The expanding family of glioneuronal tumors

Rosette-forming glioneuronal tumor of the fourth ventricle; A case report and review of the literature

Despite mostly indolent course and favorable postoperative outcome long-term follow-up studies are needed to identify the most appropriate therapeutic strategies to minimize surgical morbidity and neurologic injury in patients with RGNT.

Rosette-Forming Glioneuronal Tumor of the Fourth Ventricle: A Case of Relapse Treated with Proton Beam Therapy

Rosette-forming glioneuronal tumors (RGNTs) are rare, grade I, central nervous system (CNS) tumors typically localized to the fourth ventricle. We describe a 9-year-old girl with dizziness and occipital headache. A magnetic resonance imaging (MRI) revealed a large hypodense posterior fossa mass lesion in relation to the vermis, with cystic component. Surgical resection of the tumor was performed. A RGNT diagnosis was made at the histopathological examination. During follow-up, the patient experienced a first relapse, which was again surgically removed. Eight months after, MRI documented a second recurrence at the local level. She was a candidate for the proton beam therapy (PBT) program. Three years after the end of PBT, the patient had no evidence of disease recurrence. This report underlines that, although RGNTs are commonly associated with an indolent course, they may have the potential for aggressive behavior, suggesting the need for treatment in addition to surgery. Controversy exists in the literature regarding effective management of RGNTs. Chemotherapy and radiation are used as adjuvant therapy, but their efficacy management has not been adequately described in the literature. This is the first case report published in which PBT was proposed for adjuvant therapy in place of chemotherapy in RGNT relapse.

Papillary glioneuronal tumors: Distinctive cytological characteristics and cyto-histologic correlation

Intraoperative cytological examination and cyto-histologic correlation of papillary glioneuronal tumors have rarely been described in detail in the literature. A 23-year-old female presented at our institution with seizure-like activity, and a 3.0 cm left temporal lobe hypoattenuating lesion. She was accurately diagnosed with papillary glioneuronal tumor on Intraoperative cytology. The patient subsequently proceeded to stealth-guided awake left temporal craniotomy, confirming the diagnosis. In this article, we present a detailed report of papillary glioneuronal tumor (extremely rare central nervous system neoplasm) describing the cytologic and histologic morphologic features, its differential diagnosis with review of the literature.

Glioneuronal tumors: clinicopathological findings and treatment options

Glioneuronal tumors are very rare CNS neoplasms that demonstrate neuronal differentiation, composed of mixed glial and neuronal cells. The majority of these lesions are low grade and their correct classification is crucial in order to avoid misidentification as ‘ordinary’ gliomas and prevent inappropriate aggressive treatment; nevertheless, precise diagnosis is a challenge due to phenotypic overlap across different histologic subtype. Surgery is the standard of therapeutic approach; literature concerning the benefit of adjuvant treatments is inconclusive and a globally accepted treatment of recurrence does not exist. Targetable mutations in the genes BRAF and FGFR1/2 are recurrently found in these tumors and could take a promising role in future treatment management.

Supratentorial intraventricular rosette-forming glioneuronal tumors - Case report and review of treatment paradigms

Background

Rosette-forming glioneuronal tumors (RGNT) are slow-growing WHO Grade I tumors that are characterized by mixed histology and rosette formation. Although typically located in the posterior fossa, these tumors can rarely originate elsewhere. Here, we describe the fourth case in literature where an RGNT was localized to the lateral ventricles and detail the treatment approach.

