Two cases of atypical central neurocytomas

Central neurocytomas (CNs) are usually considered benign; however, some subsets of these tumors with histologic atypia and elevated proliferation potential have been reported to have a poor outcome. It has been proposed that those CNs exhibiting a MIB-1 labeling index (LI) greater than 2% and/or vascular proliferation be defined as atypical central neurocytoma (ACN). Two cases of ACN are reported here. Case 1 was a 13-year-old male who complained of headache. An MRI showed an enhancement of the tumor in the third ventricle and left lateral ventricle. The tumor was completely removed transcortically by a left frontotemporal craniotomy. The tumor showed anaplastic features, including microvascular proliferation, mitosis, and necrosis. The MIB-1 LI was 7.8%. The patient received 50 Gy of focal irradiation. After 16 months of follow-up, no recurrence was observed. Case 2 was a 17-year-old female who presented with headache. An MRI showed an enhancement of the tumor in the right lateral ventricle. To preserve the internal cerebral vein, the tumor was partially removed by the transcingulate approach after a bifrontal craniotomy. Histologically, the tumor displayed the typical features of a CN. The MIB-1 LI was 7.0%. Complete remission was achieved through 50 Gy of focal irradiation. After 15 months of follow-up, there was no recurrence. The differences in the histopathological findings in these two cases indicate the presence of a variety of histopathological features among ACNs.     

Primary neurocytoma of the spinal cord: a case report and review of literature

Summary Most central neurocytomas (CN) and spinal neurocytomas (SN) have a bland well-differentiated histologic picture and uneventful clinical course. However, rare examples showing histologic atypia, recurrence and even CSF dissemination have been reported. Herein we report a case of recurrent spinal neurocytoma in a 24-year-old male who presented with a 2-month history of weakness and numbness of the left upper and lower limbs, and was previously operated at the same site 10 months ago. MRI revealed a contrast enhancing intramedullary mass involving C5-T1 region. Radiologic and operative impression at both surgeries was that of a glioma, possibly anaplastic. Histologic and immunohistochemical features in both resections were those of an atypical neurocytoma. The tumor showed rare mitoses, focal mild vascular proliferation in both specimens, and necrosis in the initial specimen. MIB1 labeling indices were 9 and 10%, respectively. Based on the analysis of this case and limited data from the literature, it is hypothesized that SN shows a histopathologic picture, immunoprofile and biologic behavior very similar to CN. However, the presence of histologic atypia and increased MIB1 index in SN appear to more closely correlate with tumor recurrence and a worse overall outcome, in part due to their location in the critical region of cervical spinal cord. Therefore, we hypothesize that SN with atypia requires a close clinical follow up. As in CN, radiation therapy is perhaps best reserved for atypical, progressive and recurrent SN.     

Central Neurocytoma with Craniospinal Dissemination

Central neurocytoma was first described by Hassoun et al. in 1982. The tumor is a rare benign tumor of the central nervous system, usually located in the lateral ventricles. Most reported cases are histologically and clinically benign. Several cases with recurrence have been described. Including the case presented here, only seven cases with craniospinal dissemination have been reported. None of the previous cases with dissemination had histological atypia but most did have a high MIB-1 labeling index (MIB-1 LI). Our patient had a high MIB-1 LI (4.6%) and dissemination was found to have advanced through the anterior horns of the lateral ventricles and to the spinal cord at the T4 level. The patient underwent partial resection of the tumor with follow-up radiation treatments for the residual tumor and dissemination. After the radiation, the size of the tumor decreased. The report of this case will be helpful in the treatment of disseminated central neurocytoma.     

Central neurocytomas with MIB-1 labeling index over 10% showing rapid tumor growth and dissemination

SummaryObjective and importance Central neurocytoma is recognized as a indolent intraventricular tumor arising from the ependyma around the foramen of Monro and anterior part of the lateral ventricles, and well demarcated from the brain parenchyma. Surgical removal can be curative without postoperative therapy. However, malignant central neurocytoma refractory to even aggressive treatment is known.Clinical presentation We report two cases of extraventricular central neurocytomas with significant vascular proliferation, mitoses, and MIB-1 labeling index of more than 10%.Intervention Subtotal removal for the one patient and open biopsy for other followed by radiotherapy with chemotherapy were performed. However, the disease progressed and dissemination occurred. Both patients subsequently died 23 and 18 month after the histological diagnosis was established.Conclusion Extraventricular central neurocytoma may present with frequent vascular proliferation and high MIB-1 labeling index. Even if they lack malignant histological findings like frequent mitosis and/or necrosis, the prognosis for such patients is very poor.     

