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

Abstract

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.

Neurocytoma of the pituitary gland: A case report and literature review

“…Rades et al (12) have documented that postoperative radiotherapy improved the local control and survival rates of patients with incomplete resection. The optimal dose of radiotherapy appears to be 54-60 Gy (3).…”

Gamma Knife Radiosurgery for Central Neurocytomas

“…Central neurocytomas usually arise from the neuronal cells of the septum pellucidum, fornix, or subependymal plate of the lateral or third ventricle, so these tumors are surrounded by cerebrospinal fluid and occur as a small tumor attached to normal structures. 7,8,10,16,26,27,31) Therefore, radiosurgery has a lower risk of radiation injury than conventional radiotherapy because of the small target volume, relatively low marginal dose for tumor growth control, and steep fall-off into the peripheral normal tissue. The present series included no complication caused by radiation-induced peripheral edema or radiation necrosis, and previous studies identified only one case of side effects (Table 2).…”

“…3,4,6,7,11,12,14,15,17,21,24,27,29,30,32) Central neurocytoma tends to be radiosensitive, so postoperative conventional radiotherapy and radiosurgery have been used to treat residual tumors after incomplete surgical resection or recurrence. 15,20,[23][24][25][26]31,32,34) Gamma knife radiosurgery (GKS) is effective against postoperative residual tumors or local recurrences of central neurocytomas. [1][2][3]6,9,13,14,25,27,28,35,37) However, central neurocytoma is rare and often resected completely, with conservative treatment for the relatively small residual or recurrent tumors.…”

Neuronal and Mixed Neuronal-Glial Tumors of the Central Nervous System

“…These data suggest that central neurocytomas are genetically distinct from oligodendrogliomas. Although the expression profiles of cerebellar liponeurocytomas appear to have a closer relationship to those of central neurocytomas, the lack of TP53 mutations in central neurocytomas suggests the involvement of different genetic pathways (60,66,67).…”

“…The glial components seen in the complex forms of DNTs have a highly variable form due to many causes : 1-they may form typical nodules with diffuse pattern; 2-they may mimic usual categories of gliomas and may illustrate unusual features; 3-they usually resemble low-grade gliomas, but may demonstrate nuclear atypia, some mitotic activity, or microvascular-like proliferation and ischemic necrosis; 4-they display a microvascular network. Within the glial components, typically calcified vessels are frequent that may behave as vascular malformations and be responsible for bleeding (65,66,86,99,101,103,104,105). "Non-specific" histological variants of DNTs, identified according to clinical presentation as well as their cortical location, neuroimaging features, and steadiness on long-term preoperative imaging follow-up, have been described (77).…”