MRI of primary meningeal tumours in children

Childhood meningeal tumours are uncommon and mostly meningiomas. We reviewed the histological and radiological findings in meningeal tumours in six children aged 12 years or less (four benign meningiomas, one malignant meningioma and one haemangiopericytoma). Compared to the adult counterpart, childhood meningiomas showed atypical features: cysts, haemorrhage, aggressiveness and unusual location. MRI features varied according to the site of the tumour, histology, haemorrhage, and presence of intra- or peritumoral cysts. Diagnosis of the extra-axial tumour was relatively easy in two patients with meningiomas, one malignant meningioma and one haemangiopericytoma. MRI findings strongly suggested an intra-axial tumour in two patients with benign meningiomas, because of severe adjacent edema. Awareness of the variable findings of childhood meningiomas and similar tumours may help in differentiation from brain tumours. Received: 22 September 1998 Accepted: 18 November 1998     

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     

Meningeal hemangiopericytoma only diagnosed at the time of late bone metastasis

Hemangiopericytoma is a rare neoplasm. Primary meningeal hemangiopericytomas account for 1 to 7 % of all meningeal tumors. In the literature, meningeal hemangiopericytomas are mainly case reports, which confirm an aggressive behavior with a high rate of local recurrence and extracranial metastasis. Metastasis can be seen many years after initial surgical excision of the primary tumor, and the most common sites include the bone, liver and lung. We present a pathological study of four meningeal hemangiopericytomas with bone metastases. All patients are male with a mean age of 46.5 years. Metastases only involved bone. Three out of four lesions were initially misdiagnosed as meningiomas. Only one case was initially correctly diagnosed as meningeal hemangiopericytoma. All patients underwent surgery with complete resection. Only the patient immediately diagnosed with meningeal hemangiopericytoma received postoperative radiation therapy. Three patients had bone metastases without local recurrence including the one who received radiation therapy. One patient recurred locally after 7 years, and bone metastasis was found at the same time. Our cases confirm that meningeal hemangiopericytomas are a separate entity and have a high recurrence rate despite complete surgical resection, with extracranial metastases, mainly to bone, even after long intervals.     

Glucose utilization by intracranial meningiomas as an index of tumor aggressivity and probability of recurrence: a PET study

Seventeen patients with intracranial meningiomas were studied with positron emission tomography and fluorine-18-2-fluorodeoxyglucose (PET-FDG) to assess the glucose utilization of these tumors. Four meningiomas followed for 3-5 years after PET-FDG and surgery showed no evidence of recurrence. These tumors had significantly lower glucose utilization rates (1.9 mg/dl/min +/- 1.0) than 11 recurrent or regrowing meningiomas (4.5 mg/dl/min +/- 1.96) (P less than .01). The glucose metabolic rates of meningiomas correlated with tumor growth, as estimated from changes in tumor size on repeated computed tomographic scans. Histopathologically, a syncytial (atypical) meningioma had the highest glucose utilization rate, followed by a papillary meningioma and an angioblastic meningioma. Individual transitional and syncytial (typical) meningiomas showed marked differences in glucose metabolism despite similar microscopic appearance. Glucose utilization rate appears to be at least as reliable as histologic classification and other proposed criteria for predicting the behavior and recurrence of intracranial meningiomas.     

Primary meningeal tumors in children: correlation of clinical and CT findings with histologic type and prognosis.

PURPOSE: To identify the radiologic features that might help in preoperative differentiation of the meningiomas from the remaining primary meningeal tumors, in particular the malignant tumors. METHODS: The clinical and computed tomographic features of 21 children with histologically proved primary meningeal tumors were analyzed. FINDINGS: Benign tumors (meningiomas) are more likely to occur in older children, to have longer symptom duration, and to have CT appearances similar to the "typical" adult meningioma. Atypical CT features suggest a malignant meningeal tumor, such as meningeal sarcoma, melanoma, or meningeal primitive neuroectodermal tumor. The recent identification of a new subtype of meningioma (a "sclerosing" group) is discussed. This is common in children and the CT and clinical features are similar to those seen in other meningiomas. It is frequently mistaken histologically for an intraaxial tumor, or for an atypical or malignant meningioma. These sclerosing meningiomas may also show brain invasion but despite this, in the short term, the prognosis is no different from other meningiomas. CONCLUSION: The bad reputation previously ascribed to childhood primary meningeal tumors should be confined to that small group that are malignant. Meningiomas have a more favorable outlook.     

