CLINICAL AND SURGICAL CHARACTERISTICS OF POSTERIOR FOSSA TUMORS IN ADULTS - SINGLE-CENTER EXPERIENCE OF SURGICAL MANAGEMENT.

In contrast to tumors in children, between 6% and 20% of all brain tumors in adults arise solitary in the posterior cranial fossa. Given their rarity in adults, as well as the importance and complexity of their treatment, this paper reviews and discusses the clinical and surgical characteristics of such tumors. In a retrospective single-institution observational study, adult patients with posterior fossa tumors treated surgically over a ten-year period were analyzed. The characteristics observed were age and gender distribution, clinical symptoms, histopathologic tumor type, tumor size, location and extent of surgical resection, tumor recurrence and postoperative complications, as well as surgical outcome. Sixty-six patients who underwent surgical treatment were diagnosed with a tumor in the posterior fossa. The mean age was 63 years, and patients were evenly distributed by gender. The most common histopathologic type was metastatic tumor (59.1%), whereas meningioma was the most common primary brain tumor (16.6%) recorded. Most patients presented with vegetative and cerebellar symptoms in general and cranial nerve palsy, especially in the occurrence of vestibular schwannoma. In conclusion, posterior fossa tumors grow in a confined space and therefore may directly threaten vital centers in their immediate vicinity. Thus, it is crucial to schedule an appropriate surgical intervention as soon as possible, as it can significantly improve treatment outcome and prognosis of the disease. If possible, meticulous total tumor resection should be the treatment of choice. In the case of hydrocephalus, a ventriculoperitoneal shunt should be considered as an alternative surgical option after tumor resection.

[Classification of the types of pediatric posterior fossa brain tumors based on routine MRI using wavelet transformation analysis of whole tumor].

Objective: To evaluate the classification of the types of pediatric posterior fossa brain tumors based on routine MRI (T(1)WI, T(2)WI and ADC) using wavelet transformation analysis of whole tumor. Methods: MRI images of medulloblastoma (n=59), ependymoma (n=13) and pilocytic astrocytoma (n=27) confirmed by pathology before treatments in Children's Hospital of Nanjing Medical University from January 2014 to February 2019 were enrolled in this retrospective study as well as the clinical data of age, gender and symptoms. Registration was performed among the three sequences and wavelet features of ROI were acquired. Afterwards, the top ten features were ranked and trained among groups by using random forest classifier. Finally, the results were compared and analyzed according to the classification. Results: The top ten contribution three sequences and wavelet features of ROI were acquired from the ADC sequence. The random forest classifier achieved 100% accuracy on training data and was validated best accuracy (86.8%) when combined of first and third wavelet features. The sensitivity was 100%, 94.8%, 76.9%, and the specificity was 97.6%, 88.0%, 98.8% respectively. Conclusions: Features based on wavelet transformation of ADC sequence of entire tumor can provide more quantitative information, which could provide help in the differential diagnosis of pediatric posterior fossa brain tumors. The optimum combination to distinguish three pediatric posterior fossa brain tumors is sixth and twelfth wavelet features of ADC sequence.

[Quantitative study on the development of fetal ventricles and cisterna magna in second and third trimesters with MRI].

