Imaging findings of intraventricular and ependymal lesions

Pearls and Pitfalls of Imaging in Pediatric Brain Tumors

The central nervous system (CNS) tumors constitute the most common type of solid tumors in the pediatric population. The cerebral and cerebellar parenchyma are the most common site of pediatric CNS neoplasms. Imaging plays an important role in detection, characterization, staging and prognostication of brain tumors. The focus of the current article is pediatric brain tumor imaging with emphasis on pearls and pitfalls of conventional and advanced imaging in various pediatric brain tumor subtypes. The article also elucidates changes in brain tumor terms and entities as applicable to pediatric patients, updated as per World Health Organization (WHO) 2016 classification of primary CNS tumors. This classification introduced the genetic and/or molecular information of primary CNS neoplasms as part of comprehensive tumor pathology report in the routine clinical workflow. The concepts from 2016 classification have been further refined based on current research, by the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) group and published in the form of updates. The updates serve as guidelines in the time interval between WHO updates and expect to be broadly adopted in the subsequent WHO classification. The current review covers most pediatric brain tumors except pituitary tumors, meningeal origin tumors, nerve sheath tumors and CNS lymphoma/leukemia.

Overcoming the Elusiveness of Neurosarcoidosis: Learning from Five Complex Cases

The involvement of the central nervous system in sarcoidosis can manifest with a variety of neurological symptoms, and most of them can be nonspecific. The diagnosis of neurosarcoidosis (NS) can therefore be very challenging without a tissue biopsy. Both computed tomography (CT) and magnetic resonance imaging (MRI) are important imaging modalities in the diagnosis of NS, and MRI is the modality of choice due to its superior soft-tissue contrast resolution. We present a case series of NS with interesting neuroimaging features, complex neurological presentations, and clinical courses. We identify five cases presenting with clinically isolated neurosarcoidosis (CINS) without any other signs or symptoms of systemic disease which were diagnosed as NS on biopsy. In the first case, we describe a patient with an intramedullary cervical spinal cord lesion. In the second case we describe a patient presenting with inflammatory changes and enhancement in the orbit. The third case demonstrates a lesion with calcification around the region of the foramen of Monro. The fourth case shows multiple ring-enhancing lesions. Lastly, the fifth case exhibits unusual findings with both optic neuritis and a cerebellar nodule. We aim to describe the complicated clinical course with neurological workup, neuro-imaging, and eventual diagnosis and treatment of these challenging cases to highlight the variable presentations of NS. This case series will remind clinicians that NS should always be in the differential diagnosis when a patient presents with nonspecific neurological symptoms with unusual neuroimaging findings.

Case Presentation: Unusual Association Between Possible Bilateral Intraventricular Xanthogranulomas, Postero-inferior Cerebellar Artery Aneurysm and Thrombophilia

Introduction: Xanthogranulomas are rare, benign, usually asymptomatic, cutaneous tumors most frequently seen in children (juvenile xanthogranulomas). Some lesions can be found accidentally at randomly performed cerebral computer tomography (CT) or magnetic resonance imaging (MRI) or even on autopsy.

Case report: We present the case of a 44 year-old woman, known with a thrombophilic disorder (PAI-1 gene mutation, MTHFR C677T and A1298C) on chronic anticoagulant treatment. The onset of symptoms was in 2010, when she presented paresthesia and lower limbs weakness. Two years later the patient presents with severe intermittent headache and left hemicrania and a cerebral angio-MRI is performed showing a left postero-inferior cerebellar artery aneurysm and two choroid plexus intraventricular masses in the lateral ventricles. The patient developed a new symptom, dysarthria in 2014 and in 2015 has multiple episodes of loss of consciousness, interpreted as epileptic seizures. Routine blood tests were within normal range, except for a high cholesterol level. The patient was tested for autoimmune, infectious, endocrine and metabolic diseases that were negative. Surgical treatment and biopsy from the lesion was proposed, however the patient refused both procedures.

Conclusions: There is an association between xanthogranulomas localization and the choroid plexus, the most frequent CNS origin being in the trigon of the lateral ventricle. Our case does not resemble with any other case published, mostly because the unusual presentation, symptomatology and the association between xanthogranulomas, thrombophilia and postero-inferior cerebellar artery aneurysm which were never reported before in other cases of xanthogranulomas from the literature.

