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OBJECTIVE Infradiaphragmatic craniopharyngiomas (ICs) represent a distinct subtype, harboring a sellar-suprasellar origin and generally growing in the extra-arachnoidal space contained by the diaphragma sellae. They have been considered ideal for surgical removal through the transsphenoidal approach since the 1960s. The authors present a multicentric national study, intending to selectively analyze IC behavior and the impact of the transsphenoidal endoscopic endonasal approach (EEA) on surgical outcomes. METHODS Craniopharyngiomas that were intraoperatively recognized as infradiaphragmatic and removed with standard EEA between 2000 and 2021 at 6 Italian neurosurgical departments were included in the study. Clinical, radiological, and surgical findings and outcomes were evaluated and reviewed. RESULTS In total, 84 patients were included, with 45.23% identified as pediatric cases and 39.28% as having recurrent tumors. The most common presenting symptoms were endocrine (75%), visual (59.52%), and hypothalamic (26.19%) disorders. ICs were classified as extending below (6 intrasellar and 41 occupying the suprasellar cistern) or above (26 obliterating the anterior recesses of the third ventricle and 11 extending up to the foramina of Monro) the chiasmatic cistern. Gross-total resection (GTR) was achieved in 54 cases (64.28%). Tumor extension above the chiasmatic cistern and calcifications were associated with lower likelihood of GTR. The cumulative rate of postoperative complications was 34.53%, with CSF leak being the most common (14.28%). Endocrine, visual, and hypothalamic functions deteriorated postoperatively in 41/78 patients (52.56%), 5/84 (5.95%), and 14/84 (16.67%), respectively. Twenty-eight patients (33.33%) had recurrence during follow-up (mean 63.51 months), with a mean 5-year progression-free survival (PFS) rate of 58%. PFS was greater in patients who achieved GTR than patients with other extent of resection. CONCLUSIONS This is the largest series in the literature to describe ICs removed with standard EEA, without the need for additional bone and dural opening over the planum sphenoidale. EEA provides a direct route to ICs, the opportunity to manage lesions extending up to the third ventricle without breaching the diaphragma, and high rates of GTR and satisfactory clinical outcomes. Increased surgical complexity and morbidity should be expected in patients with extensive suprasellar extension and involvement of the surrounding vital neurovascular structures.

Dandy-Walker malformation (DWM) is a posterior fossa malformation characterized by a huge posterior fossa cyst in communication with the fourth ventricle. Hydrocephalus is associated with more than 80% of cases and is usually treated by shunting. Despite infection being a common complication of the shunt, abscess formation within the cyst was reported only once.A neonate affected by DWM developed a posterior fossa abscess following a shunt infection. The purulent collection was refractory to standard treatment (antibiotics and burr hole drainage); therefore, an endoscopic approach was performed in order to remove the purulent collection under direct vision. This material was aspirated with the help of an endoscopic ultrasonic aspirator. The outcome was favorable, with a resolution of infection and re-implantation of the ventriculo-peritoneal shunt. Surprisingly, post-operative radiological examination showed substantial modification of the anatomy of the posterior fossa with disappearing of the Dandy-Walker cyst. To the best of our knowledge, this is the first documented report of a true Dandy-Walker malformation that modified its anatomical appearance over time.Endoscopic aspiration of intracranial purulent collection should be considered a valid option to manage complicated cases. An endoscopic ultrasonic aspirator may make the procedure more effective and faster.

Medulloblastoma (MB) comprises a group of heterogeneous paediatric embryonal neoplasms of the hindbrain with strong links to early development of the hindbrain 1–4. Mutations that activate Sonic hedgehog signalling lead to Sonic hedgehog MB in the upper rhombic lip (RL) granule cell lineage 5–8. By contrast, mutations that activate WNT signalling lead to WNT MB in the lower RL 9,10. However, little is known about the more commonly occurring group 4 (G4) MB, which is thought to arise in the unipolar brush cell lineage 3,4. Here we demonstrate that somatic mutations that cause G4 MB converge on the core binding factor alpha (CBFA) complex and mutually exclusive alterations that affect CBFA2T2, CBFA2T3, PRDM6, UTX and OTX2. CBFA2T2 is expressed early in the progenitor cells of the cerebellar RL subventricular zone in Homo sapiens, and G4 MB transcriptionally resembles these progenitors but are stalled in developmental time. Knockdown of OTX2 in model systems relieves this differentiation blockade, which allows MB cells to spontaneously proceed along normal developmental differentiation trajectories. The specific nature of the split human RL, which is destined to generate most of the neurons in the human brain, and its high level of susceptible EOMES +KI67 + unipolar brush cell progenitor cells probably predisposes our species to the development of G4 MB.

