Tentorial Research Articles

Automated delineation of the clinical target volume using anatomically constrained 3D expansion of the gross tumor volume

PurposeDelineation of the clinical target volume (CTV) is arguably the weakest link in the treatment planning chain. This work aims to support clinicians in this crucial task. Methods and materialsWhile the CTV itself is ambiguous, it is much easier to identify structures that do not belong to the CTV and serve as barriers to the spread of the disease. We segment the known barrier structures using a convolutional neural network (CNN). The CTV is then obtained by starting from the manually delineated gross tumor volume (GTV) and expanding it while taking into account the barrier structures. Mathematically, we define the CTV as an iso-surface in the 3D map of shortest paths of all voxels from the GTV. The shortest paths are found with the Dijkstra algorithm. While the method is generally applicable, we test it on 206 glioma and glioblastoma cases. ResultsThe auto-segmented barrier structures for the brain cases include the ventricles, falx cerebri, tentorium cerebelli, brain sinuses, and the outer surface of the brain. Manual and auto-segmented barrier structures agree with surface Dice Similarity Coefficients (DSC) ranging from 0.91 to 0.97 at 2 mm tolerance. Comparison of manual and automatically delineated CTVs shows a median surface DSC of 0.79. ConclusionsBarrier structures for CTV definition can be auto-delineated with outstanding precision using a CNN. An algorithm for automated calculation of the CTV by 3D expansion of the GTV while respecting anatomical barriers has been developed. It shows good agreement with manual CTV definition for brain tumors.

Surface reconstruction from routine CT-scan shows large anatomical variations of falx cerebri and tentorium cerebelli

Finite element modeling of the human head offers an alternative to experimental methods in understanding the biomechanical response of the head in trauma brain injuries. Falx, tentorium, and their notches are important structures surrounding the brain, and data about their anatomical variations are sparse. To describe and quantify anatomical variations of falx cerebri, tentorium cerebelli, and their notches. 3D reconstruction of falx and tentorium was performed by points identification on 40 brain CT-scans in a tailored Matlab program. A scatter plot was obtained for each subject, and 8 anatomical landmarks were selected. A reference frame was defined to determine the coordinates of landmarks. Segments and areas were computed. A reproducibility study was done. The height of falx was 34.9 ± 3.9mm and its surface area 56.5 ± 7.7cm2. The width of tentorium was 99.64 ± 4.79mm and its surface area 57.6 ± 5.8cm2. The mean length, height, and surface area of falx notch were respectively 96.9 ± 8mm, 41.8 ± 5.9mm, and 28.8 ± 5.8cm2 (range 15.8-40.5cm2). The anterior and maximal widths of tentorial notch were 25.5 ± 3.5mm and 30.9 ± 2.5mm; its length 54.9 ± 5.2mm and its surface area 13.26 ± 1.6cm2. The length of falx notch correlated with the length of tentorial notch (r = 0.62, P < 0.05). We observe large anatomical variations of falx, tentorium, and notches, crucial to better understand the biomechanics of brain injury, in personalized finite element models.

Congenital interdural arachnoid cyst of the tentorium cerebelli.

Intracranial interdural cyst is a rare lesion. The exact pathophysiology of these cysts remains unknown. We report an infant with interdural cyst of the tentorium cerebelli. Although the cyst mimicked an arachnoid cyst on pre- and postnatal magnetic resonance images, lateral suboccipital craniotomy revealed the cyst within the tentorium. Fenestration on the infratentorial side was performed with successful results. Histologically, the inner surface of the cyst was lined with arachnoid cells. We report detailed neuroradiological, intraoperative, and histological findings, and discuss the pathophysiology of the cyst in this case.

The Anatomy of the Sigmoid-Transverse Junction According to the Tentorial Angle.

