Clinicopathological features and treatment outcome of central neurocytoma: a single institute experience – The Egyptian Journal of Neurology, Psychiatry and Neurosurgery

The present study aimed to examine the clinicopathological characteristics and treatment outcomes for central neurocytoma in a Saudi population. Inconsistent with the majority of the reported cases, our cohort was predominantly young adults below 30 years with female preponderance. Our patients’ mean age was 29 years compared to Zubair cohort which was 26 years [11] and Hallock cohort of patients which was 31 years [9].

We reported a wide range of symptoms, with headache and paresis being the most commonly found symptoms in over two-thirds of the cases, in agreement with many studies [7,8,9]. Chen et al. reported seizures and weakness in all studied patients [6]. The presence of seizures in 17.7% of our cases is comparable to the data presented by Garcia et al. [8].

We found that all of our patients had intraventricular located tumors which were comparable to the series of Zubair and Leenstra [11, 13]. Radiologically, 64.7% of cases presented with a cystic mass with heterogeneous contrast enhancement which is somewhat highly reported in our patients compared to Chen data who reported 5 out of 9 patients (55%) to have cystic changes only [6]. Calcification within the tumor was noted in 47.1% of cases which is less reported compared to Zubair data which reported 60% of cases to have calcification [11]. These radiological findings also highlight the importance of keeping neurocytoma as a differential diagnosis, along with oligodendroglioma, and anaplastic ganglioglioma, among young adults [12].

Fourteen patients (82.5%) were able to undergo GTR and NTR, whereas 17.5% of patients had STR due to technical challenges of removing intraventricular lesions. Sharma et al. [18] stated that a quarter of neurocytoma patients had STR in their comprehensive review, while Aftahy et al. showed 10% STR in their studied patients [19]. The superiority of GTR compared to STR regarding the local control rate is reported in the literature [16,17,18,19]. Considering the theoretical and data supporting the correlation between STR and local recurrence, still we cannot study that in our patients to a small number of patients.

As regards pathological data, we reported 88% positivity of NSE and synaptophysin. These data are comparable to Chen’s data which showed 7 out of 9 cases (78%) to have synaptophysin positivity and 100% NSE positivity [14]. In addition, Zubair et al. showed 100% synaptophysin positivity for his studied 35 patients [11]. We reported 100% positive Neu-N test performed for 11 cases of our patients which is comparable to the review of Lee et al. [12]. On the other hand, we reported MIB-1 labeling index as 0.7–5% in the 10 studied cases which was more than 2% in 4 out of 10 cases, while Chen reported levels of 0.1–6.8% [14].

In a multicenter retrospective multicenter study conducted by Vasiljevic et al., neuronal markers synaptophysin and Neu-N proved to be positive in all patients, similar to our data.

Overall survival reported in our cohort of patients was 100% compared to 83% in Mayo clinic data reviewed by Leenstra et al. that included 45 patients treated between 1971 and 2003 [13]. The 5-year progression-free survival (5-year PFS) was 70% in our study compared to 60% after 10 years in Leenstra data [13]. Mayo Clinic patients whose tumor had a low mitotic index experienced a 10-year local control rate of 74% compared with 46% for patients with a tumor of a high mitotic index. A comparison of GTR with STR showed no significant difference. They also showed that PORT improved local control at 10 years (75% with RT vs. 51% without RT).

Acknowledging the limitation of low patient numbers in our data, we suggest that there may be improved local control for patients who underwent RT after STR or recurrent diseases. Chen et al. studied 63 patients and concluded that the group who had RT after incomplete resection enjoyed the same overall and progression-free survival compared to those who had GTR [14].

Hallock et al. studied 19 patients treated surgically and reported 8 recurrences; 4 out of them received radiation and chemotherapy with a 10-year PFS of 62% and concluded that surgery provides durable local control rates in two-thirds of patients. Our results are marginally higher (5-year PFS 70%) compared to Hallock data, probably because the number of patients who had GTR and NTR are higher in our patients and our salvage treatment was mainly surgery.

The appropriate treatment of residual/recurrent disease remains ambiguous, with options including re-resection, salvage fractionated radiotherapy, stereotactic radiosurgery (SRS), and/or chemotherapy [15,16,17]. In our study, one patient out of the 3 cases had STR received local radiation adjuvant to surgery. In addition, among the four recurrent cases, re-resection has opted for all except one patient in whom salvage fractionated radiotherapy was offered after the third recurrence.

Genc et al. have reported one of the largest series of SRS for residual or recurrent neurocytomas. Twenty-two residual or recurrent neurocytomas patients were treated by Gamma-knife SRS. They showed a durable reduction in tumor size for 68% of patients [17].

Furthermore, a systematic review concluded that both fractionated RT and SRS were reasonable options for recurrent or residual tumors, with a trend toward better local tumor control and fewer complications among residual neurocytomas treated with SRS [8].

A multicenter retrospective study by Hung et al. stated that SRS achieves good tumor control rates with a reasonable complication profile for 60 patients with central neurocytomas. They showed a 13% recurrence rate following SRS with 93% 5-year local control and 89% 5-year progression-free survival [20].