Case Description

A 41-year-old male presented with a 10 day history of gradually worsening headaches and mild gait difficulty. Computed tomography and magnetic resonance imaging (MRI) identified a heterogeneously enhancing 6.0 cm left lateral ventricular cystic mass with hydrocephalus. An interhemispheric transcallosal approach was performed for tumor debulking. The mass was emanating from the roof of the left lateral ventricle. Sub-total resection (STR) was achieved. Pathology showed a glioneuronal neoplasm with vague neurocytic rosettes and loose perivascular pseudorosettes. Tumor vessels were thickly hyalinized and contained eosinophilic granular bodies and Rosenthal fibers. Tumor stained positive for GFAP, S-100, OLIG2, and SOX10, and patchy positive for epithelial membrane antigen (EMA), D2-40, CD99, and p16. Neurocytic rosettes and perivascular structures stained positive for synaptophysin. The patient was discharged home uneventfully and remained intact at his 6-month follow-up visit. Long-term care included MRI surveillance with repeat surgery being considered in case of progression.

Conclusion

In this report, we describe the fourth case of an RGNT being isolated to the lateral ventricles and the first where it stained positive for EMA and D2-40. Our patient's uneventful recovery after STR indicates that surgery alone continues to be a viable initial treatment option.

A glioneuronal tumor with CLIP2-MET fusion

We report a case of glioneuronal tumor (GNT) with a discovery of novel gene fusion of CLIP2-MET resulting from aberrant chromosome 7 abnormalities. We executed an elaborate genomic study on this case including whole-exome sequencing and RNA sequencing. Genomic analysis of the tumor revealed aberrations in chromosomes 1 and 7 and a CLIP2-MET fusion. Further analysis of the upregulated genes revealed substantial connections with MAPK pathway activation. We concluded that the chromosome 7 abnormalities prompted CLIP2-MET gene fusion which successively leads to MAPK pathway activation. We deliberated that MAPK pathway activation is one of the driver pathways responsible for the oncogenesis of GNT.

Rosette-forming Glioneuronal Tumor: A Rare Posterior Fossa Tumor in an Adolescent

Rosette-forming glioneuronal tumor (RGNT) is a rare variety of slow growing mixed glioneuronal tumor involving primarily fourth ventricular region and occurring predominantly in young adults. We present a case of a 16-year-old boy who presented with dizziness and occipital headache. On radiological evaluation, a fairly large hypodense posterior fossa mass lesion in relation to the left side of the vermis, with a large cystic component was found. Surgical resection of the tumor was performed. Histopathological examination showed a biphasic tumor composed of bland neurocytic cells, arranged in the form of neurocytic rosettes along with glial areas resembling low-grade glioma. The neurocytic rich region shows strong synaptophysin positivity in the neuropil-rich core of the rosettes. Methylation-inhibited binding proliferative index was low (<1%). Based on these features, a diagnosis of RGNT was made. RGNT of the fourth ventricle should be considered in differential diagnosis of posterior fossa lesions, especially in relation to fourth ventricle and vermis in young adults.

Congenital glioneuronal tumor with neuropil-like islands

The glioneuronal tumor with neuropil-islands is considered a rare variant of an astrocytoma. Congenital cases of glioneuronal tumor with neuropil-islands, which typically arise in adults, have not been reported to our knowledge. We report an autopsy case of an in-utero demise of a 38-week-gestation female fetus in a 29-year-old female. At autopsy, a previously detected supratentorial tectal mass (by fetal MRI) was identified. Histology showed a biphasic neoplasm marked by island of gray matter-like parenchyma rimmed by mature-appearing neuronal cells intermixed with variably cellular areas resembling a low grade astrocytoma. Focally, the tumor was noted to involve the overlying meninges. The neuronal cell components were highlighted with synaptophysin and neuN antibodies and the glioma areas stained with glial fibrillary acidic protein antibody. The tumor did not stain with isocitrate dehydrogenase 1 (R132H) antibody and had a low Ki-67 labeling index (1.4%), in keeping with a low grade tumor. The pathologic findings were interpreted as representing a low grade glioneuronal tumor with neuropil-like islands. There have been few reports of this tumor arising in children, with most of those developing in the spinal cord. To our knowledge, this is the first reported congenital case of this tumor described in the literature.

