Thinking outside the shunt-sterile CSF malabsorption in pilocytic astrocytomas: case series and review of the literature

MRI as a one-stop destination for evaluation of CSF shunt malfunction

Background

Despite the high-frequency rate of cerebrospinal fluid shunt malfunction, radiological evaluation of CSF shunts has remained deficient, focusing mainly on demonstrating secondary signs of shunt failure rather than evaluating the shunt tube itself. We aimed to study the utility of different MR pulse sequences in evaluating the cranial and abdominal ends of CSF shunts in order to identify the potential cause of shunt failure and its impact on patient management.

Results

Twenty-five patients (18 males, 7 females, median age 2.5 years, IQR 0.75–15) were enrolled in the study, having 28 ventriculo-peritoneal shunts and single ventriculo-gallbladder shunt. The catheter lumen and fine intraventricular septae were only demonstrated in 3D-DRIVE sequences (p < 0.001). Except for three patients (having cranial end-related complications), all patients with cranial and/or abdominal end-related complications received surgery (p < 0.001, positive likelihood and negative likelihood ratios = 7.27, 0.3, respectively, sensitivity = 0.7 and specificity = 0.9). MRI findings (luminal occlusion, disconnection, CSF collection, or migration) were consistent with operative data. There is no significant difference between patients who underwent surgery and those with conservative management, or symptomatic and asymptomatic patients in terms of the prevalence of ventricular dilatation or white matter signal abnormality. The results of the abdomino-pelvic fat-suppressed T2-WI showed excellent agreement with ultrasound findings (Cohen’s Kappa 0.9). Quantitative PC could give insights into CSF dynamics, which depend on the site and cause of shunt malfunction.

Conclusions

MRI could be a one-stop destination for evaluating patients with suspected non-acute shunt malfunction. It was found to have clinical relevance in terms of accurately locating the exact site and possible cause of shunt-related complications.

Endoscopic ultrasonic aspiration as alternative to more invasive surgery in initial management of optic pathway gliomas in children

INTRODUCTION

Optic pathway gliomas (OPGs) presenting with acute hydrocephalus represent a true neurosurgical and neurooncological challenge. Two main strategies are currently used: microsurgical removal of the tumor, restoring CSF pathways, and endoscopic biopsy associated with ventriculo-peritoneal shunt implantation. Since the availability of an ultrasonic aspirator handpiece, that can be used inside the working channel of a neuroendoscope, a different less invasive surgical strategy can be used.

METHODS

Four pediatric patients were treated by endoscopic ultrasonic aspiration, in order to remove the upper pole of the tumor, obtaining tissue for diagnosis and restoring CSF pathways as initial treatment of OPG invading the third ventricle and causing hydrocephalus due to simultaneous blockage of both Monro foramina and of the Sylvian aqueduct. Surgical technique is described. Pre-operative and post-operative volumes were calculated on magnetic resonance imaging.

RESULTS

In all cases, the surgical procedure was uneventful, the biopsy was diagnostic, and CSF pathways were restored. The amount of tumor removed ranged between 31 and 76%. All patients underwent oncological treatment of their tumors. One patient received V-P shunt only 1 year after endoscopic decompression due to tumor progression.

CONCLUSION

Our preliminary results show that the use of endoscopic cavitron aspirator is safe and effective to obtain CSF flow restoration and tumor biopsy (for histological and molecular purposes), avoiding CSF shunt implant in the acute phase and offering the chance to obtain a consistent tumor debulking in a minimally invasive fashion. Neuroendoscopic approach together with modern target therapy offers the opportunity to avoid or delay major surgery.

Clinical and molecular characteristics of pediatric low-grade glioma complicated with ventriculo-peritoneal shunt related ascites

INTRODUCTION

Ventriculo-peritoneal shunt (VPS) related ascites is a rare complication of pediatric low grade gliomas (pLGG). Physiopathology of this complication is not fully understood and there is paucity of data regarding the molecular profile of pLGG gliomas complicating with ascites and the optimal management of this unusual event.

METHODS

International multi-institutional retrospective analysis of patients diagnosed with BRAF altered pLGG and ascites arising as a complication of VPS. Demographics, tumor characteristics, therapeutic approaches and outcomes were recorded.

RESULTS

Nineteen patients were identified. Median age at diagnosis was 14 months (R: 2-144). Most patients (17; 89.4%) presented with lesions involving the optic pathway. Mean tumor standard volume was 34.8 cm² (R: 12.5-85.4). Pilocytic Astrocytoma was the most frequent histological diagnosis (14;7 3.7%). Eight (42.1%) tumors harbored BRAF V600-E mutation and seven (36.8%) KIAA1549 fusion. The onset of ascites was documented at a median time of 5 months following VPS insertion. Four (21%) patients were managed with paracentesis only, 7(36.8%) required both paracentesis and shunt diversion, 7(36.8%) required only a shunt diversion and 1 (5.2%) patient was managed conservatively. Chemotherapy regimen was changed in 10 patients following ascites. Eight patients received targeted therapy (4 dabrafenib/4 trametinib) and 5 were radiated. There were eleven survivors with a median OS of 69 months (R: 3-144).

CONCLUSIONS

Ascites is an early feature in the clinical course of young patients with midline BRAF altered pLGG, with high mortality rate observed in our cohort. The hypothesis of ascites as an adverse prognostic factor in pLGG warrants further prospective research.