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

Machine learning–based multiparametric magnetic resonance imaging radiomics model for distinguishing central neurocytoma from glioma of lateral ventricle

OBJECTIVES

To develop a machine learning-based radiomics model based on multiparametric magnetic resonance imaging (MRI) for preoperative discrimination between central neurocytomas (CNs) and gliomas of lateral ventricles.

METHODS

A total of 132 patients from two medical centers were enrolled in this retrospective study. Patients from the first medical center were divided into a training cohort (n = 74) and an internal validation cohort (n = 30). Patients from the second medical center were used as the external validation cohort (n = 28). Features were extracted from contrast-enhanced T1-weighted and T2-weighted images. A support vector machine was used for radiomics model investigation. Performance was evaluated using the sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). The model's performance was also compared with those of three radiologists.

RESULTS

The radiomics model achieved an AUC of 0.986 in the training cohort, 0.933 in the internal validation cohort, and 0.903 in the external validation cohort. In the three cohorts, the AUC values were 0.657, 0.786, and 0.708 for radiologist 1; 0.838, 0.799, and 0.790 for radiologist 2; and 0.827, 0.871, and 0.862 for radiologist 3. When assisted by the radiomics model, two radiologists improved their performance in the training cohort (p < 0.05) but not in the internal or external validation cohorts.

CONCLUSIONS

The machine learning radiomics model based on multiparametric MRI showed better performance for distinguishing CNs from lateral ventricular gliomas than did experienced radiologists, and it showed the potential to improve radiologist performance.

KEY POINTS

• The machine learning radiomics model shows excellent performance in distinguishing CNs from gliomas. • The radiomics model outweighs two experienced radiologists (area under the receiver operating characteristic curve, 0.90 vs 0.79 and 0.86, respectively). • The radiomics model has the potential to enhance radiologist performance.

Clinical features and surgical outcomes of intracranial and spinal cord subependymomas

OBJECTIVE

Subependymomas are low-grade ependymal tumors whose clinical characteristics, radiographic features, and postsurgical outcomes are incompletely characterized due to their rarity. The authors present an institutional case series and a systematic literature review to achieve a better understanding of subependymomas.

METHODS

Adult patients with histologically confirmed subependymoma or mixed subependymoma-ependymoma surgically treated at a tertiary hospital between 1992 and 2020 were identified. A systematic literature review of the PubMed, Embase, Web of Science, and Google Scholar databases from inception until December 4, 2020, was conducted according to PRISMA guidelines. Data extracted from both groups included demographics, radiographic features, tumor characteristics, management, and follow-up variables.

RESULTS

Forty-eight unique patients with subependymoma were identified by chart review; of these patients, 8 (16.7%) had mixed subependymoma-ependymoma tumors. The median age at diagnosis was 49 years (IQR 19.8 years), and 26 patients (54.2%) were male. Forty-two patients (87.5%) had intracranial subependymomas, and 6 (12.5%) had spinal tumors. The most common presentation was headache (n = 20, 41.7%), although a significant number of tumors were diagnosed incidentally (n = 16, 33.3%). Among the 42 patients with intracranial tumors, 15 (35.7%) had hydrocephalus, and the most common surgical strategy was a suboccipital approach with or without C1 laminectomy (n = 26, 61.9%). Gross-total resection (GTR) was achieved in 33 cases (68.7%), and 2 patients underwent adjuvant radiotherapy. Most patients had no major postsurgical complications (n = 34, 70.8%), and only 1 (2.1%) had recurrence after GTR. Of 2036 reports initially identified in the systematic review, 39 were eligible for inclusion, comprising 477 patients. Of 462 patients for whom tumor location was reported, 406 (87.9%) were intracranial, with the lateral ventricle as the most common location (n = 214, 46.3%). Spinal subependymomas occurred in 53 patients (11.5%), with 3 cases (0.6%) in multiple locations. Similar to the case series at the authors' institution, headache was the most common presenting symptom (n = 231, 54.0%) among the 428 patients whose presentation was reported. Twenty-seven patients (6.3%) were diagnosed incidentally, and 36 cases (8.4%) were found at autopsy. Extent of resection was reported for 350 patients, and GTR was achieved in 250 (71.4%). Fifteen of 337 patients (4.5%) had recurrence or progression.