Objective: To analyze the changes of growth and development of normal fetal ventricles and cisterna magna with gestational age(GA) and the correlation with fetal gender in the second and third trimester,and establish the MR prenatal diagnosis reference standards. Methods: A total of 633 fetuses (mean GA (27.0±4.1) weeks (18.9-40.6 weeks))without central nervous system abnormalities were retrospectively collected from the Obstetrics and Gynecology Hospital of Fudan University from June 2012 to August 2017. The lateral ventricle trigonometric width (LVTW), third ventricle width (TVW), fourth ventricle width (FVW), anterior-posterior diameter of the fourth ventricle(APDFV), cavum septum pellucidum width (CSPW) and cisterna magna width (CMW) were obtained in the standard measure planes on MR image.The correlation between the biometrics and GA and the correlation between the biometrics and fetal gender were analyzed respectively, and the normal reference values of the biometrics were calculated. Spearman correlation analysis, Pearson correlation analysis,linear regression analysis, independent samples t-test and paired samples t-test were used for statistic analysis. Results: (1)Fetal LLVTW,RLVTW,TVW,CSPW and CMW in second and third trimesters were correlated with GA at medium and low levels(the correlation coefficient r were 0.311, 0.277, 0.207, 0.226, 0.295, respectively, all P<0.01). FVW and APDFV were statistically correlated with GA, and the linear regression equations were as follows: y=0.022×GA-0.043 (adjusted R(2)=0.642); y=0.018×GA-0.159 (adjusted R(2)=0.690). (2)Fetal LLVTW,RLVTW,FVW,APDFV and CSPW were not correlated with fetal gender in second and third trimesters(r=-0.078,-0.057,-0.087,-0.004 and 0.024, P=0.124,0.258,0.085,0.931 and 0.618, all P>0.05). TVW and CMW were statistically correlated with fetal gender(r=-0.310, -0.180, P=0.000, 0.006, all P<0.05). (3) The mean values of LLVTW and RLVTW were (0.71±0.13) cm and (0.68±0.13) cm, respectively, and significant difference was found between them(t=3.180, P=0.002). The mean value of CSPW was (0.59±0.15) cm. And the mean values of male and female fetuses for TVW and CMW were (0.17±0.05) cm, (0.16±0.06) cm and (0.68±0.15) cm, (0.58±0.15) cm, respectively. The corresponding prenatal MRI diagnostic criteria were as follows: LLVTW 1.1 cm, RLVTW 1.0 cm, CSPW 1.0 cm, TVW 0.3 cm, CMW (male 1.1 cm, female 1.0 cm). Conclusions: The normal fetal ventricles and cisterna magna are increased with the GA in the second and third trimesters. TVW and CMW are related to fetal gender. The establishment of normal reference values of fetal ventricles and cisterna magna based on GA and fetal gender are conducive to enhance the accuracy of MRI prenatal diagnosis.

[Chondromucinous tumors involving craniocerebral slope area: a clinicopathological analysis of eight cases].

Objective: To investigate the histological type and clinicopathological characteristics of the craniocerebral slope tumors with chondromucinous features. Methods: Retrospective analysis was conducted to analyze chondromucinous tumors in the slope area diagnosed at Henan Provincial People's Hospital from October 2011 to June 2018. Relevant clinical and pathological data were reviewed, and immunohistochemistry was used to investigate the immunophenotype of the tumors. Results: Eight cases were identified, including 4 males and 4 females with patient age ranging from 20 to 48 years. Histologically, there were 1 case of chordoid meningioma, 1 chondromyxoid fibroma, 1 mucinous chondrosarcoma, 1 Maffucci syndrome, and 4 chondroid chordomas. Conclusion: Chondromucinous tumors of the slope area include chordoma, chordoid meningioma, chondromyxoid fibroma, and myxoid chondrosarcoma and their correct diagnosis is mainly based on the morphological characteristics, immunophenotype and comprehensive analysis of clinical data.

[Genetic analysis of posterior cranial fossa morphology in families of Chiari malformation type â ].

Objective: To explore genetic characteristic of posterior cranial fossa morphology in families of Chiari malformation type Ⅰ (CMI). Methods: From April 2010 to May 2016, a total of 47 cases of CMI families (CMI group) and their 94 parents (CMI-P group)collected were retrospectively reviewed in Department of Spinal Surgery, Drum Tower Hospital, School of Medicine, Nanjing University.Another cohort of 50 asymptomatic adults was enrolled to serve as the control group.Patients with skull fracture or other diseases which can lead to secondary CMI were excluded.On mid-sagittal T2-weighted magnetic resonance (MR) imaging, four measurements were evaluated and compared between these three groups, including the length of cerebellar tonsillar descent, the area of posterior cranial fossa(PCF area), the area of the brain tissue in posterior cranial fossa (PCF tissue area), and the PCF crowdedness indexes (PCF tissue area/ PCF area×100%). Results: Totally 47 CMI patients (21 males and 26 females; mean age, 16.4 years), 94 parents (47 males and 47 females; mean age, 39.2 years) and 50 controls (23 males and 27 females; mean age, 22.3 years) were recruited in this study.Significant differences in all four indexes were found between CMI group and the control group.The length of cerebellar tonsillar descent were much bigger in CMI-P group than in the control group (1.5±2.2 mm vs -0.9±1.1 mm), with 7 cases reach the diagnostic criteria of Chiari malformation(≥5 mm) and one with syingomyelia.Compared to the control group, CMI-P group had smaller PCF area, and its PCF crowdedness indexes averaged 90.0% as between the control group (85.3%) and the CMI group (93.6%). Conclusions: In CMI families, parents have similar posterior cranial fossa abnormalities with their CMI children, presenting obviously narrow and crowded.Their PCF crowdedness indexes are between normal subjects and CMI patients, and their cerebellar tonsils are lower, even some parents are also CMI patients, suggesting genetic mechanisms involved in the development of CMI.