OBJECTIVE The goals of this study were to evaluate the extent of resection (EOR) obtained with an occipital interhemispheric transtentorial approach (OITA) in a series of pediatric patients with pineal region tumors and to define preoperative radiological factors predictive of the EOR. METHODS This is a retrospective cohort study of a series of pediatric patients with pineal tumors who underwent surgery through a microsurgical OITA performed by the senior author during the period from January 2006 to January 2020. The tumor volume was measured preoperatively, and then on sagittal midline cuts the authors identified the most cranial point of the torcular Herophili (defined as the “Herophilus point”) and the lowest point of the inferior profile of the vein of Galen (defined as the “Galen point”). The line joining these two points (defined as the "Herophilus-Galen line" [H-G line]) was used to identify the "Herophilus-Galen plane" (H-G plane) perpendicular to the sagittal plane. Tumor volumes located below and above this plane were measured. EOR was evaluated by measuring residual tumor volume visible on T1 volumetric injected sequences of immediate postoperative MRI. RESULTS Thirty patients were selected for study inclusion. The preoperative mean tumor volume was 15.120 cm3 (range 0.129–104.3 cm3). The mean volumes were 2.717 cm3 (range 0–31 cm3) above the H-G plane and 12.40 cm3 (median 5.27 cm3, range 0.12–72.87 cm3) below the H-G plane. Three patients underwent only biopsy. Of the remaining 27 patients, gross-total resection (GTR; 100% tumor volume) was achieved in 20 patients (74%). In the remaining 7 patients, the mean residual tumor volume was 7.3 cm3 (range 0.26–17.88 cm3). In 3 of these patients, GTR was accomplished after further surgical procedures (1 in 2 patients, 3 in 1 patient) for an overall GTR rate of 85.18%. Larger tumor volume was significantly associated with incomplete resection (p < 0.001). A tumor volume ≤ 2 cm3 above the H-G plane (p = 0.003), linear extension ≤ 1 mm above the H-G line, and pineal histology were predictive of GTR at first OITA procedure (p = 0.001). CONCLUSIONS The H-G line is an intuitive, easy-to-use, and reliable indicator of the superior anatomical limit of visibility during the microsurgical OITA. This anatomical landmark may be useful as a predictor of EOR for pineal tumors performed through this approach. The main limitations of this study are the small number of patients and the exclusively pediatric age of the patient population.

Posterior fossa syndrome (PFS) is a set of debilitating complications that can occur after surgery for posterior fossa tumors. This study aimed to assess the preoperative radiological and surgical risk factors for the onset of PFS in a histologically homogeneous population of children with medulloblastoma and compare it to a similar population of young adults.Included patients underwent posterior fossa surgery for medulloblastoma at 11 Italian neurosurgical wards (2003-2019) and were referred to Fondazione IRCCS Istituto Nazionale dei Tumori in Milan (INT) for postoperative treatments. We collected patients' pre- and post-operative clinical, surgical and radiological data from the INT charts. To compare the distribution of variables, we used the Mann-Whitney and Fisher tests for continuous and categorical variables, respectively.136 patients (109 children and 27 young adults) were included in the study. Among children, 29 (27%) developed PFS, and all of them had tumors at midline site with invasion of the fourth ventricle. Radiological evidence of involvement of the right superior (39% versus 12%; p = 0.011) or middle cerebellar peduncles (52% versus 18%; p = 0.002) seemed more common in children who developed PFS. Young adults showed an expected lower incidence of PFS (4 out of 27; 15%), that may be due to anatomical, physiological and oncological elements.This study confirmed some factors known to be associated with PFS onset and shed light on other debated issues. Our findings enhance an already hypothesized role of cerebellar language lateralization. The analysis of a population of young adults may shed more light on the often-neglected existence of PFS in non-pediatric patients.