A common gene expression signature in Huntington's disease patient brain regions

Background

Gene expression data provide invaluable insights into disease mechanisms. In Huntington’s disease (HD), a neurodegenerative disease caused by a tri-nucleotide repeat expansion in the huntingtin gene, extensive transcriptional dysregulation has been reported. Conventional dysregulation analysis has shown that e.g. in the caudate nucleus of the post mortem HD brain the gene expression level of about a third of all genes was altered. Owing to this large number of dysregulated genes, the underlying relevance of expression changes is often lost in huge gene lists that are difficult to comprehend.

Methods

To alleviate this problem, we employed weighted correlation network analysis to archival gene expression datasets of HD post mortem brain regions.

Results

We were able to uncover previously unidentified transcription dysregulation in the HD cerebellum that contained a gene expression signature in common with the caudate nucleus and the BA4 region of the frontal cortex. Furthermore, we found that yet unassociated pathways, e.g. global mRNA processing, were dysregulated in HD. We provide evidence to show that, contrary to previous findings, mutant huntingtin is sufficient to induce a subset of stress response genes in the cerebellum and frontal cortex BA4 region. The comparison of HD with other neurodegenerative disorders showed that the immune system, in particular the complement system, is generally activated. We also demonstrate that HD mouse models mimic some aspects of the disease very well, while others, e.g. the activation of the immune system are inadequately reflected.

Conclusion

Our analysis provides novel insights into the molecular pathogenesis in HD and identifies genes and pathways as potential therapeutic targets.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-014-0060-2) contains supplementary material, which is available to authorized users.

An individual patient data meta-analysis on characteristics and outcome of patients with papillary glioneuronal tumor, rosette glioneuronal tumor with neuropil-like islands and rosette forming glioneuronal tumor of the fourth ventricle

Background and Purpose

In 2007, the WHO classification of brain tumors was extended by three new entities of glioneuronal tumors: papillary glioneuronal tumor (PGNT), rosette-forming glioneuronal tumor of the fourth ventricle (RGNT) and glioneuronal tumor with neuropil-like islands (GNTNI). Focusing on clinical characteristics and outcome, the authors performed a comprehensive individual patient data (IPD) meta-analysis of the cases reported in literature until December 2012.

Methods

PubMed, Embase and Web of Science were searched for peer-reviewed articles reporting on PGNT, RGNT, and GNTNI using predefined keywords.

Results

95 publications reported on 182 patients (PGNT, 71; GNTNI, 26; RGNT, 85). Median age at diagnosis was 23 years (range 4–75) for PGNT, 27 years (range 6–79) for RGNT, and 40 years (range 2–65) for GNTNI. Ninety-seven percent of PGNT and 69% of GNTNI were located in the supratentorial region, 23% of GNTNI were in the spinal cord, and 80% of RGNT were localized in the posterior fossa. Complete resection was reported in 52 PGNT (73%), 36 RGNT (42%), and 7 GNTNI (27%) patients. Eight PGNT, 3 RGNT, and 12 GNTNI patients were treated with chemo- and/or radiotherapy as the primary postoperative treatment. Follow-up data were available for 132 cases. After a median follow-up time of 1.5 years (range 0.2–25) across all patients, 1.5-year progression-free survival rates were 52±12% for GNTNI, 86±5% for PGNT, and 100% for RGNT. The 1.5-year overall-survival were 95±5%, 98±2%, and 100%, respectively.

Conclusions

The clinical understanding of the three new entities of glioneuronal tumors, PGNT, RGNT and GNTNI, is currently emerging. The present meta-analysis will hopefully contribute to a delineation of their diagnostic, therapeutic, and prognostic profiles. However, the available data do not provide a solid basis to define the optimum treatment approach. Hence, a central register should be established.

Clinical, radiological, and pathological features of 16 papillary glioneuronal tumors

BACKGROUND

Papillary glioneuronal tumors (PGNTs) are a novel distinct intracranial neoplastic entity. In this study, the authors aimed to analyze the clinical, radiological, and pathological features of PGNT.

METHODS

Clinical charts and radiographs of 16 cases of PGNT surgically treated between 2006 and 2013 were retrospectively reviewed. Follow-up evaluations and a literature review were performed.