Central,Extraventricular and Atypical Neurocytomas: a Clinicopathologic Study of 35 Cases from Pakistan Plus a Detailed Review of the Published Literature

Background: Central neurocytomas are rare neuronal neoplasms with a favorable prognosis. They are typically located in the lateral ventricles of the brain and mostly histologically correspond to WHO grade II with a Mib 1 labelling index of <2%. Similar tumors located in the cerebral hemispheres and spinal cord, for example, are called "extraventricular neurocytomas". A few tumors histologically show atypia, mitoses, vascular proliferation and/or necrosis and a Mib 1 index >2 % and are designated as "atypical neurocytomas. Aim: The aim of our study was to describe the common as well as unusual morphologic features and the role of various immunohistochemical stains in the diagnosis of these rare tumors. Materials and Methods: We retrieved and reviewed 35 cases diagnosed between 2001 and 2015. Results: Sixty percent of patients were males, and the mean age was 26 years. 31 cases (88.6%) were intraventricular and 4(11.4%) were extraventricular. Histologically, 6 cases (17.1%) were compatible with "atypical neurocytomas". All cases showed the classic morphology comprising nests and sheets of uniform, round cells with uniform round to oval nuclei with finely speckled chromatin and perinuclear cytoplasmic clearing (halos). All cases also showed delicate, fibrillary, neuropil-like matrices. Other common histologic features included capillary-sized blood vessels in a branching pattern in 57.1%, foci of calcification in 34.3% and perivascular pseudorosettes in 20%. Rare findings included Homer- Wright or true rosettes in 8.6% and ganglioid cells in 2.9%. Synaptophysin was the most consistent and valuable marker, being positive in almost all cases. GFAP positivity in tumor cells was seen in 25.7% of cases. Follow up was available in 13 patients. Of these 9 had histologically typical and 4 had atypical tumors. Only 1 (with an atypical neurocytoma) died, probably due to complications of surgery within one month, while 12 (including 3 with atypical neurocytomas) remained alive. Recurrence developed in 1 of these 12 patients (histologically consistent with typical morphology) almost 9 years after surgery. Only 4 patients, including 2 with atypical tumors, received postoperative radiotherapy, all with surgery in 2010 or later. Overall, prognosis was excellent with prolonged, recurrence free survival and most patients, even without receiving radiation therapy, were alive and well for many years, even a decade or more after surgery, without developing any recurrence, indicating the benign nature of these neoplasms.     

Identification of relevant prognostic histopathologic features in 69 intracranial ependymomas, excluding myxopapillary ependymomas and subependymomas

BACKGROUND: The results of attempts to identify histopathologic parameters that contribute to the clinical outcome of patients with ependymomas have been controversial. This may be due to the relative rareness of ependymomas. Furthermore, in many investigations, myxopapillary ependymomas and subependymomas were included and may have confounded results, because those tumors should be considered clinicopathologic entities distinct from the other ependymomas. METHODS: In this retrospective study, the influence of the histologic subtype of ependymoma and of individual histologic features on the outcome of 69 patients with ependymomas was investigated. Myxopapillary ependymomas, subependymomas, and ependymomas with spinal localizations were excluded from the analysis. The ependymomas were subdivided into cellular, papillary, clear cell, and tanycytic subtypes. The study extended over a period of 30 years. RESULTS: No differences in clinical outcome between the four histologic subtypes of ependymomas were revealed. Neither tumor localization (either infratentorial or supratentorial), patient age, nor gender affected survival. The survival of patients who underwent complete tumor resection differed significantly from that of patients who underwent partial resection. In univariate analysis, the features of nuclear atypia, the mitotic index, and the MIB-1 labeling index (LI) significantly influenced survival. With regard to survival, the presence of microcysts, blood vessel density, and the feature of vascular hyalinization demonstrated a trend but did not reach significance. In multivariate analysis, only the mitotic index and the MIB-1 LI were identified as factors with independent prognostic significance (P = 0.027 and P = 0.023, respectively). Both proliferation indices were correlated strongly with each other. CONCLUSIONS: The results of the univariate analysis indicated that, for patients with intracranial ependymoma, nuclear atypia, the mitotic index, and the MIB-1 LI significantly influenced survival. In the multivariate analysis, the mitotic index and the MIB-1 LI were the only features that had independent prognostic significance. Because both showed strong correlations, only one of them should be included in a grading scheme for intracranial ependymomas.     

