The new World Health Organization Classification of Central Nervous System Tumors: what can the neuroradiologist really say?

Choroid plexus tumours on MRI: similarities and distinctions in different grades

Background

The therapeutic planning varies for different grades of choroid plexus tumours (CPTs). The aim of this study was to define the similarities and distinctions among MRIs for different grades of CPTs, providing more guidance for clinical decisions.

Methods

We reviewed the MRI findings in 35 patients with CPT verified by surgical pathology, including 18 choroid plexus papillomas (CPPs, grade I), 11 atypical choroid plexus papillomas (aCPPs, grade II), and 6 choroid plexus carcinomas (CPCs, grade III). Nonparametric testing based on ranks was performed to evaluate the association of pathological grade with MRI findings.

Results

Among the 35 CPTs, 29 were located in the ventricular system. The tumours were generally slightly hypo- or isointense on T1WI, slightly hyper- or isointense on T2WI, and moderately or strongly enhanced in post-contrast imaging. Twenty cases were accompanied by hydrocephalus. The median tumour longest diameters of CPPs, aCPPs, and CPCs were 28.6, 44.6, and 60.6 mm, respectively. Four cases were purely cystic, 6 were papillary, 10 were lobulated, and 2 were irregular. Three cases had necrosis. The median oedema diameters of CPPs, aCPPs, and CPCs were 0, 0, and 24.1 mm, respectively. The grades of CPTs were statistically associated with tumour longest diameter (r_s = 0.68, P < 0.001), internal morphology (χ² = 10.32, P = 0.016), necrosis (Z = 2.27, P = 0.023), and oedema diameter (r_s = 0.72, P < 0.001).

Conclusion

CPTs typically appeared as intraventricular papillary or lobulated lesions, often accompanied by hydrocephalus. Larger tumour, irregular or fuzzy internal morphology, presentation of necrosis and wide-ranging peritumoural oedema might increase the likelihood of malignancy.

Pineal Parenchymal Tumors of Intermediate Differentiation: A long-Term Follow-Up Study in Helsinki Neurosurgery

BACKGROUND

Pineal parenchymal tumors of intermediate differentiation (PPTIDs) are rare lesions with particular features compared with other pineal parenchymal tumors.

METHODS

We present a retrospective review of patients with histologically confirmed PPTIDs who were operated on in our department between 1997 and 2015. A demographic analysis and an evaluation of preoperative status, surgical treatment, as well as immediate and long-term clinical and radiologic outcomes were conducted.

RESULTS

Fifteen patients with PPTIDs were operated on between 1997 and 2015. Gross total removal was achieved in 11 cases; 2 patients underwent near-total resection, 1 partial resection, and 1 received brachytherapy after an endoscopic biopsy. Nine patients required external radiation therapy (4 due to a pleomorphic histology of their lesion including pineoblastoma features in 3 of them; 3 after a subtotal resection; and 2 for tumor recurrence). No patient received chemotherapy. The survival rate of our patients was 57.1% at a mean follow-up of 137.2 ± 77.6 months (39-248 months).

CONCLUSIONS

A proper multidisciplinary management of PPTIDs based on a gross total removal of the lesion, and an adjuvant radiotherapy in selected cases, may improve the overall survival of these aggressive tumors.

Adult Brain Tumors and Pseudotumors: Interesting (Bizarre) Cases

Some brain tumors results are interesting due to their rarity at presentation and overwhelming imaging characteristics, posing a diagnostic challenge in the eyes of any experienced neuroradiologist. This article focuses on the most important features regarding epidemiology, location, clinical presentation, histopathology, and imaging findings of cases considered "bizarre." A review of the most recent literature dealing with these unusual tumors and pseudotumors is presented, highlighting key points related to the diagnosis, treatments, outcomes, and differential diagnosis.

Imaging of the Sella and Parasellar Region in the Pediatric Population

Masses in the sella and parasellar region comprise about 10% of all pediatric brain tumors but type and frequency differs from those in adults. Imaging is critical for diagnosis and characterization of these lesions. By assessing the site of origin, signal and contrast enhancement characteristics, and the presence or absence of characteristic patterns, differential diagnosis can narrow the possibilities. The clinical presentation is often characteristic for lesion type and should be considered. This article summarizes the characteristic imaging features of the most frequent pediatric tumors and tumor-mimicking lesions in children in this region.