Percutaneous transluminal angioplasty and stenting (PTAS) in patients with symptomatic intracranial vertebrobasilar artery stenosis (IVBS).

BACKGROUND: Approximately 20% of all transient ischaemic attacks (TIAs) and ischaemic strokes occur within the posterior circulation, with vertebrobasilar stenosis identified as the cause in roughly 25% of the cases. Studies have shown that about a quarter of these patients have atherosclerotic stenosis of at least 50% of the vertebrobasilar artery. Stenosis has been shown to be associated with an increased risk of 90-day recurrent vertebrobasilar stroke, particularly in the first few weeks, which is significantly higher when compared with patients with stenosis of the anterior circulation. Therefore, aggressive treatment is important for the patient's prognosis. Stenting is emerging as a promising therapeutic strategy for persistent ischaemia events that do not respond to the best medical treatment, but it is not without complications. We systematically reviewed the literature on percutaneous transluminal angioplasty and stenting (PTAS) for intracranial vertebrobasilar artery stenosis (IVBS). METHODS: PubMed, Web-of-Science and Scopus were searched upon the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to include prospective/retrospective cohort, randomised/non-randomised clinical trials and case series studies describing PTAS for IVBS. Pooled rates of intervention-related complications and outcomes were analysed with random-effect model meta-analysis using StataMP V.18.0 software. RESULTS: 31 studies were found eligible which included 1928 cases. 1103 basilar artery stenosis cases were reported in 27 studies 0.65 (95% CI 0.53, 0.76), I2: 99.72%. 648 vertebral cases were reported in 18 studies 0.60 (95% CI 0.49, 0.70), I2: 97.49%. In four studies, the rate of vertebrobasilar stenosis cases calculated as a proportion of the total sample size was 0.10 (95% CI 0.05, 0. 15). Mean stenosis in 21 included studies was found to be 0.83 (95% CI 0.79, 0.88), I2: 0.00%, which shows variation of baseline stenosis between studies was minimal. 51 deaths were recorded in 24 studies. Meta-analysis of mortality showed the overall rate of mortality was 0.03 (95% CI 0.02, 0.05), I2: 44.90%. In 14 studies, symptomatic intracranial haemorrhage events were recorded at an overall rate of 0.01 (95% CI 0.00, 0.02), I2: 0.00%. Generally, a follow-up period of at least 3 months was reported in the included studies. Furthermore, procedural stroke/TIA was evaluated in seven studies, four of which reported no events (0.03 (95% CI 0.00, 0.08), I2: 20.38%). Mean time from initial symptoms to recanalisation was 23.98 (95% CI 18.56, 29.40), I2=98.8%, p=0.00 days. CONCLUSION: In certain individuals with medically unresolved, severe, symptomatic and non-acute IVBS, elective vertebrobasilar PTAS appears to be both safe and effective. Various stent designs and angioplasty-assisted techniques should be taken into consideration based on the specific clinical and radiological traits of the lesions. Future randomised controlled trials are required to verify these results.

Predictors of malignant swelling in space-occupying cerebellar infarction.

BACKGROUND: Malignant swelling is a fatal complication that can occur abruptly in space-occupying cerebellar infarction. We aimed to establish markers that predict malignant swelling in cerebellar infarction. METHODS: We retrospectively analysed data of stroke patients who were treated in our hospital between 2014 and 2020. Malignant swelling was defined as a mass effect in the posterior cranial fossa, accompanied by a decrease in consciousness due to compression of the brainstem and/or the development of obstructive hydrocephalus. Statistical analyses were performed on multiple variables to identify predictors of malignant swelling. RESULTS: Among 7284 stroke patients, we identified 487 patients with an infarct in the cerebellum. 93 patients were suitable for analysis having space-occupying cerebellar infarction. 33 of 93 (35.5%) patients developed malignant swelling. Multivariable analysis revealed infarct volume as the main predictor being independently associated with the development of malignant swelling with a cut-off infarct volume of 38 cm3 being associated with a swelling rate of >50% (OR 32.0, p<0.001). Higher NIHSS (National Institutes of Health Stroke Scale) score on admission (median NIHSS 12 vs 4, OR 1.078; p=0.008) and the presence of additional brainstem infarction (51.5% vs 16.7%, OR 5.312; p=0.013) were associated with the development of malignant swelling in univariate analyses. 13 of 33 (39.4%) cases of malignant swellings occurred after more than 3 days. CONCLUSIONS: Infarct volume was the key significant predictor of malignant swelling in space-occupying cerebellar infarction. With many cases of malignant swelling occurring after more than 72 hours, we advocate prolonged neurological monitoring.