CONCLUSIONS

The authors' case series and literature review demonstrate that patients with subependymoma are well managed with resection and generally have a favorable prognosis.

Long-term follow-up of lateral ventricular central neurocytoma treated with subtotal resection followed by concurrent chemoradiotherapy and add on chemotherapy - Case report from a Tertiary Kenyan Cancer Hospital

Background:

Central neurocytomas are rare, mostly benign neuroectodermal tumors of the central nervous system typically located within the lateral and third ventricles of cerebrum. No consensus guidelines for the management of central neurocytoma available due to the rarity of the disease.

Case Description:

We report a case of right ventricular central neurocytoma of a 28-year-old lady who had a subtotal resection and ventriculoperitoneal shunting. Postoperatively, she was treated with concomitant chemotherapy with oral temozolomide and radiotherapy, followed by add-on chemotherapy with same drug. Imaging, microscopic evaluation, treatment modalities, and outcome of treatment are presented.

Conclusion:

Subtotal resection of tumor through transcallosal approach and ventriculoperitoneal shunt was performed. Imaging done 2 weeks postsurgery confirmed residual disease. Concurrent chemoradiotherapy (54 Gy in 30 fractions +Oral Temozolomide 75 mg/m² daily), followed by six cycles of 5-day chemotherapy with temozolomide (150 mg/m² in Cycle 1, and 175 mg/m² in subsequent cycles) at 28-day intervals, was given. No major toxicities encountered. Follow-up scan after 36 months showed complete remission.

Subependymoma and dysembryoplastic neuroepithelial collision tumor in the foramen of Monro: case report

Intracranial collision tumors have rarely been reported in the literature and generally include at least 1 malignant tumor component. Subependymoma with dysembryoplastic neuroepithelial tumor (DNET) is an as-yet unreported combination. Both components are uncommon tumors, and presentation in the foramen of Monro is even more unusual. A 16-year-old male patient with a past medical history significant for asthma presented with a 3-month history of headaches and radiographic evidence of mild obstructive hydrocephalus secondary to a nonenhancing ventricular lesion at the foramen of Monro. He underwent endoscopic biopsy and resection. Pathological analysis revealed distinct components of subependymoma and DNET. At the 1-year follow-up, the patient was doing well without regrowth of tumor. The authors describe a case of intracranial collision tumor demonstrating 2 grade I components: a novel combination of subependymoma and DNET.

Pilocytic Astrocytoma of Fornix Mimicking a Colloid Cyst: Report of 2 Cases and Review of the Literature

BACKGROUND

Colloid cyst is a gelatin-containing cyst in the brain almost always found in the third ventricle. The specific shape and location of these cysts, a round well-delineated mass in the rostral part of the third ventricle adjacent to the foramen of Monro, on imaging are the main findings for diagnosis. Several masses of the third ventricle masquerading colloid cysts on images have been reported. Based on different surgical approaches, preoperative misdiagnosis of colloid cyst may have great impact on prognosis.

METHODS

We report 2 cases that presented with severe headache and hydrocephalus, and their preoperative images were highly indicative of colloid cyst.

RESULTS

Histopathologic investigations after tumor resection showed pilocytic astrocytoma of fornix in both cases.

CONCLUSIONS

Fifteen cases of colloid cyst misdiagnosis with other masses have been reported thus far; among them, 2 cases were pilocytic astrocytoma. In this study we report 2 other cases. Furthermore, we discuss additional clues helping to differentiate pilocytic astrocytoma from colloid cyst on images.

Subependymal giant cell astrocytoma (SEGA): a case report and review of the literature

Background

Subependymal giant cell astrocytoma is a rare tumor that occurs in the wall of the lateral ventricle and foramen of Monro and, rarely, in the third ventricle. It is one of the intracranial lesions found in tuberous sclerosis complex (which include subependymal nodules, cortical tubers, retinal astrocytoma and subependymal giant cell astrocytoma), but cases without such lesions have also been reported in the literature. It was described for the first time in 1908 by Vogt as part of the typical triad of tuberous sclerosis complex. At the 2012 Washington Consensus Conference, it was decided by the invited expert panel to document the definition of subependymal giant cell astrocytoma as a lesion at the caudothalamic groove with either a size of more than 1 cm in any direction or a subependymal lesion at any location that has shown serial growth on consecutive imaging regardless of size. Most subependymal giant cell astrocytomas will show avid enhancement after contrast administration; however, a growing subependymal lesion even in the absence of enhancement should be considered a subependymal giant cell astrocytoma.