Cerebrospinal fluid (CSF) diversion for the treatment of hydrocephalus is one of the most common neurosurgical procedures. Over the years, the development of the neuronavigation system has allowed the surgeon to be guided in real time during the procedures. Nevertheless, to date, the revision rate remains as high as 30-40%. The aim of this study was to investigate the role of intraoperative image guidance in the prevention of shunt failure. We herein report the first literature meta-analysis of image guidance and shunt revision rate in the pediatric population.Principal online databases were searched for English-language articles published between January, 1980, and December, 2021. Analysis was limited to articles that included patients younger than 18 years of age at the time of primary V-P shunt. Articles reporting combined results of free-hand and image-guided placement of ventricular catheter (VC) were included. The main outcome measure of the study was the revision rate in relation to the intraoperative tools. Secondary variables collected were the age of the patient and ventricle size. Statistical analyses and meta-analysis plots were done via R and RStudio. Heterogeneity was formally assessed using Q, IA total of 9 studies involving 2017 pediatric patients were included in the meta-analysis. 55.9% of procedures were carried out with the aid of intraoperative tools, while 44.1% procedures were conducted free hand. The intraoperative tools used were ultrasound (9.1%), electromagnetic neuronavigation (21.07%), endoscope (67.32%), and combined images (2.4%).The image-guided placement of VC was not statistically associated with a lower revision rate. The pooled OR was 0.97 [CI 95% 0.88-1.07] with an IOur analysis suggest images guidance during VC shunt placement does not statistically affect shunt survival. Nevertheless, intraoperative tools can support the surgeon especially in patients with difficult anatomy, slit ventricles or complex loculated hydrocephalus.

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.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.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.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.

OBJECTIVE Widespread use of modern neuroimaging has led to a surge in diagnosing pediatric brain incidentalomas. Thalamic lesions have unique characteristics such as deep location, surgical complexity, and proximity to eloquent neuronal structures. Currently, the natural course of incidental thalamic lesions is unknown. Therefore, the authors present their experience in treating such lesions. METHODS A retrospective, international multicenter study was carried out in 8 tertiary pediatric centers from 5 countries. Patients were included if they had an incidental thalamic lesion suspected of being a tumor and were diagnosed before the age of 20 years. Treatment strategy, imaging characteristics, pathology, and the outcome of operated and unoperated cases were analyzed. RESULTS Overall, 58 children (23 females and 35 males) with a mean age of 10.8 ± 4.0 years were included. The two most common indications for imaging were nonspecific reasons (n = 19; e.g., research and developmental delay) and headache unrelated to small thalamic lesions (n = 14). Eleven patients (19%) underwent early surgery and 47 were followed, of whom 10 underwent surgery due to radiological changes at a mean of 11.4 ± 9.5 months after diagnosis. Of the 21 patients who underwent surgery, 9 patients underwent resection and 12 underwent biopsy. The two most frequent pathologies were pilocytic astrocytoma and WHO grade II astrocytoma (n = 6 and n = 5, respectively). Three lesions were high-grade gliomas. CONCLUSIONS The results of this study indicate that pediatric incidental thalamic lesions include both low- and high-grade tumors. Close and long-term radiological follow-up is warranted in patients who do not undergo immediate surgery, as tumor progression may occur.

PurposeTo evaluate the anatomical variations of dural venous sinuses in children with external hydrocephalus, proposing a radiological grading of progressive anatomic restriction to venous outflow based on brain phase-contrast magnetic resonance venography (PC-MRV); to evaluate the correlation between positional plagiocephaly and dural sinuses patency; and to compare these findings with a control group to ascertain the role of anatomical restriction to venous outflow in the pathophysiology of external hydrocephalus.MethodsBrain MRI and PC MRV were performed in 97 children (76 males, 21 females) diagnosed with external hydrocephalus at an average age of 8.22 months. Reduction of patency of the dural sinuses was graded as 1 (stenosis), 2 (complete stop) and 3 (complete agenesis) for each transverse/sigmoid sinus and sagittal sinus. Anatomical restriction was graded for each patient from 0 (symmetric anatomy of patent dural sinuses) through 6 (bilateral agenesis of both transverse sinuses). Ventricular and subarachnoid spaces were measured above the intercommissural plane using segmentation software. Positional plagiocephaly (PP) and/or asymmetric tentorial insertion (ATI) was correlated with the presence and grading of venous sinus obstruction. These results were compared with a retrospective control group of 75 patients (35 males, 40 females).ResultsBoth the rate (84.53% vs 25.33%) and the grading (mean 2.59 vs mean 0.45) of anomalies of dural sinuses were significantly higher in case group than in control group. In the case group, sinus anomalies were asymmetric in 59 cases (right-left ratio 1/1) and symmetric in 22. A significant association was detected between the grading of venous drainage alterations and diagnosis of disease and between the severity of vascular anomalies and the widening of subarachnoid space (SAS). Postural plagiocephaly (39.1% vs 21.3%) and asymmetric tentorial insertion (35.4% vs 17.3%) were significantly more frequent in the case group than in the control group. When sinus anomalies occurred in plagiocephalic children, the obstruction grading was significantly higher on the flattened side (p ≤ 0.001).ConclusionDecreased patency of the dural sinuses and consequent increased venous outflow resistance may play a role in the pathophysiology of external hydrocephalus in the first 3 years of life. In plagiocephalic children, calvarial flattening may impact on the homolateral dural sinus patency, with a possible effect on the anatomy of dural sinuses and venous drainage in the first months of life.