Angiographic findings in recurrent meningioma.

Of 147 patients who underwent radical surgery for intracranial meningioma, 25 (17%) had symptomatic recurrence requiring further surgery. Correlation between histological and angiographic findings of recurrent meningioma was poor. Following extirpation of feeding meningeal vessels in convexity meningiomas, the principal blood supply was usually from the anterior, middle, and/or posterior cerebral arteries. The angiographic appearance was that of a "tree-root" or "sunburst" pattern, indicating neoplastic invasion of the pia mater and/or underlying brain tissue. Polytomography, selective cerebral angiography, and radionuclide imaging of the brain are often necessary to detect early recurrent meningiomas. Computed tomography appears to be an innocuous and accurate method of diagnosing recurrent tumor, especially when the bone is not involved.     

Clinicopathologic Features of Aggressive Meningioma Emphasizing the Role of Radiotherapy in Treatment

BACKGROUND AND PURPOSE: Although meningiomas are typically benign, they occasionally behave in an aggressive fashion and carry a less favorable prognosis. The aim of this study was to review the clinical, radiologic and histopathologic features of these aggressive variants as well as the outcome after multimodality therapy. PATIENTS AND METHODS: 16 patients with atypical meningiomas (n = 11) and anaplastic meningiomas (n = 5) were treated in the Departments of Neurosurgery and Radiation Oncology at the University Hospital of Philipps University Marburg, Germany, between 1997 and 2003. Tumor grading was based on new WHO criteria. There were eleven men and five women with a mean age of 54 years. The median follow-up period was 34 months. RESULTS: A total of 24 surgical procedures were performed for these 16 patients. Only seven patients underwent postoperative fractionated stereotactic radiotherapy. Patients with atypical meningioma received radiotherapy only for the recurrent disease. Six patients (37.5%) experienced tumor recurrence after a mean period of 27.2 months in spite of gross total resection. Radiographic findings suggestive of aggressiveness were observed mostly with WHO grade III meningiomas. By comparing the proliferation rate in four cases with atypical meningioma operated twice, the recurrent tumor had a higher proliferation rate than the first tumor in three cases. A special proliferation pattern was noticed in MIB-1 with anaplastic meningiomas. The mean overall survival period was 66.5 months. There was no mortality among patients with atypical meningioma, while four out of five patients with anaplastic meningioma died during follow-up. CONCLUSION: Considering the higher rate of recurrence in aggressive meningiomas even after radical surgical excision and the possibility that the recurrent tumor is more aggressive than the original one, surgery should be combined with postoperative fractionated radiotherapy to improve local tumor control. The peculiar focal expression patterns of anaplastic meningioma in MIB-1 might be a marker of such malignant development.     

Detecting meningeal carcinomatosis from breast cancer with thallium-201 SPECT

Thallium-201 (201Tl) scintigraphy is one of the imaging methods used in the detection of various tumors including brain metastasis. We evaluated a patient with meningeal carcinomatosis from breast cancer by using 201Tl single-photon emission computed tomography (SPECT). Meningeal spread of a tumor was noted on enhanced CT. SPECT revealed tumor localization in meningeal carcinomatosis. These results suggest that SPECT with 201Tl may be useful in detecting meningeal carcinomatosis from breast cancer.     

