Brain stem glioma: the role of a biopsy

Cervicomedullary Gliomas in Pediatric Age: A Systematic Review of the Literature and Tertiary Care Center Experience

INTRODUCTION

Cervicomedullary gliomas (CMGs) are usually low-grade tumors often found in the pediatric age. Histological findings, treatments, and classification have been much the same for 40 years, although histological and molecular classifications have largely been developed for other pediatric CNS tumors. The management and treatment of pediatric CMG are still conducted by many authors according to their anatomical location and characteristics, independently from histology.

METHODS

We conducted a literature review in PubMed (Medline) to identify relevant contributions about pediatric CMG published until December 31, 2021. We also analyzed a series of 10 patients with CMG treated from 2006 to 2021 at IRCCS Istituto Nazionale dei Tumori. The aim of the present review was to see whether and how the diagnosis, treatment, and classification of CMGs in children have developed over time, especially in the context of molecular advancements, and to analyze our single-center experience in the last 15 years.

RESULTS

Thirty articles have been included in the review. Articles have been divided into two historical periods (1981-2000 and 2001-2021) and data from different series were analyzed to see how much the management and treatment of pediatric CMG have changed during years. Analysis of our series of 10 patients affected by CMG was also performed to compare it with the literature.

DISCUSSION

Management and classification of CMG in children have not dramatically changed during years. However, new insight from molecular diagnostics and target therapies and the development of radiological, neurophysiological, and radiotherapy techniques have updated treatment modalities in the last 20 years. Treatment modalities and their innovations have been reviewed and discussed. Further studies are needed to standardize and customize treatment protocols for these tumors.

Stereotactic Brainstem Biopsy: Technical Aspects with Emphasis on Role of Awake Craniotomy

Introduction The role of frame-based stereotactic biopsy in brainstem lesions has been well established in literature. Transfrontal, transtentorial, and transcerebellar routes are used to access various targets within the brainstem. While the transfrontal approach is preferable in midbrain lesions, a transcerebellar approach via the middle cerebellar peduncle forms the shortest possible trajectory for pontine and medullary lesions.

Objective Authors to describe the technical nuances of frame-based stereotactic biopsy of lower brainstem lesions to increase the procedural safety and efficacy.

Materials and Methods Technical modifications in frame fixation were done to acheive the desired trajectory to the target. In adult cases biopsy was performed with patient awake during the procedure.

Results Total of five patients underwent biopsy with the technical modifications. Three patients were adults and two were in pediatric age group. Their age ranged from 12 to 50 years. No complications were encountered. Two of the biopsies showed demyelination and the other three turned out to be low-grade glioma, pilocytic astrocytoma, and lymphoma, respectively.

Conclusion Despite obvious inherent risks, the transcerebellar biopsy in semi-sitting position is a well-tolerated and effective method of obtaining a diagnostic tissue sample in brainstem lesions. We have noted that adoption of the technical modifications described in this article has aided in improving the safety and ease of the procedure.

Surgical Application of the Suboccipital Subtonsillar Approach to Reach the Inferior Half of Medulla Oblongata Tumors in Adult Patients

Medulla oblongata (MO) tumors are uncommon in adults. Controversies about their treatment arise regarding the need for histological diagnosis in this eloquent area of the brain, weighing benefits of a reliable diagnosis, and the potential disadvantages of invasive procedures. As a broader variety of pathological findings could be found in this localization, the accurate histopathological definition could not only allow an adequate therapy but also can prevent the disastrous consequences of empiric treatments. There are few publications about their surgical management and all belongs to small retrospective cohorts. In this scenario, we are reporting two patients with exophytic or focal lesions in the inferior half of the medulla, who underwent surgery by suboccipital midline subtonsillar approach. This approach was not specifically described to reach MO before, and we found that the lesions produced a mild elevation of the tonsils providing a wide surgical view from the medulla to the foramen of Luchska laterally, and up to the middle cerebellar peduncle, offering a wide and safe access.