Infantile myofibromatosis is a rare and nonmalignant pediatric tumor of myofibroblastic origin that may occur in solitary or multifocal forms. Soft tissue of the head and neck, trunk, and extremities, skeleton, and viscera are usually involved. Intracranial involvement is reported to be extremely rare, and its clinical picture has been poorly characterized. We present two cases of giant infantile myofibromatosis of the skull base with intracranial involvement. The first case with prenatal diagnosis involved extensively the extradural space of the occipital region and was previously treated by chemotherapy for a previous diagnosis of hemangioperycitoma. Tumor was removed at the age of 5 months and no recurrence was observed during the 3-year follow-up. The second case in a 2-year-old baby involved the anterior cranial base, the nasal cavity, the right orbit, and presented massive involvement of the anterior cranial fossa. Surgery allowed complete removal and a recurrence-free period of 7 years after surgery. Treatment options for these unusual cases are presented and details of histological diagnosis are discussed.

Neurological manifestations, such as encephalitis, meningitis, ischemic, and hemorrhagic strokes, are reported with increasing frequency in patients affected by Coronavirus disease 2019 (COVID-19). In children, acute ischemic stroke is usually multifactorial: viral infection is an important precipitating factor for stroke. We present a case of a child with serological evidence of SARS-CoV-2 infection whose onset was a massive right cerebral artery ischemia that led to a malignant cerebral infarction. The patient underwent a life-saving decompressive hemicraniectomy, with good functional recovery, except for residual hemiplegia. During rehabilitation, the patient also developed a lower extremity peripheral nerve neuropathy, likely related to a long-Covid syndrome.

In this video, the authors present ultrasonic resection of calcified tumor of the third ventricle in a 12-year-old boy. He presented to the emergency department with a 1-week history of headache, drowsiness, and bilateral papilledema. Despite extensive calcification visible on a CT scan, a minimally invasive pure endoscopic approach was chosen. The use of an ultrasonic aspirator allows fast and safe removal of the tumor. The histological diagnosis was a low-grade glioneuronal tumor. In conclusion, the endoscopic ultrasonic aspirator is a useful tool to resect tumors in the ventricular system. The presence of calcifications within the tumor does not contraindicate an endoscopic approach. The video can be found here: https://stream.cadmore.media/r10.3171/2023.1.FOCVID22143

Endoscopic aqueductoplasty with aqueductal stenting is an effective surgical procedure for the treatment of isolated fourth ventricle (IFV). Due to the rarity of the underlying pathology, it can be considered a rare procedure that can be performed with different surgical techniques and approaches. To assess long-term functioning of permanent aqueductal stents implanted in children affected by hydrocephalus and IFV and to describe some variations of the same procedure. We reviewed retrospectively all the patients presenting at our institution in the years 1999–2019 for symptoms of isolated fourth ventricle who underwent a surgical procedure of endoscopic aqueductoplasty and/or aqueductal stent. Surgical reports, radiological images, and surgical videos were retrospectively analyzed. Thirty-three patients with symptomatic isolated fourth ventricle (IFV) underwent fifty (50) neuroendoscopic procedures in the period observed. The median age of the patients at the time of first surgery was 7 months, with 22 premature babies. In twenty-nine patients (87.8%), a precoronal approach was performed, while four patients received a suboccipital burr hole. Ten patients were never reoperated since. Twenty-three patients underwent further surgeries: a new aqueductoplasty with aqueductal stent was performed in 13 cases. The remaining 10 patients required a combination of other procedures for management of hydrocephalus. Long-term follow-up showed a permanent stent functioning rate of 87% at 2 years and 73% at 4 years, remaining stable afterwards at very long term (20 years). Endoscopic aqueductoplasty and stenting is a reliable procedure in the long-term management of isolated fourth ventricle.