Treatment of Clival Giant Cell Tumor: A Case Report and Literature Review.

Giant cell tumors (GCTs) are locally aggressive primary bone tumors of osteoclast-like cells. Most GCTs occur within the long bones, and primary GCTs involving the clivus are extremely rare. We present the case of an 18-year-old boy with binocular horizontal diplopia with an insidious onset who was found to have a hypointense enhancing mass involving the clivus and left side dorsum sellae on magnetic resonance images. The tumor was completely resected via an endoscopic endonasal transclival approach, and histopathologic examination via immunohistochemistry indicated a GCT. The patient's left abducens nerve palsy improved slightly after surgery. Because of the rarity of GCTs, there is no consensus about the definitive treatment protocol. However, we suggest that gross total resection is the treatment of choice, and denosumab plays a critical role in patients with subtotal resection.

Dural-Based Posterior Fossa Medulloblastoma Mimicking a Petrous Meningioma in Late Adulthood.

Background: Medulloblastoma of the posterior fossa is commonly encountered in pediatric populations but rarely reported in adults. Adult cases of medulloblastoma typically occur in younger patients, tend to arise intra-axially within the cerebellar hemisphere, and usually exhibit classic histopathologic features. Case Report: A 54-year-old male presented with headaches, dizziness, gait instability, and frequent falls that had worsened during the prior 3 months. Imaging and histopathologic analysis revealed extra-axial, dural-based posterior fossa medulloblastoma with desmoplastic/nodular histopathology, mimicking a petrous meningioma. The mass occupied the left cerebellopontine angle. The patient underwent microsurgical gross total resection of the tumor followed by proton beam radiation therapy and was disease-free at 1-year follow-up. Conclusion: Few dural-based posterior fossa medulloblastomas resembling petrous meningiomas have been reported, and to our knowledge, this is the first description of a case to be treated successfully with proton beam therapy in an older adult. Although rare, medulloblastoma can occur extra-axially in the cerebellopontine angle of older adults, potentially mimicking a petrous meningioma. This rare possibility should always be kept in mind, especially if expectant, nonsurgical management is being considered. To optimize outcome, posterior fossa medulloblastoma should be treated with aggressive microsurgical resection followed by radiation therapy. When available, proton beam therapy should be considered.

Delayed fenestration of Blake's pouch with or without vermian hypoplasia: fetal MRI at 3 tesla versus 1.5 tesla.

BACKGROUND: Fetal magnetic resonance imaging (MRI), mainly performed at standard field strength, plays a role in the classification of posterior fossa malformations. In the context of early second-trimester screening, upward rotation of the cerebellar vermis per se is usually compatible with a more favorable outcome than Dandy-Walker malformation and profound vermian hypoplasia. Delayed fenestration of Blake's pouch may either mimic vermian hypoplasia by compression or be associated with it in individual cases. To increase specificity, there is a growing interest in the use of high-field MRI which is believed to be safe as long as the specific absorption rate is kept within accepted limits. We aim to illustrate its added value during the second and third trimester. CASE PRESENTATION: In the first case, fetal MRI at 1.5 Tesla was performed at 21 and 27 weeks' gestation with sonographic follow up postnataly. In the second case, 3 Tesla MR images were acquired at 21 and 34 weeks' gestation as well as in the neonatal period. CONCLUSIONS: This pictorial case vignette supports the suggestion that mid-gestational MRI at 3 Tesla has the potential to exclude pronounced vermian hypoplasia with higher confidence than at 1.5 Tesla. However, the discrimination of mild hypoplasia from slight deformation of the cerebellar vermis will likely remain challenging.

Fetal posterior fossa malformations: review of the current knowledge.