Transcerebellar stereotactic biopsy for brainstem lesions in children

Brain stem lesions are pathologically heterogeneous. Pre-operative radiological diagnoses prove to be wrong in 10 to 20% of cases. It is therefore imperative to have a tissue diagnosis for appropriate therapeutic measures. We report a series of 24 patients (14 males, ten females, age range: 6-17 years) CT guided stereotactic biopsy for brain stem lesions approached via the suboccipital transcerebellar route in semi sitting position with principle used to violate only one pial plane with the biopsy probe not entering the ventral surface of the cerebellum. The inclusion and exclusion criteria with detailed material and method are discussed. Histological diagnosis was established in 23 patients (96%) with no procedure-related mortality. Our results indicate that stereotaxic approach to brain-stem lesions provides a high yield of positive histological diagnoses with a low incidence of morbidity. Awake CT-guided stereotactic biopsy via the suboccipital transcerebellar route in a semi-sitting position is a safe, reliable, and effective method for brainstem lesions that can obtain adequate tissue for histological diagnosis, thus providing each patient with the best available treatment.

Intrinsic brainstem tumours in adults: results of microneurosurgical treatment of 16 consecutive patients

Intrinsic brainstem tumours in adults have a poor prognosis and surgical resection is rarely performed. Encouraged by successful operations on children performed in our department, we began a more aggressive strategy of open operations. Between 1986 and 1997, we operated upon 16 consecutive patients over 16 years of age (five female, 11 male, mean age 36.9 years) who were suffering from intrinsic tumours located in the pons and/or medulla oblongata. The extent of first open resection was 80 - 100% in two of the cases and more than 50% in nine cases. The mean survival time after the first occurrence of symptoms was 88.1 (median 34.5) months, and 39.9 (median 11) months after the first open operation. The rate of 5-year survival from the first occurrence of symptoms was 37.5% (25% after the first open surgical procedure). Thirteen out of 16 patients died within the follow-up period of at least 6.3 years, two of them within the immediate postoperative period. Eleven patients experienced a postoperative deterioration of symptoms from which only four recovered. Eight patients had from WHO grade II astrocytoma and a similar course as patients with higher-grade gliomas (n = 4). Our results indicate that open microneurosurgery for intrinsic brainstem tumours is of questionable benefit for the patient. Although surgery offers the advantages of reliable confirmation of histopathology and may be associated with prolonged survival, neurological deterioration was common and, unlike in paediatric patients, often irreversible.

Transcerebellar stereotactic biopsy for lesions of the brainstem and peduncles under local anesthesia

OBJECTIVE

For certain brainstem lesions, a diagnostic biopsy is required for treatment planning. We reviewed the indications, safety, and diagnostic effectiveness of a transcerebellar stereotactic biopsy using local anesthesia and sedation.

METHODS

We retrospectively reviewed hospital records for all adult patients with symptomatic lesions of the pons and/or cerebellar peduncle who underwent an awake transcerebellar stereotactic biopsy at our institution over a 7-year period. Our technique features several modifications from the standard method and was performed under local anesthesia with patients in the semi-sitting position.

RESULTS

Our rate of diagnostic success (92%) was comparable to those in other published reports. However, only 5 (42%) of 12 biopsy-derived diagnoses were consistent with those predicted from preoperative magnetic resonance imaging. There were no deaths, and the only neurological complication was a cranial nerve palsy. Diagnoses in the 13 cases included infiltrative glioma (), metastases (), lymphoma (), encephalitis (), and reactive astrogliosis ().

CONCLUSION

Tissue diagnosis of lesions in the brainstem and cerebellar peduncles continues to be a significant challenge, with the potential for major morbidity. With appropriate patient selection, however, awake transcerebellar biopsy is a safe and effective procedure that can change clinical management and provide important prognostic information.