Dural sinuses have critical importance during intracranial approaches. Detailed anatomical knowledge of the dural sinuses is crucial for surgeons to reduce unexpected venous bleeding. The aim of this study was to investigate anatomical relation of sigmoid sinus and tentorium cerebelli according to clinically palpable landmarks and cranial morphometry. The authors evaluated 222 individuals' (94 women, 128 men) 3-dimensional computed tomography angiograms, retrospectively. The authors also studied on 12 mid-sagittal cut dried hemiskulls and 8 formalin fixed cadaver heads hemisected midsagitally. All measurements were completed using Osirix-Lite version 9 software. Craniometrical values were measured to define cranium morphology. Furthermore, level of the sigmoid sinus according to asterion and tentorial angle were evaluated in detail. Our results demonstrated that there were significant differences between parameters and genders, except vertical angle of the tentorium cerebelli. Distance between asterion and sigmoid sinus was statistically different between right and left sides in favor of the left side. This also varied depending on the position of the sigmoid sinus, as well. Only transverse angle between the upper point of external acoustic meatus and asterion demonstrated a significant correlation with age. This study evaluated the detailed 3D anatomy of sigmoid sinus and tentorium cerebelli related with the cranium morphology. Determining to sigmoid sinus anatomy according to clinically palpable landmarks has advantages for setting surgical protocols and reducing to unexpected injuries while surgery to these structures.

Tentorium Cerebelli: the Bridge Between the Central and Peripheral Nervous System, Part 2.

The tentorium cerebelli is a meningeal portion in relation to the skull, the nervous system, and the cervical tract. In this second part, the article discusses the systematic tentorial relationships, such as the central and cervical neurological connections, the venous circulation and highlights possible clinical alterations that could cause pain. To understand the function of anatomy, we should always remember that every area of the human body is never a segment, but a functional continuum.

Tentorium Cerebelli: Muscles, Ligaments, and Dura Mater, Part 1.

The tentorium cerebelli is an integral part of the reciprocal tension membranes that divide some brain areas: the falx cerebri, the falx cerebelli, and the diaphragma sellae. The article is divided into two parts. The first part reviews the anatomy of the tentorium cerebelli, the dura mater, and the ligaments and cervical muscles connected to the tentorium. The tentorial area may be subject to trauma or surgery and knowledge of anatomy and existing relationships is essential to better understand the clinical picture. The second part reviews the systemic relationships of the tentorium cerebelli. The neurological anatomical information, which links the tentorium to the central and peripheral nervous systems, venous brain drainage. The tentorium is not just a body segment, but a systemic communication tool.

Osteopathic approach with a patient undergoing cardiac transplantation: the five diaphragms.

The case report presents a patient with a possible neuropathic sternal pain associated with a recent heart transplant procedure. The patient could not breathe deeply and move the upper limbs, with a trunk torsion, feeling a sharp pain under and around the left breastbone. A fascial osteopathic approach in the treatment of the pelvic floor, the respiratory diaphragm, the thoracic outlet, the tongue and the tentorium cerebelli allowed the patient to access to a cardiovascular rehabilitation program. In osteopathic medicine, these anatomical parts of the body are called the five diaphragms. To our best knowledge, this is the first case report that uses osteopathic treatment in a patient with sternal pain associated with an undergoing cardiac transplantation. The clinical importance of the case report is added to other osteopathic research with patients undergoing cardiac surgery (coronary artery bypass graft) and with multiple benefits, without side effects. One of the main goals of osteopathic treatment is to provide the patient with well-being, from many clinical points of view, allowing the person to be discharged from the hospital more quickly and/or with less pain.

An Anatomic Study of the Keyhole Supra-Tentorium to Infra-Tentorium Endoscope Approach.

To provide anatomic basis for the retrosigmoid supra-tentorium to infra-tentorium keyhole approach and to explore the feasibility, 60 skulls were observed and measured to demonstrate the position relations among related bony landmarks, 12 cadaveric heads were dissected and measured for localization of the keyhole and the incision through tentorium. For giving the angle and depth for endoscopic approach, 40 adult volunteers were performed head MRI scan and the pictures were measured and analyzed. The surface projection of sigmoid and transverse sinus can be positioned by mastoidale, external occipital protuberance, and anterior end of parietomastoid suture (AEPMS) on body. There is a safe trigone of cerebellar tentorium (STCT) among inner edge of upper curve of sigmoid sinus, entrance of tentorial sinus/vein and midpoint of posterior edge of temporal arcuate eminence. 15 mm superior to the midpoint between asterion and AEPMS can be recognized as the central point of the keyhole. Magnetic resonance imaging pictures show there is potential subarachnoid space for endoscopic approach from the indicated keyhole to pontocerebellar trigone. This study demonstrated endoscopy can arrive at pontocerebellar trigone through the STCT and the keyhole supra-tentorium to infra-tentorium endoscope approach is feasible in anatomy and will contribute to excise lesions involving both supra- and infra-tentorial structures.