RESULTS

The study included nine males and seven females with a mean age of 23.8 years. The most common preoperative symptom was headache (68.8 %, 11 of 16 patients). Radiological results showed that the frontal lobe (25.0 %) was the most common portion of the brain involved, and 13 lesions (81.3 %) presented with cystic appearance with or without solid elements. All patients were misdiagnosed as non-PGNT tumors. Complete resection was achieved in 12 patients (75.0 %). Ki67 staining was positive in <1 % of cells present in eight lesions and varied in the other eight lesions, with a range of 1 % to 13 %. The mean follow-up duration was 56.2 months, and no recurrence was observed. Seventy-seven PGNTs (40 males, 51.9 %) have been reported, and 49 patients stained positive for Ki67/MIB-1. Of these cases, 28 (57.1 %) had positive staining rates of ≥1 %. In 51 patients for whom outcome information was available, six (11.8 %) exhibited recurrence, and the recurrence rates for complete resection and incomplete resection were 5.1 % and 33.3 %, respectively.

CONCLUSIONS

PGNTs displayed a wide spectrum of clinical and radiological phenotypes, and they were more frequently observed in the frontal lobe and in young patients without sex predilection. Fair outcomes could be achieved by complete resection. Although PGNT displayed indolent pathobiology, atypical appearances were observed. More patients and longer follow-up periods are needed to further elucidate the biological features of PGNTs.

Disseminated glioneuronal tumor with neuropil-like islands of the spinal cord: a distinctive entity

BACKGROUND

Glioneuronal tumor with neuropil-like islands (GTNI) was recently added as a novel lesion in the most recent update of the World Health Organization classification of tumors of the central nervous system in 2007. Since this tumor's initial description, approximately 28 cases of GTNI have been published. In this report, we describe the ninth case of a spinal GTNI in the world literature.

METHODS

We report a case arising in a 2-year-old female patient who presented with headaches associated with intermittent vomiting due to a tetraventricular hydrocephalus.

RESULTS

After ventriculoperitoneal shunt placement, the patient presented with lower extremity motor weakness and sensory disturbance. A dorsolumbar spine magnetic resonance imaging scan revealed an intramedullary spinal neoplasm involving T12 through L2 in association with the thick linear enhancement of the spinal cord surfaces. A brain magnetic resonance imaging scan demonstrated focal leptomeningeal enhancement in the Sylvian fissures, the basal cistern, tentorium, and multiple small cystic-like lesions extending on the cerebellar surface, brainstem, and temporal lobes. The patient underwent a T11-L2 laminectomy for a gross total tumor resection. Histology revealed a World Health Organization grade II GTNI.

CONCLUSIONS

GTNI is a rare type of glioneuronal tumor that has recently been described in the literature. The outcome of this case seems to have an unfavorable clinical course despite their low-grade morphology. However, the combination of gross total resection and adjuvant chemo-radiotherapy can enhance chances for longer survival among children with spinal GTNI associated with meningeal dissemination, and a clinical follow-up of a large series will be necessary to evaluate the long-term prognosis.

Rosette-forming glioneuronal tumor in the pineal gland and the third ventricle: a case with radiological and clinical implications

A 39-year-old man presented with more than 20 years history of episodic headache and one year history of dizziness, impaired vision and memory disorders. Computed tomography and Magnetic resonance imaging revealed a cystic mass involving the pineal gland, tectum and the third ventricle and obstruction of the aqueduct. Interestingly, the fourth ventricle was not involved in this case. The pathological diagnosis was rosette forming glioneuronal tumor (RGNT). These lesions are considered low-grade tumors (WHO grade I). We describe here the fifth reported patient with a pineal gland RGNT and the eighth reported patient with a RGNT outside the fourth ventricle.

