Ataxia and mobility in children following surgical resection of posterior fossa tumour: A longitudinal cohort study

Purpose To report the course of ataxia in children up to 2 years post-operatively, following surgical resection of a posterior fossa tumour (PFT). Methods Thirty-five children, (median age 9 years, range 4–15) having resection of PFT, were assessed using the Scale for the Assessment and Rating of Ataxia (SARA), Brief Ataxia Rating Scale (BARS) and the mobility domain of the Paediatric Evaluation of Disability Index (PEDI-m) at initial post-operative period (baseline), 3 months, 1 year and 2 years post-operatively. Results Baseline median scores of the SARA and BARS were 8.5 (range 0–35.5), and 7 (0–25) respectively. Ataxia improved at 3 months (median SARA and BARS reduction 3.5 and 4, respectively). Additional gradual improvements in SARA were recorded at 1 (median reduction 2) and 2 years post-operatively (median reduction 0.5). Median baseline PEDI-m was 54.75 (range 15.2–100) with improvement at 3 months (median increase 36.95) and small improvement at 1 year (median increase 2.5) and 2 years (median increase 5.8). Children with medulloblastoma and midline tumours (median baseline SARA 10 and 11, respectively) demonstrated more severe ataxia than children with low-grade gliomas and unilateral tumours (median baseline SARA 7.5 and 6.5, respectively). Conclusion The largest improvement in ataxia scores and functional mobility scores is demonstrated within the first 3 months post-operatively, but ongoing gradual improvement is observed at 2 years. Children with medulloblastoma and midline tumour demonstrated higher ataxia scores long term.

Extra-axial tentorial medulloblastoma: a rare presentation of a common posterior fossa tumour

Medulloblastoma is a common paediatric posterior fossa tumour typically presenting as midline intra-axial mass involving the cerebellar vermis and/or roof of fourth ventricle with typical radiological features. These can be extra-axial in extremely rare instances with less than 50 cases reported so far in literature. We present a case of 18-year-old boy presenting with ataxia and headache. MRI showed dural mass (involving the left tentorium cerebellum) with typical imaging features of extra-axial lesion. The patient underwent near total excision of the tumour. Histopathology along with immunohistochemistry revealed the mass to be medulloblastoma. We present this case to highlight rarity of this location for medulloblastoma and the importance of considering this in the differential diagnosis of atypical posterior fossa extra-axial lesions. This can help in performing other relevant preoperative workup similar on the lines of medulloblastoma and planning of relevant management.

IMG-18. ASSESSMENT OF SUSPECTED DISEASE PROGRESSION USING MULTIPARAMETRIC 18F-CHOLINE PET/MRI IN CHILDHOOD AND TEENAGE-YOUNG ADULT GLIOMAS

OBJECTIVES Evaluation of post-treatment glioma burden remains a significant challenge in children, teenagers and young adults (TYA). The aim of this study was to evaluate the utility of ChoPET/MRI for evaluation of suspected disease progression in childhood and TYA gliomas. METHODS 27 patients (mean age 14 years, range 6–21 years) with suspected glioma disease progression were evaluated with ChoPET/MRI (n=59). Relative cerebral blood volume (rCBV), apparent diffusion coefficient (ADC) and maximum standardised uptake values (SUVmax) in enhancing (enh) and non-enhancing (ne) tumour and normal-appearing white matter (wm) were calculated (rCBVenh, rCBVne, rCBVwm, ADCenh, ADCne, ADCwm, SUVenh, SUVne, SUVwm). 2 blinded radiologists scored tumour probability (1 = unlikely; 5 = definitely). Sensitivity and specificity calculated with gold standard histopathology or clinical follow-up. RESULTS Accuracy for the detection of residual/recurrent tumour on conventional MRI was 96.3% (91.7% ≤14 years, 100% ≥15 years) and ChoPET was 73.1% (66.7% ≤14 years, 80.0% ≥15 years). Lack of agreement was observed in 9/27 patients, with ChoPET superior to MRI in 1 case of a posterior fossa tumour. Tumour component analysis demonstrated significantly higher SUVenh and SUVne than SUVwm (SUVenh: p<0.001; SUVne: p=0.004, equivalent to results were observed for ADV and rCBV (ADCenh, ADCne: p<0.001 vs ADCwm; rCBVenh, rCBVne: p<0.001 vs rCBVwm). CONCLUSIONS MRI is more sensitive than ChoPET in the evaluation of suspected disease progression in TYA gliomas. However, quanititative ChoPET is able to detect enhancing and non-enhancing tumour and may be helpful in evaluating posterior fossa disease where MRI is equivocal.

An analysis of factors determining the requirement of ventriculoperitoneal shunt surgery in the children suffering from posterior fossa tumour: a single centre retrospective review

Background: Hydrocephalus is a relatively common occurrence in a children suffering from the posterior fossa tumour (PFTm). However, there is a divided opinion regarding the ventriculoperitoneal shunt (VPS) surgery before the posterior fossa tumour resection in a child. For the better clinical outcome, we should be able to predict which patient will require VPS following the resection of PFTm. Purpose of our retrospective analysis is to analyse various factors that predicts the necessity of VPS following PFTm resection.Methods: A consecutive series of twenty-six patients who underwent PFTm resection without undergoing VPS preoperatively are analysed in our series.Results: In our series, we found that the younger age at presentation, incomplete tumour resection, longer period of artificial ventilatory support, insertion of external ventricular drain (EVD) and its duration during the postoperative period correlate the necessity of VPS following PFTm resection. However, the severity of hydrocephalus prior to tumor surgery, tumour size, anatomical location of the tumour, tumour dissemination, use of Dural grafts during closure and histopathological type do not predict the requirement of the VPS following PFTm.Conclusions: Patients who are younger at diagnosis should be treated with utmost importance. Gross total resection should be the goal. Factors which predict the likelihood of the EVD which parallels the likelihood of postresection hydrocephalus must be prevented for the better clinical outcome.