Pilomyxoid Astrocytoma Research Articles

Disseminated Juvenile Pilomyxoid Astrocytoma of the HypothalamicChiasmatic Region

Pilomyxoid astrocytoma (PMA) is a recently described histological type of pilocytic astrocytoma (PA), but the tumors show histological differences. PMA has more aggressive malignant behavior than PA. Magnetic Resonance Imaging (MRI) may play a crucial role in the preoperative setting and also help to establish an appropriate therapeutic regimen. In this case report, we illustrated MRI findings of a hypothalamic-chiasmatic PMA in a 15-year-old female patient presenting with extensive leptomeningeal seeding. The patient was operated for total tumor resection, but could not survive the second post-operative day. We have comprehensively discussed the clinical, imaging, and histopathological features of these relatively rare tumors and also reviewed the recent literature.

Treatment outcome of optic pathway glioma in children with diencephalon syndrome

Objective To explore the clinical treatment outcomes of the optic pathway glioma in children with diencephalic syndrome. Methods The clinical data of 8 cases of optic pathway glioma with diencephalic syndrome were analyzed retrospectively who were admitted to Department of Neurosurgery, Beijing Children′s Hospital, Capital Medical University from July 2015 to December 2018. The range of the children′s ages was from 8.0 to 42.2 months. No weight gain was reported in all those patients before the age of 1 year, and they showed a cachexia state of extreme emaciation at admission. The range of children′s preoperative weights was from 5.5 to 11.5 kg. The weight-for-age Z score was lower than -2 in all 8 patients who underwent microsurgical resection of tumor followed by chemotherapy post operation. Results Among the 8 cases of optic pathway glioma combined with diencephalic syndrome, subtotal resection was achieved in 7 cases, near-total resection in 1, and there was no death related to operation. Postoperative pathological examination confirmed 2 cases of pilocytic astrocytoma and 6 cases of pilomyxoid astrocytoma. The range of follow-up period of 8 children was from 1 to 18 months, the range of postoperative weight was from 8.0 to 20.0 kg, the weight of all patients increased to various degrees, and some of the patients′ clinical symptoms were alleviated. One patient died after discharge, and chemotherapy was applied to the rest of 7 patients. Residual tumor shrank in 4 patients, progressed in 2 and disseminated in 1. Conclusions Subtotal tumor resection in children with optic pathway gliomas and diencephalic syndrome could significantly improve the symptom of emaciation and alleviate some other symptoms. There seems to be great variability in the tumor sensitivity to postoperative chemotherapy. Key words: Glioma; Child; Optic pathway glioma; Diencephalic syndrome; Treatment outcome

Association of the FGFR1 mutation with spontaneous hemorrhage in low-grade gliomas in pediatric and young adult patients.

The authors aimed to investigate genetic alterations in low-grade gliomas (LGGs) in pediatric and young adult patients presenting with spontaneous hemorrhage. Patients younger than 30 years of age with a pathological diagnosis of World Health Organization (WHO) grade I or II glioma and who had undergone treatment at the authors' institution were retrospectively examined. BRAF V600E, FGFR1 N546/K656, IDH1 R132, IDH2 R172, and KIAA1549-BRAF (K-B) fusion genetic alterations were identified, and the presence of spontaneous tumoral hemorrhage was recorded. Among 66 patients (39 with WHO grade I and 27 with grade II tumors), genetic analysis revealed K-B fusion in 18 (27.3%), BRAF V600E mutation in 14 (21.2%), IDH1/2 mutation in 8 (12.1%), and FGFR1 mutation in 4 (6.1%). Spontaneous hemorrhage was observed in 5 patients (7.6%); 4 of them had an FGFR1 mutation and 1 had K-B fusion. Univariate analysis revealed a statistically significant association of an FGFR1 mutation and a diencephalic location with spontaneous hemorrhage. Among 19 diencephalic cases including the optic pathway, hypothalamus, and thalamus, an FGFR1 mutation was significantly associated with spontaneous hemorrhage (p < 0.001). Four FGFR1 mutation cases illustrated the following results: 1) a 2-year-old female with pilomyxoid astrocytoma (PMA) harboring the FGFR1 K656E mutation presented with intraventricular hemorrhage (IVH); 2) a 6-year-old male with PMA harboring FGFR1 K656E and D652G mutations presented with intratumoral hemorrhage (ITH); 3) a 4-year-old female with diffuse astrocytoma harboring FGFR1 K656M and D652G mutations presented with IVH; and 4) a young adult patient with pilocytic astrocytoma with the FGFR1 N546K mutation presented with delayed ITH and IVH after 7 years of observation. Although the mechanism remains unclear, the FGFR1 mutation is associated with spontaneous hemorrhage in pediatric and young adult LGG.

