Diffusion weighted MR imaging and proton MR spectroscopy findings of central neurocytoma with pathological correlation

Imaging of supratentorial intraventricular masses in children: a pictorial review-part 2

PURPOSE

This article is the second in a two-part series aimed at exploring the spectrum of supratentorial intraventricular masses in children. In particular, this part delves into masses originating from cells of the ventricular lining, those within the septum pellucidum, and brain parenchyma cells extending into the ventricles. The aim of this series is to offer a comprehensive understanding of these supratentorial intraventricular masses, encompassing their primary clinical findings and histological definitions.

METHODS

We conducted a review and analysis of relevant epidemiological data, the current genetics/molecular classifications as per the fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System (WHO CNS5), and imaging findings. Each supratentorial intraventricular mass was individually evaluated, with a detailed discussion on its clinical and histological features.

RESULTS

This article covers a range of supratentorial intraventricular masses observed in children. These include colloid cysts, subependymal giant cell astrocytomas, ependymomas, gangliogliomas, myxoid glioneuronal tumors, central neurocytomas, high-grade gliomas, pilocytic astrocytomas, cavernous malformations, and other embryonal tumors. Each mass type is characterized both clinically and histologically, offering an in-depth review of their individual imaging characteristics.

CONCLUSION

The WHO CNS5 introduces notable changes, emphasizing the vital importance of molecular diagnostics in classifying pediatric central nervous system tumors. These foundational shifts have significant potential to impact management strategies and, as a result, the outcomes of intraventricular masses in children.

Tumors of Choroid Plexus and Other Ventricular Tumors

Tumors arising inside the ventricular system are rare but represent a difficult diagnostic and therapeutic challenge. They usually are diagnosed when reaching a big volume and tend to affect young children. There is a wide broad of differential diagnoses with significant variability in anatomical aspects and tumor type. Differential diagnosis in tumor type includes choroid plexus tumors (papillomas and carcinomas), ependymomas, subependymomas, subependymal giant cell astrocytomas (SEGAs), central neurocytomas, meningiomas, and metastases. Choroid plexus tumors, ependymomas of the posterior fossa, and SEGAs are more likely to appear in childhood, whereas subependymomas, central neurocytomas, intraventricular meningiomas, and metastases are more frequent in adults. This chapter is predominantly focused on choroid plexus tumors and radiological and histological differential diagnosis. Treatment is discussed in the light of the modern acquisition in genetics and epigenetics of brain tumors.

Central neurocytoma-positive and differential diagnosis: An example through a case report

Central neurocytoma is a rare intraventricular tumor, occurring typically in the lateral ventricle of young adults. It is considered as a neuronal-glial benign tumor with favorable prognosis. Imaging is a cornerstone allowing the accurate preoperative diagnosis on the basis of several characteristic features. We report the case of a 31-year-old man who has been complaining of progressive headaches and in whom brain magnetic resonance imaging revealed a central neurocytoma. We remind then, through a literature review, the main criteria to set the diagnosis of this tumor and rule out the other possible diagnoses.

Gamma Knife radiosurgery for the treatment of central neurocytoma: a single-institution experience of 25 patients

Central neurocytomas (CNs) are extremely rare tumors that account for 0.1-0.5% of all intracranial neoplasms. Recently, Gamma Knife radiosurgery (GKRS) has become a treatment option in patients with CN. We aimed to evaluate the efficacy and safety of GKRS in 25 CN patients and review the results along with relevant literature. GKRS patient database was searched, and 25 patients who underwent GKRS for CN between 2009 and 2018, were evaluated retrospectively. The study cohort included 15 female and ten male patients with a median age of 32 years (range, 5-60). The most common presenting symptom was headache (88%). The neurological examination was unremarkable in all patients, except for one patient with decreased vision. Twenty patients (80%) had a history of surgical resection. Most of the tumors (92%) were located in the ventricles, and the median tumor volume was 4.8 cm³ (range, 0.8-28.1). The median marginal dose was 14 Gy (range, 12-15) to a median isodose of 50% (range, 40-50). Following a median follow-up of 80 months (range, 36-138), local tumor control was achieved in 100% of patients. Distant recurrence was observed in one patient (4%). No adverse radiation effect was observed. Regarding non-specific post-GKRS symptoms, one patient experienced a prolonged headache, and one epileptic patient experienced a brief partial seizure. In our patient cohort, GKRS yielded favorable local tumor control (100%) during a median follow-up of 6.6 years. Our series demonstrates that GKRS is an effective and safe treatment option for patients with primary or residual CNs.

