Meningioma of the scapula

Meningiomas account for approximately 15% of all intracranial tumors and are the most common non-glial primary tumors of the central nervous system. Most meningiomas are benign neoplasms with characteristic imaging features. Primary extradural meningiomas account for only 1–2% of all meningiomas. They must be differentiated from intradural meningiomas with secondary extradural extension and/or metastases. The vast majority of extradural meningiomas are found in the skull or in the head and neck region. We report on an extremely rare case of primary extradural meningioma that was located in the scapula. The lesion was resected. Radiographic findings and pathologic features are discussed. To the best of our knowledge, this form of presentation of an extradural meningioma has not been previously described.     

Imaging and clinical characteristics of temporal bone meningioma

BACKGROUND AND PURPOSE: Imaging characteristics of temporal bone meningioma have not been previously reported in the literature. CT and MR imaging findings in 13 cases of temporal bone meningioma are reviewed to define specific imaging features. METHODS: A retrospective review of our institutional case archive revealed 13 cases of histologically confirmed temporal bone meningioma. CT and MR imaging studies were reviewed to characterize mass location, vector of spread, bone changes, enhancement characteristics, and intracranial patterns of involvement. Clinical presenting signs and symptoms were correlated with imaging findings. RESULTS: Thirteen temporal bone meningiomas were reviewed in 8 women and 5 men, aged 18-65 years. Meningiomas were stratified into 3 groups on the basis of location and tumor vector of spread. There were 6 tegmen tympani, 5 jugular foramen (JF), and 2 internal auditory canal (IAC) meningiomas. Tegmen tympani and JF meningiomas were characterized by spread to the middle ear cavity. IAC meningiomas, by contrast, spread to the cochlea and vestibule. Hearing loss was the most common clinical presenting feature in all cases of temporal bone meningioma (10/13). The presence of tumor adjacent to the ossicles strongly correlated with conductive hearing loss (7/9). CONCLUSION: Meningioma involving the temporal bone is rare. Three subgroups of meningioma exist in this location: tegmen tympani, JF, and IAC meningioma. Tegmen tympani and JF meningiomas spread to the middle ear cavity. IAC meningiomas spread to intralabyrinthine structures. Conductive hearing loss is commonly seen in these patients and can be surgically correctable.     

Characterization of necrotic meningioma using diffusion MRI,perfusion MRI,and MR spectroscopy: case report and review of the literature

Necrotic meningiomas are relatively rare, accounting for 1.3–3.9% of primary intracranial tumours and for 10–15% of meningiomas, but are of special clinical importance as they may resemble metastases or malignant gliomas. We report the magnetic resonance findings of diffusion-weighted imaging, perfusion-weighted imaging, and spectroscopy in a patient with a necrotic meningioma, in whom clinical symptoms and signs suggested a central nervous system infection.     

Contribution of dynamic contrast MR imaging to the differentiation between dural metastasis and meningioma

Purpose To determine the perfusion-sensitive characteristics of cerebral dural metastases and compare them with the data on meningiomas.Methods Twenty-two patients presenting with dural tumor underwent conventional and dynamic susceptibility-contrast MR imaging: breast carcinoma metastases, two patients; colorectal carcinoma metastasis, one patient; lung carcinoma metastasis, one patient; Merkel carcinoma metastasis, one patient; lymphoma, one patient; meningiomas, 16 patients. The imaging characteristics were analyzed using conventional MR imaging. The cerebral blood volume (CBV) maps were obtained for each patient and the relative CBV (rCBV) in different areas was calculated using the ratio between the CBV in the pathological area (CBVp) and in the contralateral white matter (CBVn).Results The differentiation between a meningioma and a dural metastasis can be difficult using conventional MR imaging. The rCBVs of lung carcinoma metastasis (1 case: 1.26), lymphoma (1 case: 1.29), breast carcinoma metastasis (2 cases: 1.50,1.56) and rectal carcinoma metastasis (1 case: 3.34) were significantly lower than that of meningiomas (16 cases: mean rCBV = 8.97±4.34, range 4–18). Merkel carcinoma metastasis (1 case: 7.56) showed an elevated rCBV, not different from that of meningiomas.Conclusion Dural metastases are sometimes indistinguishable from meningiomas using conventional MR imaging. rCBV mapping can provide additional information by demonstrating a low rCBV which may suggest the diagnosis of metastasis.     

