Pediatric high-grade astrocytoma with piloid features of the spinal cord: A report of two cases and literature review

Beibei Yu; Yang Lu; Linkai Jing; Guihuai Wang

doi:10.4103/glioma.glioma_10_21

CASE REPORT

Year : 2021 | Volume : 4 | Issue : 3 | Page : 49-53

Pediatric high-grade astrocytoma with piloid features of the spinal cord: A report of two cases and literature review

Beibei Yu¹, Yang Lu², Linkai Jing², Guihuai Wang²
¹ Department of Neurosurgery, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China
² Department of Neurosurgery, School of Clinical Medicine, Beijing Tsinghua Changgung Hospital, Tsinghua University, Beijing, China

Date of Submission	02-Aug-2021
Date of Decision	04-Sep-2021
Date of Acceptance	24-Sep-2021
Date of Web Publication	11-Nov-2021

Correspondence Address:
Dr. Guihuai Wang
Department of Neurosurgery, School of Clinical Medicine, Beijing Tsinghua Changgung Hospital, Tsinghua University, Changping, Litanglu 168, Beijing - 102 218
China
Mr. Linkai Jing
Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, School of Clincal Medicine, Tsinghua University, Changping, Litanglu 168, Beijing 102218
China

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/glioma.glioma_10_21

Abstract

Although the 2021 World Health Organization classification update of the central nervous system tumors redefined "pilomyxoid astrocytoma" as high-grade astrocytoma with piloid features (HGAP), the craniocerebral HGAP exhibits poorer clinical outcomes when compared to pilocytic astrocytoma. However, in the spinal cord, the paucity of information of HGAP cases inhibits the judgment of prognosis and optimal management approaches for patients with spinal HGAP. Here, we summarized the clinical characteristics, management methods, and prognosis of ten cases of spinal HGAP reported in the literature and two cases of spinal HGAP who underwent tumor surgery in our institution. Here, the detailed clinical information we provided may help clinical decision-making for such rare childhood lesions. This study was approved by the Human Research Ethics Committees in our institution on June 29, 2021.

Keywords: Case report, high-grade astrocytomas with piloid features, intramedullary, pilocytic astrocytoma, spinal cord tumor

How to cite this article:
Yu B, Lu Y, Jing L, Wang G. Pediatric high-grade astrocytoma with piloid features of the spinal cord: A report of two cases and literature review. Glioma 2021;4:49-53

How to cite this URL:
Yu B, Lu Y, Jing L, Wang G. Pediatric high-grade astrocytoma with piloid features of the spinal cord: A report of two cases and literature review. Glioma [serial online] 2021 [cited 2023 Jun 4];4:49-53. Available from: http://www.jglioma.com/text.asp?2021/4/3/49/330192

Introduction

The pediatric pilocytic astrocytoma (PA), whose unique histological features include the lack of Rosenthal fibers, was first described by Jänisch et al.^[1] In 1999, this condition was renamed "pilomyxoid astrocytoma."^[2] Pilomyxoid astrocytoma was considered to be a pathological variant of PA and had initially not yet been classified at any specific level in the 2016 World Health Organization (WHO) classification scheme but was renamed to high-grade astrocytoma with piloid features (HGAP) in the 2021 WHO classification update. Although both PA and HGAP share multiple clinical and morphological features, there are a few differences in terms of specific DNA methylation profile and pathological symptoms.^[3]

HGAP can occur in many parts of the central nervous system, especially in the hypothalamic/chiasmatic region.^[4] However, primary spinal HGAP is extremely rare. Here, we reported two cases who were pathologically diagnosed with spinal HGAP. By reviewing the literature, we explored different clinical features and prognoses for spinal HGAP.

Case Reports

Case 1

A 10-year-old boy presenting with pain in both lower extremities and fatigue was treated in another institution before 4 years. A spine magnetic resonance imaging (MRI) showed the occurrence of T11– T12 intramedullary space-occupying lesion in the spinal cord [Figure 1]A. Subsequently, subtotal intramedullary tumor resection and laminoplasty of T10– T12 were performed [Figure 1]B, and the postoperative pathological diagnosis revealed low-grade PA (WHO Grade I) with active local growth.