Application of diffusion-weighted imaging combined with apparent diffusion coefficient in differential diagnosis between central neurocytoma and ependymoma

PURPOSE

Differential diagnosis between central neurocytoma and ependymoma is very important for making preoperative scheme. We explored the application of diffusion-weighted imaging (DWI) combined with apparent diffusion coefficient (ADC) in differential diagnosis between both.

METHODS

The data of preoperative MR plain and contrast-enhanced scan, DWI and ADC values of neoplastic solid parts from 18 cases with central neurocytoma and 19 cases with lateral ventricular ependymoma, were retrospectively analyzed. Mann-Whitney test was used for the comparison of ADC values between central neurocytoma and ependymoma. The application of ADC values in the differential diagnosis between central neurocytoma and ependymoma was evaluated by ROC curve.

RESULTS

The lesions showed hyperintensity-dominant mixed signal intensity on DWI and mean ADC was (0.65 ± 0.13) × 10^-3 mm²/s in the 18 cases with central neurocytoma. In the 19 cases with ependymoma, 13 had hyperintensity-dominant mixed signal intensity on DWI and 6 had hypointensity-dominant mixed signal intensity on DWI, and mean ADC was (1.20 ± 0.23) × 10^-3 mm²/s. The mean ADC value was significantly higher in the 19 cases with ependymoma than in the 18 cases with central neurocytoma (P < 0.001). The ADC of 0.87 × 10^-3 mm²/s might be used as a threshold for differential diagnosis between central neurocytoma and ependymoma with an area under ROC curve of 0.98 ± 0.02 and a 95% confidence interval of 0.95-1.00. Its sensitivity, specificity, and accuracy were 90%, 100%, and 90%, respectively.

CONCLUSION

There is a certain overlap in MRI imaging features between central neurocytoma and ependymoma. DWI combined with ADC value can improve peoperative diagnostic accuracy.

Histogram Analysis Parameters ADC for Distinguishing Ventricular Neoplasms of Ependymoma, Choroid Plexus Papilloma, and Central Neurocytoma

Background

To determine if histograms of ADC can be used to differentiate ventricular ependymomas, choroid plexus papillomas (CPPs), and central neurocytomas (CNCs).

Material/Methods

We retrospectively reviewed records from 185 patients from 1 January 2014 to 1 November 2018. We finally included a total of 60 patients: 36 (60.00%) had histologically confirmed ependymomas, 10 (16.67%) had CPPs, and 14 (23.33%) had CNCs, as determined by routine MRI scanning at 3.0T. The ADC histogram features were derived and then compared by Kruskal-Wallis test (they were not normally distributed). Bonferroni test was used to compare the 2 groups and then we determined the ROC.

Results

Ependymomas had significantly higher mean, perc.01%, perc.10%, perc.50%, perc.90%, and perc.99% than CNCs. Ependymomas had significantly lower skewness than CNCs. Histogram metrics derived from mean, perc.01%, perc.10%, perc.50%, and perc.90% were significantly lower in the CNCs group than in the CPPs group. CPPs showed significantly lower skewness than CNCs. A threshold value of 86.50 for perc.50% to predict ependymomas from CNCs was estimated (AUC=0.97, sensitivity=97.20%, specificity=85.70%). Optimal diagnostic performance to predict CPPs from CNCs (AUC=0.96, sensitivity=100.00%, specificity=85.70%) was obtained when setting Perc.50%=84.00 as the threshold value.

Conclusions

The ADC histogram analysis may help to discriminate ependymomas, CPPs, and CNCs.

Stereotactic radiosurgery for hypervascular intracranial tumors

OBJECTIVE

To evaluate the safety and efficacy of SRS treatment of central neurocytomas (CNCs), cavernous sinus hemangiomas (CSHs), and glomus tumors (GTs); and to compare upfront stereotactic radiosurgery (SRS) and adjuvant SRS in the treatment of these hypervascular tumors.