Proliferative activity of central neurocytoma: Measurement of tumor volume doubling time,MIB-1 staining index and bromodeoxyuridine labeling index

Central neurocytoma is considered to be a benign intracranial neoplasm, but little is known about the biological behavior of this type of tumor.Proliferative activity of central neurocytoma was measured in 10 cases using MIB-1 staining for Ki-67 antigen.The MIB-1 staining value varied from < 0.1% to 5.6%, to indicating that some of these tumors have proliferative potential similar to that of anaplastic astrocytoma or malignant meningioma. Thebromodeoxyuridine labeling index (BUdR LI, BrdU LI) was measured in 2 cases and the results correlated well with those of the MIB-1 analysis. Tumor volume doubling time (Td) measured in one case was 358 days which is similar to that of malignant meningioma.In one case, the MIB-1 value taken beforeand after 58 Gy of radiation treatment decreased markedly from 5.6%to 0.2%. The other 9 cases were also treated by radiation therapy (50—60 Gy) and no tumor recurrence was observed during follow-up periods ranging from 23 to 160 months. Another two patients with partially removed and 3 with subtotallyremoved tumors showing relatively high MIB-1 values might also have benefited from radiation therapy.     

Treatment of atypical neurocytomas

BACKGROUND: The majority of central neurocytomas are benign. Approximately 25% of these rare central nervous system tumors are more aggressive, with an MIB-1 labeling index > 2% or atypical histologic features, and are classified as atypical neurocytomas. The objective of this analysis was to define the optimal treatment for patients with these atypical tumors. METHODS: The first atypical neurocytoma was described in 1989. The patients reported since then were reviewed for age, gender, extent of resection, MIB-1 index, histology, irradiation, local control, and survival. In addition to the data available in the literature, more relevant data were obtained from the authors of that literature. Treatment approaches included complete resection alone (CR), complete resection followed by radiotherapy (CR-RT), incomplete resection alone (IR), and incomplete resection followed by radiotherapy (IR-RT). These four therapies were compared for local control and survival using Kaplan-Meier analysis and the log-rank test. RESULTS: Complete data were available on 85 patients (15 patients who underwent CR, 13 patients who underwent CR-RT, 17 patients who underwent IR, and 40 patients who received IR-RT). Local control rates at 3 years and 5 years were 73% and 57% after CR, 81% and 53% after CR-RT, 21% and 7% after IR, and 85% and 70% after IR-RT, respectively (P < 0.0001). Survival rates at 3 years and 5 years and were 93% and 93% after CR, 90% and 90% after CR-RT, 65% and 43% after IR, and 87% and 78% after IR-RT, respectively (P = 0.0076). CONCLUSIONS: Patients who underwent CR achieved better local control and survival rates compared with patients who underwent IR. After IR, patients appeared to benefit from RT. A beneficial effect of RT after CR was not observed.     

Management of neurocytomas: case report and review of the literature

The purpose of this report is to review the available literature on the presentation, pathology, and treatment of central nervous system (CNS) neurocytomas. A case report of an extraventricular neurocytoma is presented along with a comprehensive literature search of patients with a diagnosis of CNS neurocytoma. CNS neurocytomas are rare neoplasms, with fewer than 240 cases reported in the literature. The majority of neurocytomas are found in the ventricular system of the brain. Immunohistochemistry is frequently used to help distinguish this tumor from other CNS neoplasms. MIB-1 proliferation index is commonly used in an attempt to predict biologic behavior. Little is known about the management of patients with this tumor, because most reports are from the pathologic literature and contain sparse information regarding clinical management. Neurocytomas are rare CNS tumors with varied biologic behavior. MIB-1 index may help direct adjuvant therapy. An excellent prognosis can be expected if a gross total resection is achieved. Postoperative radiation therapy (RT) may be considered after subtotal resection. Otherwise, RT is an option for medically inoperable or recurrent disease.     

