Central Neurocytomas:the Study Of Characteristics, Treatment Strategies And Relationship With Extraventricular Neurocytomas

Objective:Comparing central neurocytomas with other pathological types of intraventricular brain tumors, we investigated the clinical, imaging and pathological characteristics and explored biological behavior of central neurocytomas.Materials and Methods:We retrospectively described and studied the relevant clinical, radiological, pathological and immunohistochemical data of31patients with central neurocytomas (including electron microscopy examination results of3patients) and46patients with other pathological types of intraventricular tumors (25ependymomas,7oligodendrogliomas,7subependymomas,5diffuse astrocytomas and2subependymal giant cell astrocytomas). All of these patients were treated and diagnosed in the department of neurosurgery in our hospital from January2008to July2014. We compared central neurocytomas with other pathological types of intraventricular tumors, and studied the clinical, imaging and pathological characteristics of central neurocytomas and explored the biological behavior of central neurocytomas.Result: Comparing with other pathological types of intraventricular tumors, central neurocytomas mainly occurred in young adults in the third decade of life (p=0.023), showed a slight male predominance, frequently presented with increased intracranial hypertension due to obstructive hydrocephalus (p=0.004) with the duration less than6months (p=0.373) and were easy to merge hydrocephalus (p=0.006) and papilledema (p=0.045). Radiologically, central neurocytomas commonly located in the frontal horns of lateral ventricles near the foramen of Monro, with well-circumscribed border and no invasion to the adjacent tissue (p<0.05), and usually had calcification, cystic degeneration and signal voids of vessels (p<0.05). Histopathologically, central neurocytomas were composed of homogenous, round and small uniform cells, alternating with neuropil in anuclear areas. Atypical histological features including necrosis, microvascular proliferation and high mitotic count (>3mitoses/10high-power fields) were uncommon in central neurocytomas, and only3case revealed atypical histological features of microvascular proliferation and high mitotic count under light microscopy. Immunohistochemically, central neurocytomas were positive for the neuronal markers synaptophysin (Syn), neuron-specific nuclear protein (NeuN) and neuron-specific enolase (NSE). The Ki-67index of central neurocytomas was low, with an average of2.37%. Three patients with central neurocytomas showed remarkable choline (Cho) resonance and reduced N-acetyl aspartate (NAA) resonance when they were examined by proton magnetic resonance spectroscopy (’H-MRS), and another three cases of central neurocytomas demonstrated clear and dense core vesicles, microtubules, and synapse formation under electron microscopy.Conclusion:Comparing with other pathological types of intraventricular tumors, central neurocytomas have typical clinical, radiological, histopathological, immunohistochemical and ultrastructural characteristics. On the basis of these characteristics, we can establish accurate diagnosis of central neurocytomas. Central neurocytomas mainly differentiate into neurons, exhibit benign biological behavior and rarely appear atypical hyperplasia or distant metastasis. Objective: To explore the treatment strategies for patients with central neurocytomas in this study.Materials and Methods:We retrospectively evaluated the clinical, surgical and follow-up data of31patients with central neurocytomas, who were treated and diagnosed in the department of neurosurgery in our hospital from January2008to July2014. Statistical methods were applied to compare the degree of surgical resection, postoperative complications and clinical outcome with transcortical and interhemispheric transcallosal approaches for the treatment of central neurocytomas, as well as to find the risk factors associating with recurrence in patients with central neurocytomas.Results:All of31patients were performed microsurgical resection and one patient died within one month postoperatively. In the remaining30patients, sixteen patients received radiotherapy and one patient treated with oral temozolomide as chemotherapy. In9patients with recurrent central neurocytomas during the follow-up, six patients with were treated by r knife and3patients treated by second operation, there was no recurrence subsequently and5patients’ Karnofsky Performance Scale (KPS) scores were less than70points. There was no significant difference of degree of surgical resection, postoperative complications and clinical outcome between transcortical and interhemispheric transcallosal surgical approaches in31patients with central neurocytomas (p>0.05). Univariate and multivariate analyses all showed that atypical features (p=0.031) and subtotal resection (p=0.037) were risk