Rosette-forming Glioneuronal Tumor Research Articles

The ‘rosette‐forming glioneuronal tumor’ of the fourth ventricle

Tumors containing both neuronal and glial components are a rare heterogeneous group with unique features that require further subclassification. The rosette-forming glioneuronal tumor of the fourth ventricle is one of a number of recently described glioneuronal tumors, which has been accorded official WHO nosologic status only in 2007. We describe the clinical and pathologic features of two patients with rare rosette-forming glioneuronal tumors of the fourth ventricle, one of which was associated with dysgenetic tricho-rhinopharyngeal type I syndrome.

ROSETTE-FORMING GLIONEURONAL TUMOR

Rosette-forming glioneuronal tumor is a rare, rather recently described tumor featuring a highly distinctive, biphasic histological pattern, including a cytologically uniform neuronal component of Homer-Wright type pseudorosettes and an accompanying astrocytic element resembling pilocytic astrocytoma. Its occurrence in the posterior fossa and association with the fourth ventricle is stereotypical and a feature of all reported cases. In this article, we describe the first rosette-forming glioneuronal tumor arising outside this site, a histologically classic example involving the anterior visual pathway and associated with neurofibromatosis type 1. Genetic (fluorescent in situ hybridization) studies demonstrated no large deletion in either normal or neoplastic tissue, indicating that the genetic abnormality underlying neurofibromatosis type 1 in this patient is likely a very small deletion or point mutation. The relation of the tumor to the underlying neurofibromatosis type 1 cannot be assessed.

A rosette-forming glioneuronal tumor of the spinal cord: the first case of a rosette-forming glioneuronal tumor originating from the spinal cord

Rosette-forming glioneuronal tumors of the fourth ventricle are rare brain tumors, and only 19 such lesions have been previously reported. This report presents the first case of a rosette-forming glioneuronal tumors arising from the spinal cord. A 44-year-old woman presented with a 15-year history of dissociated sensory disturbance of the lower extremities that gradually spread through her upper extremities. She also experienced continuing motor disturbance. Magnetic resonance imaging demonstrated a mass in the cervicothoracic spinal cord that suggested an intramedullary spinal tumor. A total gross resection of the tumor was performed. As is typical of rosette-forming glioneuronal tumors of the fourth ventricle, this spinal cord example manifested neurocytic and astrocytic components. Neurocytic rosettes were detected in the neurocytic component, and the center of rosettes showed positive immunostaining for synaptophysin. The astrocytic component showed characteristic features of a pilocytic astrocytoma, as is often the case in the fourth ventricle examples.

The Expanding Family of Glioneuronal Tumors

Three new entities have been recently added to the group of glioneuronal tumors in the most recent update of the World Health Organization classification of tumors of the central nervous system: papillary glioneuronal tumor, rosetted glioneuronal tumor with neuropil-like islands, and rosette-forming glioneuronal tumor of the fourth ventricle. These tumors are relatively infrequent lesions, and because of that, they can be challenging to diagnose for the practicing pathologist. In this article, we summarize the clinical and pathologic findings of these new lesions.

Clinicoradiological features of rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle: report of four cases and literature review

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a recently characterized rare tumor entity. Despite benign histological features and a reported favorable postoperative course, there is still limited clinical experience with this tumor. Retrospective analysis of the clinical, radiological, and surgical data in four patients with RGNT was performed. Mean age at diagnosis was 35 years, and the median follow-up was 19 (range 2-30) months. The results were compared with the literature. Patient 1 presented on an emergency basis due to intratumoral hemorrhage and tumor enlargement followed by life-threatening obstructive hydrocephalus. Patient 2 suffered from headaches and left-sided hemiparesthesia 6 months prior to surgery. Patient 3 developed headaches with nausea and vomiting, followed by left-sided tinnitus 1 year prior to surgery. In patient 4, RGNT was detected incidentally. No differentiating radiological characteristics were seen except for the presence of minute satellite lesions in two patients. Histopathological findings were distinct and showed their typical biphasic neurocytic and glial architecture. No progression/recurrence was seen in the postoperative course. The spectrum of presenting symptoms of RGNT is wide, nonspecific, and typically depends on tumor size and extent. This tumor entity should be considered in the differential diagnosis of posterior fossa masses in order to avoid undue surgical aggressiveness.

