Intraventricular neurocytoma: clinicopathological features of six cases

Central neurocytoma-positive and differential diagnosis: An example through a case report

Central neurocytoma is a rare intraventricular tumor, occurring typically in the lateral ventricle of young adults. It is considered as a neuronal-glial benign tumor with favorable prognosis. Imaging is a cornerstone allowing the accurate preoperative diagnosis on the basis of several characteristic features. We report the case of a 31-year-old man who has been complaining of progressive headaches and in whom brain magnetic resonance imaging revealed a central neurocytoma. We remind then, through a literature review, the main criteria to set the diagnosis of this tumor and rule out the other possible diagnoses.

The last decade's experience of management of central neurocytomas: Treatment strategies and new options

Background:

The purpose of the presented work is to evaluate the last decade’s experience in surgical management of central neurocytoma (CN) and elucidate on the treatment strategies and new options.

Methods:

The current series consists of the remaining 125 patients (70 females and 55 males) operated on during the past decade from 2008 to 2018. Most tumors were resected through transcortical (n = 76, 61%), or transcallosal (n = 40, 32%) approaches. In 5 (4%) patients with predominantly posterior location of the tumor, non-dominant superior parietal lobule approach was utilized. Both approaches (transcortical + transcallosal) were used in 4 (3%) of cases. Seven consecutive patients with large CN underwent prophylactic intraventricular stenting to prevent hydrocephalus.

Results:

Gross total resection was achieved in 45 patients (36%), subtotal resection (STR) in 40 (32%) cases. After surgery, 63 (50%) patients had neurocognitive problems, including disorientation, attention deficit, global amnesia, short-term memory deficits, and perceptual motor and social cognition problems. A total of 26 patients (21%) had postoperative hemorrhage in the resection bed. Obstructive hydrocephalus was noted in 25 (20%) patients. The entrapment of the occipital and/or temporal horns was observed in seven cases. None of the seven patients with prophylactic intraventricular stents required shunting.

Conclusion:

Although high rates of gross total or STR can be expected, the mortality and morbidity remain significant even in the modern neurosurgical era. Prophylactic intraventricular stenting in patients with large posteriorly located tumors with hydrocephalus may prevent ventricular entrapment and shunting. The main risk factors for recurrence are presence of residual disease and Ki-67 index over 5%. Recurrent symptomatic tumors should be treated surgically, whereas asymptomatic progression can be managed with stereotactic radiosurgery. Both treatment modalities are associated with low risk of complications and high tumor control rates.

[Central neurocytomas: surgical treatment outcomes and new trends and approaches in the treatment]

AIM

Central neurocytomas of the brain are rare benign tumors of the cerebral lateral ventricles. The main treatment for them is surgical resection. Resection provides a long-term relapse-free period, but surgical intervention is associated with a number of significant difficulties due to the location, size, and blood supply features of these tumors. The postoperative period is often accompanied by hemorrhagic complications, impaired cerebrospinal fluid circulation, and worsening of neurological symptoms.

PURPOSE

The study purpose was to evaluate the effectiveness of surgical treatment in neurocytoma patients, assess the risk of complications after neurocytoma resection, and develop techniques for their prevention.

MATERIAL AND METHODS

The paper presents surgical treatment outcomes in 115 patients with central neurocytomas for the period from 2008 to 2017. The choice of a surgical approach and the surgical features are described in detail, and the radicality is assessed with allowance for the location and size of tumors. The immediate clinical outcomes of treatment are evaluated, complications are analyzed, and methods for prevention and treatment of complications are described.

RESULTS

Analysis of the data revealed that the tumor was resected totally in 41 (36%) patients, subtotally - in 37 (32%), and partially in 37 (32%). The most common and dangerous complications were as follows: CSF circulation occlusion with the development of hydrocephalus in 23 (20%) patients; hemorrhage into the residual tumor, which required immediate revision of the surgical wound in most cases, in 25 (22%) patients. In the early postoperative period after tumor resection, almost all patients developed deterioration of condition with transient worsening of cerebral and focal symptoms. The degree and duration of this worsening were different. In 50% of cases, the postoperative condition was characterized by reduced voluntary activity, drowsiness or jitteriness, and motor or speech anxiety.

CONCLUSION

We consider resection of neurocytomas as the main treatment option, despite the potential complications and effects of the operation.

Central Neurocytoma. A Clinico-Pathologic study of Five Cases

Five cases of central neurocytomas are described. The tumors occurred in relatively young patients (range 14 to 43 years; mean age, 27) with no predilection for sex. All the lesions were located in the anterior portion of the lateral ventricles or in the third ventricle, involving the septum pellucidum or the fornix. Histologically, they were composed of uniform cells with round nuclei and clear cytoplasm resembling oligodendrogliomas or, to a lesser extent, ependymomas. In 4 tumors, protein cell nuclear antigen immunostaining showed a low cell proliferation rate. All cases were positive for neuron-specific enolase. Four of the 5 cases were strongly immunoreactive for synaptophysin. The immunohistochemical data were consistent with neuronal differentiation. Resection was subtotal in 4 cases and total in one. Postoperative radiotherapy was given in only one case. The follow-up revealed a good prognosis: 4 patients were alive and had a long survival (from 2 to 8 years). Only one patient died after 14 months for causes unrelated to the neoplasm. The authors emphasize the importance of immunohistochemistry to recognize this benign intraventricular tumor.