Multiple meningiomas. Clinical and computed tomographic observations

Summary The same histological types of tumor are found in multiple as in solitary meningiomas. Multiple meningiomas cannot be considered in every case to be a forme fruste of von Recklinghausen's disease. The incidence of multiple meningiomas in this paper is higher than had been reported before the introduction of computed tomography (CT) into clinical practice. The number of tumor nodes is determined more accurately by CT than by angiography because tumors are detected in patients without neurological deficit. CT has limitations in the verification of small meningioma nodules near the base of the skull and in the differentiation of multiple meningiomas from meningeal meningiomatosis or primary meningeal sarcomatosis.Presented in part at the 16. Jahrestagung der Deutschen Gesellschaft für Neuroradiology Munich, 9–11 October 1980     

Evaluation of the effect of high-energy proton irradiation treatment on meningiomas by means of 11C-L-methionine PET

A remnant meningioma of WHO grade I that is located at the base of the skull and is treated with radiotherapy has to be followed up for at least 5-10 years to evaluate the treatment effect and detect recurrence. The tumour has to grow considerably to show detectable volume increase on computed tomography (CT) or magnetic resonance imaging (MRI). Owing to the location at the base of the skull, a small increase in tumour volume may be hazardous. It is thus important to find a method to evaluate treatment effects earlier and potentially detect those tumours that have a tendency to grow. Nineteen patients with intracranial meningiomas were given irradiation with the 180-MeV proton beam at the Svedberg Laboratory, Uppsala, Sweden. The fractionation schedule used was in general a total dose of 24 Gy in four consecutive daily 6-Gy fractions. Serial 11C-Lmethionine PET examinations were used to evaluate the effect of stereotactic proton beam treatment. The radioactivity uptake in the tumour was evaluated as the ratio to the uptake in normal brain tissue. The follow-up period thus far is 36 months. In 15 of the 19 patients, 11C-L-methionine uptake was reduced 36 months after irradiation compared with the pre-treatment uptake of the tracer. In the total patient group the average reduction was 19.4%. Our results reveal that proton beam irradiation of meningiomas had an inhibitory effect on the methionine uptake in the meningiomas, although tumour size remained unchanged. The combination of unchanged tumour morphology and a reduction in methionine uptake after irradiation suggests that 11C-L-methionine PET might enable earlier evaluation of the treatment effect than is possible with CT or MRI.     

18F-FDG-PET-CT imaging findings of recurrent intracranial haemangiopericytoma with distant metastases

A 42-year-old woman presented with local recurrence and distant lung and liver metastases 7 years after resection of a primary intracranial haemangiopericytoma. Whole-body ¹⁸F-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET)-CT scan showed no increased uptake in local recurrence or distant metastases except for a focus of increased FDG uptake within a hepatic metastasis. The hypermetabolic area correlated with an intratumoral hypoenhancing area on the CT scan. PET-CT scan may be useful to allow further understanding of the tumour.Haemangiopericytoma is an uncommon tumour and accounts for less than 1% of all intracranial tumours. It caused much confusion because of its imaging similarities to meningioma and its uncertain cellular origin. Its rarity, non-specific imaging findings and lack of specific tumour markers pose diagnostic difficulties.We report a case of intracranial haemangiopericytoma treated with surgical resection. Local recurrence and distant metastases in the lung and liver occurred seven years after complete resection of the primary intracranial tumour. ¹⁸F-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography–computed tomography (PET-CT) was performed for assessment of the extent of disease.     

"Benign" metastasizing meningiomas

Less than one in 1000 meningiomas metastasizes. Although the angioblastic and hemangiopericytic tumors are believed by some authors to metastasize with a greater frequency than the other histologic forms of meningioma, most investigators believe that neither the histologic pattern, local aggressiveness, size, nor location of the tumor can be used accurately to predict which tumors will metastasize. Three new cases are presented, bringing the total reported number of metastasizing meningiomas to 113. If the angioblastic meningiomas and hemangiopericytomas are eliminated from this group, 69 reported cases of "benign" metastasizing meningioma remain.     

Lung metastasis of a meningioma

Case report of a 35-year-old male patient. 1976: operation for a falx-meningioma. 1981: meningioma recurrence and further intracranial meningiomas. Histology: 1976 and 1981 endotheliomatous meningioma: no signs of malignancy. Prior to the 2nd operation in 1981 a lung tumor was diagnosed for the first time. Histology of the lung tumor: endotheliomatous meningioma, same histology as in cerebral meningiomas.     