O.025 Noninvasive intracranial compliance from MRI-based measurements of transcranial blood and CSF Ffows: Indirect vs. direct approach

Pure aqueductal tumor (PAT) typically originates from pure aqueductal region and is extremely rare. It is radiographically similar to tectal glioma. We examined two patients with PATs who were diagnosed with pilocytic astrocytoma and rosette-forming glioneuronal tumor. Both cases showed a progressive clinical course. It is important to distinguish between PAT and tectal glioma by radiographic imaging because the treatment strategy is different. While observation is common for tectal gliomas, a biopsy is recommended at the same time of endoscopic third ventriculostomy for PAT with hydrocephalus. Low-grade PATs show an aggressive clinical course in some cases. Our two cases also showed aggressive course in spite of no genetic aggressive mutations. Sagittal view by constructive interference in steady state (CISS) imaging was helpful to make an accurate diagnosis of PAT. Close observation is needed if PAT is diagnosed as low-grade tumor.

O.026 Prognostic value of CSF pulse waveform analysis in NPH patients

Pure aqueductal tumor (PAT) typically originates from pure aqueductal region and is extremely rare. It is radiographically similar to tectal glioma. We examined two patients with PATs who were diagnosed with pilocytic astrocytoma and rosette-forming glioneuronal tumor. Both cases showed a progressive clinical course. It is important to distinguish between PAT and tectal glioma by radiographic imaging because the treatment strategy is different. While observation is common for tectal gliomas, a biopsy is recommended at the same time of endoscopic third ventriculostomy for PAT with hydrocephalus. Low-grade PATs show an aggressive clinical course in some cases. Our two cases also showed aggressive course in spite of no genetic aggressive mutations. Sagittal view by constructive interference in steady state (CISS) imaging was helpful to make an accurate diagnosis of PAT. Close observation is needed if PAT is diagnosed as low-grade tumor.

CLINICAL IMPLICATIONS OF THE INFRATENTORIAL ROSETTE-FORMING GLIONEURONAL TUMOR

This article describes our experience with two patients who presented with unusual tumors in the cerebellar vermis and cerebral aqueduct. Although sparing the fourth ventricle proper, both tumors had histological features consistent with the rare diagnosis of a rosette-forming glioneuronal tumor of the fourth ventricle, of which only 19 cases have been reported previously. A review of the clinical features and courses of all 21 cases is presented and management recommendations are given. Patient 1 was a 42-year-old man who presented with a headache of 1 day's duration and no neurological signs, in whom magnetic resonance imaging disclosed a nonenhancing mass lesion occupying the proximal cerebral aqueduct. Patient 2 was a 38-year-old woman with a long history of intermittent giddiness, no neurological signs, and a magnetic resonance imaging scan that demonstrated a nonenhancing and subtle abnormality in the cerebellar vermis. Biopsy was performed on both lesions, the first endoscopically and the second via craniotomy. The only postoperative complication was short-lived double vision and poor upgaze in Patient 1. These cases demonstrate that the rosette-forming glioneuronal tumor may be more accurately categorized as an infratentorial tumor rather than a tumor of the fourth ventricle. Because the literature indicates that this is a tumor with little potential for malignant behavior and considerable morbidity can accompany attempts at resection, a conservative management approach would seem well advised. If this tumor is to be managed conservatively, because of the paucity of extended follow-up data, long-term radiological and clinical surveillance is strongly recommended.

ROSETTE-FORMING GLIONEURONAL TUMOR

Rosette-forming glioneuronal tumor is a newly described mixed glial and neuronal tumor. We describe two cases and review the literature to better characterize this entity. Patients were surgically treated, and tumors were diagnosed by light microscopy and immunohistochemistry using the avidin-biotin complex method. PubMed was searched for previously reported cases. Patient 1 was a 38-year-old woman who presented with headaches and no neurological abnormality. Magnetic resonance imaging showed a solid mass in the fourth ventricle. Subtotal excision of the mass caused transient gait ataxia. Patient 2 was a 51-year-old woman with dizziness who fell and sustained head trauma. Magnetic resonance imaging revealed a right paramedian cerebellar cystic and nodular mass and a separate nodule in the vermis, which were excised gross totally with no morbidity. Microscopic examination showed neuroepithelial tumors composed of neurocytic cells focally forming well-defined rosettes that were immunopositive for neuronal markers and of elongated, glial fibrillary acidic protein-immunoreactive astrocytes. No histological anaplasia was present. Both patients were well 18 and 8 months after surgery, respectively. Eighteen rosette-forming glioneuronal tumors were identified with the literature search. These are tumors of young adulthood (range, 12-59 yr) usually in or close to the fourth ventricle. Histologically, they are low-grade, although multiple foci or local extension may prevent total excision and account for some recurrences. On imaging, they are cystic, solid, or both, with minimal perilesional edema or mass effect. They are composed of neurocytic and glial elements, probably arising from a common progenitor in the subependymal plate, and need to be differentiated from a variety of glioneuronal tumors.