MR Appearance of Central Neurocytoma

To provide a detailed description of the MR appearances of central neurocytoma, MR images of 13 patients with central neurocytoma were retrospectively reviewed and compared with CT examinations. The histology was confirmed by ultrastructural and immunohistochemical studies. In 12 patients the tumors were histologically benign and located in the anterior part of the lateral ventricle, 6 of which extended to the 3rd ventricle. There was one case of a histologically malignant variant involving the thalamus and lateral ventricle. The tumors were primarily solid, but contained cysts (85%, 11/13), calcifications (69%, 9/13), and signal void from tumor vessels (62%, 8/13), frequently producing heterogeneous signal intensity on both T1- and T2-weighted images. Most of the solid portion appeared isointense or slightly hyperintense relative to the cerebral cortex on all MR pulse sequences. Calcifications were iso- or hypointense on MR, making them difficult to characterize with MR alone. Intratumoral hemorrhage was seen in 2 patients on MR but not on CT. Contrast enhancement was variable in degree and pattern. Coronal and sagittal MR images were valuable in evaluating the tumor extent and origin site, and in planning the surgical approach. It is concluded that MR imaging appears to be more useful than CT in the overall evaluation of central neurocytoma, even though calcification is better characterized with CT.

Central Versus Extraventricular Neurocytoma in Children: A Clinicopathologic Comparison and Review of the Literature

BACKGROUND

Central neurocytomas (CN) are rare pediatric CNS tumors most often with a benign clinical course. Occasionally, these tumors occur outside the ventricles and are called extraventricular neurocytomas (EVN). We present a retrospective institutional analysis of children with neurocytoma with prolonged follow-up.

PROCEDURE

Twelve patients were diagnosed with neurocytoma at our institution between 1993 and 2004.

RESULTS

Six patients were male and the median age at diagnosis was 12 years (1.5 to 16 y). Seven patients had CN and 5 had EVN. Presenting symptoms included headaches (67%), vomiting (50%), nausea (33%), seizures (33%), and mental status changes (25%). Obstructive hydrocephalus was present at diagnosis in 42% of the cases. Younger age and seizures were more common in patients with EVN. Gross total resection (GTR) was achieved in 42% (5/12) of the patients. Patients with GTR received no adjuvant therapy upfront; 1 patient subsequently had recurrence with leptomeningeal disease. Patients with subtotal resection received additional treatment: 1 underwent reoperation (GTR), 2 patients received focal radiation, 2 patients received adjuvant chemotherapy, and 2 patients received craniospinal irradiation followed by chemotherapy. The 20-year overall survival for this cohort was 83% with event free survival of 56%. Overall survival for CNs was 100%, versus 40% for EVN. Event free survival for CNs was 57% and 53% for the EVNs. An MIB-1 fraction >2% was associated with worse prognosis.

CONCLUSIONS

Neurocytomas are rare brain tumors in children usually cured with GTR. Adjuvant focal radiation therapy and/or chemotherapy may improve disease control in cases with subtotal resection, but case-by-case analysis should be done. EVNs might be associated with worse outcome due to a higher proliferative index.

Immunohistochemical and Ultrastructural Studies of Oligodendrogliomas Revealed Features of Neuronal Differentiation

In an attempt to characterize differentiation in oligodendrogliomas, 39 cases were examined immunohistochemically with 5 neuronal markers, synaptophysin, neuron- specific enolase, neurofilament proteins, protein gene product (PGP) 9.5, and micro tubule-associated protein 2 (MAP2), in addition to glial fibrillary acidic protein (GFAP). Positive immunolabeling was obtained for neuron-specific enolose in 29 cases (74%), synaptophysin in 21 cases (54%), PGP 9.5 in 33 cases (85%), and MAP2 in 23 cases (59%). All cases were negative for neurofilament, and 90% stained for GFAP. Eight cases were further studied ultrastructurally, and in five cases features of neuronal differentiation were identified in some of the typical neoplastic oligodendro cytes—small neuritic cellular processes with microtubules and focal synapse-like junc tions, as well as sparse neurosecretory granules. It was concluded that, both immuno histochemically and ultrastructurally, oligodendrogliomas may exhibit features of neuronal differentiation. These previously unreported features of oligodendrogliomas call into question conventional immunohistochemical and electron microscopic crite ria used in distinguishing oligodendrogliomas from tumors showing similar histologic appearance, especially central neurocytomas and dysembryoplastic neuroepithelial tu mors. Int J Surg Pathol 2(1):47-56 1994

Intraventricular Central Neurocytoma

A case of central neurocytoma treated surgically is described. The authors review the literature. Emphasis is placed on radiological and pathological features not previously described. In particular, the intra-operative ultrasound appearance is described. The role of adjunctive radiotherapy is also discussed.

Neurocytoma of the spinal cord

This article presents an overview of spinal neurocytomas. A rare manifestation of an uncommon tumor, extraventricular neurocytomas (EVNs) should be included in the differential for spinal intradural and intramedullary tumors. Spinal EVNs are generally benign with an indolent pathologic course but may display a variety of acute or chronic clinical behaviors, depending on their anatomic location. Only a handful of spinal EVNs have been described in the literature, often in the form of individual case reports or small case series. Discussion includes a review of the literature and an overview of the clinical, pathologic, and radiologic features of this rare tumor type, as well as the differential diagnosis, treatment options, and general prognosis.