Ultrasound diagnosis of posterior fossa malformations in the prenatal period is a challenge, having major implications for the counseling and follow-up of pregnant women. The purpose of this study was to review aspects of the ultrasound evaluation of the fetal posterior fossa, as well as to describe the most relevant ultrasound findings of the main posterior fossa malformations that can affect the fetus in the prenatal period.

Congenital malformations of the posterior fossa: a review of clinical and radiological features through an Illustrated guide / Malformações congênitas da fossa posterior: uma revisão das características clínicas e radiológicas por meio de um guia ilustrado

Congenital malformations of the posterior fossa (PF) encompass a wide spectrum of morphological anomalies that arise during embryonic development. This paper provides a narrative review of these most common disorders from a morphological approach based on the division into cystic (Dandy-Walker malformation, Blake's Pouch cyst, mega cisterna magna, arachnoid cyst, and cerebellar vermis hypoplasia) and non-cystic malformations (Joubert syndrome, rhomboencephalosynapsis, and pontocerebellar hypoplasia). The embryogenesis of PF structures is briefly outlined. While magnetic resonance imaging is the preferred modality for evaluation, computerized tomography and ultrasonography serve complementary roles. In conjunction with clinical aspects, specific radiological features, such as cerebellar vermis morphology, Torcular Herophili position, and the presence/absence of mass effect, are highlighted for accurate diagnosis. We also present some typical radiological findings in non-cystic malformations, such as molar tooth sign, diamondshaped fourth ventricle, and dragonfly-shaped cerebellum. This comprehensive review aims to assist radiologists, neuropediatricians, and general neurologists in recognizing and describing PF malformations, thereby facilitating appropriate management strategies.

As malformações congênitas da fossa posterior (FP) abrangem um amplo espectro de anomalias morfológicas que surgem durante o desenvolvimento embrionário. Este artigo fornece uma revisão narrativa desses distúrbios mais comuns a partir de uma abordagem morfológica baseada na divisão em malformações císticas (malformação de Dandy-Walker, cisto da bolsa de Blake, mega cisterna magna, cisto aracnoide e hipoplasia do vermis cerebelar) e não císticas (syndrome de Joubert, rombencefalossinapse e hipoplasia pontocerebelar). A embriogênese das estruturas da FP é brevemente descrita. Embora a ressonância magnética seja a modalidade preferida para avaliação, a tomografia computadorizada e a ultrassonografia desempenham funções complementares. Em conjunto com os aspectos clínicos, características radiológicas específicas, como a morfologia do vermis cerebelar, a posição da torcula Herophili e a presença/ausência de efeito de massa, são destacadas para um diagnóstico preciso. Apresentamos também alguns achados radiológicos típicos de malformações não císticas, como sinal do dente molar, quarto ventrículo em forma de diamante e cerebelo em forma de libélula. Esta revisão abrangente visa auxiliar radiologistas, neuropediatras e neurologistas gerais no reconhecimento e na descrição das malformações da FP, facilitando, assim, estratégias de manejo adequadas.

Rosette-forming glioneuronal tumor of the fourth ventricle. Two cases report and literature review. / Tumor glioneuronal formador de rosetas del IV ventrículo. Presentación de 2casos y revisión de la literatura.

Rosette-forming glioneuronal tumor of the fourth ventricle is a primary central nervous system tumor introduced in the group of glioneuronal tumors in the WHO classification of 2007. Initially it was described around the fourth ventricle, but recently have been published cases in different locations. We present 2cases of this rare tumor, both surgically treated. The first in a 41 year old man with typical symptoms of posterior fossa injury. The second in an 18 year old woman, with incidental finding of posterior fossa injury that was also surgically treated. We present pre- and post-surgical magnetic resonance images, histological pictures of this tumor and we make a review of the literature.

