Central neurocytoma: two case reports and review of the literature

Epigenetic Alteration of H3K27me3 as a Possible Oncogenic Mechanism of Central Neurocytoma

Central neurocytoma (CN) is a low-grade neuronal tumor that mainly arises from the lateral ventricle (LV). This tumor remains poorly understood in the sense that no driver gene aberrations have been identified thus far. We investigated immunomarkers in fetal and adult brains and 45 supratentorial periventricular tumors to characterize the biomarkers, cell of origin, and tumorigenesis of CN. All CNs occurred in the LV. A minority involved the third ventricle, but none involved the fourth ventricle. As expected, next-generation sequencing performed using a brain-tumor-targeted gene panel in 7 CNs and whole exome sequencing in 5 CNs showed no driver mutations. Immunohistochemically, CNs were robustly positive for FGFR3 (100%), SSTR2 (92%), TTF-1 (Nkx2.1) (88%), GLUT-1 (84%), and L1CAM (76%), in addition to the well-known markers of CN, synaptophysin (100%) and NeuN (96%). TTF-1 was also positive in subependymal giant cell astrocytomas (100%, 5/5) and the pituicyte tumor family, including pituicytoma and spindle cell oncocytoma (100%, 5/5). Interestingly, 1 case of LV subependymoma (20%, 1/5) was positive for TTF-1, but all LV ependymomas were negative (0/5 positive). Because TTF-1-positive cells were detected in the medial ganglionic eminence around the foramen of Monro of the fetal brain and in the subventricular zone of the LV of the adult brain, CN may arise from subventricular TTF-1-positive cells undergoing neuronal differentiation. H3K27me3 loss was observed in all CNs and one case (20%) of LV subependymoma, suggesting that chromatin remodeling complexes or epigenetic alterations may be involved in the tumorigenesis of all CNs and some ST-subependymomas. Further studies are required to determine the exact tumorigenic mechanism of CN.

Systematic Analysis of Clinical Outcomes Following Stereotactic Radiosurgery for Central Neurocytoma

Central neurocytoma (CN) typically presents as an intraventricular mass causing obstructive hydrocephalus. The first line of treatment is surgical resection with adjuvant conventional radiotherapy. Stereotactic radiosurgery (SRS) was proposed as an alternative therapy for CN because of its lower risk profile. The objective of this systematic analysis is to assess the efficacy of SRS for CN. A systematic analysis for CN treated with SRS was conducted in PubMed. Baseline patient characteristics and outcomes data were extracted. Heterogeneity and publication bias were also assessed. Univariate and multivariate linear regressions were used to test for correlations to the primary outcome: local control (LC). The estimated cumulative rate of LC was 92.2% (95% confidence interval: 86.5-95.7%, p<0.001). Mean follow-up time was 62.4 months (range 3-149 months). Heterogeneity and publication bias were insignificant. The univariate linear regression models for both mean tumor volume and mean dose were significantly correlated with improved LC (p<0.001). Our data suggests that SRS may be an effective and safe therapy for CN. However, the rarity of CN still limits the efficacy of a quantitative analysis. Future multi-institutional, randomized trials of CN patients should be considered to further elucidate this therapy.

Clinical manifestations of central neurocytoma

Central neurocytomas (CNs) are rare central nervous system tumors that occur in the lateral ventricles. They are prevalent in young adults and are typically benign with excellent prognosis following surgical resection. Because of the rarity of the disease and its similar features with more common tumors, misdiagnosis becomes an issue. Optimal treatment is achieved only when the correct tumor types are distinguished. Typical clinical manifestations include symptoms of increased intracranial pressure, although no clinical feature is pathognomonic to CN. Radiologic imaging, histology, magnetic resonance spectroscopy, and immunohistochemistry must be used to elucidate tumor characteristics and properly diagnose CN.

FDG PET differentiation of tumor recurrence from post-stereotactic radiosurgical scar in a central neurocytoma

Central neurocytoma is a rare benign tumor of neuronal origin. The tumor is often located in the ventricular system and can proliferate within the ventricle. Five months after stereotactic radiosurgery for recurrent neurocytoma, a 33-year-old woman had a 2.0-cm lesion in the right third ventricle on the MRI. FDG PET demonstrated intense uptake of the lesion. The subsequent MRI follow-up showed growth of the lesion and confirmed recurrence.

Pathologic features and clinical outcome of central neurocytoma: analysis of 15 cases

OBJECTIVE

To get better recognition of central neurocytoma and diminish misdiagnosis.

METHODS

A retrospective review identified 15 cases of central neurocytoma. All cases of central neurocytoma were analyzed for their clinical symptoms, pathologic changes, immunohistochemical staining, prognosis and differential diagnosis. Clinical follow up was performed.