Histology and molecular aspects of central neurocytoma

Central neurocytoma (CN) is a well-differentiated tumor of neural cells occurring within the ventricles. It is composed of monomorphic cells with round, regular nuclei within clear cytoplasm and must be distinguished from other clear cell tumors. Immunohistochemical markers of CN that aid in diagnosis include synaptophysin and neuronal nuclear antigen. The molecular biology of these tumors is becoming increasingly elucidated, particularly with the use of microarray analyses. Several oncogenic pathways have been suggested by these studies. Although progress continues to be made, knowledge of CN has yet to dictate targeted therapies in treating patients with these tumors.

[Central neurocytomas of the lateral ventricle. A series of 35 cases with review of the literature]

Central neurocytoma is the second most frequent tumor in our series of 284 lateral ventricle tumors (12%). Mean age was 32.6 years. There was a male predominance (20/35). Most frequent clinical signs were neuropsychological disturbances and intracranial hypertension. On imaging, these tumors concentrate central calcifications in more than half of cases. Main locations were frontal horn and corpus of lateral ventricle (82%). Uneventful postoperative course was recorded in 52% of cases. Immunoreactivity against neuron-specific enolase (NSE), synaptophysin, S100 protein, Microtubul Associated Protein de type 2 (MAP2) and calcineurin confirms the neuronal nature of the neoplasm. This tumor has a good prognosis. Local control after surgery is obtained in 68% of cases. Gamma knife surgery seems to be useful in cases of little volume with tumoral remnants or recurrence, when radiological appearance is well circumscribed and round-shaped.

Neurocytoma of the cerebellum

Background:

Neurocytomas are benign central nervous system tumor composed of small cells with characteristics of neuronal differentiation; they are usually located in the supratentorial periventricular region, in close relation to the septum pellucidum and the foramen of Monro.

Case Description:

Herein we report a rare case of a neurocytoma located in the cerebellar hemisphere. To date there are only four such reported cases.

Conclusion:

Neurocytomas should be considered in the differential diagnosis of mass lesions in the cerebellum.

[Central neurocytoma: Study of 32 cases and review of the literature]

Central neurocytoma is a rare benign neoplasm of the central nervous system. The intraventricular location close to the Monro foramina and the attachment to the septum pellucidum are characteristic for the diagnosis. However, atypical appearances may be encountered and confused with other neoplasms. The authors report the radiological findings of 32 surgically treated and pathologically confirmed neurocytomas.

Endoscopic removal of a central neurocytoma from the posterior third ventricle

Central neurocytoma is a rare benign tumor that most commonly arises within the ventricular system of young adults. Its occurrence in the posterior third ventricle is one of the least reported presentations. These tumors are usually treated by a combination of either biopsy or open surgical resection, often followed by radiation (Gamma knife or Novalis) with or without chemotherapy. A 37-year-old woman with a posterior third ventricle neurocytoma presented with acute signs of aqueductal stenosis. The patient underwent endoscopic assisted gross total resection of the tumor with the aid of intraoperative laser followed by standard third ventriculostomy; no further treatment was required. The patient did not develop any subsequent neurological deficit. A 36-month follow-up was still consistent with a normal neurological examination. Serial post-operative MRIs show neither residual nor recurrent tumor. Thus, posterior third ventricle central neurocytomas are relatively benign tumors that can be successfully removed using a minimally invasive approach, thereby avoiding both the morbidity related to conventional open craniotomy and the potential toxicity of any adjuvant treatment.

Central neurocytoma: Management recommendations based on a 35-year experience

PURPOSE

To examine the outcomes of patients with histologically confirmed central neurocytomas.

METHODS AND MATERIALS

The data from 45 patients with central neurocytomas diagnosed between 1971 and 2003 were retrospectively evaluated. Various combinations of surgery, radiotherapy (RT), and chemotherapy had been used for treatment.

RESULTS

The median follow-up was 10.0 years. The 10-year overall survival and local control rate was 83% and 60%, respectively. Patients whose tumor had a mitotic index of <3 (per 10 high-power fields) experienced a 10-year survival and local control rate of 89% and 74%, respectively, compared with 57% (p = 0.040) and 46% (p = 0.14) for patients with a tumor mitotic index of > or =3. The 10-year survival and local control rate was 90% and 74% for patients with typical tumors compared with 63% (p = 0.055) and 46% (p = 0.41) for those with atypical tumors. A comparison of gross total resection with subtotal resection showed no significant difference in survival or local control. Postoperative RT improved local control at 10 years (75% with RT vs. 51% without RT, p = 0.045); however, this did not translate into a survival benefit. No 1p19q deletions were found in the 19 tumors tested.

CONCLUSION

Although the overall prognosis is quite favorable, one-third of patients experienced tumor recurrence or progression at 10 years, regardless of the extent of the initial resection. Postoperative RT significantly improved local control but not survival, most likely because of the effectiveness of salvage RT. For incompletely resected atypical tumors and/or those with a high mitotic index, consideration should be given to adjuvant RT because of the more aggressive nature.