COT-14 CLINICAL FEATURES OF PEDIATRIC CENTRAL NERVOUS SYSTEM TUMORS

INTRODUCTIONHere,we discuss the presentation,histology,therapy,and outcome of central nervous system tumors in children.METHODSTreatment outcome and management was assessed for children diagnosed with central nervous tumors from 2007 to 2017 at Kagoshima University.RESULTSEight-eight patients (56 boys,32 girls) with a mean age of 10.3 years were included in this study. Patient tumor types included: germ cell tumor (n = 26); medulloblastoma (n = 16); pilocytic astrocytoma (n = 8); glioblastoma (n = 8); ependymoma (n = 6,1 with grade 2,5 with grade 3); hemangioblastoma,schwannoma,and ganglioglioma (n = 3 each); SEGA,pilomyxoid astrocytoma,and diffuse astrocytoma (n = 2 each),and anaplastic astrocytoma,PPTID,PNET,PXA,DIA,central neurocytoma,astroblastoma,meningioma,and choroid plexus papilloma (n = 1 each). The most common patient clinical features were headache and vomiting associated with hydrocephalus. The median follow-up period was 61 months. All patients with germ cell tumors underwent adjuvant chemotherapy and radiation therapy (RT); patients with germinoma or immature teratoma were still alive,while patients with embryonal carcinoma,yolk sac tumor,or choriocarcinoma had poor prognosis with a median survival of 16 months. For cases of ependymoma,three patients received ICE chemotherapy and RT,and two patients received RT alone; median survival time was 31 months. For high grade glioma,seven patients received temozolomide and RT,and two patients received temozolomide alone; median survival time was 13 months.CONCLUSIONSPatients with germ cell tumors had a relatively good prognosis,while patients with ependymoma or high grade glioma had a poor prognosis. As treatment strategies for ependymoma and high grade glioma are currently limited,it is necessary to evaluate treatment options in consideration of clinical course and quality of life,in addition to histologic and genetic findings.

PATH-52. ANAPLASTIC PILOMYXOID ASTROCYTOMA HARBORING BRAF FUSION, PTEN AND TERT MUTATIONS

Abstract Pilomyxoid astrocytomas (PMA) are focal neoplasms that are often cured with total resection. We present a case of a progressive PMA with histologic and molecular features suggestive of malignant transformation. A 13-year old boy presented with headaches, diplopia, and seizures. He had previously been followed for 7 years by serial imaging for a cystic/solid enhancing mass in the right temporal lobe without biopsy that had remained stable up to 6 months prior to his current illness. MRI of brain demonstrated significant progression of the solid component with extension into the subependymal portions of the lateral ventricles, leptomeningeal spread in brain and spine, and hydrocephalus. Patient underwent a partial resection of tumor and VP shunt placement. Pathology demonstrated a prominent myxoid matrix with angiocentric arrangement of monomorphous bipolar cells. PHH3 and Ki-67 stains confirmed multiple mitoses and elevated proliferation rate. Next Generation sequencing of tumor confirmed the presence of a KIAA1549-BRAF duplication/fusion, CDKN2A deletion, along with PTEN and TERT promoter mutations without BRAF V600E or ATRX mutations. The histology and molecular features was suggestive of a pilomyxoid astrocytoma (PMA) with anaplastic transformation. Patient is currently receiving carboplatin + vincristine plus a MEK inhibitor (TrametinibTM, Novartis Corporation, Cambridge, MA) for tumor control. We believe that the tumor was initiated by the oncogenic BRAF fusion and the dramatic progression and spread of disease after a long period of stability was probably related to recent acquisition of additional deleterious mutations that have been previously reported in anaplastic pilocytic astrocytoma.