Hsa-miR-495 acts as a tumor suppressor gene in glioma via the negative regulation of MYB

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression at the post-transcriptional level. Previous studies have reported that there are causative links between the abnormal regulation of miRNAs and cancer development. Hsa‑miR‑495 has previously been demonstrated to be downregulated, and to function as a tumor suppressor, in numerous types of human cancer. However, the function and molecular mechanism of hsa‑miR‑495 in glioma remains unclear. In the current study, the expression and effects of hsa‑miR‑495 on glioma were evaluated. It was identified that the expression levels of hsa-miR-495 were downregulated in glioma tissues and cell lines. Furthermore, restoration of hsa-miR-495 inhibited glioma cell proliferation and invasion in vitro. Notably, a luciferase reporter assay revealed that hsa‑miR‑495 was able to directly target v‑myb avian myeloblastosis viral oncogene homolog (MYB) in glioma cells. In addition, an RNA interference assay indicated that MYB knockdown inhibited glioma cell proliferation and invasion in vitro. In conclusion, the results of the present study suggested that hsa‑miR‑495 may act as a tumor suppressor gene in glioma by directly inhibiting MYB expression, which may provide a novel therapeutic strategy for the treatment of glioma.

Are we over treating Pineal Parenchymal tumour with intermediate differentiation? Assessing the role of localised radiation therapy and literature review

Pineal Parenchymal tumour with intermediate differentiation (PPTID) is a rare disorder, first classified by World Health Organisation in 2000. There are very few published data available and optimal management is yet to be determined. Management has varied from surgery alone to craniospinal radiotherapy with or without chemotherapy. We present our experience of PPTID treated with radiotherapy alone. We conducted a retrospective review of patients who were diagnosed with PPTID and treated with radiation therapy at our institute from 2010 onwards. Between January 2010 to January 2013, 5 patients of PPTID were treated at our institute. Median age is 44 (range 24-62). All patients had preoperative MRI scan of brain and spine. Imaging did not identify any spinal dissemination. None of the patients underwent a gross total resection, due to the tumour location and technical difficulties. All patients were treated with external beam radiation therapy to primary lesion only with a dose of 54 Gy in 30 fractions after surgery. 4 patients had good partial response and the remaining 1 has stable disease. After 21.4 months of median follow up no disease recurrence was reported. So far there is no evidence of cerebral white matter abnormalities on MRI scan or neurocognitive disorders. Our experience indicated that localised radiation therapy could be an effective treatment strategy for PPTID, considering the long natural course of the disease and the late adverse effects of intensive treatment.

SRL-Coated PAMAM Dendrimer Nano-Carrier for Targeted Gene Delivery to the Glioma Cells and Competitive Inhibition by Lactoferrin

Glioma, as a primary tumor of central nervous system, is the main cause of death in patients with brain cancer. Therefore, development of an efficient strategy for treatment of glioma is worthy. The aim of the current study was to develop a SRL peptide-coated dendrimer as a novel dual gene delivery system for targeting the LRP receptor, an up-regulated gene in both BBB and glioma cells. To perform this investigation, our newly developed nanocarrier (PAMAM-PEG-SRL) was used for gene delivery to C6 glioma cell lines. DNA (GFP) was loaded in these functionalized nanoparticles and their cellular uptake/distribution and gene transfection efficacy was evaluated by fluorescence and confocal microscopy. In vitro studies showed that SRL-modified nanoparticles have good transfection efficacy. Results revealed improved gene transfection efficiency of newly-synthesized delivery system. We also found that lactoferrin, as a LRP ligand, reduced the gene transfection efficacy of the delivery system due to its higher affinity compared to SRL peptides (Competitive inhibition). The present results suggest that the synthesized delivery system has the potential to be used as an alternative targeted drug delivery system for brain tumors.

Angiocentric glioma, a recently added WHO grade-I tumor

Angiocentric glioma (AG) is a distinct group of tumors, grade I according to the 2007 WHO classification of tumors of the central nervous system. It is a rare group predominantly seen in children and young adults, with good prognosis following gross total resection. A young child presented with progressively worsening seizure activity; MRI revealed a lesion involving the left posterior frontal lobe. The lesion was surgically resected, and the child is now free of seizure medications, with good neurological function.

High accuracy of arterial spin labeling perfusion imaging in differentiation of pilomyxoid from pilocytic astrocytoma

INTRODUCTION

Pilomyxoid astrocytoma (PMA) is a relatively new tumor entity which has been added to the 2007 WHO Classification of tumors of the central nervous system. The goal of this study is to utilize arterial spin labeling (ASL) perfusion imaging to differentiate PMA from pilocytic astrocytoma (PA).

METHODS

Pulsed ASL and conventional MRI sequences of patients with PMA and PA in the past 5 years were retrospectively evaluated. Patients with history of radiation or treatment with anti-angiogenic drugs were excluded.