Central neurocytoma: two case reports and review of the literature

Central neurocytomas are low grade tumours usually located in the lateral ventricles next to Monro foramina. This paper reviews the literature on central neurocytomas observed in the last few years and discusses their clinical, histopathological, immunohistochemical and genetic characteristics. Important correlations between therapeutic strategies and biological findings as well as new genetic discoveries are also discussed. Two illustrative cases in which the authors report preliminary results about molecular analysis of some genetic markers are described.

Central neurocytoma: a novel appraisal of a polymorphic pathology. Our experience and a review of the literature

Central neurocytoma should be considered in the differential diagnosis of intraventricular tumours. The records of 20 patients operated on between 1975 and 2000 for central neurocytoma were retrospectively reviewed, and the histological gradings and clinical outcomes were compared. On the basis of our previous cases, in the latter five of this series, the following therapeutic protocol was adopted. In those cases in which total removal was achieved, no further treatment was given if the MIB-1 index was <4%; vice versa, if it was >4%, a course of conformational radiotherapy was delivered. In subtotally removed cases, radiosurgery with linac was also performed (median dose 20 Gy) as well as conformational radiotherapy whenever there was a recurrence of the lesion (median dose 45 Gy). In cases in which there was only partial cytoreduction, conformational radiotherapy was administered with the adjunct of polychemotherapy if the MIB-1 was >4%. Twenty patients were surgically treated: 11 men and nine women, with an average age of 26 years (range 17 years to 42 years).Total, subtotal and partial removals were achieved in, respectively, ten, three and seven cases. At average follow-up of 7 years, 16 patients had been cured, had significantly improved or were at least stable [Karnofsky performance status score (KPS)] >70 or more)]. On the other hand, four patients had worsened; of these, two had died and two had a KPS=50 and an unfavourable prognosis. The presence of histological atypia has proved to be a significantly negative risk factor for survival (P=0.02) while an MIB score >4% was significantly correlated with an unfavourable outcome (death or worsening of neurological status). The "atypical" neurocytoma seems to be a distinct entity, with a less favourable prognosis and a higher tendency to recur.

Recurrent central neurocytomas

BACKGROUND

Since the first description of Central neurocytomas (CNs) as a benign tumor entity in 1982, there has been great enthusiasm regarding the benign course and the curative surgical approach to this disease. The current study was performed to investigate the frequency of disease recurrence during long-term follow-up.

METHODS

A retrospective analysis of the medical files with emphasis on clinicoradiologic findings and histologic and immunohistochemical features was performed.

RESULTS

Between 1985-2003. surgical resection was performed in 14 patients with CNs ages 16-43 years (7 were female and 7 were male). Two patients (14%) died postoperatively and one patient had a malignant disease course (7%). In the remaining 11 patients, one patient with an incompletely resected CN had disease progression after 37 months but at the time of last follow-up had had stable disease for 10 years. In addition, the authors reported 5 patients with disease recurrence occurring at a median of 67 months after surgery (range, 51-79 months after surgery), all of which occurred after complete surgical resection was performed. The observation period for the remaining 5 patients was short (median of 34 months [range, 5-44 months]). Extensive histologic and immunohistochemical workup did not identify any significant prognostic parameters. The MIB-1 proliferation index ranged from 0.8-11% (median of 4.6%), but was reported to be 46.8% in the malignant transformed tumor. All patients with disease recurrence responded well to different forms of focal radiation therapy (gamma knife radiosurgery in three patients and interstitial irradiation in one patient) and for one patient with a recently detected recurrence, gamma knife radiosurgery was planned.

CONCLUSIONS

CNs appear to have a higher tendency to recur during long-term follow-up than previously reported, even after complete resection. Therefore, periodic neuroradiologic follow-up examinations should be considered mandatory in all patients, even after several years.

Central neurocytoma: a clinicopathological and neuroradiological study

Central neurocytoma (CNC) is an uncommon benign tumor of the central nervous system (CNS) occurring in adults and is more likely to be located in the region of the foramina of Monra. Few studies have described the neuroradiological features of CNC, and most are single case reports. Our aim was to analyze the clinicopathological and neuroradiological characteristics of CNC. We retrospectively studied the preoperative CT (n=2) and MRI (n=5) of three men and two women (mean age 45 years, ranging from 30 to 63 years) with pathologically proven CNC. The tumors were primarily located in the region of the foramina of Monra. Two of them occupied the lateral ventricle, appearing to be attached to the septum pellucidum, and the other three tumors arose from the septum pellucidum and extended into the lateral ventricles. The tumors were of mixed density with cystic features and patchy or fine calcification on noncontrast CT scans, and they were of low or isointense signal on T1- and heterogeneously hyperintense signal on T2- and FLAIR weighted images. Contrast enhancement varied greatly from very slight to intense. Immunohistochemical staining showed a positive reaction for synaptophysin (Syn), neuro-specific enclase (NSE), neurofilament protein (NF) in the tumor cells and glial fibrillary acid protein (GFAP) in the fibrillar zones. CNC should be taken into consideration first if a tumor arises from the region of the foramina of Monra with CNC neuroradiological characteristics and the patient is an adult.