Recently Established Entities of Central Nervous System Tumors

Several new entities of central nervous system tumors have been established in the past decade. By reviewing our cases and previous reports, we describe 4 neuronal and mixed neuronal-glial tumors (papillary glioneuronal tumor, extraventricular neurocytoma, rosette-forming glioneuronal tumor of the fourth ventricle, and glioneuronal tumor with neuropil-like islands), angiocentric glioma and papillary tumor of the pineal region, with an attempt to explain the pathological basis of the imaging features.

Rosette‐forming glioneuronal tumors: a report of three cases.

Rosette‐forming glioneuronal tumor of the fourth ventricle (RGNT‐4th) is a newly recognized entity by the 2007 WHO classification. Similar rosette‐forming neuropil islands have been described in infiltrative gliomas at sites other than the 4th ventricle (RGNT). In the latter, rosette formation does not seem to impart the same favorable prognosis as in the WHO grade I RGNT‐4th. We describe three examples of RGNTs occurring outside the 4th ventricle. Tumors were located in the right frontal lobe, cerebellar vermis away from the 4th ventricle and cervical spinal cord. Radiographically, the tumors appeared as well‐circumscribed, solid masses with focal contrast enhancement. All three tumors were characterized by extensive well‐formed rosette formation surrounding neuropil islands. The latter stained intensely with synaptophysin and negatively for GFAP. MIB‐1 labeling was virtually undetectable. The glial component was characterized as low‐grade astrocytic in two cases, and as infiltrative oligodendroglial‐like in another. The oligodendrolial component did not show 1p/19q co‐deletion on FISH analysis. Ultrastructural examination showed some of the cells to have secretory granules, while others had processes filled with glial filaments. All three patients remain recurrence free approximately two years following surgery. The striking morphologic resemblance between RGNT‐4th and RGNT suggests that these are probably the same entity; even if one chooses to designate them both as mixed glioneuronal tumors or alternatively as glial neoplasms with divergent differentiation.

Rosette-forming glioneuronal tumor of the fourth ventricle: Report of two cases with a differential diagnostic overview

We report on clinicopathological findings in two cases of rosette-forming glioneuronal tumor of the fourth ventricle (RGNT) occurring in females aged 16 years (Case 1) and 30 years (Case 2). Symptoms included vertigo, nausea, cerebellar ataxia, as well as headaches, and had been present for 4-months and 1 week, respectively. Magnetic resonance imaging (MRI) indicated a cerebellar-based tumor of 1.8 cm (Case 1) and 5 cm (Case 2) diameter each, bulging into the fourth ventricle. Case 2 involved a cyst-mural-nodule configuration. In both instances, the solid component appeared isointense on T 1 sequences, hyperintense in the T 2 mode, and enhanced moderately. Gross total resection was achieved via suboccipital craniotomy. However, functional recovery was disappointing in Case 1. On microscopy, both tumors comprised an admixture of low-grade astrocytoma interspersed with circular aggregates of synaptophysin-expressing round cells harboring oligodendrocyte-like nuclei. The astrocytic moiety in Case 1 was nondescript, and overtly pilocytic in Case 2. The architecture of neuronal elements variously consisted of neurocytic rosettes, of pseudorosettes centered on a capillary core, as well as of concentric ribbons along irregular lumina. Gangliocytic maturation, especially “floating neurons”, or a corresponding immunoreactivity for neurofilament protein was absent. Neither of these populations exhibited atypia, mitotic activity, or a significant labeling for MIB-1. Cerebellar parenchyma included in the surgical specimen did not reveal any preexisting malformative anomaly. Despite sharing some overlapping histologic traits with dysembryoplastic neuroepithelial tumor (DNT), the presentation of RGNT with respect to both patient age and location is consistent enough for this lesion to be singled out as an autonomous entity.