METHODS

This was a retrospective review of consecutive CNCs, CSHs, and GTs treated with SRS between 1993 and 2017. Tumor response was categorized based on volumetric analysis on magnetic resonance imaging: (1) tumor regression [> 10% decrease in tumor volume (TV)]; (2) stable tumor (≤ 10% change in TV); or (3) tumor progression (> 10% increase in TV).

RESULTS

Sixty hypervascular tumors (CNC: 28; CSH: 16; GT: 16) underwent SRS between 1993 and 2017. Margin doses were 13 Gy, 12 Gy, and 14 Gy for CNCs, CSHs, and GTs, respectively. Tumor regression was observed in 54 tumors (90%) with initial SRS after a median follow-up of 82 months. Relative reductions in TVs for CNCs were 38%, 52%, and 73% at 12, 24, and 48 months, respectively. Relative reductions in TVs for CSHs were 51%, 68%, and 88% at 12, 24, and 48 months, respectively. Relative reductions in TVs for GTs were 22%, 31%, and 47% at 12, 24, and 48 months, respectively. Upfront SRS was performed in 26 patients (43%). No difference in relative TV reductions were found between upfront and adjuvant SRS. Adverse radiation effects were observed in five patients. No mortality was encountered.

CONCLUSION

SRS for hypervascular tumors is associated with high rates of tumor regression with low risk of complications. No significant difference in rates of relative TV reduction were found between upfront and adjuvant SRS. Hence, upfront SRS may be considered in select patients.

Clinical, radiological, pathological and prognostic aspects of intraventricular oligodendroglioma: comparison with central neurocytoma

Studies comparing intraventricular oligodendroglioma (IVO) and central neurocytoma (CN) in terms of their clinical, radiological and pathological features are scarce. We, therefore, investigated the similarities and differences between these types of tumors to get a better understanding of how they may be more properly diagnosed and treated. The clinical manifestations, CT/MRI findings, pathological characteristics and clinical outcomes of 8 cases of IVOs and 12 cases of CNs were analyzed retrospectively. Both IVO and CN occurred most commonly in young adults and manifested with symptoms of increased intracranial pressure secondary to obstructive hydrocephalus. However, they were radiologically different in location (p = 0.007), diffusion-weighted imaging (p = 0.001), "scalloping" appearance (p = 0.006), flow void sign (p = 0.006) and ventricular wall invasion (p = 0.000). Histologically, significant differences in mitotic count (p = 0.008) and parenchymal infiltration (p = 0.01) were noted. Immunohistochemically, significant differences in the expression of Olig2 (p = 0.000), Syn (p = 0.01) and NeuN (p = 0.000) were observed. In addition, MIB-1 labeling index (p = 0.035) and case fatality rate (p = 0.021) of IVO were much higher than those of CN, while survival rate of IVO was much lower than that of CN (p = 0.028). IVO and CN are similar in onset age and clinical manifestations, but have different imaging and pathological features. Patients with IVOs may have a relatively poorer prognosis compared to those with CNs.

Tetraventricular central neurocytoma: A rare presentation with imaging-pathologic correlation

Central neurocytoma (CN) is a benign intraventricular neuronal tumor with a favorable prognosis. It accounts approximately 0.25–0.5% of intracranial tumors. In this report, we describe a very rare case of tetraventricular CN with imaging-pathologic correlation, and discuss their atypical features in a location together with treatment options. A 27-year-old man was admitted to the hospital with symptoms of progressive headaches of several months’ duration. Magnetic resonance imaging of the brain revealed a well-circumscribed, lobulated intraventricular mass with numerous intratumoral cystlike areas. The mass was located in the enlarged lateral ventricles bilaterally extending to the third and the fourth ventricle. Surgical removal of the 4^th ventricle component of the tumor was performed. Histomorphological and immunohistochemical findings of the tumor were consistent with CN. After pathological diagnosis, gamma knife surgery was performed. CN may present with atypical features in a location with a usual histopathological findings. To our knowledge, we described the third case of tetraventricular CN, which was partially treated with both surgical resection and radiosurgery.