Differentiation of pilocytic and pilomyxoid astrocytomas using dynamic susceptibility contrast perfusion and diffusion weighted imaging.

Pilocytic (PA) and pilomyxoid astrocytomas (PMA) are related low-grade tumors which occur predominantly in children. PMAs have a predilection for a supratentorial location in younger children with worse outcomes. However, the two have similar imaging characteristics. Quantitative MR sequences such as dynamic susceptibility contrast (DSC) perfusion and diffusion (DWI) were assessed for significant differences between the two tumor types and locations. A retrospective search for MRI with DSC and DWI on pathology-proven cases of PMA and PA in children was performed. Tumors were manually segmented on anatomic images registered to rCBV, K2, and ADC maps. Tumors were categorized as PA or PMA, with subclassification of supratentorial and infratentorial locations. Mean values were obtained for tumor groups and locations compared with Student's t test for significant differences with post hoc correction for multiple comparisons. ROC analysis for significant t test values was performed. Histogram evaluation was also performed. A total of 49 patients met inclusion criteria. This included 30 patients with infratentorial PA, 8 with supratentorial PA, 6 with supratentorial PMA, and 5 with infratentorial PMA. Mean analysis showed significantly increased rCBV for infratentorial PMA (2.39 ± 1.1) vs PA (1.39 ± 0.16, p = 0.0006). ROC analysis for infratentorial PA vs PMA yielded AUC = 0.87 (p < 0.001). Histogram analysis also demonstrated a higher ADC peak location for PMA (1.8 ± 0.2) vs PA (1.56 ± 0.28). PMA has a significantly higher rCBV than PA in the infratentorial space. DSC perfusion and diffusion MR imaging may be helpful to distinguish between the two tumor types in this location.

Spectroscopic measurement of 5-ALA-induced intracellular protoporphyrin IX in pediatric brain tumors.

5-Aminolevulinic acid (5-ALA)-guided resection of gliomas in adults enables better delineation between tumor and normal brain, allowing improved resection and improved patients' outcome. Recently, several reports were published regarding 5-ALA for resection of pediatric brain tumors. The aim of the study was to determine the intracellular fluorescence of protoporphyrin IX (PPIX) in pediatric brain tumors by hyperspectral imaging and to compare it with visually observed intraoperative fluorescence. 5-ALA was administered orally 4h prior to surgery. During tumor resection, the surgeon assessed the fluorescence signal to be strong, weak, or absent. Subsequently, fluorescence intensity of tumor samples was measured via spectroscopy. In addition, clinical data, imaging, and laboratory data were analyzed. Eleven children (1-16years) were operated. Tumor entities included three (n = 3) medulloblastomas, two (n = 2) pilocytic astrocytomas (PA), two (n = 2) anaplastic ependymomas and one (n = 1) diffuse astrocytoma, anaplastic astrocytoma (n = 1), pilomyxoid astrocytoma (n = 1) and anaplastic pleomorphic xanthoastrocytoma (n = 1). Strong fluorescence was visible in all anaplastic tumors and one PA; one PA demonstrated weak fluorescence. Visible fluorescence was strongly associated with intracellular fluorescence intensity and PPIX concentration (P < 0.05). Within all tumors with visible fluorescence, the intracellular PPIX concentration was greater than 4μg/ml. Except for moderate and transient elevation of liver enzymes, no 5-ALA related adverse events were reported. We demonstrate a strong association between intraoperative observations and spectrometric measurements of PPIX fluorescence in tumor tissue. As in former studies, fluorescence signal was more commonly observed in malignant glial tumors. Further prospective controlled trials should be conducted to investigate the feasibility of 5-ALA-guided resection of pediatric brain tumors.