Anti-NMDAR encephalitis with simultaneous hypertrophic pachymeningitis in a 68-year-old male: a rare case report

BackgroundAnti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most frequent types of autoimmune encephalitis. However, the instigating mechanisms are as yet not fully ascertained. Cardinal clinical manifestations of anti-NMDAR encephalitis include acute behavioural change, psychosis, and catatonia. As the level of diagnosis increases, encephalitis becomes more common, but there are never been published in patients with anti-NMDAR encephalitis and simultaneous hypertrophic pachymeningitis.Case presentationA sixty-eight-year-old man who presented with mental, behavioral abnormalities, unstable walking, headaches, and erratic hand movements. The neuropsychiatric symptoms and cerebrospinal fluid examination was consistent with the diagnosis criteria of anti-NMDAR encephalitis. Magnetic resonance imaging of the brain showed a thickening of dura mater localized at the left tentorium cerebelli, left cerebral hemisphere, and cerebral falx; the thickening dura mater was characterized by an intense contrast enhancement after the administration of gadolinium. High doses of intravenous methylprednisolone were administrated during his hospitalization. After 5 days, the patient’s condition improved.ConclusionsWe herein describe a rare case of a 68-year-old man with anti-NMDAR encephalitis presenting with concomitant hypertrophic pachymeningitis. We systematically expounded anti-NMDAR encephalitis and hypertrophic pachymeningitis, and made bold conjectures on the etiology and pathogenesis of these two diseases, hoping to stimulate new ideas from clinicians and basic medical researchers.

Impact of morphological measurements on symptoms in Chiari malformation type 1

Aim: Chiari malformation Type 1 (CM1) is a pathology resulting from herniation of cerebellar tonsils or tonsils into the spinal canal. We aimed to examine the impact of the cranium’s morphological measurements on the symptoms with CM1 patients.Methods: This research was designed as a retrospective case-control study in a single-center. 2309 patients aged between 18-70 who underwent brain magnetic resonance imaging (MRI) to confirm or exclude the diagnosis of CM1 as a result of clinical and examination findings were evaluated. Cranium’s morphological measurements, the amount of herniation, patient’s symptoms, and the modified Asgari score were retrospectively assessed. Results: Patients with a final diagnosis of CM1 after the MRI evaluation were classified as study group (n=212), and the others control group (n=2097). The maximum cranial length, maximum cranial height, supra occiput length, posterior cranial fossa (PCF) anteroposterior length, in the study group were shorter, whereas the sagittal diameter of the foramen magnum and the longest anteroposterior diameter of the cerebrum were longer (P&lt;0.001 for all mentioned comparisons). Tentorium cerebelli slope was found to be significantly lower in the study group (P&lt;0.001). The most prevalent symptoms were a headache (92%). The herniation amount had a negative correlation with maximum cranial length and maximum cranial height (r=-0.184, P=0.07; r=-0.158 and P=0.022, respectively) and a positive correlation with the modified Asgari score (r=0.598; P&lt;0.001).Conclusion: The cranium’s morphological measurements have an impact on the symptoms of patients with CM1.

Embryological Consideration of Dural AVFs in Relation to the Neural Crest and the Mesoderm.

Intracranial and spinal dural arteriovenous fistulas (DAVFs) are vascular pathologies of the dural membrane with arteriovenous shunts. They are abnormal communications between arteries and veins or dural venous sinuses that sit between the two sheets of the dura mater. The dura propria faces the surface of brain, and the osteal dura faces the bone. The location of the shunt points is not distributed homogeneously on the surface of the dural membrane, but there are certain areas susceptible to DAVFs. The dura mater of the olfactory groove, falx cerebri, inferior sagittal sinus, tentorium cerebelli, and falx cerebelli, and the dura mater at the level of the spinal cord are composed only of dura propria, and these areas are derived from neural crest cells. The dura mater of the cavernous sinus, transverse sinus, sigmoid sinus, and anterior condylar confluence surrounding the hypoglossal canal are composed of both dura propria and osteal dura; this group is derived from mesoderm. Although the cause of this heterogeneity has not yet been determined, there are some specific characteristics and tendencies in terms of the embryological features. The possible reasons for the segmental susceptibility to DAVFs are summarized based on the embryology of the dura mater.