RESULTS

There were 8 males and 7 females aged 10-64 years (median 32.93 years). The most common presenting symptoms were those related to increased intracranial pressure (ICP), including headache (100%), papilledema (93%) and vomiting (80%). All tumors were located in the ventricular system. The tumors were composed of uniform cells with round nuclei and a fine chromatin pattern, and in some areas, small cells with perinuclear halo could be seen. In particular, the anuclear areas may have a fine fibrillary matrix (neuropil). Nuclear atypia and vascular proliferation appeared in two cases, respectively. Focal necrosis could be seen in one case. Immunohistochemical findings included expression of synaptophysin (15/15), neuron specific enolase (12/15) and glial fibrillary acidic protein (GFAP) (3/15). MIB-1 proliferation index ranged from 0.8-12.5%, and was more than 2% in 3 of 15 cases assessed. Follow-up information of 11 patients was available.

CONCLUSIONS

Central neurocytoma has a favorable prognosis in general, but in some cases, the clinical course could be aggressive. Increase of GFAP positivity, proliferation index and vascular proliferation might suggest a more malignant process.

Frontal transcortical approach in 12 central neurocytomas

BACKGROUND

Central neurocytomas (CN) are rare intraventricular tumors with benign clinical behavior that typically affect young adults. Although a favorable prognosis is generally expected after adequate management, there is no general consensus on the standard of therapy. We evaluated the efficacy and safety of radical surgery for the management of CN.

METHODS

Between 1996 and 2010, 12 patients with CN (eight males and four females; range, 18 to 62 years; mean age, 28.5 years) were surgically treated in our institution. The initial goal of therapy was complete resection through a frontal transcortical approach, and repeat surgery was done in cases of residual or recurrent disease. The mean follow-up period was 51.2 months (range, 14-149 months).

RESULTS

Complete resection was achieved in all patients either with primary (nine patients, 75 %) or second-look surgery (three patients, 25 %). No mortalities occurred and there were four surgery-related complications (two events of transient hemiparesis, one transient aphasia, and onepostoperative subdural hygroma). All patients were alive with normal activities of daily living at the last follow-up. Two patients (16.6 %) experienced a single recurrence at 26 and 66 months, one of whom underwent redo-surgery.

CONCLUSION

For the management of CN, complete resection is feasible, effective, and safe. Repeat surgery may be a viable option in cases of residual or recurrent disease and the use of radiotherapy can be avoided in this young population.

Surgical management of intraventricular central neurocytoma: 92 cases

OBJECTIVE

To analyse the clinical characteristics of intraventricular central neurocytomas and gain a better understanding of the surgical management and treatment strategies.

METHODS

A total of 92 cases of intraventricular central neurocytomas with initial treatment using surgical resection were studied retrospectively.

RESULTS

Among 48 male and 44 female patients, 65 underwent gross total resection and 27 underwent subtotal resection. Transcortical or transcallosal approaches were performed, and there was no significant difference between the two approaches in terms of effects and complications. Tumours with calcification or adhesion had a significant lower gross total resection rate. Three patients died after surgery. During follow-up, 55 patients underwent postoperative radiotherapy and four patients had a recurrence of the tumour.

CONCLUSION

Central neurocytomas mostly occur in the lateral ventricle system near the foramen of Monro. Therefore, total resection is the best treatment. Two surgical approaches are possible as treatment. Calcifications or adhesions affect the gross total resection of the tumour. Radiation therapy or radiosurgery therapy can be chosen as a salvage treatment in case of recurrence.

Proton MR spectroscopy of central neurocytoma using short and long echo time: new proofs for the existence of glycine and glutamate

RATIONALE AND OBJECTIVES

Central neurocytomas (CNCs) are rare benign tumors typically located in the lateral ventricle of the central nervous system. The authors report five patients with CNCs and review 16 previously published studies that included 52 patients with CNCs to explore the magnetic resonance spectroscopic features of CNCs.

MATERIALS AND METHODS

Five patients with CNCs were retrospectively reviewed. They were examined using point-resolved spectroscopic series with short and/or long echo times. The integrals of choline, creatine, and the 3.55-ppm peak were determined using Magnetic Resonance User Interface software, and the metabolite ratios relative to creatine were obtained. In two cases, T2 relaxation times of choline and the metabolite resonance at 3.55 ppm were calculated using data points acquired with different echo times and an exponential decay model.

RESULTS

Consistent with previously published studies, all five patients showed highly increased choline and reduced N-acetylaspartate and creatine. Four patients in the present study and 35 in published data demonstrated prominent peaks at 3.55 ppm, which were assigned to glycine because of its relaxation pattern and long T2 relaxation time. In addition, increased in vivo glutamate and glutamine was also confirmed in three patients examined with short echo times. Alanine and lactate peaks were observed in three and two patients, respectively.

CONCLUSIONS

The present study shows that the 3.55-ppm peak characteristic of CNC should be assigned to glycine according to its T2 relaxation time. Besides increased glycine and choline, the presence of glutamate or glutamine, which appears on series with short echo times, may further confirm the diagnosis of CNC.