Clinical features and neurosurgical treatment of trigonal cavernous malformations

The goals of this study were to analyze the incidence, clinical manifestations, neuroimaging findings, surgical treatments, and neurological outcomes of trigonal cavernous malformations (TCMs). Among 1395 cases of intracranial and intraspinal cavernous malformations (CMs) surgically treated between 2003 and 2016 at Beijing Tiantan Hospital, a series of 12 patients with TCM was chosen for analysis and their records were reviewed. We also performed an exhaustive literature search using PubMed to identify all previously reported cases in the literatures. TCMs accounted for 0.86% of the entire series of the central nervous system (CNS) CMs. The case series consisted of five male and seven female patients (ratio 1:1.4), with an average age at presentation of 32.9 years (7-53 years). In all the cases, headache was the most common initial symptom (66.7%). Complete resection without surgical mortality was achieved in all the cases. Postoperative complications included fever, lower limb weakness, sensory aphasia, and calculational capacity declination. Follow-up period after diagnosis was 15 to 74 months (mean 48.3 months); no patient was lost to follow-up. All the patients were considered to be in excellent clinical condition. TCMs are rare lesions; they can reach large size, and their symptoms and signs commonly resulted from mass effect. Surgical intervention is the treatment of choice for TCMs; patients can obtain favorable neurological outcomes after complete resection.

Endoscopic diagnosis of an MRI-occult, low-grade glioma with ependymal dissemination

A 21-year-old man presented with triventricular hydrocephalus due to a tectal mass. He underwent an endoscopic third ventriculostomy, and multiple nodules were identified at the floor of the third ventricle intraoperatively. Surgical pathology of one of these lesions demonstrated that the tissue represented a low-grade astrocytoma. The case highlights the existing potential of neuroendoscopy to reveal neuroimaging-occult lesions, in spite of the significant advances of MRI. Furthermore, the combination of the age of the patient, the nonenhancing MRI appearance, and the multifocality of the lesions constitutes a rare and interesting neoplastic presentation within the brain. The constellation of findings likely represents dissemination of a low-grade tectal glioma via the CSF compartment.

Pilocytic astrocytoma presenting with atypical features on magnetic resonance imaging

Pilocytic astrocytoma, which is classified as a grade I astrocytic tumor by the World Health Organization, is the most common type of glioma in children and young adults. Pilocytic astrocytoma generally appears as a well-circumscribed, contrast-enhancing lesion, frequently with cystic components on magnetic resonance imaging (MRI). However, it has been reported that the MRI appearance of pilocytic astrocytoma may be similar to that of high-grade gliomas in some cases. We here report on 6 cases of pilocytic astrocytoma with atypical MRI findings, including small cyst formation, heterogeneously enhancing tumor nodules, irregularly enhancing tumor nodules, and enhancing tumor nodules with internal hemorrhage. All tumors were successfully resected, and the histological diagnoses were pilocytic astrocytoma. When the tumor is located near a cerebral cistern or ventricle, the risk of leptomeningeal dissemination is increased. Furthermore, partial resection has also been associated with a higher risk of recurrence and leptomeningeal dissemination. To date, all but one patient are alive and recurrence-free. Because the preoperative diagnosis influences the decision on the extent of resection and because of the high risk of leptomeningeal dissemination associated with these tumors, careful and correct diagnosis by MRI is important.

[Pathognomonic magnetic resonance imaging (MRI) finding of fluid-fluid level in pyogenic ventriculitis: two case reports]