Benign central neurocytoma

BACKGROUND: "Central neurocytoma" is classically considered as an intraventricular benign tumor, largely based on data from small retrospective series. The authors present prospective data on 12 patients with tumors diagnosed as central neurocytoma, to highlight the diverse nature of this tumor and challenge the classic notion. METHODS: Between 1991 and 1997, 12 patients had tumors diagnosed prospectively as "central neurocytoma". Clinical, radiologic, and histologic data were collected, and Karnofsky performance score was evaluated for each patient. Proliferation marker studies were performed using Ki-67 labeling index. RESULTS: In two patients, the tumors were located in atypical locations, namely, the parietal lobe and the spine. Aggressive behavior characterized by clinical and radiologic evidence of tumor progression was noted in two additional patients. In both these cases, unusually high proliferation rates of 5.3% and 11.2% were noted. Total excision of the tumor, when possible, was the treatment of choice. Postoperative radiotherapy to the residual tumor may be of benefit in patients with clinically aggressive tumors, or those with high proliferation rates. CONCLUSIONS: Given the findings of this study, it is suggested that the traditional concept of central neurocytoma as a benign intraventricular tumor warrants reconsideration.     

Well-differentiated neurocytoma: what is the best available treatment?

Most neurocytomas are well differentiated, being associated with better long-term survival than the more aggressive atypical lesions. Atypical neurocytomas are characterized by an MIB-1 labeling index >3% or atypical histologic features. This analysis focuses on well differentiated neurocytomas in order to define the optimal treatment. A case with a follow-up of 132 months is presented. The patient developed two recurrences two and four years after first surgery, each showing an increasing proliferation activity. Furthermore, all published well-differentiated neurocytoma cases were reviewed for surgery, radiotherapy, and prognosis. Additional relevant data were obtained from the authors. Complete resection (CTR), complete resection plus radiotherapy (CTR + RT), incomplete resection (ITR), and incomplete resection plus radiotherapy (ITR + RT) were compared for outcome by using the Kaplan-Meier method and the log-rank test. Data were complete in 301 patients (CTR, 108; CTR + RT, 27; ITR, 81; ITR + RT, 85). Local control and survival were better after CTR than after ITR (P < 0.0001 and P = 0.0085, respectively). Radiotherapy improved local control after ITR (P < 0.0001) and after CTR (P = 0.0474), but not survival (P = 0.17 and P = 1.0, respectively). In the ITR + RT group, doses < or =54 Gy (n = 33) and >54 Gy (n = 32) were not significantly different for local control (P = 0.88) and survival (P = 0.95). The data demonstrated CTR to be superior to ITR for local control and survival. After CTR and ITR, radiotherapy improved local control, but not survival. A radiation dose of 54 Gy appeared sufficient. Application of postoperative radiotherapy should be decided individually, taking into account the risk of local failure, the need for another craniotomy, and potential radiation toxicity.     

Clinical Course of Central Neurocytoma with Malignant Transformation—An Indication for Craniospinal Irradiation

Central neurocytoma is generally considered to be a benign tumor and the literature suggests that a cure may be attained by surgery ± adjuvant focal irradiation. However, there is a need for change in the therapeutic strategy for the subgroup of patients with aggressive central neurocytoma. An example case is presented and the literature on central neurocytoma cases with malignant features and dissemination via the cerebrospinal fluid is reviewed and the radiotherapeutic strategies available for central neurocytoma treatment is discussed. Nineteen cases including the present report with a malignant course and cerebrospinal fluid dissemination have been described to date, most of them involving an elevated MIB-1 labeling index. Our case exhibited atypical central neurocytoma with an initially elevated MIB-1 labeling index (25–30 %). The primary treatment included surgery and focal radiotherapy. Three years later the disease had disseminated throughout the craniospinal axis. A good tumor response and symptom relief were achieved with repeated radiation and temozolomide chemotherapy. Central neurocytoma with an initially high proliferation activity has a high tendency to spread via the cerebrospinal fluid. The chemo- and radiosensitivity of the tumor suggest a more aggressive adjuvant therapy approach. Cases with a potential for malignant transformation should be identified and treated appropriately, including irradiation of the entire neuroaxis and adjuvant chemotherapy may be considered.     