Values of the apparent diffusion coefficient in the differential diagnosis of tumors of the posterior fossa in the pediatric population of Colombia / Valores del coeficiente de difusión aparente en el diagnóstico diferencial de los tumores de la fosa posterior en población pediátrica de Colombia

Abstract Introduction: Posterior fossa tumors are common in the pediatric population and require adequate characterization by means of structural magnetic resonance imaging (MRI) and advanced MRI techniques to achieve an appropriate therapeutic approach. Objectives: To determine the usefulness of apparent diffusion coefficient (ADC) values for the differential diagnosis of posterior fossa tumors in the pediatric population treated at a reference hospital in Bogotá D.C., Colombia. Materials and methods: Diagnostic accuracy study carried out in 28 pediatric patients diagnosed with posterior fossa tumor between 2017 and 2019 at the Fundación Hospital de la Misericordia, a quaternary care institution. ADC values were measured and compared with histopathological diagnosis as gold standard, obtaining sensitivity, specificity, and positive and negative predictive values. Differences between medians were determined using the Kruskall-Wallis test. The p value between the quantitative ADC value and the gold standard was calculated using Pearson's chi-squared test, with a significance level of p<0.05. Results: The mean age of the participants was 83.9 months (SD=57 months), and 64.28% of them were boys. Medulloblastoma was the most frequent tumor (39.29%). For the diagnosis of medulloblastoma, an ADC value of 0.6210x10-3mm2/s was established, obtaining a sensitivity and specificity of 81.82% and 76.47%, respectively. For the diagnosis of pilocytic astrocytoma, an ADC of 1.03x10-3mm2/s was determined, with a sensitivity of 66.67% and a specificity of 89.40%. Conclusions: ADC value is useful to classify and differentiate posterior fossa tumors in the Colombian pediatric population, showing an inversely proportional relationship with the tumor grade.

Resumen Introducción. Los tumores de la fosa posterior son frecuentes en población pediátrica y requieren de una adecuada caracterización mediante resonancia magnética (RM) estructural y técnicas avanzadas de RM para lograr un enfoque terapéutico apropiado. Objetivo. Determinar la utilidad de los valores del coeficiente de difusión aparente (ADC cuantitativo) en el diagnóstico diferencial de los tumores de la fosa posterior en población pediátrica de un hospital de referencia en Bogotá D.C., Colombia. Materiales y métodos. Estudio de validez de prueba diagnóstica realizado en 28 pacientes pediátricos diagnosticados con tumor de fosa posterior entre 2017 y 2019 en la Fundación Hospital Pediátrico de la Misericordia, hospital de IV nivel de complejidad. Se midieron los valores del ADC cuantitativo, los cuales fueron comparados con el diagnóstico histopatológico como estándar de oro, obteniendo datos de sensibilidad, especificidad, valores predictivos positivos y negativos. Las diferencias entre medianas fueron determinadas mediante la prueba de Kruskall-Wallis. El valor p entre el valor del ADC cuantitativo y el estándar de oro se calculó con la prueba X2 de Pearson, con un nivel de significancia de p<0.05. Resultados. La edad media fue 83.9 meses (DE=57 meses) y 64.28% fueron niños. El tumor más frecuente fue el meduloblastoma (39.29%). Para el diagnóstico de meduloblastoma se estableció un valor ADC cuantitativo de 0.6210x10-3mm2/s, obteniéndose una sensibilidad y especificidad de 81.82% y 76.47%, respectivamente, y para el diagnóstico de astrocitoma pilocítico, un ADC cuantitativo de 1.03x10-3mm2/s, con una sensibilidad de 66.67% y una especificidad de 89.40%. Conclusiones. El valor del ADC cuantitativo es útil para clasificar y diferenciar los tumores de la fosa posterior en población pediátrica colombiana, mostrando una relación inversamente proporcional con el grado tumoral.

SKULL BASE SURGERY - A NEW CONCEPT IN REGIONAL SURGERY.

Surgery of the skull base has evolved over the past 100 years. This anatomical area has been approached by neurosurgeons, otologists, maxillofacial surgeons and plastic surgeons from different angles. Presently, the combined skills of these surgeons are utilized in treating lesions of this area once considered a 'bony no man's land'. Modern microsurgical techniques are based on the principle that removal of adequate bone from the cranial base could provide sufficient access without the necessity to retract dura. Accurate preoperative assessment by imaging, the use of microsurgical techniques, preservation of vital structures such as nerves by intraoperative monitoring, and modern anaesthetic and postoperative management have all contributed to the reduction in mortality and morbidity to acceptable levels. In the future, with refinements in imaging, stereotactic radiosurgery and chemotherapy, the above management protocol would be tailored to suit each individual patient and decided by a team of experts.

Clival lesion incidentally discovered on cone-beam computed tomography: A case report and review of the literature.