Intraventricular neurocytomas

The literature to date on the treatment of CNC reflects an evolution of clinical practice in neurooncology. The advent of sophisticated tools, such as MRS and molecular pathology, has facilitated more efficient diagnosis of CNC. Decreased morbidity associated with surgical intervention has resulted in better outcomes in patients undergoing resection of CNC. Prospective monitoring of treated patients with MRI coupled with judicious use of radiosurgery will likely further decrease treatment-related morbidity.

Tratamiento del neurocitoma central. Experiencia en nuestro centro

Central neurocytomas are classically considered as a rare, intraventricular benign tumours with neuronal differentiation derived from precursor cells of subventricular matrix. However some patients with neoplasms with histologic atypia and elevated proliferation potential may have a poor outcome. Treatment of choice is complete surgical excision. Adjuvant therapy is reserved for patients with residual or recurrent lesions including reoperation, radiotherapy or chemotherapy. We review our experience with the treatment of this neoplasm. Five patients with an intraventricular mass studied with magnetic resonance imaging underwent craniotomy for tumour resection. All cases were reviewed retrospectively. Histopathological analysis confirmed central neurocytoma in all cases. Proliferation index was assessed by Ki-67 immunohistochemistry. Complete radiological tumor resection through transcortical approach was achieved in all except one patient. In this case adjuvant therapy with radiosurgery was given with important reduction in tumor size. All the tumours had a proliferation index below 2% except one with 5%. Follow-up in four patients ranged from 12 to 36 months. There were no tumour recurrences in this period. Complete surgical excision of central neurocytoma provides better local control and survival compared with other treatments. Radiosurgery as adjuvant therapy in incomplete resections may eliminate the need of reoperation and avoid long-term side effects from conventional radiotherapy.

Extraventricular neurocytoma: morphological and immunohistochemical considerations on differential diagnosis

Neurocytoma is an unusual neuronal tumor especially affecting young people. It commonly arises in the ventricles and has a benign outcome. Herein, we report on a rare case of extraventricular neurocytomas (right parietal lobe) in a young girl admitted to hospital for a cranial trauma subsequent to a seizure. The tumor, radiologically well-circumscribed, cystic and enhancing, was surgically excised. The patient, who received no post surgical treatment, is alive and well after 18 months of follow-up. Pathological examination showed a well-differentiated lesion composed of uniform, round cells with perinuclear halos in a neuropil background and immunohistochemically positive for neuronal markers (synaptophysin, neuron-specific enolase, neurofilaments). The authors emphasize the role of the morphological and immunohistochemical evaluations to recognize this rare tumor.

MR imaging and histopathologic findings of a case of cerebral ganglioneurocytoma

We report a case of ganglioneurocytoma manifesting as a complex partial seizure in a young adult male. MR images depicted a well-marginated cystic mass with a heterogeneous solid portion abutting the dura in the parietal lobe. The solid portion showed minimal heterogeneous enhancement, and pressure erosion of the overlying calvarium had occurred. Following gross total resection, the clinical outcome was satisfactory, with no further seizures, and during the five-year follow-up period, the tumor did not recur.

Treatment of central neurocytomas

Central neurocytomas are uncommon tumors of the CNS, representing approximately 0.1-0.5% of all primary CNS tumors. Patients most often present with symptoms of increased intracranial pressure (headache, nausea/vomiting, diplopia) due to obstructive hydrocephalus. Rarely, central neurocytomas may present with a hemorrhage. Central neurocytomas are intraventricular tumors with a predilection for arising in either the lateral or third ventricles. CT or MR cranial imaging demonstrates a circumscribed mass in the ventricles, frequent calcification and moderate contrast enhancement. Surgery provides definitive treatment, as little evidence exists as to response of these tumors to either radiotherapy or chemotherapy. Histopathology reveals a homogenous neoplastic cell population with neuronal differentiation, frequent calcification, occasional perivascular pseudorosettes and infrequent mitoses. Uncommonly, anaplastic variants of central neurocytomas (malignant central neurocytomas) are encountered and are distinguished by frequent mitoses, necrosis and endothelial cell proliferation. Following complete resection, central neurocytomas have a favorable prognosis usually obviating the need for either radiotherapy or chemotherapy.

Tumours around the foramen of Monro: clinical and neuroimaging features and their differential diagnosis

The clinical and neuroimaging features of 20 patients with lateral ventricular tumours located around the foramen of Monro were reviewed retrospectively with special emphasis on the differential diagnoses. Histologic types were: eight neurocytomas, four subependymal giant cell astrocytomas (SGCAs), three subependymomas, two fibrillary astrocytomas, and one each of pilocytic astrocytoma, malignant astrocytoma and malignant teratoma. The mean age of the patients with neurocytoma was 29.6 years, with SGCA 13.3 years and with subependymoma 55.3 years. All tumours appeared nodular in shape, and on computed tomography (CT) neurocytomas were either isodense or highdense with the brain, while all subependymomas and SGCAs were lowdense. Calcification was observed in two SGCAs, and one neurocytoma. Five neurocytomas and all four SGCAs showed mild to moderate contrast enhancement, while all three subependymomas showed either no, or scarce, enhancement. Magnetic resonance imaging (MRI) studies were available in 10 patients, with the signal characteristics of four neurocytomas and three SGCAs being nonspecific, while two subependymomas were both hypointense on T1-weighted images and hyperintense on T2-weighted images. Thus important features for differential diagnosis included age of the patient and density on precontrast CT. In this series, either an extensive excision of the tumour or a partial removal, thus relieving the obstruction of the foramina of Monro, usually provided long term survival, with 18 patients surviving a mean of 10.8 years.