Intraosseous meningioma of the skull: radiologic pathologic correlation

Intraosseous meningiomas are rare ectopic meningiomas. The authors report the case of a hyperostotic intraosseous meningioma of the parietal bone without dural extension. The preoperative imaging findings, as well as imaging features of the surgical specimen and pathologic findings are discussed.     

Utility of proton MR spectroscopy in the diagnosis of radiologically atypical intracranial meningiomas

Our aim was to evaluate the usefulness of proton MR spectroscopy ((1)H MRS) in the diagnosis of radiologically atypical brain meningiomas. We studied 37 patients with intracranial meningiomas with MRI and (1)H MRS (TE 136 ms). Their spectra were quantitatively assessed and compared with those of 93 other intracranial brain neoplasms: 15 low-grade and 14 anaplastic astrocytomas, 30 glioblastomas and 34 metastases. The most characteristic features of meningiomas were the presence of alanine, high relative concentrations of choline and glutamine/glutamate and low concentrations of creatine-containing compounds, N-acetyl-containing compounds and lipids. These resonances were assembled in algorithms for two-way differentiation between meningioma and the other tumours. The performance of the algorithms was tested in the 130 patients using the leave-one-out method, with 94% success in differentiating between meningioma and other tumour. Of the 37 meningiomas, five (14%) were thought atypical on MRI, and in only one of these, found to be malignant on histology, was a diagnosis other than meningioma suggested by the algorithm. The other four were correctly classified. We suggest that (1)H MRS provides information on intracranial meningiomas which may be useful in diagnosis of radiologically atypical cases.     

The role of advanced MRI techniques in differentiating typical,from atypical and malignant meningiomas

Background

Meningiomas are the commonest primary, non-glial intracranial tumors. The diagnosis is often correctly predicted from characteristic imaging appearances. Some meningiomas have atypical imaging appearance that may cause diagnostic confusion.

Aim

Is to evaluate the role of advanced MR imaging techniques in differentiating typical from atypical and malignant meningiomas before surgery.

Patient

Thirty patients were retrospectively included in this study. They were referred from Neurosurgery Department and all of them suspected to have intracranial meningioma according to the contrast enhanced CT.

Methods

All patients were subjected to conventional magnetic resonance imaging followed by advanced magnetic resonance imaging in the form of diffusion weighted imaging, perfusion weighted imaging and MR spectroscopy by single-voxel techniques.

Results

The overall results based on differentiation of typical from atypical and malignant meningiomas by advanced MRI techniques. Twenty four patients had typical meningioma and 6 patients had atypical and malignant Meningiomas by advanced MRI techniques.

Conclusion

Appearance of meningiomas on DWIs and the calculation of ADC values could be correlated with their histopathological grading. On MRS, alanine was not found to be increased in all meningiomas, so MRS cannot reliably differentiate typical intracranial meningomas from atypical meningiomas.     

Dural invasion of meningiomas adjacent to the tumor margin on Gd-DTPA-enhanced MR images: histopathologic correlation

In intracranial meningiomas a flat, contrast-enhancing, dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA-enhanced MR images. We wished to evaluate whether there is a correlation between MR images and meningeal invasion of intracranial meningiomas. The study included 54 patients with intracranial meningioma and the meningeal sign. MR studies included T2-weighted and gadolinium-DTPA-enhanced T1-weighted images in axial, coronal, and sagittal planes. Histopathologic examinations were done on the meningiomas adjacent to the dura mater. The meningeal sign on MRI was observed from 2 up to 35 mm from the main tumor mass in 31 (57 %) of the 54 patients. In 20 of these 31 the histopathologic examination showed tumor invasion, while 11 patients had no tumor invasion but tissue proliferation, hypervascularity, and vascular dilatation. Seven of the 23 meningiomas without the meningeal sign had histologically proven infiltration of the adjacent dura. MR imaging is not able to determine definitive whether or not there is dural infiltration of the meningiomas. In conclusion, resection of the tumor with a wide margin is necessary to achieve complete excision of meningioma and to avoid recurrence. Received 23 July 1997; Revision received 10 October 1997; Accepted 17 October 1997     

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features.Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings.ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes.ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.     