OBJECTIVE The authors’ objective was to measure the effect of posterior cranial vault distraction (PCVD) plus foramen magnum decompression (FMD) on dural sinus volume and venous flow in patients with syndromic craniosynostosis. METHODS The volumes of the sagittal, straight, transverse, and sigmoid sinuses of 5 consecutive patients with syndromic craniosynostosis who underwent PCVD+FMD were calculated in cubic centimeters with T2-weighted volumetric MRI sequences before surgery, immediately after surgery, and after the end of the distraction process. Tridimensional reconstructions of phase-contrast magnetic resonance angiography (PC-MRA) images were obtained with multiplanar reconstruction (MPR). RESULTS The average total volume of all dural sinuses increased immediately after surgery (from 10.06 cm3 to 12.64 cm3) and continued to increase throughout the 30-day distraction period (from 12.64 cm3 to 14.71 cm3) (p = 0.04), except that the right sigmoid sinus remained stable after the initial increase. The most important increases were observed for the left transverse sinus (+113.2%), right transverse sinus (+104.3%), left sigmoid sinus (+91.3%), and sagittal sinus (+41.8%). Less important modifications were evident for the right sigmoid sinus (+33.7%) and straight sinus (+23.4%). Significant improvements in venous flow were noted on the tridimensional reconstructions of the PC-MRA images. Venous obstruction grading score improved in 4 patients (average [range] 2.4 [ 2–5]) (p = 0.023) and remained stable in 1 patient. All patients had chronic tonsillar herniation (CTH) (mean [range] 16.6 [8–26] mm), and 3 had syringomyelia. CTH showed improvement on the last follow-up MRI evaluation in 4 patients (mean [range] 10.5 [0–25] mm) and worsened from 15 mm to 19 mm in 1 patient. Syringomyelia improved in 2 patients and remained unchanged in 1. CONCLUSIONS This study has provided the first radiological evidence of the impact of craniofacial surgery on dural sinus anatomy and venous drainage. The venous anomalies described in patients with syndromic craniosynostosis are not static, and PCVD+FMD triggers a dynamic process that can lead to significant modifications of intracranial venous drainage. The traction exerted by the distracted bone flap onto the occipitoparietal dura mater adherent to the inner calvaria may account for the enlargement of the dural sinus throughout the distraction period. The impact of these modifications on venous pressure, intracranial pressure, CTH, and hydrocephalus remains to be determined.

Neonatal falls during hospital stay after childbirth have an incidence of around 2.1-5.9 / 10,000 births. In general, they are linked to co-sleeping with the mother in the rooming-in or heedlessness on the part of relatives. Neonatal falls have a good prognosis, although they may be complicated with intracranial haematoma. The paper discusses the appropriate workout, recognizing that current guidelines for head trauma are not specific to the neonatal age.

Background Chronic subdural hematoma associated with dural calcifications in previously pediatric shunted patients is a rare condition. The inner dural membrane opening can lead to progressive brain herniation into the subdural space due to brain reexpansion. Case Description A 15-year-old boy, previously shunted at birth for congenital hydrocephalus, presented with a giant chronic right hemispheric subdural hematoma. After 2 surgical procedures in which the subdural calcified neomembrane was opened and a subdural shunt was implanted, he developed a cortical brain herniation into the subdural space, resulting in brain ischemia and upper limb weakness and vomiting. The final surgical treatment consisted of an extensive wide peeling of visceral calcified membrane mutually to programmable valve placement along the subduroperitoneal shunt, in order to create a positive gradient between the subdural space and the ventricles. The patient experienced a prompt clinical improvement. Conclusions This case illustrates a rare complication of the treatment of a chronic subdural hematoma caused by insufficient opening of the calcified inner mambrane of the hematoma and encouraged by gradient pressure between the ventricular and subdural compartments. To avoid this complication, it is preferable to not open a thick, calcified, unelastic inner membrane. However, in case of lack of clinical and radiologic improvement, it may become necessary to open it: a wide opening should be attempted, in order to prevent brain strangulation.

We present an uncommon case of holocord, "rosary bead-like," multiloculated syringomyelia consistent with a fourth ventricle outlet obstruction in a 2-month-old infant who was previously shunted for posthemorrhagic hydrocephalus of prematurity. The shunt malfunction resulted in a syringomyelia because of the simultaneous obstruction of the 3 outlets of the fourth ventricle, resulting in an enlargement of the central canal of the spinal cord. The syringomyelia resolved with shunt revision, avoiding further complex surgical procedures.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant disorder affecting multiple systems, due to inactivating mutations of TSC1 or TSC2 mTOR pathway genes. Neurological manifestations are observed in about 95% cases, representing the most frequent cause of morbidity and one of the most common causes of mortality. Neuroimaging is crucial for early diagnosis, monitoring, and management of these patients. While computed tomography is generally used as first-line investigation at emergency department, magnetic resonance imaging is the reference method to define central nervous system involvement and investigate subtle pathophysiological alterations in TSC patients. Here, we review the state-of-the-art knowledge in TSC brain imaging, describing conventional findings and depicting the role of advanced techniques in providing new insights on the disease, also offering an overview on future perspectives of neuroimaging applications for a better understanding of disease pathophysiology.