A neurocytoma and an associated lenticulostriate artery aneurysm presenting with intraventricular hemorrhage: case report

OBJECTIVE AND IMPORTANCE

Hemorrhage associated with central neurocytoma has been described previously, but never in association with an aneurysm originating from a feeding artery. We present the first reported case of a central neurocytoma in a patient with intraventricular hemorrhage caused by rupture of an aneurysm on a lenticulostriate artery that supplied the tumor.

CLINICAL PRESENTATION

A 35-year-old man who presented with an intraventricular hemorrhage underwent magnetic resonance imaging and cerebral angiography that disclosed a right lateral intraventricular mass and a 7-mm fusiform aneurysm from a lateral lenticulostriate branch of the right middle cerebral artery.

INTERVENTION

The patient underwent a contralateral transcallosal exploration and resection of the tumor, with excision of the adjacent lenticulostriate artery aneurysm. Pathological review demonstrated that the tumor was a neurocytoma. The aneurysm was discrete from the tumor but occurred on a vessel that supplied the tumor.

CONCLUSION

Previous reports have demonstrated that intraventricular neurocytoma may present with tumor hemorrhage. In this case, an aneurysm separate and distinct from the tumor was the bleeding culprit, and the aneurysm was on an artery that fed into the tumor. Any such aneurysm must be identified and treated appropriately for therapy to be complete.

Radiosurgery for the treatment of recurrent central neurocytomas

OBJECTIVE

Central neurocytomas are benign neoplasms with neuronal differentiation typically located in the lateral ventricles of young adults. Although the treatment of choice is complete surgical excision, patients may experience local recurrence. Adjuvant therapy for patients with residual or recurrent tumor has included reoperation, radiotherapy, or chemotherapy. To avoid the side effects of conventional radiotherapy in young patients, we present a series of patients with clear evidence of tumor progression who were treated with gamma knife radiosurgery.

METHODS

Four patients (ages 20-49 yr; mean, 28 yr) who presented with an intraventricular mass on magnetic resonance imaging scans and underwent craniotomy for tumor resection were reviewed retrospectively. Histopathological analysis confirmed central neurocytoma in all cases. Each patient was followed up clinically and radiographically with serial magnetic resonance imaging. When radiographic signs of tumor progression were evident, patients were treated with radiosurgery.

RESULTS

Complete radiographic tumor resection was achieved in all patients. There were no major postoperative complications. Local tumor progression was detected on magnetic resonance imaging scans 9 to 25 months after surgery (median, 17.5 mo). All patients achieved complete response to radiosurgery with reduction in tumor size. There have been no complications from radiosurgery. Follow-up ranged from 12 to 28 months (mean, 16.5 mo) after radiosurgery, and from 24 to 84 months (mean, 54.5 mo) after initial presentation.

CONCLUSION

Radiosurgery with the gamma knife unit provides safe and effective adjuvant therapy after surgical resection of central neurocytomas. Radiosurgery may eliminate the need for reoperation and avoid the possible long-term side effects from conventional radiotherapy in young patients.

Nerve cell tumours of the cerebrum: variable clinical and pathological manifestations

Nerve cell tumours of the cerebrum tend to display a high degree of morphological variability from case to case, and this leads to poor understanding of these tumours. We retrospectively reviewed the clinical and patho-anatomic features of 16 primary nerve cell tumours of the cerebrum (M:9; F:7; average age at onset: 10.2 years). Intraventricular tumours were not included. In 13 patients epileptic seizures were the only symptoms, while three had headache or hemiparesis. Seven tumours were located in the frontal lobe, four in the parietal lobe, two in the temporal lobe and one each in the fronto-parietal lobes, occipital lobe and the midbrain. Tumours were histologically classified into three groups. In the first group, six tumours had the morphological features of classic gangliocytoma or ganglioglioma. In the second group six cerebral and midbrain tumours were composed of small cells, which showed apparent neuronal differentiation including positive immunoreactivity for synaptophysin and the presence of synaptic structures. These tumours usually involved both the cortex and white matter. In the third group, three tumours were composed of small nerve cells and ganglioid cells. All tumours were relatively well circumscribed, and thus eight tumours were totally removed, five subtotally and three partially. Following surgery, three patients, except one, are alive with stable imaging findings for 4 months - 19.3 years (average 11.6 years) after treatment. While small nerve cell tumours are found throughout the cerebrum and its identification broadens the spectrum of neuronal and mixed neuro-glial tumours, most of these tumours are biologically indolent.

Gamma knife radiosurgery of recurrent central neurocytomas: a preliminary report

OBJECTIVES

A series of three recurrent central neurocytomas treated by gamma knife radiosurgery (GKRS), which were initially totally resected, are described. Up to now, no reports exist on this treatment modality for this rare tumour entity.