The proliferative potential of the pilocytic astrocytoma: The relation between MIB-1 labeling and clinical and neuro-radiological follow-up

The proliferative potential of 39 pilocytic and 5 low grade astrocytomas was studied in relation to the Ki-67 activity as measured by the MIB-1 Labelings Index. The results were correlated to the biological behaviour of the tumor as measured by clinical and neuro-radiological (CT- or MRI-scans) follow-up of the patient. This study was undertaken to answer the question whether MIB-1 expression reflects differences in biological behaviour of these tumors, such as rapid progression of residual tumor or stable remaining tumor. MIB-1 LI values ranged from 0 to 19% in the group of pilocytic astrocytomas (mean 4,2%) and from 0 to 15% in the 5 low grade astrocytomas (mean 4,2%). All patients were operated and 23 of them had incomplete tumor resection as proven on postoperative neuro-imaging studies. Those 23 patients could be subdivided into two groups; one without progression of residual tumor during follow-up (n=12) and the other with tumor progression (n=11). mean MIB-1 LI in the group with quiescent tumor tended to be lower than in the group with progressive tumor: 3,3% vs. 6,6%. Residual tumors which were negative for MIB-1 staining showed fewer progressions of residual tumor compared to those being positive for MIB-1 staining, however this difference was not significant (p=0, 15, Fisher exact test). Tumor samples of a second operation of the same patient had lower MIB-1 LI values than those of the samples taken at first operation. The proliferating potential seemed to be decreased after part of the tumor was resected. Pilocytic astrocytomas with a negative MIB-1 LI are unlikely to show progression of residual tumor after partial resection. MIB-1 staining might be an additional tool in determining the frequency and duration of follow-up and in making decisions regarding further treatment of a patient operated for a pilocytic astrocytoma with residual tumor.     

Value of postoperative stereotactic radiosurgery and conventional radiotherapy for incompletely resected typical neurocytomas

BACKGROUND: Two groups of central neurocytomas have been identified: typical and atypical neurocytomas. The more benign typical neurocytomas have a better prognosis. Complete resection of typical neurocytomas results in significantly better outcome than incomplete resection. The current study investigated whether the outcome after incomplete resection can be improved by postoperative stereotactic radiosurgery (SRS) or by conventional radiotherapy. METHODS: The data of all neurocytoma patients reported since 1997, when the first neurocytoma patient treated with SRS was described, were reviewed. Patients who underwent complete resection or those with atypical neurocytoma were excluded from the analysis. Three different therapies were compared for overall survival (OS) and local control (LC): incomplete resection alone (ITR), ITR followed by conventional radiotherapy (ITR+cRT), and ITR followed by stereotactic radiosurgery (ITR+SRS). RESULTS: Data were complete in 121 patients (59 ITR, 41 ITR+cRT, and 21 ITR+SRS). The 5-year-LC after ITR was 51%. LC was significantly better after ITR+cRT (87%, P = 0.001) and after ITR+SRS (100%, P = 0.004). The difference between ITR+cRT and ITR+SRS was not significant (P = 0.45). The 5-year-OS was 93% after ITR, 100% after ITR+cRT, and 100% after ITR+SRS. The differences between the various groups were not significant. The P-values were 0.13 for ITR versus ITR+cRT, 0.29 for ITR versus ITR+SRS, and 1.0 for ITR+cRT versus ITR+SRS. CONCLUSIONS: After ITR of typical neurocytomas, LC is significantly improved by both conventional radiotherapy and SRS. The results of both radiation treatments were similar. SRS is a reasonable alternative to conventional radiotherapy in selected patients.     

Extraventricular neurocytoma of the sellar region with spinal dissemination

Extraventricular neurocytoma (EVN) is a rare tumor that mainly occurs in the cerebral hemispheres and spinal cord. Sellar neurocytoma is extremely rare, with only two previously reported cases. We report a sellar EVN in a 48-year-old man presenting with visual impairment. This tumor was partially resected. The residual tumor disappeared on MRI with adjuvant radiotherapy. However, 2 years later the tumor recurred with craniospinal dissemination, which is also very rare, with only four previously reported cases. The recurrent tumor showed atypical features with an MIB-1 LI score of 3 %. It is suggested that postoperative adjuvant radiation therapy with long-term follow-up is required for incompletely resected EVN.     

Prognosis and treatment outcomes of central neurocytomas: clinical interrogation based on a single center experience

Introduction

Central neurocytoma (CN) is a very rare neuronal neoplasm. The clinical implications of the potential prognostic factors for these lesions, including tumor atypia, have therefore not been clarified.

Methods

Forty CN patients were enrolled and reclassified as typical or atypical in accordance with an MIB-1 labeling index (LI) of above and below 2%.

