ABSTRACT
Meningiomas are among the most common central nervous system tumors, with an incidence that ranges from 15% to 40% of intracranial tumors. Of these, only 0.5% to 3% are intraventricular, and the rarest of them occurs in the fourth ventricle. Fourth-ventricle meningiomas originate generally fromthe choroid plexus and have no dural adhesions. Most often, they manifest in young patients, around 41 years of age, with a possible predominance in females, through intracranial hypertension and cerebellar syndromes. The treatment consists of surgical resection, which commonly presents good results due to the characteristics of the tumor. So, for better preoperative planning, the radiological differentiation of the most frequent tumors in this location is important. Themost common histologic subtypes are fibroblastic and meningothelial, both grade I according to the World Health Organization (WHO), although there are reports of tumors of grades II and III. We report a case ofmeningioma of the fourth ventricle operated in our institution, and we have conducted a literature review, through which we found that 57 cases have been reported so far, with the first one reported in 1938.
Subject(s)
Humans , Male , Adult , Fourth Ventricle/pathology , Meningioma/surgery , Meningioma/epidemiology , Meningioma/diagnostic imaging , Cerebellar Neoplasms/epidemiology , Meningioma/physiopathologyABSTRACT
Objective To explore the clinical characteristics of infratentorial primary angiitis in central nervous system (PACNS).Methods A total of 5 cases diagnosed as infratentorial PACNS in the neurology department of Navy General Hospital of PLA in 2015 were enrolled in the study.The clinical,imaging and pathological data were collected and analyzed.Results All the 5 cases were male with the median onset age of thirty-four.Five cases presented with dizziness,two with headache,three with walking unstable,two with facial numbness and one with dysarthria.Rising pressure of cerebrospinal fluid (CSF) (190-245 cmH2O,1 cmH2O =0.098 kPa) was found in 4 cases by the lumbar puncture,mildly increased number of leukocyte in 2 cases [(12-28) × 106/L],increased CSF protein in 3 cases(540-979 mg/L) and increased IgG index in 3 cases (0.84-1.45).Pons lesions were revealed by magnetic resonance imaging(MRI) in 4 cases,brachium pontis lesions in 2 cases,cerebellum lesions in 2 cases,one with midbrain lesion in 1 case,unilateral lesions in 4 cases and bilateral lesion in 1 case.Different degree of edema and mass effect were shown in all lesions by MRI.Patch like enhancement was found by contrast MRI in 5 cases and meningeal enhancement in 2 cases.Elevation of choline (Cho) peak was found by magnetic resonance spectroscopy (MRS) in 4 cases,reduction of N-acetyl aspartate (NAA) peak in 3 cases,appearance of lactate peak in 1 case and lipid peak in another case.Arterial spin labeling (ASL) was performed in 4 cases and no hyperperfusion was found.Susceptibility weighted imaging(SWI) was performed in 3 cases and microhemorrhage in the lesions was found in 2 cases and normal in 1 case.Magnetic resonance arteriography(MRA) was performed in 1 case and no stenosis was found.Digital subtraction arteriography(DSA) was performed in 1 case and multiple stenosis of the intracranial arteries was showed.Two cases had taken the stereotactic brain biopsy and the histopathologic diagnosis was angiitis.Five cases were treated with methylprednisolone and cyclophosphamide was added on in 1 case.Good prognosis was found in all cases.Conclusions Infratentorial PACNS mostly attacks middle-aged males.The lesions tend to locate in unilateral pons,brachium pontis,cerebellum and midbrain.Hemorrhage or microhemorrhage in lesions is often found by SWI and no hyperperfusion is shown by ASL,which would be useful to distinguish PACNS from malignant tumors.Given the limitations of brain biopsy in clinical practice,clinical and imaging features would be helpful to diagnose PACNS.
ABSTRACT
OBJETIVO: Correlacionar os achados de ressonância magnética convencional, difusão e espectroscopia de prótons nos meduloblastomas, e compará-los aos dados da literatura. MATERIAIS E MÉTODOS: Análise retrospectivade exames de ressonância magnética pré-operatórios de nove pacientes na faixa pediátrica com diagnóstico histológico de meduloblastoma (oito desmoplásicos e um de células gigantes). Foram considerados dados demográficos e características do tumor como localização, característica morfológica, intensidade de sinal, realce, disseminação e achados na difusão e espectroscopia. RESULTADOS: Na maioria dos casos os tumores apresentaram epicentro no vermis cerebelar (77,8%), sendo predominantemente sólido (88,9%), com hipossinal nas seqüências ponderadas em T1 e iso/hipersinal nas seqüências ponderadas em T2 e FLAIR, realce heterogêneo (100%), sinais de disseminação/extensão tumoral (77,8%) e restrição à movimentação das moléculas de água (100%). A espectroscopia de prótons pela técnica STEAM (n = 6) demonstrou redução da relação Naa/Cr (83,3%) e aumento de Co/Cr (100%) e mI/Cr (66,7%), e pela técnica PRESS (n = 7) evidenciou pico de lactato (57,1%). CONCLUSÃO: O conjunto dos achados macroscópicosobtidos pela ressonância magnética, somado às características bioquímicas dos meduloblastomas, têm sido úteis na tentativa de diferenciação entre os principais tumores da fossa posterior.
OBJECTIVE: To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. MATERIALS AND METHODS: Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumorscharacteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, anddiffusion-weighted imaging and spectroscopy findings. RESULTS: In most of cases the tumors were centeredin the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T1-weighted images andintermediate/hyperintense on T2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquiredwith STEAM technique (n = 6) demonstrated decreased Naa/Cr ratio (83.3%) and increased Co/Cr (100%)and mI/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). CONCLUSION: Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. Keywords: Medulloblastoma; Infratentorial neoplasms; Pediatric brain tumors; Magnetic resonance imaging;Diffusion-weighted magnetic resonance imaging; Magnetic resonance spectroscopy.