Dysphagia, dysarthria and falls in an elderly man

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Chemotherapy for progressive pilocytic astrocytomas in the chiasmo-hypothalamic regions

Over the past 25 years, we have treated 17 patients with chiasmo-hypothalamic astrocytomas. Before 1988, the initial treatments consisted of surgery and/or radiotherapy, while since 1989, 4 children (1 male, 3 females, aged 3-8 years) were treated primarily with chemotherapy. None of them was associated with neurofibromatosis. After a biopsy of the tumor, the intravenous administration of ranimustine (MCNU; 30-86 mg/m2) and/or nimustine (ACNU; 30.3-64.1 mg/m2) was given without radiation therapy. Chemotherapy was usually given as an out-patient, with a total of 5-13 courses. The total doses of MCNU and ACNU administered ranged from 150 to 570 mg and from 64.8 mg to 100 mg, respectively. After chemotherapy 2 patients showed clinical improvement and tumor regression on neuro-imaging, while one patient showed clinical improvement and tumor size stabilization on neuro-imaging. The remaining one child, however, showed a clinical worsening and tumor progression on neuro-imaging studies. He was thus treated with a second chemotherapy regimen with carboplatin and etoposide, which brought about tumor regression. The acute and subacute toxicity of chemotherapy was mild. All patients are now leading almost normal lives with a median of 43 months after diagnosis. Although a longer and more careful clinical observation is required, the authors conclude that chemotherapy with MCNU and/or ACNU may benefit patients with unresectable pilocytic astrocytoma requiring treatment. The advantages of this therapy include its mild side effects and the lack of any hospitalization in most patients. It may also delay the need for radiation therapy, which can have a deleterious effect on the young developing brain.

The role of image-directed biopsy in the diagnosis and management of brainstem lesions

The appreciation that brainstem tumours do not comprise a homogeneous pathological group and that up to 20% of the preoperative radiological diagnoses of brainstem lesions prove at operation to be wrong, has established the need for a firm histological diagnosis prior to treatment. Current neuro-imaging modalities may have increased the diagnostic accuracy and the detection rate of intrinsic brainstem lesions, but open exploration in cases without an exophytic component is still associated with a low diagnostic yield and considerable morbidity. A series of 72 brainstem lesions approached stereotactically with CT or MRI guidance is presented. A transcortical frontal precoronal trajectory was used in 58 and a suboccipital transcerebellar route in 14. Haematoma was diagnosed preoperatively in 16 cases and therapeutic aspiration was planned. In 56 cases the diagnosis was uncertain, although intrinsic tumour was suspected. A histological diagnosis was established in 52 cases, although in the remaining four cases a tumour was excluded. Unexpected findings occurred in over 15% of the cases. There were no operative deaths and the morbidity was low. In no case was there a permanent neurological deterioration directly related to the procedure, although there was a transient deterioration in two patients and another patient required early re-aspiration of a haematoma.

Image directed stereotactic surgery for brain stem lesions

Advances in neurological imaging may have increased the diagnostic accuracy and the detection rate of intrinsic brain stem lesions, but a histological diagnosis is still an essential requirement for rational and appropriate management. Open exploration allows biopsy and resection in cases where an exophytic component is present. The surgical inaccessibility and the resultant morbidity of these approaches, however, associated with a low diagnostic yield in cases with no visible surface abnormality, are important limiting factors. A series of 45 brain stem lesions stereotactically approached with CT or MRI guidance is presented. A transcortical frontal pre-coronal trajectory was used in all of them. Haematoma was preoperatively diagnosed in 10 cases and the procedure was for therapeutic aspiration. Of 35 cases where the diagnosis was uncertain, although intrinsic tumour was suspected, positive results were obtained in 33, while unexpected findings of granuloma, lymphoma, angioma, leucoencephalopathy, vasculitis and radiation necrosis were found in over 10% of the cases. There were no operative deaths and the morbidity was low. In no case was there a permanent neurological deterioration directly related to the procedure, although there was a transient deterioration in two patients and one patient required early reaspiration of a haematoma. Image directed stereotactic approaches to brain stem lesions can combine a high degree of accuracy (offering positive histological diagnoses) with a low operative morbidity. MRI directed biopsies can complement CT guided ones thus increasing the number of suitable cases and improving the success rate. The frontal precoronal transcortical trajectory provides safe access to the majority of the brain stem targets.