Case presentation

We report a case of subependymal giant cell astrocytoma in a 10-year-old white girl, who had no clinical symptoms of tuberous sclerosis. A computed tomography scan revealed a voluminous mass in her perilateral ventricle. An extemporaneous examination was in favor of a benign ganglioglioma tumor. After fixation in 10 % neutral-buffered formalin, embedding in paraffin and staining with hematoxylin, eosin and safran, the definitive diagnosis was subependymal giant cell astrocytoma.

Conclusions

Subependymal giant cell astrocytoma is a rare tumor of the central nervous system whose diagnosis is based on clinical, radiological, histological and immunohistochemical arguments. For its rarity, we must consider this diagnosis when faced with a mass near the foramen of Monro in the pediatric population even if there are no other features of tuberous sclerosis complex.

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.

The management of incidental central neurocytoma

This article elucidates the role of stereotactic radiosurgery for the management of central neurocytoma. This rare intraventricular tumor is usually benign and is best treated with surgical excision if the tumor is large and symptomatic. However, some distinctive neuroimaging features are found in this tumor that help to identify the tumor based on detailed MRI and computed tomography examinations. The cumulative experience shows that single-session radiosurgery using Gamma Knife radiosurgery is an effective and safe alternative treatment of incidental central neurocytoma. After radiosurgery, a serial MRI examination performed every 6 months for long-term follow-up is necessary to monitor radiosurgical response of the tumor.

Clinical, radiological, and pathological features in 43 cases of intracranial subependymoma

OBJECT

Intracranial subependymomas are rarely reported due to their extremely low incidence. Knowledge about subependymomas is therefore poor. This study aimed to analyze the incidence and clinical, radiological, and pathological features of intracranial subependymomas.

METHODS

Approximately 60,000 intracranial tumors were surgically treated at Beijing Tiantan Hospital between 2003 and 2013. The authors identified all cases in which patients underwent resection of an intracranial tumor that was found to be pathological examination demonstrated to be subependymoma and analyzed the data from these cases.

RESULTS

Forty-three cases of pathologically confirmed, surgically treated intracranial subependymoma were identified. Thus in this patient population, subependymomas accounted for approximately 0.07% of intracranial tumors (43 of an estimated 60,000). Radiologically, 79.1% (34/43) of intracranial subependymomas were misdiagnosed as other diseases. Pathologically, 34 were confirmed as pure subependymomas, 8 were mixed with ependymoma, and 1 was mixed with astrocytoma. Thirty-five patients were followed up for 3.0 to 120 months after surgery. Three of these patients experienced tumor recurrence, and one died of tumor recurrence. Univariate analysis revealed that shorter progression-free survival (PFS) was significantly associated with poorly defined borders. The association between shorter PFS and age < 14 years was almost significant (p = 0.51), and this variable was also included in the multivariate analysis. However, multivariate analysis showed showed only poorly defined borders to be an independent prognostic factor for shorter PFS (RR 18.655, 95% CI 1.141–304.884, p = 0.040). In patients 14 years of age or older, the lesions tended to be pure subependymomas located in the unilateral supratentorial area, total removal tended to be easier, and PFS tended to be longer. In comparison, in younger patients subependymomas tended to be mixed tumors involving the bilateral infratentorial area, with a lower total removal rate and shorter PFS.

CONCLUSIONS

Intracranial subependymoma is a rare benign intracranial tumor with definite radiological features. Long-term survival can be expected, although poorly defined borders are an independent predictor of shorter PFS. All the features that differ between tumors in younger and older patients suggest that they might have different origins, biological behaviors, and prognoses.

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.

