|Year : 2021 | Volume
| Issue : 2 | Page : 85-88
Management of pediatric cervicomedullary astrocytoma
Gopal Pemmaraju, Anand Parab, Anuradha Singh, Shubhangi Barsing
Department of Advanced Centre for Radiation Oncology, Dr. Balabhai Nanavati Hospital, Mumbai, Maharashtra, India
|Date of Submission||04-Aug-2020|
|Date of Acceptance||13-Aug-2020|
|Date of Web Publication||21-Apr-2021|
Dr. Gopal Pemmaraju
Department of Advanced Centre for Radiation Oncology, Dr. Balabhai Nanavati Hospital, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Cervicomedullary astrocytomas are low grade gliomas of childhood and young age which are typically centered at the junction of brainstem and cervical spine and present with a long duration of symptoms. The diagnosis of cervicomedullary astrocytomas is normally delayed as these tumours are slow growing and patients present with a long duration of symptoms. The symptoms are typical and can be correlated to the location of the tumour. Histopathology and Immunohistochemistry(IHC) guides us proving the diagnosis. Management of cervicomedullary astrocytomas includes surgery, radiotherapy and chemotherapy. A 13 years old female child presented with complaints of headache, vomiting, neck pain and progressive neck tilt. MRI of brain and cervical spine revealed moderate to significant expansile lesion in the dorsal aspect of lower medulla, cervicomedullary junction and the upper cervical cord upto C4-5 disc level.She underwent subtotal resection of the tumour. Histopathology and IHC confirmed her diagnosis as Astrocytoma WHO Grade-II. Patient underwent adjuvant radiation treatment to a radiation dose of 54 Grey in 27 fractions by Volumetric modulated arc therapy(VMAT) technique over a period of 6 weeks to the gross residual tumour and post-op tumour bed. Patient tolerated the treatment well. Patient experienced mild symptoms like nausea and vomiting during the course of treatment but well managed with supportive medications.
Keywords: Cervicomedullary astrocytomas, positron-emission tomography computed tomography, radiation treatment
|How to cite this article:|
Pemmaraju G, Parab A, Singh A, Barsing S. Management of pediatric cervicomedullary astrocytoma. J Radiat Cancer Res 2021;12:85-8
| Introduction|| |
Cervicomedullary astrocytomas are low-grade gliomas of childhood and young age which are typically centered at the junction of brainstem and cervical spine and present with a long duration of symptoms. These tumors are thought to arise in the spinal cord and extend dorsally into the medulla and 4th ventricle. The direction of growth may be due to resistance at the pyramidal decussation area., Radiologically, cervicomedullary astrocytomas come under a subset of Type IV brainstem gliomas. The World Health Organization (WHO) classified astrocytomas into Grades I–IV and majority of brainstem tumors are either Grade-I (pilocytic) or Grade-II (fibrillary) astrocytomas.
The diagnosis of cervicomedullary astrocytomas is normally delayed as these tumors are slow growing and patients present with a long duration of symptoms. The symptoms are typical and can be correlated to the location of the tumor. Nausea, vomiting, lower cranial dysfunction, sleep apnea, and chronic aspiration are seen in patients with a focus within the medulla, whereas cervical lesions present with pain, head tilt, progressive weakness, and motor dysfunction. Magnetic resonance imaging (MRI) is the gold standard in the radiological identification of cervicomedullary astrocytomas. Histopathology and immunohistochemistry (IHC) guide us in proving the diagnosis. Management of cervicomedullary astrocytomas includes surgery, radiotherapy, and chemotherapy. Gross total resection (GTR) or subtotal resection is the surgery being performed in cervicomedullary astrocytomas. Radiation treatment has been an excellent treatment option with long-term disease-free survival benefit. Chemotherapy may be used as an adjuvant treatment along with radiotherapy or in recurrent tumor settings.
| Case Report|| |
A 13-year-old female child presented with complaints of headache, vomiting, neck pain, and progressive neck tilt. MRI of the brain and cervical spine revealed moderate-to-significant expansile lesion in the dorsal aspect of lower medulla, cervicomedullary junction, and the upper cervical cord up to C4–C5 disc level with a hyperintense signal on T2-weighted and isointense on T1-weighted images with prominent central canal/thin syrinx in the cervicodorsal cord distal to the lesion from C5 to D1 level [Figure 1], [Figure 2], [Figure 3], [Figure 4]. The patient underwent subtotal resection of the tumor. Microscopically, the tumor composed of mild pleomorphic glial cells. On IHC, the tumor cells were positive for glial fibrillary acidic protein (GFAP) and S100, retained expression of ATRX, and Ki-67 proliferation index about 2%–3% and her diagnosis was confirmed as Astrocytoma WHO Grade-II.