An osteolytic lesion with a small central area of mineralization and sclerotic borders was discovered incidentally in the clivus on the cone-beam computed tomography (CBCT) of a 27-year-old male patient. This benign appearance indicated a primary differential diagnosis of non-aggressive lesions such as fibro-osseous lesions and arrested pneumatization. Further, on magnetic resonance imaging (MRI), the lesion showed a homogenously low T1 signal intensity with mild internal enhancement after post-gadolinium and a heterogeneous T2 signal intensity. These signal characteristics might be attributed to the fibrous tissues, chondroid matrix, calcific material, or cystic component of the lesion; thus, chondroblastoma and chondromyxoid fibroma were added to the differential diagnosis. Although this report was limited by the lack of final diagnosis and the patient lost to follow-up, the incidental skull base finding would be important for interpreting the entire volume of CBCT by a qualified oral and maxillofacial radiologist.

Fetal posterior fossa malformations: review of the current knowledge / Malformações da fossa posterior fetal: revisão do conhecimento atual

Abstract Ultrasound diagnosis of posterior fossa malformations in the prenatal period is a challenge, having major implications for the counseling and follow-up of pregnant women. The purpose of this study was to review aspects of the ultrasound evaluation of the fetal posterior fossa, as well as to describe the most relevant ultrasound findings of the main posterior fossa malformations that can affect the fetus in the prenatal period.

Resumo O diagnóstico ultrassonográfico das malformações da fossa posterior no período pré-natal é um desafio, com importantes implicações no aconselhamento e acompanhamento dessas gestações. O objetivo deste estudo é revisar aspectos da avaliação ultrassonográfica da fossa posterior do feto e descrever os principais achados ultrassonográficos das principais malformações da fossa posterior que podem acometer o feto no período pré-natal.

Skull base aneurysmal bone cyst presented with foramen jugular syndrome and multi-osseous involvement.

Aneurysmal bone cyst (ABC) is an expansile bone lesion that usually involves the long bones. Skull base involvement is rare. Hereby, we describe a 17-year-old man with hoarseness, facial asymmetry, left sided sensorineural hearing loss and left jugular foramen syndrome. CT scan and MRI showed a skull base mass that was confirmed as ABC in histopathology. The case was unusual and interesting due to the clinical presentation of jugular foramen syndrome and radiological findings such as severe enhancement and multiosseous involvement.

Magnetic resonance imaging of the clivus and its age-related changes in the bone marrow.

BACKGROUND: The clivus is a bone region between dorsum cella and foramen magnum. It can be evaluated very clearly in routine brain magnetic resonance imaging (MRI) dueto its central location. OBJECTIVES: Quantitative and qualitative evaluation of the clivus and its changes according to age in a group of healthy people. PATIENTS AND METHODS: The transition of clival bone marrow to fatty marrow by the increasein age is examined by MRI in 105 men and 105 women who had no clival and bone marrow pathology on MRI. The clivus/pons, clivus/CSF intensity values and clival bone marrow imaging patterns according to age groups were prospectively evaluated using a 1.5 Tesla MR device. RESULTS: When age groups were individually compared, there were meaningful statistical differences both in men and women in terms of clivus/CSF and clivus/pons intensity ratios (both Ps < 0.05). Clivus/pons and clivus/CSF intensity ratios were found to be increased with age in all cases. The distribution of age groups according to stages in all individuals was statistically meaningful (P < 0.05). When the appearance patterns of both genders in every ten-fold age were examined, stage III bone marrow was observed more in elder ages. CONCLUSIONS: As a result, besides the fact that standard ranges determined for clivus/CSF, clivus/pons intensity ratios according to age may be used in the assessment of potential pathological cases involving bone marrow; they can also be leading in the diagnosis of bone marrow diseases when taken into consideration together with clinical and laboratory data.

Mastoiditis causing Sinus Thrombosis and Posterior Fossa Epidural Haematoma: Case report.

Spontaneously occurring epidural haematomas are an uncommon entity. A spontaneous post fossa epidural haematoma due to sigmoid sinus thrombosis secondary to mastoiditis has not been reported in English medical literature. We report a 40 year-old man who presented to us with headache and incoordination. A magnetic resonance imaging (MRI) confirmed epidural sub-acute bleeding in the right side of posterior fossa with mastoiditis and right sigmoid sinus thrombosis. A right suboccipital craniotomy and evacuation of the haematoma was done and the patient was relieved of his complains.