METHODS

Three male patients, aged between 20 and 25 years, presented with large intraventricular tumours. Total tumour removal was achieved by a single surgical procedure (one patient) or two operations (two patients). Neuropathological investigation showed a central neurocytoma, immunohistochemically all three tumours expressed a neuronal antigenic profile typical for neurocytomas, and the MIB-1 proliferation index ranged from 2.4% to 8.7%. Each patient experienced a tumour recurrence after 5 to 6 years. The recurrence was multifocal in two and a singular tumour mass in one patient. Gamma knife radiosurgery was performed. The tumours were enclosed within the 30% to 60% isodoseline, and delivered a tumour marginal dose of 9.6 to 16 Gy. During the follow up period, the patients were tested clinically and the volume of the tumours was measured on MRI.

RESULTS

Within follow up periods of 1 to 5 years, control MRI showed a significant decrease of the tumour mass in all cases. None of the patients developed new neurological symptoms after GKRS. Two patients returned to work in their previous employment, whereas one patient remained permanently disabled due to a pre-existing visual impairment and abducens palsy.

CONCLUSION

GKRS proved to be a useful tool in the treatment of recurrent central neurocytomas. Tumour control and even tumour shrinkage can be achieved with a single procedure and a low risk of morbidity.

Central neurocytoma: long-term follow-up of a paediatric case

In order to gain a better understanding of the clinical and histological features of central neurocytoma and the role of radiotherapy in the treatment of these tumours, we present an unusual paediatric case and review the pertinent literature. Most patients present in the second and third decade of life, rarely in the teenage years and exceptionally in children. Our patient was treated by a combined surgical and radiation therapy treatment for a central neurocytoma at the age of 7 years, but the tumour had been diagnosed when she was 3 years old. At a 38-year follow-up, she is well with no evidence of tumour progression. This patient seems to be the youngest histologically proven case of central neurocytoma and with the longest recorded survival.

Sudden death due to a central neurocytoma

The central neurocytoma is a common, usually intraventricular tumor with bland histologic features. We report a case of a 51-year-old man who died suddenly. At autopsy, a neurocytoma with acute hemorrhage filled the anterior left lateral ventricle. The tumor matrix and surrounding brain tissue contained accumulations of hemosiderin. Previously, 2 cases of central neurocytoma with associated hemorrhage have been reported. Hemorrhage appears to be a serious complication associated with these neoplasms.

Magnetic resonance features of the enigmatic oligodendroglioma

RATIONALE AND OBJECTIVES

The authors characterize magnetic resonance (MR) features of oligodendroglioma that permit diagnosis. These features may be used to guide MR stereotactic biopsies.

METHODS

Fifteen patients with mixed oligodendroglioma and four with pure oligodendroglioma were studied on a 1.5-tesla MR unit with contrast and also by computed tomography (CT). All patients had their diagnosis confirmed by light and electron microscopy, and by immunohistochemical staining.

RESULTS

The most characteristic finding was a honeycomb tumor matrix (4 of 19) in oligodendroglioma. The most common finding was an amorphous pattern (12 of 19) and the least common was a large cystic pattern (3 of 19). Contrast enhancement most commonly was minimal and dot-like or lacy in appearance (11 of 19), or absent (5 of 19). Calcification was present in the majority (11 of 19).

CONCLUSIONS

The honeycomb and stippled amorphous patterns reflect the cytoarchitecture of oligodendroglioma and were the most characteristic MR features. The amorphous pattern was the most commonly encountered pattern. There was a wider range of imaging findings on MR compared with CT; the flocculent calcification on CT was typical, but it was not always detected on MR. Including these characteristic areas that appear along the path of the stereotactic biopsy may ensure a correct diagnosis of oligodendroglioma because it most often is seen with another tumor, usually of the astrocytic family. Identifying the oligodendrogliomatous portion of the tumor will influence the therapy. No differences could be found in the MR appearance or biologic behavior of pure versus mixed oligodendrogliomas.

Central neurocytoma: a correlative clinicopathologic and radiologic analysis

BACKGROUND

Central neurocytoma was described as a well differentiated tumor of neuronal origin, distinct from ganglion cell tumors and neuroblastoma. An initially perceived benign biologic behavior has been questioned by subsequent reports of anaplastic and recurrent tumors. We report six cases of central neurocytoma, with variable clinical and pathologic features that stimulate discussion on the management of these tumors.

METHODS

Of the 95 oligodendrogliomas treated in our institution in the last 40 years, three tumors were reclassified as central neurocytomas on histologic reappraisal. Three additional cases prospectively diagnosed as central neurocytomas are reported. The clinical, pathologic, and radiologic features are reviewed.

RESULTS

Early recurrence, not related to malignant histologic features, was noted in two patients who had not received postoperative radiotherapy. Anaplastic histologic changes were not accompanied by malignant biologic behavior in another patient. Neither patient with recurrent tumor was controlled by radiotherapy alone. Chemotherapy with carboplatin reduced tumor size temporarily in one of these patients.

CONCLUSION

An entirely benign nature for this tumor is questioned and it appears that there may be malignant variants. Surgery should aim for maximum possible excision, as the location of the tumor allows. The role of postoperative radiotherapy remains controversial and may be considered in cases of subtotal excision of tumors with anaplastic histologic features. Chemotherapy may be of benefit in cases recurring despite surgery and radiotherapy.