Imaging features of unusual intracranial cystic meningiomas.

OBJECTIVE: To describe the imaging features of unusual intracranial cystic meningiomas in infants and adults. METHODS: We retrospectively reviewed the magnetic resonance and computed tomography findings for 2 female patients and 3 male patients, ranging in age from 1 to 73 years (median 41 years), with histopathologically proven cystic meningioma. RESULT: Although cystic meningiomas usually appear as solid and cystic masses, they may present as a mainly multicystic lesion. The wall of a cystic part of the meningioma may include both enhancing and unenhancing areas at imaging. The cystic portion of a meningioma is hypointense on diffusion-weighted images and markedly hyperintense on corresponding apparent diffusion coefficient maps. CONCLUSION: Cystic meningiomas may vary in appearance at imaging. They can be very challenging when present in infants. Knowledge of imaging findings and awareness of variability in the differential diagnosis can help to avoid preoperative diagnostic pitfalls.     

Lymphoplasmacyte-rich meningioma: A rare histologic variant of benign meningioma with atypical bone invasion

Meningiomas are the most common primary intracranial brain tumor and have been divided into 15 histologic subtypes, which are further classified into 3 grades according to biological behavior. Lymphoplasmacyte-rich meningioma is a rare histologic subtype of benign (grade 1) meningiomas characterized by prominent infiltration of plasma cells and lymphocytes, with a variable proportion of meningothelial elements. These benign meningioma variants usually cause significant peritumoral brain edema and mimic higher-grade lesions, which is believed to represent inflammatory cell infiltration rather than true neoplastic invasion. Bone invasion in these tumors is exceedingly rare and its clinical significance remains elusive. We describe the case of a lymphoplasmacyte-rich meningioma with skull invasion and peritumoral brain edema in a 57-year-old female patient presenting with left hemiparesis. Gross total resection of the lesion and adjacent skull were performed and histophatological examination disclosed a lymphoplasmacyte-rich meningioma. Gradual decrease of the parenchymal edema was seen on postoperative imaging studies and the patient showed progressive improvement of the motor deficit. This case report depicts rare bone invasion by lymphoplasmacyte-rich meningioma and highlights the other imaging features of this rare histologic subtype of benign meningioma. Due to the paucity of cases, gross total resection, and long-term follow-up are warranted as the prognosis of these tumors is still not fully understood.Kewyords: Lymphoplasmacyte-rich meningioma, WHO grade 1 tumor, Vasogenic edema, Magnetic resonance imaging     

Metastatic meningioma: positron emission tomography CT imaging findings

The imaging findings of a case of metastasing meningioma are described. The case illustrates a number of rare and interesting features. The patient presented with haemoptysis 22 years after the initial resection of an intracranial meningioma. CT demonstrated heterogeneous masses with avid peripheral enhancement without central enhancement. Blood supply to the larger lesion was partially from small feeding vessels from the inferior pulmonary vein. These findings correlate with a previously published case in which there was avid uptake of fluoro-18-deoxyglucose peripherally with lesser uptake centrally. The diagnosis of metastasing meningioma was confirmed on percutaneous lung tissue biopsy.     

MR digital subtraction angiography in the diagnosis of meningiomas

OBJECTIVE: MR digital subtraction angiography (DSA) is a technique for demonstrating the vasculature combining a rapid two-dimensional T1-weighted sequence with a bolus injection of gadolinium. We attempted to determine its contribution to the diagnosis of intracranial meningiomas. METHODS AND PATIENTS: MR DSA was performed in 18 patients with meningioma as well as in 28 patients with other tumors. The findings were analyzed regarding demonstration of tumor stain and tumor-related vessels. RESULTS: All meningiomas except one were visualized as a homogeneous and intense stain. Feeding arteries were visualized in 2 patients, and draining or abnormal veins in three. In 21 of the 28 patients with other tumors, tumor stains of varying degrees were demonstrated. CONCLUSION: MR DSA can serve as an adjunct to routine MR imaging, because it enables assessment of the hemodynamics of meningiomas and facilitates its differential diagnosis from other tumors.     