|Figure 1: MRI - T2 W(Axial) showing hyperintense lesion in the cervical spine|
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|Figure 2: MRI - T2 W (Axial) showing hyperintense lesion in the brainstem|
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The patient underwent adjuvant radiation treatment after proper immobilization and computed tomography (CT) simulation on Halcyon 2.0 with kV cone-beam CT (CBCT) Linear accelerator from M/s. Varian, USA, using 6 MV Flattening Free Filter (FFF) beam. She received a radiation dose of 54 Gy in 27 fractions by volumetric modulated arc therapy (VMAT) technique over a period of 6 weeks to the gross residual tumor and postoperative tumor bed. Radiation planning was done on Eclipse 15.6 and the optimized VMAT plan was achieved with V95%–99.9% of the planning target volume [Figure 5] and [Figure 6] and sparing all the critical structures. The same plan was then compared with intensity-modulated radiotherapy (IMRT) plan [Table 1]. Precise treatment was delivered with image guidance by daily kV-CBCT prior to treatment and setup error corrections. The patient tolerated the treatment well. The patient experienced mild symptoms such as nausea and vomiting during the course of treatment but well managed with supportive medications. No major side effects or neurologic deficits were noticed during or after the completion of treatment.
|Figure 5: Planning CT scan(Axial) showing dose distribution including residual tumour and post op tumour bed|
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|Figure 6: Planning CT scan(Sagittal) showing dose distribution including residual tumour and post op tumour bed|
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|Table 1: Comparision between IMRT and VMAT plans regarding dose coverage and dosage to Organs at risk (OAR)|
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| Discussion|| |
Cervicomedullary astrocytomas represent a subset of low-grade brainstem gliomas and, as per definition, are intramedullary tumors that span the cervicomedullary junction. These tumors generally grow into the medulla in a dorsal exophytic fashion and compress the cranial nerves which produce signs and symptoms related to the same. As these tumors have good prognosis, timely diagnosis is essential though difficult and frequently delayed.
Robertson et al. demonstrated that longer the preoperative duration of symptoms (>15 weeks), longer is the progression-free survival.
MRI is a better tool to identify cervicomedullary astrocytomas. On MRI, they show heterogeneous enhancement with contrast and appear hypo- or isointense on T1-weighted images and hyperintense on T2-weighted images. As ependymomas also appear the same on MRI, biopsy, histopathological examination, and IHC are crucial in diagnosis. Histopathologically, WHO Grades II–IV are categorized as diffuse infiltrative astrocytomas. WHO Grade-II astrocytomas are composed of atypical fibrillary or gemistocytic astrocytes. These tumors express GFAP, low proliferation index (MIB-1), and no detectable mitosis. Molecular genetic studies showed activation of ERK/MAPK pathway, KIAA1549-BRAF gene fusions, and loss of NF1 gene with hyperactivation of oncogene KRAS.
GTR is an optimal surgical procedure which is rarely possible. Any damage to densely packed neural pathways can have disastrous clinical outcomes. Most surgical interventions are hence limited to biopsy or partial excision of spinal tumor. Radiation therapy very often is the only option of treatment. Radiation therapy is also considered following inadequate surgery or for salvage of recurrent gliomas.
Klimo et al. have unequivocally demonstrated the effectiveness of radiation therapy even after complete resection of the tumor. Radiotherapy is also indicated as an adjuvant treatment in cases with residual tumors after surgery or in recurrent tumors. Radiation to a dose of 45–54 Gy has been the standard proven schedule with improved outcomes. With the advent of modern radiotherapy techniques such as VMAT and IMRT and with image guidance, precise treatment can be delivered sparing organs at risk with less toxicities to the patient. Experiences from the past have shown that VMAT is comparable to IMRT in the treatment of cervicomedullary and spinal tumors. Chemotherapy may be considered as an adjuvant treatment option concurrent with radiation or as salvage treatment in recurrent and progressive lesions.
| Conclusion|| |
Cervicomedullary astrocytomas are rare, low-grade tumors of pediatric and young age group which present with typical symptoms of long duration and are associated with good prognosis. MRI, histopathology, and IHC guide us in diagnosis. Surgical resection (gross total or subtotal) plays an important role in the treatment. The role of radiation has traditionally been the standard and cannot be replaced. Newer techniques such as VMAT and IMRT can deliver the desired radiation dose to the target sparing all the critical structures.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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