Ultrastructure of microvessels and tumor cell processes on central neurocytoma

A case of central neurocytoma that was confirmed with ultrastructural and immunohistochemical studies has been reported. Ultrastructurally, thin cytoplasmic processes of tumor cells showed differentiation into neuronal cells containing parallel bundles of microtubules and abortive synapses with dense-core vesicles and/or clear vesicles. It was frequently found that the clusters of tumor cell processes were close to or around the microvessels. Microvessels were composed of endothelial cells without fenestrations and had tight junctions in the endothelial clefts. Neurosecretory granules in thin cell processes appeared close to microvessels and may have been secreted around microvessels.

Neurocytoma in the cerebellum. Case report

A neurocytoma is a central nervous system tumor composed of small cells with features of neuronal differentiation; it typically occurs in the periventricular region, close to the septum pellucidum and the foramen of Monro. In this article, the authors report the case of a neurocytoma located in the cerebellum, which to their knowledge is the first reported case of its kind. The finding of a neurocytoma at a nonclassic location refutes the theory that this tumor has its origins in subependymal progenitor cells, unless an ectopic location of progenitor cells is invoked to explain the occurrence of a neurocytoma away from the ventricles. On the basis of this case, the authors suggest that neurocytomas should be added to the differential diagnosis of mass lesions in the supratentorial intraventricular regions as well as in the posterior fossa.

Central neurocytoma: the role of radiation therapy and long term outcome

BACKGROUND

It has been suggested that the biologic behavior of central neurocytoma is indolent, although little is known regarding the role of radiation therapy and long term outcome. To clarify the role of radiation therapy and long term outcome, the authors retrospectively analyzed 15 cases of central neurocytoma.

METHODS

Clinical records and radiologic findings of 15 cases of central neurocytoma diagnosed at Seoul National University Hospital between January 1982 and February 1995 were carefully reviewed. The duration of follow-up was from 18-168 months (mean, 52 months); follow-up images were reviewed and the patient's Karnofsky performance scale (KPS) was assessed up to the time of last follow-up.

RESULTS

The age of the patients ranged from 15 to 60 years (mean, 25 years) and the male to female ratio was 11:4. Macroscopic total resection of the tumor was performed in seven patients, two of whom received fractionated radiation therapy. Subtotal removal of the tumor was performed in eight patients, five of whom received this same therapy. In 2 of the 5 patients who did not receive radiation therapy after macroscopic total resection, the tumors recurred 8 and 21 months after surgery, respectively; in contrast, recurrence was not detected in the 2 patients who received fractionated radiation therapy after macroscopic total resection. In all five patients who received fractionated radiation therapy after subtotal resection, the tumor shrank (n = 3) or disappeared (n = 2) during the postsurgical follow-up period ranging from 27-113 months; the tumor began to shrink from 6 months to 2 years after radiation. No change was found in the three patients who did not receive radiation therapy after subtotal resection. At the time of last follow-up, the KPS was greater than 90 in all patients except one who required assistance in his daily activities because of complications from radiation therapy.

CONCLUSIONS

It is suggested that even if the biologic behavior of a central neurocytoma is benign, radiation therapy appears to have an effect on tumor control. However, it should be carefully decided whether to use radiation therapy for a residual tumor because radiation can cause delayed complications and the clinical course of subtotally resected patients who do not receive radiation therapy is extremely benign.

Craniospinal dissemination of central neurocytoma. Report of two cases

Central neurocytoma was first described in the literature in 1982 and has been noted to be a benign neuronal tumor usually located in the ventricular system. Of the more than 100 reported cases, only seven recurrences have been reported, all of which have been local. The authors report two cases of recurrent central neurocytoma that disseminated through the ventricular system with seeding to the spine, as evidenced by magnetic resonance images and positive cerebrospinal fluid cytology. The histological appearance of these two tumors was typical for the lesion and lacked evidence of malignant change. Central neurocytoma may not be as benign as previously thought, and the recognition of this more malignant behavior has implications for patient follow up and therapy.

Central neurocytomas

BACKGROUND

This analysis was performed to examine the outcome of patients with histologically confirmed central neurocytomas.

METHODS

Thirty-two patients with histologically confirmed central neurocytomas were evaluated retrospectively. Patients were treated with various combinations of surgery, chemotherapy, and radiotherapy (RT). Follow-up ranged from 2.3 to 15.3 years (median, 4.7 years).

RESULTS

The overall 5-year survival and local control rates were 81% and 79%, respectively. No patient developed metastases. The 5-year local control rate was 70% for patients undergoing subtotal resection (STR) and 100% for those undergoing gross total resection (GTR) (P = 0.08). The 5-year survival rate was 77% for patients undergoing STR and 90% for those undergoing GTR (P = 0.44). The effect of RT was evaluated for patients undergoing STR. The 5-year local control rate was 100% for patients who received RT after STR compared with 50% for those who did not (P = 0.02). The 5-year survival rate was 88% for patients who received RT after STR compared with 71% for those who did not (P = 0.3). Three patients received salvage RT for local progression after resection. All were alive and free of disease 1 to 6 years after RT.

CONCLUSIONS

GTR results in a very high likelihood of local control and survival. Postoperative RT appears to improve local control rates significantly for patients who have undergone STR. The overall prognosis of patients with central neurocytomas is quite favorable, with an actuarial 5-year survival rate of 81%.