Glioneuronal tumor with neuropil-like islands: clinical, morphologic, immunohistochemical, and molecular features of three pediatric cases

Glioneuronal tumors with neuropil-like islands are rare. The 1st reported cases were localized in the cerebral hemispheres of adults, showed homogeneous histopathologic features (infiltrating astrocytic growth and neuropil-like islands rimmed by neuronal cells), and had an unfavorable behavior. We report 3 pediatric cases (1 boy and 2 girls, ages 4, 6, and 8 years, respectively). The boy had a cerebral tumor, and the girls had a spinal tumor. The younger girl also had multiple posterior fossa lesions. The boy and older girl underwent a gross total resection. The younger girl underwent a subtotal resection of the spinal tumor; posterior fossa lesions were not surgically treated. The boy and younger girl are in complete remission at 33 and 24 months, respectively, after surgery and subsequent high-dose chemoradiotherapy. The older girl had a recurrence that was partially resected. Afterward, she started high-dose chemoradiotherapy and had an optimal radiologic response at 4 months follow up. Microscopically, the common denominator was the presence of synaptophysin-positive neuropil-like islands. One tumor showed ependymal features (pseudorosettes and punctate epithelial membrane antigen immunopositivity). Two tumors had 1p deletion. 19q deletion, MGMT gene promoter methylation, EGFR amplifications or polysomy, and EGFR, IDH1, IDH2, and TP53 genes mutation analyses yielded negative results. In conclusion, glioneuronal tumor with neuropil-like islands can affect children, arise in the spinal cord, and show ependymal features in its glial component. A high-dose chemoradiotherapy program is effective.

Spinal cord glioneuronal tumor with neuropil-like islands with 1p/19q deletion in an adult with low-grade cerebral oligodendroglioma

Glioneuronal tumor with neuropil-like islands (GTNI) is considered a rare variant of astrocytoma, characterized by discrete aggregates of cells expressing neuronal markers that punctuate a GFAP-positive glial background. Of the 24 published GTNI cases, only two occurred in adult spinal cords; none occurred concurrent with another CNS tumor; and none of those tested exhibited the 1p/19q deletion typical of oligodendroglioma. A 48-year-old man without significant past medical history was diagnosed with a WHO grade II oligodendroglioma by stereotactic biopsy of a lesion discovered after the patient suffered a generalized tonic-clonic seizure. By FISH analysis, this tumor exhibited the 1p/19q deletion present in up to 80% of oligodendrogliomas. The patient received 14 monthly cycles of temozolomide, and his cerebral tumor had a minor response. When the patient subsequently reported progressive paresthesias of his lower extremities, an MRI revealed an enhancing, cystic tumor of the thoracic spinal cord that was diagnosed as GTNI by histological analysis. By FISH analysis, this lesion exhibited the same 1p/19q deletion present in the concurrent cerebral oligodendroglioma. This case of a spinal cord GTNI with 1p/19q deletions constitutes the third report of a spinal cord GTNI in an adult patient; the first report of a GTNI in an individual with a separate CNS neoplasm; and the first report of a GTNI with 1p/19q deletions. This case establishes a potential genetic kinship between GTNI and oligodendroglioma that warrants further investigation.

Conjunctival ganglioglioma as a feature of basal cell nevus syndrome

Basal cell nevus syndrome (MIM #109400), also known as Gorlin syndrome, is a rare, autosomal-dominant disorder with complete penetrance and variable expressivity. The syndrome is characterized by odontogenic keratocysts of the mandible, postnatal tumors, and multiple basal cell carcinomas. Mutations in the PTCH1 gene (a tumor suppressor gene) or, more rarely, the NBCCS or the TRPC1 genes are responsible for the development of many postnatal tumors. We present a case of Gorlin syndrome presenting as a conjunctival ganglioglioma in a 13-year-old girl. While cases of cerebral ganglioglioma have been described in association with Gorlin syndrome, conjunctival ganglioglioma has not, to the best of our knowledge, been reported.