RESULTS

A total of 24 patients (9 PMA, 15 PA) were included. There were statistically significant differences between PMA and PA in mean tumor/gray matter (GM) cerebral blood flow (CBF) ratios (1.3 vs 0.4, p < 0.001) and maximum tumor/GM CBF ratio (2.3 vs 1, p < 0.001). Area under the receiver operating characteristic (ROC) curves for differentiation of PMA from PA was 0.91 using mean tumor CBF, 0.95 using mean tumor/GM CBF ratios, and 0.89 using maximum tumor/GM CBF. Using a threshold value of 0.91, the mean tumor/GM CBF ratio was able to diagnose PMA with 77 % sensitivity, 100 % specificity, and a threshold value of 0.7, provided 88 % sensitivity and 86 % specificity. There was no statistically significant difference between the two tumors in enhancement pattern (p = 0.33), internal architecture (p = 0.15), or apparent diffusion coefficient (ADC) values (p = 0.07).

CONCLUSION

ASL imaging has high accuracy in differentiating PMA from PA. The result of this study may have important applications in prognostication and treatment planning especially in patients with less accessible tumors such as hypothalamic-chiasmatic gliomas.

Pineal region masses--imaging findings and surgical approaches

The anatomy of the pineal region is complex. Despite advances in surgical techniques since the first reported successful pineal region surgery in the early 20th century, pineal region surgery remains challenging owing to the proximity of deep cerebral veins and dorsal midbrain structures critical for vision. In this article, we review the relevant surgical anatomy of the pineal region and discuss historically important and current surgical approaches. We describe specific imaging features of pineal region masses that may affect surgical planning and review neoplastic and nonneoplastic masses that occur in the pineal region.

Concomitant microRNA-31 downregulation and radixin upregulation predicts advanced tumor progression and unfavorable prognosis in patients with gliomas

PURPOSE

To clarify the clinical significance of microRNA-31 (miR-31) and radixin (RDX) in human glioma.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was used to characterize the expression patterns of miR-31 and RDX mRNA in 108 glioma and 20 normal brain tissues. The associations of miR-31 and RDX mRNA expressions with clinicopathologic factors and prognosis of glioma patients were also statistically analyzed.

RESULTS

The expression levels of miR-31 in glioma tissues were significantly lower than those in normal brain tissues (P<0.001), while RDX mRNA was significantly overexpressed in glioma tissues compared with normal brain tissues (P<0.001). There was a negative correlation between miR-31 and RDX mRNA expression in glioma tissues (r=-0.69, P=0.01). Additionally, concomitant miR-31 downregulation and RDX upregulation (miR-31-low/RDX-high) was significantly associated with advanced pathological grade (P=0.001) and low Karnofsky performance score (P=0.01). Moreover, Kaplan-Meier survival and Cox regression analyses showed that the glioma patients with miR-31-low/RDX-high expression had poorest overall survival (P<0.001) and conjoined expression of miR-31-low/RDX-high was an independent prognostic indicator of glioma (P=0.01). Furthermore, subgroup analyses showed that miR-31-low/RDX-high expression was significantly associated with poor overall survival in glioma patients with high pathological grades (for grade III-IV: P<0.001).

CONCLUSIONS

Our findings have implications concerning the importance of concomitant miR-31 downregulation and RDX upregulation in tumor progression and poor prognosis of patients with gliomas. A combined detection of miR-31/RDX expression may benefit us in predicting clinical outcomes of glioma patients with high pathological grades.

Choroid plexus tumours: classification, MR imaging findings and pathological correlation

INTRODUCTION

Choroid plexus tumours (CPTs) are extremely rare intraventricular neoplasms and are prone to bleeding during surgery. The purpose of this study was to summarise the MR imaging characteristics of 13 CPT cases.

METHODS

Magnetic resonance images of 13 patients (six men and seven women; mean age 21.1 years) with pathologically proved CPTs were retrospectively reviewed. MR findings of the tumours were evaluated, with emphasis on their location, size, shape, internal architecture, margin and pattern and degree of enhancement. Differences in signal intensity characteristics were also investigated on MR images and analysed according to histological subtypes.

RESULTS

Lesions were in the lateral ventricles (n = 7), fourth ventricle (n = 5) and cisterna magna (n = 1), with a mean size of 5.0 cm (range 2.0-7.9 cm). The tumour parenchyma was a mixture of nodular or patchy areas of inhomogeneous isointense to slightly hyperintense signal on T2-weighted images. On postcontrast MR images, all lesions, except for one, had moderate to marked contrast enhancement. Multiple tortuous areas of 'flow void' signal extended through all the tumours except for two. A thin capsule could be seen in six cases.

CONCLUSION

Observation of large intraventricular tumours with inhomogeneity on T2-weighted images and flow void is suggestive of CPTs. Checking for signs of a thin capsule, extensive peritumoural oedema and necrosis may be useful when classifying CPTs.