Genetics and Molecular Biology of Intramedullary Spinal Cord Tumors

Comparison of intraoperative blood loss and perioperative complications between preoperative embolization and nonembolization combined with spinal tumor surgeries: a systematic review and meta-analysis

PURPOSE

The present study aimed to comparatively evaluate intraoperative blood loss (IBL) and perioperative complications between preoperative embolization (PE) and nonembolization (NE) combined with spinal tumor surgeries as well as to determine the subgroup of spinal tumor surgeries suitable for PE.

METHODS

A systematic search in PubMed and EMBASE and an additional search by reference lists of the retrieved studies were undertaken by two reviewers. The mean IBL and perioperative complication rate were employed as the effect size in the general quantitative synthesis through direct calculation. Meta-analysis was performed using standardized mean difference (SMD) and weighted mean difference (WMD) of IBL and the odds ratio (OR) of complications. Heterogeneity was assessed using the I2 statistic.

RESULTS

The reviewers selected 17 published studies for the general quantitative synthesis and meta-analyses. The mean IBL of spinal tumor surgeries was 1786.3 mL in the NE group and 1716.4 mL in the PE group. The mean IBL between the two groups was similar. The pooled WMD and SMD of IBL in spinal tumor surgeries was 324.15 mL (95% CI 89.50-1640.9, p = 0.007) and 0.398 (95% CI 0.114-0.682, p = 0.006), respectively. The reduction of the PE group compared with the NE group for the rates of major complications and major hemorrhagic complications were 7.80% and 5.71%, respectively. The risk of PE-related complications in the PE group was only 1.53% more than in the PE group. The pooled OR of major complications in spinal tumor surgeries was 1.426 (95% CI 0.760-2.674; p = 0.269).

CONCLUSIONS

PE may be suitable for spinal tumor surgeries and some subgroups. From the perspective of complications, PE may also be a feasible option for spinal tumor surgeries.

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.

Anaplastic myxopapillary ependymoma: A case report and review of literature

BACKGROUND

Myxopapillary ependymoma (MPE) is a pathological grade I tumor that arises in the filum terminale. MPE with anaplastic features is extremely rare, and only 5 cases have shown malignancy at the time of recurrence.

CASE SUMMARY

The patient (a 46-year-old woman) had undergone a MPE operation 30 years ago. After subtotal resection of the tumor located in L4-S1, it had a solid component that extended to the adjacent subcutaneous region. Histologically, the tumor consisted of a typical MPE with anaplastic features. The anaplastic areas of the tumor showed hypercellularity, a rapid mitotic rate, vascular proliferation, and connective tissue proliferation. Pleomorphic cells and atypical mitotic figures were occasionally observed. The MIB-1 index in this area was 12.3%. The immunohistochemical study showed immunoreactivity for vimentin, glial fibrillary acidic protein and S100. The morphological pattern and immunohistochemical profile were consistent with anaplastic MPE. The patient tolerated surgery well without new neurological deficits. She underwent local irradiation for the residual tumor and rehabilitation.

CONCLUSION

Although extremely rare, anaplastic MPE occurs in both pediatric and adult patients, similar to other ependymomas. At a minimum, close monitoring is recommended, given concerns about aggressive biological potential. In the future, further study is needed to determine the WHO classification criteria and genetic indicators of tumor progression. The possibility of malignant transformation of MPE should be taken into account, and patients with MPE should be treated with care and follow-up.

Genomic Landscape of Intramedullary Spinal Cord Gliomas

Intramedullary spinal cord tumors (IMSCTs) are rare neoplasms that have limited treatment options and are associated with high rates of morbidity and mortality. To better understand the genetic basis of these tumors we performed whole exome sequencing on 45 tumors and matched germline DNA, including twenty-nine spinal cord ependymomas and sixteen astrocytomas. Though recurrent somatic mutations in IMSCTs were rare, we identified NF2 mutations in 15.7% of tumors (ependymoma, N = 7; astrocytoma, N = 1), RP1 mutations in 5.9% of tumors (ependymoma, N = 3), and ESX1 mutations in 5.9% of tumors (ependymoma, N = 3). We further identified copy number amplifications in CTU1 in 25% of myxopapillary ependymomas. Given the paucity of somatic driver mutations, we further performed whole-genome sequencing of 12 tumors (ependymoma, N = 9; astrocytoma, N = 3). Overall, we observed that IMSCTs with intracranial histologic counterparts (e.g. glioblastoma) did not harbor the canonical mutations associated with their intracranial counterparts. Our findings suggest that the origin of IMSCTs may be distinct from tumors arising within other compartments of the central nervous system and provides the framework to begin more biologically based therapeutic strategies.

Feasibility of total en-bloc spondylectomy on L5 by a posterior-only approach: An autopsy study

Purpose

To obtain a better understanding of the structures around L5 vertebra and provide some anatomical evidence of the feasibility of total en-bloc spondylectomy (TES) on L5 in a posterior-only approach.

Methods

12 simulated TESs on L5 by a posterior-only approach were conducted on human cadavers. The distance between the traction point of L4 nerve root and the dural sac (Da), the anterior-posterior diameter of the vertebral body,(Va), the distance between the start point of L4 nerve root and the traction point of L5 nerve root (Dh) and the height of the vertebral body (Vh) were measured. Paired t-test and liner regression were performed to determine the difference and correlation between Da and Va, and between Dh and Vh. The risk of nerve roots or blood vessels damages, and the obstruction caused by iliac wings were evaluated.