Pilomyxoid astrocytomas: a short review.

Pilomyxoid astrocytoma is a variant of pilocytic astrocytoma and the clinical, histological and molecular data point to a very close relationship as well as a more aggressive biological behavior for the former. WHO 2016 classification does not provide a specific grade for these neoplasms, but there is sufficient evidence in the literature that pilomyxoid astrocytoma has slightly worse prognosis than typical pilocytic astrocytoma. There is increasing evidence that in addition to the MAPK pathway alterations, pilomyxoid astrocytomas harbor genetic alterations that distinguish them from typical pilocytic astrocytoma.

Recent Progress in the Pathology and Genetics of Pilocytic and Pilomyxoid Astrocytomas

Pilocytic and pilomyxoid astrocytomas are some of the most common gliomas in children and young adults. These gliomas are indolent neoplasms with long overall survival probability. The genetic characteristics of these neoplasms are well known, and our deepened understanding of their associated molecular alterations has led to the development of novel treatment strategies and approaches. Currently, we can account for some of the unusual behavior, such as oncogene-induced senescence, associated spontaneous regression, anaplastic transformation, and cerebrospinal dissemination, of these gliomas. Nevertheless, enigmatic issues continue to surround these chronic tumors. Here, we review the classical and uncommon clinical pathological and genetic features of these indolent gliomas.

EAPH-10. SUCCESSFUL TREATMENT OF A SECONDARY PEDIATRIC HIGH GRADE GLIOMA WITH A NOVEL BEND4-NTRK2 FUSION WITH ENTRECTINIB, A TRK INHIBITOR

A 2 month old child with a large hemispheric tumor; after subtotal resection, pathology showed pilomyxoid astrocytoma with BRAFV600E mutation by immunohistochemistry and pyrosequencing. He had multiple episodes of radiographic and clinical progression. Over the course of 5 years, therapy included carboplatin, TPCV, velban, and immunotherapy. Vemurafenib and dabrafenib were administered with no response. MRI showed rapid tumor progression in the brain with spinal dissemination and significant clinical deterioration. Patient underwent tumor debulking and pathology confirmed a high grade astrocytoma, without BRAF V600E mutation, but with a novel BEND4-NTRK2 fusion by molecular genetic testing. He underwent whole brain radiation of 33 Gy in 16 fractions and boost to primary tumor bed to a total dose of 43 Gy. No radiation was given to the spine. One month later, patient started compassionate treatment with entrectinib, a novel, CNS-active, TRK inhibitor, at 400 mg/m2/day. MRI obtained after 28 days on treatment demonstrated significant radiographic regression, with rapid improvement in clinical symptoms. His dose was then increased to 550 mg/m2/day. After 2 additional cycles, the tumor continues to decrease in size in the brain and a spine MRI demonstrated complete response despite no radiation to the spine. Toxicities included Grade 1 ALT, cholesterol and peripheral edema. In summary, we report the case of a refractory BRAF V600E mutated low grade glioma transformed into a high grade with a novel BEND4-NTRK2 fusion, and profound radiographic and clinical response to entrectinib.

Atypical pilocytic astrocytoma of adult spinal cord: A case report

Pilomyxoid astrocytoma (PMA) is an atypical subtype of pilocytic astrocytoma (PA), which presents in children and young adults. The incidence of PMA is low, so there is no standardized treatment protocol for it. Here, we present a 62-year-old woman with recurrent PMA, which is important for the understanding and treatment of the disease.