The 2007 WHO Classification of Nervous System Tumors: Newly Recognized Members of the Mixed Glioneuronal Group

The clinical and pathologic features of two glioneuronal neoplasms newly incorporated in the 2007 revision of the WHO classification of nervous system tumors are reviewed. These are the papillary glioneuronal tumor and the rosette-forming glioneuronal tumor of the fourth ventricle.

Mixed Glioneuronal Tumors: Recently Described Entities

Several distinctive mixed glioneuronal tumors that warrant recognition as clinicopathologic entities have been recently described by neuropathologists. To summarize important clinical, radiologic, and pathologic findings for 3 novel glioneuronal tumors (papillary glioneuronal tumor, rosetted glioneuronal tumor, and rosette-forming glioneuronal tumor of the fourth ventricle). Recent reports in the pathology literature and the authors' experience with mixed glioneuronal tumors at a major cancer center. Histologic features enabling recognition of these recently described glioneuronal tumors are presented along with remarks concerning the classification of mixed neuronal and glial tumors exhibiting unconventional appearances.

Mixed glioneuronal tumors: recently described entities.

Abstract Context.—Several distinctive mixed glioneuronal tumors that warrant recognition as clinicopathologic entities have been recently described by neuropathologists. Objective.—To summarize important clinical, radiologic, and pathologic findings for 3 novel glioneuronal tumors (papillary glioneuronal tumor, rosetted glioneuronal tumor, and rosette-forming glioneuronal tumor of the fourth ventricle). Data Sources.—Recent reports in the pathology literature and the authors' experience with mixed glioneuronal tumors at a major cancer center. Conclusions.—Histologic features enabling recognition of these recently described glioneuronal tumors are presented along with remarks concerning the classification of mixed neuronal and glial tumors exhibiting unconventional appearances.

Fourth ventricle rosette-forming glioneuronal tumor

The authors describe a rosette-forming glioneuronal tumor of the fourth ventricle in a 29-year-old woman. She had been experiencing dizziness for 1 year and headaches for 1 month. Cranial computed tomography revealed a relatively circumscribed mass involving the inferior cerebellum and floor of the fourth ventricle with extension into the ventricle. Histologically, much of the tumor was piloid with Rosenthal fibers as well as telangiectatic blood vessels; other areas contained complete or incomplete neurocytic rosettes. This tumor type must be differentiated from pilocytic astrocytomas, other gliomas with a piloid glial component, and glioneuronal tumors arising from the floor of the fourth ventricle or inferior cerebellum. Recognition of, and long-term follow up for, this recently described pathological entity may clarify the nature of this lesion and strategies for its optimal management.

Mixed neuronal-glial tumor of the fourth ventricle and successful treatment of postoperative mutism with bromocriptine: case report

Background Tumors composed of both neurocytic and astrocytic cells are uncommon and poorly understood. We describe the clinicopathologic features of a very rare rosette-forming glioneuronal tumor of the fourth ventricle and propose bromocriptine as a useful therapeutic agent for cerebellar mutism after posterior fossa surgery. Case Description A fourth ventricle tumor was incidentally discovered in an 18-year-old woman. Magnetic resonance imaging revealed ventriculomegaly and a solid tumor with low-intensity signals on T1-weighted images and high-intensity signals on T2-weighted images. There was slight gadolinium enhancement. The tumor was subtotally resected. Although its lower half was well circumscribed, its upper half manifested invasive growth. Histologically, 2 components were identified, synaptophysin-positive neurocytic cells forming perivascular pseudorosettes and glial fibrillary acidic protein–positive astrocytic cells with Rosenthal fibers. Overall, cellular atypia was minimal and the MIB-1 labeling index was low. On the basis of these histologic findings, the tumor bore striking similarity to the recently described rosette-forming glioneuronal tumors of the fourth ventricle. Postoperatively, the patient manifested cerebellar mutism. The administration of bromocriptine improved her neurological status dramatically. Conclusion The natural history of rosette-forming glioneuronal tumors of the fourth ventricle is not yet fully understood. Therefore, careful and long-term follow-up monitoring of the tumor hosts is necessary. Bromocriptine therapy may promote recovery from mutism after posterior fossa surgery.