Figure 1: Magnetic resonance imaging of Case 1. The first preoperative T2-weighted MRI showed T11–T12 space-occupying lesion (A, arrow). Four months after subtotal resection in other clinics, T2-weighted MRI re-examination showed that tumors in the T10–T11 segment (arrow) had recurred (B). The sagittal T1-weighted contrast-enhanced images (C) showed a solid cystic mass in the intramedullary level of T10–T11 (arrow). The T1-weighted contrast-enhanced MRI at 3 months post-gross total resection was performed in Tsinghua Changgung Hospital, as shown in the picture (D). The contrast-enhanced T1-weighted images (E) demonstrated abnormal enhancement (white arrow) of the conical spinal area without enlargement in the 5-year follow-up. MRI: Magnetic resonance imaging

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After 4 months of the first surgery, the patient was admitted to our hospital with a history of lumbosacral pain for more than 2 weeks. Physical examination revealed that the muscle strength of the triceps of both lower limbs was Grade IV, the left tibialis anterior muscle was Grade III, and the right tibialis anterior muscle was Grade II. Moreover, the preoperative neurological status was Grade II according to the McCormick scale. Dynamic contrast-enhanced MRI imaging showed a solid cystic mass in the intramedullary level of T10–T11 [Figure 1]C. Laminectomy and gross total resection (GTR) were performed to remove the cystic mass under the intraoperative electrophysiological monitoring. The short-term D-wave drop during the operation returned to the baseline level after stopping the surgical procedure. The pathological diagnosis of the lesion was HGAP features [Figure 2]A and [Figure 2]B. The results of immunohistochemical staining showed the positive of GFAP, S100, VIM, OLIG-2, P53, and the MIB proliferation index of 5%–8%.

Figure 2: Histological findings. Hematoxylin-eosin staining of the spinal cord tumor resection specimens in Case 1 (A and B) and Case 2 (C and D) illustrating medium density glial cell tumor located on mucus-like background, with uneven cell density, and sparse areas with microcapsules of tumor cells, focal tumors growing around blood vessels, forming pseudo-chrysanthemums, focal vascular endothelial hyperplasia, showing no clear eosinophilic granule bodies and Rosenthal fibers (A and C: Original magnification, ×100; B and D: Original magnification, ×400)

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Three months after the second surgery, re-examination imaging revealed scoliosis of the thoracolumbar spine and little residual tumor [Figure 1]D. Spinal orthosis was worn to improve the Cobb angle. Four years later, an enhanced MRI showed abnormal enhancement of the conus terminalis [Figure 1]E. During the preparation of this case report, the patient was not exhibiting any other neurological symptoms and was under close follow-up.

Case 2

A 5-year-old boy, previously treated in our hospital, presented with complaints of recurring neck pain for more than 4 months. Physical examinations indicated deviation of his head position to the left from the middle axis. The boy experienced neck pain whenever he attempted to turn his head toward the right position. Moreover, his right upper limb muscle strength was Grade IV, based on the muscle strength grading system. In this case, we assessed his neurological function was McCormick I grade. MRI examinations revealed signs of the abnormally thickened spinal cord from the medulla oblongata to the T1 level, with hypoisointense hybrid signals on T1-weighted image (T1WI) and hyperintense T2WI signals. Furthermore, the MRI scan exhibited the most obvious characteristics of spinal cord ring enhancement lesion at the C3–C7 level [Figure 3]A and [Figure 3]B.

Figure 3: Magnetic resonance imaging of Case 2. Sagittal T2-weighted images (A) and T1-weighted contrast-enhanced images (B) of the cervical spine showing an intramedullary, ring-enhancing mass lesion on C3–C7 (arrows). Postoperative T2-weighted images (C) and contrast-enhanced T1-weighted sagittal images of the cervical spinal cord (D) demonstrating no recurrence (arrows) at 5 years postsurgery

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Intraoperative fluorescence-guided subtotal resection (STR) was performed to remove the tumor. The tumor appeared gray to red in color and exhibited necrosis to some extent. The border of the tumor with the spinal cord was unremarkable, while yellow cyst fluid and gliosis were apparent with abundant blood supply. No significantly change was observed in the intraoperative monitoring of motor- and sensory-evoked potentials. Postoperative pathological examinations indicated signs characteristics of HGAP features [Figure 2]C and [Figure 2]D. Immunohistochemical staining of this lesion yielded the following positive results: S-100⁺, Vimentin⁺, Olig-2⁺, GFAP⁺, CD34⁺, P53⁺, and Ki-67 positivity rate of 10%.

During the immediate postoperative therapeutic course, the patient's upper limb muscle strength was slightly weakened to Grade III. However, it was improved after shock treatment with methylprednisolone. After 2 years of functional fitness exercises, the patient's right upper limb muscle strength was restored to normal, and he could perform all his daily activities. Follow-up MRI showed that the patient's condition was clinically stable, and the tumor residue remained benign or unchanged during 5-year follow-up postsurgery [Figure 3]C and [Figure 3]D.

The Human Research Ethics Committees in our institution gave approval for this study on June 29, 2021, and the guardians of the patients gave informed consent.

Discussion

A recent retrospective study based on the data from the National Cancer Database found that only 9% of the total cases of PA occurred within the spine; however, the clinicopathological characteristics of spinal HGAP incidences have not been clearly established.^[5] Notably, two cases of primary spinal HGAP have been admitted in our institution over the past 5 years, accounting for 0.65% and 3.90% of spinal glioma (n = 308) cases, respectively. By searching the PubMed and Embase databases for published studies on spinal HGAP, we could find only ten pediatric reports with detailed information, which have been documented between 1999 and 2020. The characteristics of 12 spinal HGAP cases with detailed information^{[6],[7],[8],[9],[10],[11],[12],[13]} are summarized in [Table 1].