Transverse Diameter of Cerebellum: Is There Any Age and Sex Related Change Among Bangladeshi People

Background: Cerebellum is ovoid in shape, but is constricted in the median plane, flattened from above downwards and widest from side to side. The cerebellum occupies the posterior cranial fossa, where it is covered by the tentorium cerebelli and lies behind the fourth ventricle, the pons and the medulla oblongata.&#x0D; Objective: The study was done to assess the transverse diameter of cerebellum in relation with age and sex in Bangladeshi people.&#x0D; Materials and Methods: A cross sectional descriptive study was performed on 60 (32 of male and 28 of female) postmortem. The specimens were collected from morgue in the department of Forensic Medicine, Mymensingh Medical College by purposive sampling technique. All the specimens were grouped into four categories: group A (20 to 29 years), group B (30 to 39 years), group C (40 to 49 years), group D (50 to 59 years). Dissection was performed according to standard autopsy techniques. Transverse diameter of cerebellum was measured with the help of slide caliper. For statistical analysis, differences between age groups were analyzed by using unpaired student't' test.&#x0D; Results: The mean (±SD) transverse diameter of cerebellum was 10.53 ± 0.55 cm in group A, 10.09 ± 0.51 cm in group B, 10.03 ± 0.44 cm in group C, 9.72 ± 0.40 cm in group D. The mean differences of the transverse diameter of cerebellum between groups A &amp; C, A &amp; D, A &amp; B, B &amp;D were statistically significant, differences between B &amp; C, D &amp; C were non significant.&#x0D; Conclusion: The study would help to increase the information pool on the transverse diameter of cerebellum of Bangladeshi people.&#x0D; KYAMC Journal Vol. 9, No.-4, January 2019, Page 159-162

Interdural high signal on CISS sequence: an alternative CSF pathway?

The falx cerebri, falx cerebelli, and tentorial notch exhibit a peculiar morphology with a two-layered, dural leaf that protrudes into the cranial cavity with a free edge. However, there are few studies exploring this morphology using neuroimaging techniques. The present study aimed to explore these dural structures using magnetic resonance imaging. A total of 65 outpatients were included in this study. Following initial examinations with conventional sequences, the constructive interference in steady-state (CISS) sequences were performed in thin-sliced, coronal sections. In 78% of the subjects, the interdural spaces presenting with high signal were identified in the falx cerebri. These spaces were located adjacent to the uppermost part of the falx, formed by two dural leaves and the superior sagittal sinus, and tapered downward where the leaves united to form the falx cerebri. At the tentorial notch, these spaces were found in 52% of the 65, most predominantly in the medial edge followed by the tentorium cerebelli-tentorial notch junctional region. Forty-one percent of patients had a dural opening into the cerebral cistern. The interdural spaces with high signal were not identified in the tentorium cerebelli in any of the subjects. The falx cerebri and tentorial notch form the interdural spaces that may provide alternative cerebrospinal fluid pathways. The coronal CISS sequence is suitable for delineating such interdural spaces.

Automatic and efficient MRI-US segmentations for improving intraoperative image fusion in image-guided neurosurgery.

Knowledge of the exact tumor location and structures at risk in its vicinity are crucial for neurosurgical interventions. Neuronavigation systems support navigation within the patient's brain, based on preoperative MRI (preMRI). However, increasing tissue deformation during the course of tumor resection reduces navigation accuracy based on preMRI. Intraoperative ultrasound (iUS) is therefore used as real-time intraoperative imaging. Registration of preMRI and iUS remains a challenge due to different or varying contrasts in iUS and preMRI. Here, we present an automatic and efficient segmentation of B-mode US images to support the registration process. The falx cerebri and the tentorium cerebelli were identified as examples for central cerebral structures and their segmentations can serve as guiding frame for multi-modal image registration. Segmentations of the falx and tentorium were performed with an average Dice coefficient of 0.74 and an average Hausdorff distance of 12.2 mm. The subsequent registration incorporates these segmentations and increases accuracy, robustness and speed of the overall registration process compared to purely intensity-based registration. For validation an expert manually located corresponding landmarks. Our approach reduces the initial mean Target Registration Error from 16.9 mm to 3.8 mm using our intensity-based registration and to 2.2 mm with our combined segmentation and registration approach. The intensity-based registration reduced the maximum initial TRE from 19.4 mm to 5.6 mm, with the approach incorporating segmentations this is reduced to 3.0 mm. Mean volumetric intensity-based registration of preMRI and iUS took 40.5 s, including segmentations 12.0 s.