Results

Liner correlations were found between Da and Va, and between Dh and Vh. The regression equations were Da = 0.6673Va + 11.28 and Dh = 1.009Vh + 1.003. There are statistical significant differences between Dh and Vh, and between Da and Va in those whose Va < 34.96 mm. Nerve roots or blood vessels damages and the obstruction caused by iliac wing were able to be avoided.

Conclusions

If the patient has an anterior-posterior diameter of L5 vertebral body shorter than 34.96 mm, it is possible that the vertebral body can be taken out during TES in a posterior-only approach. Prevention of nerve roots or blood vessels damages, and the obstruction caused by iliac wings are difficulties of this procedure yet not insurmountable. TES on L5 by a posterior-only approach might a possible alternative in treating diseases like L5 vertebral body tumors.

Myxopapillary ependymoma with anaplastic features: A case report with review of the literature

Background:

Myxopapillary ependymoma (MPE) with anaplastic features is extremely rare, with only three case reports in the literature.

Case Description:

We report the case of a MPE with anaplastic features in a 24-year-old female who presented with a dominant lumbar mass along with intracranial and sacral metastases. Upon gross total resection of the dominant tumor located at L2-L3, it appeared to arise from the filum terminale, and had a solid component in addition to soft or necrotic areas. Histologically, the tumor was composed of the two classic components of MPE: (1) low-grade ependymal cells surrounding blood vessels, producing the papillary appearance and (2) perivascular myxoid material between blood vessels and ependymal cells, creating the myxopapillary appearance. The high-grade anaplastic component showed hypercellularity, brisk mitotic rate, and vascular proliferation, with frequent pleomorphic cells and atypical mitotic figures. It was positive for vimentin and glial fibrillary acidic protein (GFAP); negative for epithelial membrane antigen (EMA), CAM5.2, creatine kinase 7 (CK7), CK20; and the MIB-1 index (Ki-67) was 8–38%. Ten months after initial resection, follow-up magnetic resonance imaging revealed new lesions in (1) the hypothalamus, (2) the left pons, and (3) the left medial temporal lobe, which were treated with radiosurgery. Eight months later (18 months from initial surgery), the patient underwent thoracic laminectomy for a large leptomeningeal metastasis at T6 and T8.

Conclusion:

The present case of MPE with anaplastic features is the fourth case on record in the medical literature.

Spinal cord tumours: advances in genetics and their implications for treatment

Tumours of the spinal cord, although rare, are associated with high morbidity. Surgical resection remains the primary treatment for patients with this disease, and offers the best chance for cure. Such surgical procedures, however, carry substantial risks such as worsening of neurological deficit, paralysis and death. New therapeutic avenues for spinal cord tumours are needed, but genetic studies of the molecular mechanisms governing tumourigenesis in the spinal cord are limited by the scarcity of high-quality human tumour samples. Many spinal cord tumours have intracranial counterparts that have been extensively studied, but emerging data show that the tumours are genetically and biologically distinct. The differences between brain and spine tumours make extrapolation of data from one to the other difficult. In this Review, we describe the demographics, genetics and current treatment approaches for the most commonly encountered spinal cord tumours--namely, ependymomas, astrocytomas, haemangioblastomas and meningiomas. We highlight advances in understanding of the biological basis of these lesions, and explain how the latest progress in genetics and beyond are being translated to improve patient care.

Surgical treatment of primary intramedullary spinal cord tumors in adult patients

BACKGROUND

Primary spinal cord intramedullary tumors are rare and present with insidious symptoms. Previous treatment protocols emphasized biopsy and radiation/chemotherapy but more aggressive protocols have emerged.

OBJECTIVE

To report our experience.

METHOD

Forty-eight patients were diagnosed with primary intramedullary tumors. The cervical cord was involved in 27% and thoracic in 42% of patients. Complete microsurgical removal was attempted whenever possible without added neurological morbidity.

RESULTS

Complete resection was obtained in 33 (71%) patients. Neurological function remained stable or improved in 32 patients (66.7%). Ependymoma was the most frequent tumor (66.7%).

CONCLUSION

Neurological outcome is superior in patients with subtle findings; aggressive microsurgical resection should be pursued with acceptable neurological outcomes.

Spinal tumors in neurofibromatosis-2: management considerations - a review

Neurofibromatosis Type 2 (NF-2) is a distinct clinical entity, characterized by multiple intracranial and spinal tumors. While bilateral vestibular schwannomas are the pathological hallmark of the disease, significant morbidity in NF-2 is attributable to the presence of both intramedullary and extramedullary spinal tumors. With the advent of MRI as a screening modality, multiple, extensive spinal tumors in the NF-2 population are often seen, which may be clinically quiescent at the time of initial diagnosis. All NF-2 patients should have routine screening with full spinal MRI at the time of diagnosis, regardless of symptoms. Early surgical intervention is indicated in cases where a neurological deficit is attributable to a focal expanding spinal lesion. In asymptomatic patients, the decision to operate is tailored to the individual patient, with the ultimate goal of preserving function. In these cases, surgery should be considered where there is evidence of progressive tumor growth, with attendant risk to the patient of functional deterioration.