Results

We classified our retrospective study cohort as 21 (52.5%) typical and 19 (47.5%) atypical CN cases. No significant differences were found in terms of sex, mean age, mean tumor size or tumor location between these groups. Recurrences occurred in 2 (9.5%) typical and 6 (33.3%) atypical cases. The typical CN 2-,3- and 5-year PFS rates were 100%, 100%, 92.3%, and those for the atypical group were 93.8%, 78.1%, 65.1%, respectively (p?=?0.02). The PFS rates did not statistically differ by treatment modality (gross total resection alone, subtotal resection (STR) alone and STR plus radiation therapy (RT) or radiosurgery (RS)) either in the whole cohort (p?=?0.75) or in the typical CN and atypical CN subgroups (p?=?0.45 and 0.98, respectively). An atypical histology was the only prognostic indicator of recurrence by univariate analysis (hazard ratio: 5.40, p?=?0.04).

Conclusions

An atypical lesion (MIB-LI?>?2%) is an important prognostic indicator in CN. The clinical implications of the extent of resection for CN patients are still debatable. The use of STR plus RT or RS may be a viable treatment strategy for CN but different therapeutic and follow-up approaches for atypical CN will be needed.

     

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 0.812.5%,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.     

Central nervous system neurocytoma and neuroblastoma in adults-report of eight cases

Summary The clinical features, pathologic findings and treatment courses of eight adults with central nervous system small-cell neuronal tumors were reviewed. Five patients had central neurocytomas, two patients central nervous system neuroblastomas, and one patient a neurocytoma-like spinal cord tumor. The neurocytomas were intraventricular, moderately cellular tumors with bland nuclei and perinuclear halos. Patients with neurocytoma were treated with surgery, radiation therapy, and/or chemotherapy, and have followed favorable clinical courses. The neuroblastomas were intraparenchymal, hypercellular tumors with necrosis and frequent mitoses. Patients with neuroblastomas were treated with surgery, radiation therapy and chemotherapy, with some clinical response, but overall poor survival. One of the two patients developed extracranial metastasis. The spinal cord tumor had histologic features of neurocytoma, and responded well to biopsy and radiation therapy. The cases are compared with the varieties of small-celled neuronal tumors described in the literature, and pathologic, histogenetic and treatment implications are discussed. This paper was presented in part at the United States and Canadian Academy of Pathology meeting, Boston, MA, March 7, 1990     

Ependymomas: MIB-1 proliferation index and survival

The biologic behavior of ependymomas is highly variable, and its correlation with histologic features is at best imprecise. This retrospective study attempted to correlate the malignant histologic characteristics of ependymomas with MIB-1 proliferation index and survival. Biopsy and resection specimens taken from 34 patients who received treatment 1972 to 1996 were histologically examined. The patients' ages range was 1 to 59 years. The histologic specimens were assessed for anaplastic features (necrosis, mitosis, vascular proliferation, cellular pleomorphism, and overlapping of nuclei) and an MIB-1 (Ki-67 antigen) proliferation index was also determined. The overall median MIB-1 proliferation index was 7.8% (range 0.1 – 62.5%). An MIB-1 of 20% was significant for a decrease in survival (RR=5.7) (p=0.0013). The median MIB-1 for patients < 20 years old was 20.6% with range (0.1, 43%), while that for patients > 20 years was 5.1% (range 0.2, 9.4%) (KW p=0.055). Three of 5 histological features evaluated were significantly associated with outcome: > 5 mitotic figures per high-power field, necrosis, and vascular proliferation, but not nuclear overlap or pleomorphism. All pathologic factors except pleomorphism were significantly related to the MIB-1 proliferation index. In brief, our data support the association of poor prognoses in ependymomas with young age, the presence of three to four anaplastic histologic features, and an MIB-1 proliferation index > 20%.     

Rapid shrinkage of remnant central neurocytoma after gamma knife radiosurgery: a case report

Central neurocytomas are typically benign tumors that have high local control rates after gross total resection. Radiotherapy for residual or recurrent central neurocytomas is controversial.We report a 30-year-old male with a central neurocytoma in the lateral ventricle. The tumor was subtotally resected through a transcallosal approach, and subsequently treated with gamma knife radiosurgery. The tumor had shrunken markedly by 2 months after radiosurgery and remained unchanged during the one year follow-up period.Gamma knife radiosurgery may be an option for effective treatment of patients with residual or recurrent central neurocytomas.