study, a rodent intramedullary glioma model is established to study IMSCT progression. Fischer 344 rats received a intramedullary implantation of RG2 glioma cells. The neurological state of each rat was evaluated on daily basis using the Basso, Beattie and Bresnahan (BBB) scale. Rats implanted with RG2 cells developed significant hind limb paraplegia 20 days after implantation. Magnetic resonance imaging (MRI) scans after three weeks revealed significant intramedullary RG2 tumors in the rats. Forty days post implantation, rats were sacrificed for histopathological examination. Neuro-imaging and HE staining cross sections confirmed intramedullary RG2 glioma cells invading to the spinal cord. Thus, our model displayed many of the same invasive characteristics as human IMSCTs. This model should be a reliable and reproducible methodology to correlate well with the features of human IMSCT.

[Contribution of temozolomide chemotherapy for intramedullary grade II spinal cord astrocytomas in adults: Our experience]

INTRODUCTION

Grade II intramedullary astrocytomas are rare tumors. Despite a well-defined role of adjuvant temozolomide chemotherapy for brain gliomas, the contribution of this therapy for intramedullary gliomas is not yet clearly defined.

METHOD

We retrospectively analyzed the data of 5 adult patients treated with temozolomide between 2008 and 2015 for a grade II intramedullary astrocytoma with progression after surgery.

RESULTS

Five patients from 19 to 70 years of age (median, 37years) underwent a second surgery for the progression of a grade II intramedullary astrocytoma (median progression-free survival 26months [8-90]). All tumors remained grade II. Due to a second clinical or/and radiological tumor progression, the patients were treated with temozolomide after a 37months median progression-free survival (5-66). All patients received at minimum 12 cycles (mean 14 ± 5; range 12-24) of temozolomide (150-200mg/m²/day, 5days/28days). All patients were alive after a 10-year median follow-up after diagnosis (6-13). All patients were able to walk except one, who was previously in McCormick autonomy grade IV before chemotherapy. The McCormick autonomy rating after temozolomide was stable for 4 patients and improved for 1 patient. The treatment was delayed once for hematological toxicity.

CONCLUSION

Temozolomide stabilized all 5 patients without any major toxicity. Based on this experience that needs to be confirmed, we consider that temozolomide should be envisaged within the therapeutic arsenal for progressive intramedullary grade II astrocytomas.