Neuroendoscopic biopsy represents the procedure of choice for pure intraventricular lesions. Instead, in case of deep-seated paraventricular tumors, with intact ependyma, the advantage of neuroendoscopy over stereotactic biopsy is not so evident, because the lesion is not under direct vision; the tissue sample may be limited to more superficial ependymal layer, and bleeding may obscurate vision. Also, stereotactic biopsy may reserve additional problems for these lesions: inaccuracy caused by leak of cerebrospinal fluid and increased risk of severe hemorrhage due to damage of the ependymal vessels. We report two cases of young children affected by thalamic tumors that were biopsied using a modification of a recently proposed technique: endoscopic visual control, neuronavigated needle biopsy. This technique may combine the accuracy of a stereotactic needle biopsy with the advantage of visual control on site of ependymal puncture and possibility of immediate bleeding control.

Introduction: Hydrocephalus is not usually part of Down syndrome (DS). Fourth ventricle outlet obstruction is a rare cause of obstructive hydrocephalus, difficult to diagnose, because tetraventricular dilatation may suggest a communicant/nonobstructive hydrocephalus. Case Presentation: We describe the case of a 6-year-old boy with obstructive tetraventricular hydrocephalus, caused by Luschka and Magen­die foramina obstruction and diverticular enlargement of Luschka foramina (the so-called fourth ventricle outlet obstruction) associated with DS. He was treated with endoscopic third ventriculostomy (ETV) without complications, and a follow-up MRI revealed reduction of the ventricles, disappearance of the diverticula, and patency of the ventriculostomy. Conclusion: Diverticular enlargement of Luschka foramina is an important radiological finding for obstructive tetraventricular hydrocephalus. ETV is a viable option in tetraventricular obstructive hydrocephalus in DS.

OBJECTIVE Colloid cysts (CCs) are rare at all ages, and particularly among children. The current literature on pediatric CC is limited, and often included in mixed adult/pediatric series. The goal of this multinational, multicenter study was to combine forces among centers and investigate the clinical course of pediatric CCs. METHODS A multinational, multicenter retrospective study was performed to attain a large sample size, focusing on CC diagnosis in patients younger than 18 years of age. Collected data included clinical presentation, radiological characteristics, treatment, and outcome. RESULTS One hundred thirty-four children with CCs were included. Patient age at diagnosis ranged from 2.4 to 18 years (mean 12.8 ± 3.4 years, median 13.2 years, interquartile range 10.3–15.4 years; 22% were < 10 years of age). Twenty-two cases (16%) were diagnosed incidentally, including 48% of those younger than 10 years of age. Most of the other patients had symptoms related to increased intracranial pressure and hydrocephalus. The average follow-up duration for the entire group was 49.5 ± 45.8 months. Fifty-nine patients were initially followed, of whom 28 were eventually operated on at a mean of 19 ± 32 months later due to cyst growth, increasing hydrocephalus, and/or new symptoms. There was a clear correlation between larger cysts and symptomatology, acuteness of symptoms, hydrocephalus, and need for surgery. Older age was also associated with the need for surgery. One hundred three children (77%) underwent cyst resection, 60% using a purely endoscopic approach. There was 1 death related to acute hydrocephalus at presentation. Ten percent of operated patients had some form of complication, and 7.7% of operated cases required a shunt at some point during follow-up. Functional outcome was good; however, the need for immediate surgery was associated with educational limitations. Twenty operated cases (20%) experienced a recurrence of their CC at a mean of 38 ± 46 months after the primary surgery. The CC recurrence rate was 24% following endoscopic resection and 15% following open resections (p = 0.28). CONCLUSIONS CCs may present in all pediatric age groups, although most that are symptomatic present after the age of 10 years. Incidentally discovered cysts should be closely followed, as many may grow, leading to hydrocephalus and other new symptoms. Presentation of CC may be acute and may cause life-threatening conditions related to hydrocephalus, necessitating urgent treatment. The outcome of treated children with CCs is favorable.