Intraoperative cytology of central neurocytoma mimicking oligodendroglioma

Central neurocytomas (CNs) are uncommon tumors of the central nervous system. These tumors have a predilection for the lateral ventricles of young adults and are known to display characteristic neuroimaging and histomorphologic features. Typically, CNs are associated with a favorable outcome, although cases with more aggressive clinical course with recurrences are not unknown. Most descriptions of this tumor are available in the form of isolated histopathology-based case reports and small series. Cytology-based publications of CN are rare. Here, we report a case of CN in a 22-year-old girl. Intra-operative squash cytology and subsequent histopathology of the tumor simulated an oligodendroglioma and a clear cell ependydoma. Final confirmation was obtained on immunohistochemistry. This paper discusses the salient cytological, histomorphological and immunohistochemical features of CN that are useful in distinguishing from its mimickers.

[Subependymomas of lateral ventricle. Analysis of our series and review of literature]

Subependymoma is a benign lesion, slow-growing neoplasm, representing 0.2 to 0.7 % of intracranial tumors. They are often clinically silent, incidentally discovered at autopsy. These symptoms are related to big volume. They are attached to the septum pellucidum, leading to hydrocephalus by Monro foramen obstruction. Overall mean age at diagnosis is 39 years with more males than females. At CT-scan, subependymoma shows a slightly low attenuation compared to gray matter. There is no or mild enhancement following contrast injection. On MR T1-weighted imaging, subependymoma is isointense and hyperintense on MR T2-weighted imaging. Intramural calcifications and cystic components are noted in 20 to 30 % of patients. Peritumoral oedema is absent. Immunohistochemicals studies show intense positivity for S-100 and GFAP. The treatment is surgical with an excellent prognosis.

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.

Subependymoma in the lateral ventricle manifesting as intraventricular hemorrhage

A 32-year-old man presented with subependymoma in the lateral ventricle causing intraventricular hemorrhage and manifesting as severe headache and disturbance of consciousness. Computed tomography on admission showed a massive intraventricular hemorrhage and acute obstructive hydrocephalus. Cerebral angiography revealed no abnormal findings. Emergency external ventricular drainage was performed, and his neurological deficits gradually improved. Magnetic resonance imaging at 5 weeks after admission showed a tumor arising from the septum pellucidum or the floor of the right lateral ventricle, appearing as a mixed-intensity solid tumor, which was partially enhanced following gadolinium administration. The tumor had arisen from the septum pellucidum and was totally removed via an interhemispheric anterior transcallosal approach. Histological examination found typical subependymoma, with little vascularity. Intraventricular hemorrhage from cerebral neoplasms is usually due to highly vascular tumors. Since subependymomas are quite benign and show poor vascularity, intraventricular or subarachnoid hemorrhages are very rare, but do occasionally occur.

Forniceal glioma in children. Clinical article

OBJECT

Five to ten percent of pediatric brain tumors are located in the ventricles. Among them, forniceal lesions are rare and their management has not often been described. The aim of this study was to review the clinical, radiological, and histopathological features as well as the feasibility of surgical excision and the outcomes in these patients.

METHODS

From a retrospective analysis of 250 cases of supratentorial pediatric glioma, the records of 8 children presenting with forniceal lesions were selected and reviewed.

RESULTS

The median age of patients in the cohort was 13.5 years. Presenting features included intracranial hypertension (7 cases), hypothalamic dysfunction (2), and memory dysfunction (3). Complete resection was possible in only 1 case, where the lesion was mainly exophytic; the remaining patients had either a partial resection or biopsy. On histological review, the tumors were confirmed as pilocytic astrocytoma (4 lesions), WHO Grade II astrocytoma (3), and ganglioglioma (1). Postoperatively, working and retrograde memory was normal for all patients, but the authors found a mild alteration in verbal episodic memory in 5 patients. Despite fatigability for 5 patients, academic achievement was normal for all but 2, both of whom had preoperative school difficulties. Additional treatment was required for 5 patients for tumor progression, with a median interval of 19 months from surgery. At a median follow-up duration of 4.9 years, all patients had stable disease.