Pilomyxoid Astrocytoma: Case Report

AbstractThe pilomyxoid astrocytoma (PMA) is a rare glioma recently described as a separate entity, which is generally located on the hypothalamic area. The PMA was previously described as pilocytic astrocytoma (PA) due to similarities shared between them. Recent studies provided a deeper understanding of PMA, setting it as a separate entity, though PMA is still considered by many authors a variant of PA. The PMA is considered to be more aggressive than PA; however, further studies are necessary for a better comprehension of its behavior and, hence, for neurosurgeons and neurologists to get to a consensus about its management.This study presents a 16-year-old female patient who looked for medical assistance complaining of headaches of over 6 months and vomiting for 2 weeks prior to the visit to the doctor. She presented no other symptoms. The physical examination displayed only bilateral papilledema. The magnetic resonance imaging (MRI) scans showed an intraventricular and thalamic lesion composed of solid and cystic material associated with peritumoral edema. The patient underwent ventriculoperitoneal shunt and subtotal resection of the lesion. The histological and immunohistochemical studies showed typical features of PMA. The patient started adjuvant therapy with chemotherapy and radiosurgery. She has been asymptomatic for 9 months and has shown no signs of progression of the disease on the follow-up scans.

Development of a pre-operative scoring system for predicting risk of post-operative paediatric cerebellar mutism syndrome

Background: Despite previous identification of pre-operative clinical and radiological predictors of post-operative paediatric cerebellar mutism syndrome (CMS), a unifying pre-operative risk stratification model for use during surgical consent is currently lacking. The aim of the project is to develop a simple imaging-based pre-operative risk scoring scheme to stratify patients in terms of post-operative CMS risk.Methods: Pre-operative radiological features were recorded for a retrospectively assembled cohort of 89 posterior fossa tumour patients from two major UK treatment centers (age 2–23yrs; gender 28 M, 61 F; diagnosis: 38 pilocytic astrocytoma, 32 medulloblastoma, 12 ependymoma, 1 high grade glioma, 1 pilomyxoid astrocytoma, 1 atypical teratoid rhabdoid tumour, 1 hemangioma, 1 neurilemmoma, 2 oligodendroglioma). Twenty-six (29%) developed post-operative CMS. Based upon results from univariate analysis and C4.5 decision tree, stepwise logistic regression was used to develop the optimal model and generate risk scores.Results: Univariate analysis identified five significant risk factors and C4.5 decision tree analysis identified six predictors. Variables included in the final model are MRI primary location, bilateral middle cerebellar peduncle involvement (invasion and/or compression), dentate nucleus invasion and age at imaging >12.4 years. This model has an accuracy of 88.8% (79/89). Using risk score cut-off of 203 and 238, respectively, allowed discrimination into low (38/89, predicted CMS probability <3%), intermediate (17/89, predicted CMS probability 3–52%) and high-risk (34/89, predicted CMS probability ≥52%).Conclusions: A risk stratification model for post-operative paediatric CMS could flag patients at increased or reduced risk pre-operatively which may influence strategies for surgical treatment of cerebellar tumours. Following future testing and prospective validation, this risk scoring scheme will be proposed for use during the surgical consenting process.

Pediatric Optic Pathway/Hypothalamic Glioma.

Optic pathway/hypothalamic gliomas (OP/HGs) are rare astrocytic tumors that appear more commonly among young children and often are unresectable. They comprise approximately 2% of all central nervous system tumors and account for 3–5% of pediatric intracranial tumors. Initial manifestations are often visual disturbances, endocrinopathies and hypothalamic dysfunction such as the diencephalic syndrome, and sometimes hydrocephalus due to cerebrospinal fluid (CSF) outflow obstruction. In many cases, the tumors are diagnosed late in the clinical course because they silently enlarge. These tumors consist mostly of histologically benign, World Health Organization (WHO) grade I tumors represented by pilocytic astrocytomas (PA), the rest being pilomyxoid astrocytomas (PXA) – WHO grade II tumors. In young pediatric patients, however, can be seen PXA that show aggressive clinical course such as CSF dissemination. Our small series of 14 non-Neurofibromatosis type 1 (NF-1) OP/HGs PA patients underwent extended resection without any adjuvant treatments. The median age at initial treatment was 11.5 ± 6.90 years (range, 1–25 years) and median follow up 85.5 ± 25.0 months. Surgical resection for OP/HGs results in acceptable middle-term survival, tumor control and functional outcome equivalent to chemotherapy. There is, however, no longer doubt that chemotherapy with or without biopsy and as-needed debulking surgery remains the golden standard in management of OP/H. Clinical conditions and treatment plans for OP/HGs vary depending on their structure of origin.