Hypertrophic pachymeningitis associated with antineutrophil cytoplasmic antibody-associated vasculitis: a case series of 15 patients

Objective: We aimed to describe the clinical characteristics and treatment course of hypertrophic pachymeningitis (HPM) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).Methods: We retrospectively analysed 15 patients (11 men and four women). HPM was diagnosed based on thickening and enhancing of the brain and/or spinal dura mater on gadolinium-enhanced magnetic resonance imaging (MRI) T1 sequence.Results: The median age at HPM onset was 60 years. Headache and cranial nerve impairment were observed in 14 and 10 patients, respectively. Otitis media and/or mastoiditis were found as complications of AAV in 11 patients. Fourteen patients were classified as having granulomatosis with polyangiitis (GPA). Single-positive myeloperoxidase-ANCA, single-positive proteinase 3-ANCA, and double-positive ANCA were identified in seven patients, five patients, and one patient, respectively. With MRI, thickening of the dura mater in the cranial fossa and tentorium cerebelli was found in 10 and eight patients, respectively. For remission induction, all patients were treated with corticosteroids, and immunosuppressants were added in 10 patients. Dura mater thickening partially improved in all patients, and cranial neuropathy completely remitted in eight patients. In a median follow-up of 43 months, four patients had HPM relapse and underwent reinduction therapy. All six patients treated with cyclophosphamide at initial therapy did not relapse.Conclusions: HPM was mostly associated with patients with GPA with otitis media and/or mastoiditis having either type of ANCA serology. Treatment with corticosteroids with or without immunosuppressants was effective. However, HPM relapse occasionally occurred, especially when cyclophosphamide was not used in initial treatment.

Rethinking origins of pineal meningiomas

Objective To investigate the clinical data and origin of pineal meningiomas, and to discuss the definite meaning of the term interpositum . Methods From January 2005 to December 2016, 21 cases of pineal region meningiomas underwent operations at Department of Neurosurgery, Nanfang Hospital, Southern Medical University and were enrolled into this retrospective study. Analysis was conducted on the clinical characteristics, imaging findings and surgical video data of those patients who were divided into 2 groups according to literature: falcotentorial meningioma group and velum interpositum meningioma group. Comparison was conducted between the 2 groups. Results Among 12 cases of falcotentorial meningiomas, 4 cases were originated from cerebral falx, 4 from cerebellar tentorium and 4 from straight sinus. Among 9 cases of velum interpositum meningiomas, 7 were originated from the cerebral arachnoidal envelope, 1 from the posterior cerebral vein and 1 from pineal surface. Postoperative pathological examination confirmed the diagnosis of meningioma in all cases. Among those, total resection was achieved in 16 cases and subtotal resection in 5. There were 3 cases of vertical movement limitation of the eyes, 7 cases of isotropic hemianopia, 1 case of hemiplegia, and 1 case of death. Conclusions The falcotentorial meningioma and primary pineal meningioma might be more appropriate for classification of origins of pineal meningiomas. The term interpositum may not be able to accurately reflect the origin of meningioma in the pineal gland region. During resection of pineal gland meningiomas, the protection of large veins and collateral circulation is of much significance. Key words: Meningioma; Pinealoma; Classification; Neurosurgical procedures

Solitary fibrous tumor/hemangiopericytoma expanding the superior and inferior cerebellar tentorium: A case report

Abstract Background A rare case of a solitary fibrous tumor/hemangiopericytoma (SFT/HPC) expanding the superior and inferior cerebellar tentorium is described. Case description A 28-year-old male presented with convulsions. Magnetic resonance imaging revealed a tumor around the right cerebellar tentorium. The tumor was completely removed after embolization of the feeding arteries, and the pathological diagnosis was World Health Organization grade III SFT/HPC. The patient's postoperative course was uneventful, and there was no recurrence or extracranial metastasis at 1.5 years following the operation. Conclusions It was possible to fully remove the SFT/HPC tumor; however, strict observation of the whole body is needed because of the possibility of recurrence and extracranial metastasis.

The Tentorium Cerebelli: A Comprehensive Review Including Its Anatomy, Embryology, and Surgical Techniques.