factors related to the tumor recurrence. There were5patients with atypical central neurocytomas, and patients with surgical treatment and adjuvant radiotherapy had lower recurrence rate than patients with simple surgical resection in these five patients. Conclusion:Patients with central neurocytomas usually have a good prognosis. The first choice of treatment is microsurgical resection of the tumor with transcortical or interhemispheric transcallosal approache, and we should try to achieve the goal of the maximum safe surgical resection. Atypical features and subtotal resection were risk factors associated with tumor recurrence. R knife therapy is effective for the local recurrent tumors, and radiation therapy should be performed as the postoperative adjuvant therapy for patients with atypical central neurocytomas. Objective:The2007World Health Organization (WHO) classification of tumors of the central nervous system recommended the term’extraventricular neurocytoma’as a single entity from central neurocytoma, and proposed an ICD-O code identical to that of central neurocytoma (9506/1). We described and evaluated the clinical, radiological and pathological features of extraventricular neurocytoma, and explored the treatment strategies for extraventricular neurocytoma. Comparing extraventricular neurocytoma with central neurocytoma, we discussed the relationship between extraventricular neurocytoma and central neurocytoma.Materials and Methods:We retrospectively described the clinical, radiological, pathological and follow-up data of15patients with extraventricular neurocytoma and31patients with central neurocytoma, who were treated and diagnosed in the department of neurosurgery in our hospital from January2008to July2014. The clinical, radiological and pathological features of extraventricular neurocytoma were analyzed, and the treatment for extraventricular neurocytoma was explored. We compared the similarities and differences in central neurocytoma and extraventricular neurocytoma with statistic methods, and discussed the relationship between them.Results:Our group of15patients with extraventricular neurocytoma had the similar expression of histopathology and immunohistochemistry to31patients with central neurocytomas reported in Part I in this study. The15patients with extraventricular neurocytomas were also composed of homogenous, small and round uniform tumor cells and had typical neuropil within anuclear areas. The result of patients with extraventricular neurocytomas showed that extraventricular neurocytomas were positive for the neuronal markers synaptophysin (Syn,15/15), neuron-specific nuclear protein (NeuN,12/15) and neuron-specific enolase (NSE,2/2) immunohistochemically. All15patients with extraventricular neurocytoma underwent microsurgical resection, and one patient died two weeks postoperatively. Nine patients received adjuvant radiotherapy among the rest14patients and2of them treated with oral temozolomide as chemotherapy simultaneously. During the follow-up of the rest14patients with extraventricular neurocytoma,9extraventricular neurocytomas recurred. Seven of the recurrent patients underwent the second surgery and the rest2patients received r knife treatment, and no patients recurred again in the follow-up. Two patients’ Karnofsky Performance Scale (KPS) scores were less than70points and the others recovered well. Atypical features (p=0.013) and subtotal resection (p=0.041) were risk factors related to the tumor recurrence in extraventricular neurocytomas as well. Comparing with patients with central neurocytoma, patients with extraventricular neurocytomas often displayed general seizures (p=0.018) or oppression symptoms (p=0.005), and rarely presented symptoms of increased intracranial pressure (p<0.05) and hydrocephalus (p<0.05). There were higher rates of calcification (p=0.044) and cystic degeneration (p=0.029) in patients with extraventricular neurocytomas. Patients with extraventricular neurocytomas appeared to exhibit a wider morphologic spectrum with higher ki-67index (p=0.002), higher rate of atypia (p=0.027), higher relapse rate (p=0.044), and shorter relapse time (p=0.044).Conclusion:Extraventricular neurocytomas have the similar histological features and immunohistochemical form types with central neurocytomas. However, extraventricular neurocytomas appeared to exhibit a somewhat larger morphological spectrum and greater proliferation potential, and were more likely to show malignant biological behavior associated with atypical features and recurrence. Extraventricular neurocytomas were classified as a distinct entity of neuronal and mixed neuronal-glial tumors at present. Microsurgical resection followed by adjuvant radiotherapy is the primary therapy for patients with extraventricular neurocytomas. Extraventricular neurocytomas showing atypical features or receiving subtotal resection will cause an easier recurrence and a worse prognosis postoperatively.