Significance of H3K27M mutation with specific histomorphological features and associated molecular alterations in pediatric high-grade glial tumors.

Pediatric high-grade gliomas (pHGGs) constitute almost 15% of all childhood brain tumors. Recurrent mutations such as H3K27M mutation in H3F3A and HIST1H3B genes encoding histone H3 and its variants were identified in approximately 30% of pediatric glioblastomas. This study aimed to ascertain the morphological and molecular characteristics of pHGGs with H3K27M mutation. In total, 61 cases of pHGGs (anaplastic astrocytoma, 12; glioblastomas, 49) from four university hospitals were studied. The histomorphological features were examined and immunohistochemistry was performed to evaluate the mutation status of H3K27M, ATRX, IDH1, BRAF V600E, and p53 genes. The study comprised 25 females and 36 males (age range, 1-18years) with a clinical follow-up of up to 108months. From the total, 31 patients were positive for H3K27M mutation located in the midline, mostly in the pons and thalamus. H3K27M mutation was commonly associated with ATRX loss (32.3%) and p53 (74.2%) immunoreactivity with a co-expression rate of 25.8%. While IDH1 mutation was not detected in pHGGs with H3K27M mutation, BRAFV600E mutation was rarely observed. Among the various histomorphological features, increased number of mitosis, increased Ki-67 proliferation index, and palisading and geographical necrosis along with small cell patterns were significantly associated with the H3K27M wild-type tumors. Focal infarct-like necrosis and pilomyxoid morphology was significantly associated with these tumors. H3K27M mutation occurs exclusively in pHGGs arising from the midline and presents with varied histomorphological features ranging from low-grade pilomyxoid astrocytoma to highly pleomorphic glioblastoma along with ATRX loss and p53 mutations.

Characterization of gliomas: from morphology to molecules.

This article reviews the histologic and molecular characterization of gliomas, including the new "integrated diagnoses" of the World Health Organization Classification, 2016 edition. The entities reviewed within include diffuse gliomas (astrocytoma, oligodendroglioma, glioblastoma), as well as circumscribed and low-grade gliomas (angiocentric glioma, pilocytic astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma, pilomyxoid astrocytoma, ependymoma, myxopapillary ependymoma, and subependymoma). Diagnostic, prognostic, and predictive biomarkers are discussed for each entity. We review how molecular testing for IDH1 and ATRX and detection of chromosome 1p/19q codeletion can be used to categorize glioblastomas as IDH-wildtype or IDH-mutant, and lower grade diffuse gliomas into three molecular groups that correlate better with patient outcomes than histologic subtyping. Pediatric diffuse gliomas are highlighted, including diffuse midline glioma, H3 K27M-mutant, and inherited germline mutations that predispose to pediatric gliomas. The utility of genomic profiling of certain gliomas is discussed, including identifying candidates for experimental therapies. This review is meant to be a concise summary of glioma characterization for the practicing pathologist.

Endothelium-Independent Primitive Myxoid Vascularization Creates Invertebrate-Like Channels to Maintain Blood Supply in Optic Gliomas