CONCLUSIONS

In this series, forniceal gliomas were found to be low-grade gliomas. They are surgically challenging, and only exophytic lesions may be cured surgically. Due to the high rate of progression of residual disease, adjuvant therapy is recommended for infiltrative tumors, and it yielded excellent results.

Central neurocytoma in third and fourth ventricles with aqueductal involvement

Central neurocytomas are characterized by their intraventricular locations, usually arising from the lateral ventricles and their benign clinical course. Variations in location, histology and clinical behaviour have been reported in recent years. The authors present two cases of central neurocytomas arising in the third and fourth ventricles with aqueductal involvement. The atypical features in their location and behaviour are discussed. The cases represent the extended spectrum of central neurocytomas.

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: 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.

Neurocytoma: a comprehensive review

Central neurocytomas (CN) are uncommon tumors of the central nervous system, most descriptions of which available in the literature are in the form of isolated case reports and small series. Owing to this rare incidence, diagnosis and management of this neoplasm remain controversial. Usually, these tumors affect lateral ventricles of young adults and display characteristic neuroimaging and histomorphologic findings. Neurocytomas often mimic oligodendrogliomas when confirmation of diagnosis rests on immunohistochemistry, ultrastructure, and genetic studies. Extraventricular neurocytomas, situated entirely within the brain parenchyma and spinal cord, have also been reported. Typically, CN are associated with a favorable outcome although cases with more aggressive clinical course with recurrences are not unknown. MIB-1 labeling index (LI) of >2% often heralds poor prognosis and tumour recurrence. Safe maximal resection is presently considered the ideal therapeutic option, with best long-term prognosis in terms of local control and survival. The role of adjuvant radiotherapy apparently seems to benefit patients with incomplete resection and in atypical neurocytoma. Utility of other therapeutic regimen, however, remains shrouded in controversy. Epidemiology, histogenesis, clinical profile, histology, neuroimaging and therapeutic modalities of neurocytomas have been comprehensively reviewed, with special emphasis on CN and extraventricular neurocytomas and their atypical counterparts.

Subependymomas: An analysis of Clinical and Imaging Features

OBJECTIVE:

Subependymomas are slow-growing, benign tumors usually found incidentally in the fourth ventricle at autopsy. They are typically associated with the ventricular system and become apparent clinically only when symptoms of hydrocephalus or mass effect develop. We review clinical, histological, and contemporary radiographic presentations of 16 subependymomas, including 2 intraparenchymal tumors.

METHODS:

We retrospectively evaluated eight patients with pathologically proven subependymomas. Initial magnetic resonance imaging and magnetic resonance spectroscopy were reviewed when available. Imaging was also available on eight outside subependymoma cases reviewed by our radiology department.

RESULTS:

Twelve of these subependymomas were intraventricular, one was in the posterior fossa, two were intraparenchymal, and one was an intramedullary spinal cord tumor. These lesions were hypo- to hyperintense on T1- and T2-weighted magnetic resonance imaging, with minimal to moderate enhancement. Initial complaints included headache, seizures, tingling sensations, and weakness. Among our eight patients who underwent gross total resection with no adjuvant therapy, no recurrences have been noted on follow-up magnetic resonance imaging.

CONCLUSION:

Subependymomas are rare, representing only 0.51% of all central nervous system tumors operated on during an 8-year period at the University of Utah. Clinical symptoms were associated with tumor location: intracranial masses caused headaches, seizures, and neurological complaints, and spinal cord locations resulted in neurological deficit. The authors review the clinical presentation, management, and contemporary radiographic appearance of this rare tumor.

Central neurocytoma: report of two cases

INTRODUCTION: Central neurocytomas are rare neuroectodermal tumors believed to arise from the subependymal matrix of the lateral ventricles. CASE REPORTS: A 26-year-old woman and a 33-year-old man each had a large, heterogeneous, contrast enhancing mass in the lateral ventricles at the foramen of Monro causing bilateral hydrocephalus. The woman died after surgery, but the man is asymptomatic after three years. HISTOPATHOLOGY: Both tumors were composed of isomorphic rounded cells positive for synaptophysin, chromogranin and NSE, while some reacted for GFAP, vimentin and S-100 protein. Electron microscopy revealed neuropil-like tissue between cells, but synapses were rare.

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.