Surgical management of glioneuronal tumors with drug-resistant epilepsy

In this review, we discuss the options for the surgical management of glioneuronal tumors (GNTs) associated with drug-resistant epilepsy, with an emphasis on the surgical issues involved in addressing the epileptogenic nature of these lesions. We briefly summarize the pathological hallmarks of these lesions in order to outline how these tumors contribute to seizure activity. Understanding the pathophysiology of these lesions is important in discussing the advantages and disadvantages of different surgical strategies. There have been a number of studies that have investigated the utility of different surgical approaches in improving seizure outcome, and we highlight some of these studies in order to shed light on surgical issues related to these tumors.

Glioneuronal tumor with neuropil-like islands of the spinal cord with diffuse leptomeningeal neuraxis dissemination

A 54-year-old Caucasian female presented with a 1 year history of intermittent numbness of the left leg progressing to bilateral, lower extremity sensory loss that advanced to include impaired vibration and proprioception. The subsequent thoracic spine magnetic resonance imaging (MRI) scan revealed a heterogeneous, avidly enhancing, centrally situated spinal cord mass involving T7 through T10 in association with thick linear enhancement of the anterior and posterior cord surfaces extending both superiorly and inferiorly. Both the cervical and lumbar spine MRI demonstrated diffuse leptomeningeal disease as well. A brain MRI revealed focal leptomeningeal enhancement in the left and right sylvian fissures, the suprasellar cistern, and the posterior fossa; a pattern consistent with metastatic disease. The patient underwent a T6-T10 laminectomy for tumor biopsy and debulking. Histology revealed a WHO grade III glioneuronal tumor with rosetted neuropil-like islands. Synaptophysin and neurofilament (NF) positive staining was noted within the neural appearing component, whereas, glial fibrillary acidic protein (GFAP) immunopositivity was evident in the fibrillary astrocytoma component of the tumor. The Ki-67 labeling index was 7%. This tumor pattern, now included in the 2007 World Health Organization (WHO) classification of central nervous system tumours as a pattern variation of anaplastic astrocytoma (Kleihues et al. In: Louis et al. (eds) WHO classification of tumours of the central nervous system, 2007), was first described in a four-case series by Teo et al. in 1999. The majority of subsequently reported cases described them as primary tumors of the cerebrum. Herein, we report a unique example of a spinal glioneuronal tumor with neuropil-like islands with associated leptomeningeal dissemination involving the entire craniospinal axis.

Rosette-forming glioneuronal tumor: a pineal region case with IDH1 and IDH2 mutation analyses and literature review of 43 cases

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a mixed glio-neuronal neoplasm recently codified by the World Health Organization WHO Classification of Central Nervous System (CNS) Tumors (2007). To date, 43 cases have been described in the literature; most occurring in the fourth ventricle region. We report the fourth case involving the pineal region in a 16-year-old female with signs of increased intracranial pressure (ICP). A stereotactic biopsy of the mass was followed by a debulking procedure. Both specimens revealed classic RGNT histology. The patient had stable scans 7 months post-resection. The clinical, radiological and histopathologic features of the previously described 43 cases are reviewed along with our illustrative case. Mean age of patients was 30 ± 12.8 years with 1.9:1 female to male ratio. The most common presenting signs related to increased ICP and posterior fossa involvement, including: headache (62.8%), ataxia (39.5%) and vomiting and vertigo (both 16.3%). This tumor usually presents with cystic changes (54.5%) with focal enhancement (60.9%) and hydrocephalus (43.2%). Microcalcifications and satellite lesions were common radiographic observations. All reported cases had the classic biphasic pattern. Rosenthal fibers and eosinophilic granular bodies are each present in approximately two thirds of cases. Ki-67 labeling index is consistently low (mean (%): 1.8 ± 0.75 SD). The isocitrate dehydrogenase 1 or 2 mutation found in low grade diffuse gliomas is not identified in this RGNT case. Reported outcome is nearly uniformly excellent after complete or subtotal resection. A solitary report of recurrence after 10 years and the limited experience with this entity suggest that long term follow up is advisable.