Gamma knife radiosurgery for cranial neurocytomas

Gamma-knife surgery may be an effective alternative for treatment of central neurocytomas owing to its relative safety compared with conventional radiotherapy. In this paper we present results of gamma-knife treatment (GKS) of residual or recurrent neurocytomas. Twenty-two patients (14 female, 8 male) with recurrent or residual neurocytomas who underwent GKS were included. Diagnosis was based on histological findings. The proliferative potential of the tumors was examined by immunostaining with MIB-1 antibody, which is specific for detection of Ki-67 antigen. Tumor volume was determined by using post-gadolinium magnetic resonance images. After GKS treatment, MR imaging was scheduled at three-month intervals in the first year, at six months intervals in the second year, and yearly thereafter. Histopathological diagnoses were: 18 cases of central neurocytomas, two liponeurocytomas, one cerebral neurocytoma and one cerebellar neurocytoma. The MIB1 labeling index (LI) varied from 0 to 5.7%. Marked reduction in tumor volume was seen in 15 patients. In six patients, the tumor volume remained unchanged, and progression was observed for one patient. No complications because of GKS were noted. Shrinking effect on tumor volume increased with increasing duration of follow-up. On the other hand, high MIB labeling index did not seem to have an effect on tumor response to GKS treatment. Findings of this study suggest that GKS is an effective and safe treatment alternative for residual or recurrent neurocytomas. However, its effectiveness should be confirmed with larger studies.

Gamma knife radiosurgery for central neurocytoma: retrospective analysis of fourteen cases with a median follow-up period of sixty-five months

OBJECT

Central neurocytoma (CN) is considered to be a benign neuronal tumor with possible atypical behavior. Microsurgery, radiation therapy (RT) and radiosurgery all have been used in treating this rare disease during the past decade. In this study, the authors present the experience with gamma knife radiosurgery (GKRS) on 14 patients with CN during a median follow-up period of 65 months and document the safety and efficacy of GKRS in the treatment of CN.

METHODS

Between November 1997 and December 2009, 14 patients pathologically diagnosed with CN were treated with GKRS. Follow-up magnetic resonance imaging (MRI) was performed at 6-month intervals. Tumor volume and adverse radiation effects (ARE) were documented to evaluate tumor response to GKRS. The Karnofsky Performance Scale (KPS) and neurological status were used to assess clinical outcome. The mean radiation dose prescribed to the tumor margin was 12.1 Gy (ranging from 11 to 13 Gy). The mean tumor volume was 19.6 ml (ranging from 3.5 to 48.9 ml). The mean follow-up period was 70 months (ranging from 30 to 140 months), and the median follow-up period was 65 months.

RESULTS

Tumor shrinkage was found in all patients at the final MRI follow-up. The mean volume reduction was 69% (ranging from 47 to 87%). No tumor progression, ARE or radiation-related toxicity developed in any of the cases. The KPS scores of all patients were the same or had increased, and the neurological functions were all stable without deterioration at the final follow-up.

CONCLUSION

In our observations, GKRS was found to be an effective and safe alternative as adjuvant therapy for pathology-confirmed CN. The tumor volume and functional outcome can be controlled with a favorable result in long-term observation. Compared with RT and microsurgery, GKRS plays an important role in the treatment of CN as a minimally invasive technique with low morbidity. Regular long-term MRI follow-up should be mandatory to document the tumor response and possible recurrence. Multicenter consortia should be considered for further investigation and evaluation of GKRS for such a rare tumor.

Central neurocytoma: the neuroradiological perspective

BACKGROUND

Central neurocytoma (CN) represents a rare, relatively recently described primary central nervous system tumor. It ranks among intraventricular tumors due to its predominant location within the lateral brain ventricles. CN occurs mostly in young adults around the 3rd decade of life; almost a fifth of the cases are children under 18 years of age.

OBJECTIVES

The authors present three cases of patients with histopathologically confirmed CN, emphasizing diagnostic imaging issues. A review of the literature concerning differential diagnosis and clinical and therapeutic aspects is also presented.

CONCLUSION

Literature reports of CN comprise most likely case reports, small cohorts of patients, and meta-analytic studies due to the generally low incidence of this tumor. In the current paper, the authors summarize up-to-date knowledge of this rare disease on the background of their own observations. CN should be included in the list for differential diagnostics of intraventricular brain tumors, especially those located in lateral ventricles.

Central neurocytoma responsive to topotecan, ifosfamide, carboplatin

A 5-year-old male presented with spinal cord drop metastasis from a recurrent neurocytoma. Topotecan (0.5 mg/m(2)) and carboplatin (250 mg/m(2)) were administered on days 1-3 and ifosfamide (1,800 mg/m(2)) on days 1-5, every 21 days, for three cycles and resulted in complete response without severe complications. A literature review yielded 20 patients with central neurocytoma but no complete responses. The complete response of central neurocytoma to chemotherapy only reported here should be helpful to those caring for patients with this rare tumor.