Table 1: Ten cases of pediatric spinal high-grade astrocytoma with piloid features by literature review and two cases in our institution

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Because of similar clinical characteristics, about 10% of HGAP cases were misdiagnosed as PA before it was pathologically defined.^[4] The spinal HGAP's clinical features resemble those of PA in terms of pain, numbness, progressive weakness in the extremities, sphincter dysfunction, and other nonspecific symptoms. The most common initial symptoms include pain and paresthesia. In addition, it has been observed that patients exhibit severe difficulties in breathing and swallowing when the tumor is located on higher parts of the cervical spinal cord, that is, toward the craniovertebral junction. In our study, the medical history of spinal HGAP was 6.5 months. However, the medical history for spinal PA documented was 12.2 months.^[14] Moreover, the spinal HGAP frequently detected in the cervical and thoracic cord.

Neuroradiological features do not distinctly distinguish between HGAP and PA. Typically, spinal HGAP lesion on T1-weighted MRI shows hypo- or isointense signals, while on T2-weighted MRI, the lesion exhibits hyperintensity. Furthermore, the enhancement phase shows heterogeneous ring enhancements on T1-weighted MRI. In order to set parameters to clinically distinguish between spinal PA and HGAP on MRI examination, Horger et al.^[15] compared T2 signals and apparent diffusion coefficients in both spinal PA and HGAP cases. Although the myxoid matrix on spinal HGAP was more dominant and exhibited higher apparent diffusion coefficients values as well as increased T2 signal intensities, the general imaging features of spinal PA and HGAP were nonspecific for the overlapping values.

In addition to the absence of the Rosenthal fiber, eosinophilic granular bodies, and typical "biphasic architecture," HGAP's subtle histological features showed monomorphous bipolar piloid cells arranged in a prominent matrix background along with scattered mitoses. Moreover, histopathological examination of the tumor in case 1 suggested that the tumor's pathology had both PA and HGAP features, as previously reported by Johnson et al.^[16] These kinds of tumors were collectively referred to as "intermediate tumors." These findings illustrate the correlations between the biological behaviors of spinal PA and HGAP. Moreover, the probability for malignant transformation of HGAP is probably higher compared to that of PA in pediatric population. Paraskevopoulos et al.^[9] reported a case where spinal HGAP rapidly turned into malignant glioblastoma within 3 months, and the patient died in 1 year after surgery.

As is with spinal PA, surgery is the optimal choice for spinal HGAP. In this literature review, seven patients (7/12) underwent partial resection or biopsy and laminectomy for decompression, followed by chemotherapy or radiotherapy to stabilize the condition. Since there was no standard guideline for the spinal HGAP adjuvant treatments, in most cases, therapeutic measures were not implemented until the patient's condition deteriorated. This "wait and watch" approach might have aggravated the damage to the nervous system. Based on the pathological characteristics of the tumors, STR and GTR procedures were performed on the two patients whom we treated. During the average follow-up period of 55 months, the neurological function of cases we reported was improved when compared to the preoperation period. Moreover, their health conditions remained stable. The combination of cisplatin and etoposide chemotherapy after partial resection was recommended by Matsuzaki et al.^[8] Almubarak et al.^[12] applied a more aggressive chemotherapy strategy and fractionated radiotherapy as a salvage treatment for tumor recurrence. Their therapeutic strategies were found promising in stabilizing the patient's condition at 64 months and 60 months separately. However, these radical strategies exhibited limited success in postoperative function improvement in patients and might induce strong side effects in children.

Conclusion

Spinal HGAP is a very rare intramedullary spinal cord tumor. Besides as a pathological variant of PA, there are no apparent differences in terms of clinical manifestations and imaging features between spinal PA and HGAP. The gold standard for spinal HGAP diagnosis is postoperative pathology. Compared to spinal PA, spinal HGAP do not show a poorer clinical prognosis in our research. According to our investigation, the clinical management of spinal HGAP should include early tumor removal and subsequent monitoring of neurological functions. Postoperative radiotherapy and chemotherapy can be considered further as advanced therapeutic options for cases with recurrence or metastasis.

Financial support and sponsorship

Nil.

Institutional review board statement

This study was approved by the Human Research Ethics Committees in our institution on June 29, 2021, and the guardians of the patients gave informed consent.

Declaration of patient consent

The authors certify that they have obtained the patient consent forms. In the forms, the guardians of the patients have given their consent for the patients' images and other clinical information to be reported in the journal. The guardians of the patients understand that the patients' names and initials will not be published and due efforts will be made to conceal the patients' identity.

Conflicts of interest

The authors declare no conflicts of interest.

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