Optic gliomas are brain tumors characterized by slow growth, progressive loss of vision, and limited therapeutic options. Optic gliomas contain various amounts of myxoid matrix, which can represent most of the tumor mass. We sought to investigate biological function and protein structure of the myxoid matrix in optic gliomas to identify novel therapeutic targets. We reviewed histological features and clinical imaging properties, analyzed vasculature by immunohistochemistry and electron microscopy, and performed liquid chromatography-mass spectrometry on optic gliomas, which varied in the amount of myxoid matrix. We found that although subtypes of optic gliomas are indistinguishable on imaging, the microvascular network of pilomyxoid astrocytoma, a subtype of optic glioma with abundant myxoid matrix, is characterized by the presence of endothelium-free channels in the myxoid matrix. These tumors show normal perfusion by clinical imaging and lack histological evidence of hemorrhage organization or thrombosis. The myxoid matrix is composed predominantly of the proteoglycan versican and its linking protein, a vertebrate hyaluronan and proteoglycan link protein 1. We propose that pediatric optic gliomas can maintain blood supply without endothelial cells by using invertebrate-like channels, which we termed primitive myxoid vascularization. Enzymatic targeting of the proteoglycan versican/hyaluronan and proteoglycan link protein 1 rich myxoid matrix, which is in direct contact with circulating blood, can provide novel therapeutic avenues for optic gliomas of childhood.

Cerebellar Pilomyxoid Astrocytoma

Pilomyxoid astrocytomas (PMA) are new class of Pilocytic Astrocytoma (PA.), which typically have their origin in hypothalamus and Chiasmatic region. There are very few case reports of PMAs arising from cerebellum. Their imaging features are similar to PA but they behave more aggressively than PA. To increase awareness of PMA within the neurosurgical community, the authors reviewed a case of 11-year-old male child who presented with truncal and cerebellar ataxia and vomiting and right cerebellar tumor diagnosed as PA radiologically but PMA on histopathology examination. These findings indicate that PMA may be a unique entity that is distinct from PA, or it may be an unusual variant. Key words : -Pilocytic astrocytoma • pilomyxoid astrocytoma • diagnosis • cerebellar

Pilomyxoid astrocytoma showing malignant transformation in adult male

Pilomyxoid astrocytomas are type of tumors rarely seen in the central nervous system as a variant of pilocytic astrocytoma. They are often localized in hypothalamic-chiasmatic area and seen in early childhood. They exhibit different histological characteristics and more aggressive behaviors compared to pilocytic astrocytomas. Although cases with malignant transformation were reported in pilocytic astrocytomas, no pilomyxoid astrocytoma patients was reported with malignant transformation. We have presented a pilomyxoid astrocytoma patient, since it is rarely seen in adulthood and shows malignant transformation histopathologically.

PP39. 5-AMINOLEVULINIC ACID AIDED RESECTION OF PAEDIATRIC BRAIN TUMOURS: THE UK’S FIRST CASE SERIES

BACKGROUND: 5-aminolevulinic acid (5-ALA, Gliolan) use is well documented and established in the resection of adult high-grade gliomas. There is growing interest in its safety and usefulness in the paediatric populations. The main challenge in the latter is the diverse range of histopathological tumour types that can occur. We present the UK’s first case series of 5-ALA use in the paediatric population. METHODS: Parental consent was obtained for the 6 patients (age 1.6–15 years, median 6.5 years) to be given a dose of 20mg/kg of 5-ALA 3 hours pre-operatively. Intra-operatively the tumours were viewed under violet-blue light and the presence of fluorescence was recorded. Fluorescence status was compared with histopathological classification and grade. RESULTS: The case series included: a pilocytic astrocytoma (grade I), a pilomyxoid astrocytoma (II), a glioneuronal tumour (II), a ganglioglioma (II-III), an anaplastic ependymoma (III) and an anaplastic medulloblastoma (IV). Only the grade III ependymoma showed strong fluorescence with 5-ALA. The pilocytic astrocytoma (I) and pilomxyoid astrocytoma (II) showed moderate fluorescence and the ganglioglioma (II-III) showed weak fluorescence. No fluorescence was observed in the glioneuronal tumour (II) or the medulloblastoma (IV). No significant adverse drug reactions were recorded. CONCLUSION: This case series adds to the growing body of evidence demonstrating the safety of 5-ALA in the paediatric population. Our case series highlights the need for larger trials into the usefulness of 5-ALA in the different paediatric brain tumour types. KEYWORDS: 5-aminolevulinic, 5-ALA, Gliolan, Fluoresence, Paediatric, Child, Brain tumour