The tentorium cerebelli functions as a partition, dispelling the burden of weight from supratentorial structures upon inferior brain matter. Clinicians and neurosurgeons, when assessing pathological findings, should have knowledge regarding the tentorium cerebelli anatomy. This work of literature is a comprehensive review of the tentorium cerebelli, including its anatomy, embryology, and clinical and surgical implications. The evolutionary pattern demonstrates sequential stages to higher mammalian lineage. An understanding of the complexity of the neurovascular structures and the anatomy of the tentorium cerebelli is crucial for surgical procedures by neurosurgeons.

Basal Cell Carcinoma, Odontogenic Cysts, Brain and Skeletal Abnormalities (Gorlin Goltz) Syndrome in a 46-Year-Old Woman

Objective: To present the case of a 46-year-old woman with basal cell carcinoma, odontogenic cysts, brain anomalies and skeletal abnormalities.&#x0D; Method: &#x0D; Design: Case Report&#x0D; Setting: Tertiary National University Hospital&#x0D; Patient: One&#x0D; Results: A 46-year-old woman consulted for a non-healing, necrotic left orbital ulcer that started as a skin-colored, papilla-like lesion on the upper eyelid. There were also hyperpigmented lesions with ill-defined borders over both paranasal areas. Tissue biopsies revealed basal cell carcinoma. Radiologic imaging showed cystic lesions in the mandible, straightening of cervical vertebrae and calcifications of the falx cerebri, tentorium cerebelli, pineal gland and choroid plexus. Based on established major and minor clinical and radiologic criteria, we arrived at a diagnosis of Gorlin Goltz Syndrome or Nevoid Basal Cell Carcinoma Syndrome (NBCCS). She underwent wide excision of the left orbital mass with exenteration, excision of left and right paranasal masses, left total parotidectomy with facial nerve preservation, enucleation of mandibular cyst, and cervicofacial reconstruction with skin grafts of the left orbital area and ala.&#x0D; Conclusion: NBCCS is a rare autosomal dominant disorder with a high tendency for neoplasms and developmental anomalies. Diagnosis can easily be missed if the physician is unaware of its classic but bizarre presentation. Early recognition and prompt specialist referral is very important in order to prevent complications and provide better prognosis. Patients should be reminded of the importance of follow-up as other presentations of the syndrome may manifest later in life, and family genetic screening and counseling should be undertaken.&#x0D; Keywords: Gorlin Goltz Syndrome; Nevoid Basal Cell Carcinoma Syndrome; odontogenic keratocyst

Primary meningeal sarcoma in children: a survey from the French Society of Pediatric Oncology (SFCE)

Objectives: To describe the outcome of primary meningeal sarcoma (PMS) in a pediatric population. Methods: We conducted a retrospective study on patients harbouring a PMS based on the French registry of paediatric tumours. Questionnaires were sent to all French paediatric oncologists. Data on patient characteristics and treatments were collected. Pathology and imaging were centrally reviewed. Results: Between August 1989 and May 2010, 12 patients from 6 French centres, aged 3 months to 14.5 years (mean: 3.3 years) were treated for a PMS. Mean follow-up was 12 years (range: 3 months to 24 years). Tumour locations were: frontal (3), parieto-occipital (2), parietal (1), temporal (1), occipital (1), thalamic (1), pontocerebellar angle (1), cerebellar tentorium (1), ambient cistern (1). No metastasis was observed. The first-line treatment was surgery in 10 cases, chemotherapy in 2. Resection was total in 6 cases, partial in 6. Central pathology review concluded to: high-grade undifferentiated sarcoma (8), chondrosarcoma (2), fibrosarcoma (1), myxoid desmoplastic tumour (1). Seven tumours were smaller than 5 cm in size. Eleven patients received 2 to 10 courses of chemotherapy (median: 5) but no response was observed. Four out of 6 patients for whom a total resection was performed were still alive at time of study, compared to 2 when only partial resection was possible. Four out of 6 patients who received radiotherapy are still alive, compared to 1 out of 4 patients without radiotherapy. The 5-year Event-Free Survival (EFS) and Overall Survival (OS) rates were 50%. The median EFS in case of total resection was 39 months versus 16 months in case of partial resection. Neither correlation was found between tumour size and location or between age at diagnosis and EFS/OS. Conclusions: We report the first multicentre case series describing clinical, radiological presentation and outcome of PMS in children. In this short series of very rare tumours, age and tumour size did not seem to be prognostic factors. Total resection and radiotherapy seem to be essential. The role of chemotherapy remains unclear.