Pyogenic ventriculitis is an uncommon and potentially fatal central nervous system infection. Delayed treatment due to non specific clinical symptoms may lead to an unfavorable outcome. Brain magnetic resonance imaging (MRI) plays an important role in the diagnosis of pyogenic ventriculitis. We describe two patients with pyogenic ventriculitis presenting with a pathognomonic MRI finding. The first patient, a 77-year-old female, developed high fever and consciousness disturbance. MR images revealed hyperintense lesions with a fluid-fluid level in the bilateral lateral ventricles on diffusion-weighted images (DWIs) and hypointense lesions on T2-weighted images (T2WIs). MR images also revealed findings of left otitis media. The second patient, a 63-year-old male, who had a past history of multiple myeloma and had received chemotherapy, developed high fever and left hemiparesis. MR images revealed a hyperintense lesion with a fluid-fluid level in the right lateral ventricle on DWIs and a hypointense lesion on T2WIs, multiple ring-enhancing lesions on gadolinium enhanced T1-weighted images, and pontine infarction on DWIs. Chest computed tomography revealed an infiltrative shadow in the lower lobe of the left lung. On the basis of MRI findings, both patients were diagnosed as having pyogenic ventriculitis and were administered high-dose meropenem intravenously. The second patient was also administered sulfamethoxazole-trimethoprim orally. Intraventricular abnormalities disappeared and the patients achieved complete remission after the antibacterial treatment. Intraventricular hyperintense lesions on DWIs and hypointense ones on T2WIs with a fluid-fluid level is a pathognomonic finding of pyogenic ventriculitis and has not been previously reported in other diseases. Recognition of the characteristic MRI features and initiation of high-dose and appropriate antibiotics in an early stage may lead to a favorable outcome of the disease.

Magnetic resonance features of pyogenic brain abscesses and differential diagnosis using morphological and functional imaging studies: a pictorial essay

The aim of this paper is to illustrate the potential of magnetic resonance imaging (MRI) in diagnosis, differential diagnosis, treatment planning and evaluation of therapy effectiveness of pyogenic brain abscesses, through the use of morphological (or conventional) and functional (or advanced) sequences. Conventional MRI study is useful for the identification of lesions, to determine the location and morphology and allows a correct hypothesis of nature in the most typical cases. However, the differential diagnosis from other brain lesions, such as non-pyogenic abscesses or necrotic tumors (high-grade gliomas and metastases) is often only possible through the use of functional sequences, as the measurement of diffusion with apparent diffusion coefficient (DWI-ADC), proton magnetic resonance spectroscopy ((1)H-MRS) and perfusion weighted imaging (PWI), which complement the morphological sequences and provide essential information on structural, metabolic and hemodynamic characteristics allowing greater neuroradiological confidence. Modern diagnostic MRI of pyogenic brain abscesses cannot be separated from knowledge, integration and proper use of the morphological and functional sequences.

Diffusion weighted MR imaging and proton MR spectroscopy findings of central neurocytoma with pathological correlation

PURPOSE

Three cases of histopathologically confirmed central neurocytoma (CN) are presented, emphasizing diagnostic imaging issues: conventional magnetic resonance imaging with Proton magnetic resonance spectroscopy (MRS) and diffusion-weighted imaging (DWI) findings of CN.

MATERIALS AND METHODS

Patients age ranged from 17 to 32 years, Imaging include a CT scan and MR examination with DWI and proton MRS on a 1.5-T system. DWI and subsequent apparent diffusion coefficient (ADC) were obtained in all. Single voxel MRS was performed prior to surgery using a point resolved spectroscopy sequence (PRESS) with short 35 ms and long echotime (TE) 144 ms, associated with a two-dimensional chemical Shift Imaging (2D-CSI) with 144 ms TE (one case). Histopathological examination included immunostaining with synaptophysin.

RESULTS

With the long TE, a variable amount of glycine with markedly increased choline, very small to almost complete loss of N-acetylaspartate and creatine, and inverted triplet of alanine-lactate were observed in all three patients. Increased glutamate and glutamine complex (Glx) was also observed in all with short TE. DWI demonstrated variable low ADC which appeared well correlated with the tumor signal intensity and cell density: the most homogeneous and highly dense cellular tumor with increased nucleus to cytoplasm ratio demonstrated the lower ADC. Histological pattern was typical in two cases and demonstrated an oligodendroglioma-like pattern in one case. Positivity for synaptophysin confirmed the neuronal origin in all.

CONCLUSION

The demonstration within an intraventricular tumor of both glycine and alanine on MRS along with high choline, bulky Glx and restricted diffusion appear diagnostic of CN.