Chordoid Meningioma: Differentiating a Rare World Health Organization Grade II Tumor from Other Meningioma Histologic Subtypes Using MRI

BACKGROUND AND PURPOSE:Meningiomas are very commonly diagnosed intracranial primary neoplasms, of which the chordoid subtype is seldom encountered. Our aim was to retrospectively review preoperative MR imaging of intracranial chordoid meningiomas, a rare WHO grade II variant, in an effort to determine if there exist distinguishing MR imaging characteristics that can aid in differentiating this atypical variety from other meningioma subtypes.MATERIALS AND METHODS:Ten cases of WHO grade II chordoid meningioma were diagnosed at our institution over an 11-year span, 8 of which had preoperative MR imaging available for review and were included in our analysis. Chordoid meningioma MR imaging characteristics, including ADC values and normalized ADC ratios, were compared with those of 80 consecutive cases of WHO grade I meningioma, 21 consecutive cases of nonchordoid WHO grade II meningioma, and 1 case of WHO grade III meningioma.RESULTS:Preoperative MR imaging revealed no significant differences in size, location, signal characteristics, or contrast enhancement between chordoid meningiomas and other meningiomas. There were, however, clear differences in the ADC values and normalized ADC ratios, with a mean absolute ADC value of 1.62 ± 0.33 × 10⁻³ mm²/s and a mean normalized ADC ratio of 2.22 ± 0.47 × 10⁻³ mm²/s in chordoid meningiomas compared with mean ADC and normalized ADC values, respectively, of 0.88 ± 0.13 × 10⁻³ mm²/s and 1.17 ± 0.16 × 10⁻³ mm²/s in benign WHO grade I meningiomas, 0.84 ± 0.11 × 10⁻³ mm²/s and 1.11 ± 0.15 × 10⁻³ mm²/s in nonchordoid WHO grade II meningiomas, and 0.57 × 10⁻³ mm²/s and 0.75 × 10⁻³ mm²/s in the 1 WHO grade III meningioma.CONCLUSIONS:Chordoid meningiomas have statistically significant elevations of ADC and normalized ADC values when compared with all other WHO grade I, II, and III subtypes, which enables reliable preoperative prediction of this atypical histopathologic diagnosis.

Meningiomas are the second most common primary intracranial neoplasm, constituting approximately 13%–25% of such tumors.¹ There are 15 variants of meningioma according the 2007 World Health Organization (WHO) classification of tumors of the central nervous system.² Although 80%–90% of meningiomas are classified as benign WHO grade I tumors, WHO grade II and III varieties demonstrate a more aggressive clinical course and have a greater propensity for recurrence, and the grade and extent of original resection accounts for these differences.³ Ideally, preoperative imaging to identify the potentially more aggressive grade II and III varieties would be helpful for presurgical planning and subsequent imaging follow-up. One such rare variant is the WHO grade II chordoid meningioma. A little more than 100 cases of chordoid meningioma have been described in the English-language literature, the majority of which are in the pathology and neurosurgery literature.^4–9Attempts to distinguish benign from atypical and malignant meningiomas have been undertaken with variable results, and DWI and ADC values have provided the most reliable means of differentiation,^10,11 though no data analysis specifically examining the chordoid morphologic variant has been performed. To the best of our knowledge, only 3 case reports in which the MR imaging characteristics of chordoid meningiomas were described have been published in the radiology literature.^12–14We compared 8 cases of intracranial chordoid meningioma to 80 consecutive cases of WHO grade I meningioma, 21 consecutive cases of nonchordoid WHO grade II meningioma, and 1 WHO grade III meningioma in an effort to determine if there exist distinguishing MR imaging characteristics that can aid in differentiating this particular subtype.     

Intracanalicular meningioma mimicking vestibular schwannoma

Summary: Three cases of intracanalicular meningioma mimicking vestibular schwannoma are presented. In each case, a contrast-enhancing mass filling the internal auditory canal was identified on MR images and was originally diagnosed as a vestibular schwannoma. Although it is difficult to differentiate definitively between these lesions preoperatively, imaging findings inconsistent with a diagnosis of vestibular schwannoma can be identified. Preoperative identification of intracanalicular meningiomas permits alterations in surgical planning that allow for the more complete resection of these rare tumors.     

Calcifying pseudoneoplasms of the neuraxis (CAPNON): The great tumor mimicker

Calcifying pseudoneoplasms of the neuraxis (CAPNON) are very rare intracranial lesions with less than 50 cases reported in literature. These are non-neoplastic in etiology and despite having unique imaging characteristics, are often misdiagnosed as a neoplastic condition like meningioma, chordoma and gliomas. These do not have any predilection for any age, gender or intracranial location and can be seen in a wide range of age groups. Despite having an imaging overlap with neoplastic conditions, CAPNONs have classic histopathologic findings including chondromyxoid matrix, palisading spindle cells and calcific or ossific metaplasia. As more cases are being described in literature the imaging features are also being better defined. We discuss the clinical, imaging and histopathological findings of 2 cases of CAPNON mimicking posterior fossa meningioma and glial neoplasm.     

Intraosseous intracranial meningioma

Primary intraosseous lytic meningiomas are rare tumors, with only 16 cases described in the literature. We present a case in which CT and MR imaging with contrast agent helped diagnose preoperatively an enlarging skull mass as a primary intraosseous lytic meningioma in a 70-year-old woman. Radiographic findings revealed a lytic mass centered on the coronal suture line that separated and thinned both the outer and inner tables of the frontal bone.     

Evaluation of different cerebral mass lesions by perfusion-weighted MR imaging

PURPOSE: To investigate the contribution of perfusion-weighted MR imaging (PWI) by using the relative cerebral blood volume (rCBV) ratio in the differential diagnosis of various intracranial space-occupying lesions. MATERIALS AND METHODS: This study involved 105 patients with lesions (high-grade glioma (N=26), low-grade glioma (N=11), meningioma (N=23), metastasis (N=25), hemangioblastoma (N=6), pyogenic abscess (N=4), schwannoma (N=5), and lymphoma (N=5)). The patients were examined with a T2*-weighted (T2*W) gradient-echo single-shot EPI sequence. The rCBV ratios of the lesions were obtained by dividing the values obtained from the normal white matter. Statistical analysis was performed with the Mann-Whitney U-test. A P-value less than 0.05 was considered statistically significant. RESULTS: The rCBV ratio was 5.76+/-3.35 in high-grade gliomas, 1.69+/-0.51 in low-grade gliomas, 8.02+/-3.89 in meningiomas, 5.27+/-3.22 in metastases, 11.36+/-4.41 in hemangioblastomas, 0.76+/-0.12 in abscesses, 1.10+/-0.32 in lymphomas, and 3.23+/-0.81 in schwannomas. The rCBV ratios were used to discriminate between 1) high- and low-grade gliomas (P<0.001), 2) hemangioblastomas and metastases (P<0.05), 3) abscesses from high-grade gliomas and metastases (P<0.001), 4) schwannomas and meningiomas (P<0.001), 5) lymphomas from high-grade gliomas and metastases (P<0.001), and 6) typical meningiomas and atypical meningiomas (P<0.01). CONCLUSION: rCBV ratios can help discriminate intracranial space-occupying lesions by demonstrating lesion vascularity. It is possible to discriminate between 1) high- and low-grade gliomas, 2) hemangioblastomas and other intracranial posterior fossa masses, 3) abscesses from high-grade gliomas and metastases, 4) schwannomas and meningiomas, 5) lymphomas and high-grade gliomas and metastases, and 6) typical and atypical meningiomas.     

脑室脑膜瘤的影像诊断

目的　探讨脑室脑膜瘤的影像学表现,以提高对脑室脑膜瘤的认识和诊断正确率。方法　经手术病理证实的脑室脑膜瘤 22例,其中男 8例,女 14例,年龄 17~72岁(平均 45岁 )。行MRI检查 21例,其中增强 17例;行CT检查 11例,其中增强 4例;同时行CT和MRI检查 10例,结合手术和病理结果进行分析。结果　脑室脑膜瘤以纤维型多见,主要位于侧脑室三角区,多数表现为实质性肿块,边界清晰,明显强化。可见钙化,出血及囊变少见。结论　脑室脑膜瘤有特殊的影像学表现,CT和MRI在诊断中具有一定的价值,尤其是MRI。