Intracranial perineural metastasis of adenoid cystic carcinoma of head and neck

Three cases of intracranial perineural metastasis from adenoid cystic carcinoma of the head and neck are presented. The metastases presented more than 1 year (14 months to 5.5 years) after the primary tumor had been successfully treated without any evidence of local recurrence. Computed tomography of the intracranial metastasis demonstrated well-demarcated, hyperdense, enhancing extraaxial masses indistinguishable from meningioma. An intracranial extraaxial mass lesion with the appearance of a meningioma in a patient with known adenoid cystic carcinoma of the head and neck, regardless of the presence or absence of local recurrence, should be considered as metastasis until proved otherwise.     

Imaging intracranial haemangiopericytomas: study of seven cases

Imaging features of intracranial haemangiopericytomas are similar to those of meningiomas. Preoperative identification of these tumours is important because of their aggressive nature, high rate of local recurrence and propensity for late metastasis. We reviewed the CT, MRI and angiographic findings in seven pathologically proved haemangiopericytomas, to determine if imaging characteristics might distinguish them from meningiomas. None showed hyperostosis or tumour calcification. All showed marked enhancement. Five had prominent internal signal voids, suggesting feeding arteries. On angiography, one had only pial-cortical supply but six also had meningeal supply; all showed a persistent stain. Only one had multiple corkscrew feeding vessels.     

"脑膜瘤"MRI误诊分析

目的　研究MRI在脑膜瘤诊断实践中的差距。方法　 15 2例经MR扫描初诊为脑膜瘤的病例与手术、病理相对照 ,从中遴选出诊断不符合的 16例进行分析。结果　脑膜瘤误诊为其他肿瘤的共 10例 ,占 6.5 % ;其他肿瘤误诊为脑膜瘤的共 6例 ,占4%。总误诊率为 10 .5 %。结论　因组织学结构复杂、设备性能和扫描技术 ,构成了MRI对脑膜瘤误诊的不可避免性 ;而舍弃年龄、部位的先入思想、注重典型特征、仔细阅片及善用病史等 ,又是提高符合率的关键。     

Intra-osseous meningioma of the orbit: an unusual presentation (2007: 5b)

Primary calvarial or intra-osseous meningiomas are uncommon lesions often confused preoperatively with other primary or secondary bone tumors of the skull. We present details of a patient with a primary calvarial meningioma involving the frontal, zygomatic, sphenoid and temporal bones that was radiographically diagnosed as fibrous dysplasia and initially treated conservatively for many years. Progressive vision loss and significant proptosis, with difficulty of eye closure, prompted surgical removal with cranioplasty and a 3D reconstructed prosthetic flap. Histological examination revealed intra-osseous meningioma. The clinical and radiological findings of intra-osseous meningiomas are discussed, together with a review of the literature.     

Typical, atypical, and misleading features in meningioma.

Meningiomas are the most common nonglial primary tumors of the central nervous system and the most common extraaxial neoplasms, accounting for approximately 15% of all intracranial tumors. They are usually benign neoplasms, with characteristic pathologic and imaging features. However, there are several important histologic variants of meningioma, and even a histologically typical meningioma can have unusual or misleading radiologic features that may not be suggestive of meningioma. The typical meningioma is a homogeneous, hemispheric, markedly enhancing extraaxial mass located over the cerebral convexity, in the parasagittal region, or arising from the sphenoid wing. Meningiomas may originate in unexpected locations such as the orbit, paranasal sinus, or ventricles or be entirely intraosseous (within the calvaria). Unusual imaging features such as large meningeal cysts, ring enhancement, and various metaplastic changes (including fatty transformation) can be particularly misleading. Because meningiomas are so common, the radiologist must be aware of their less frequent and uncharacteristic imaging features in order to suggest the correct diagnosis in cases that are atypical.     

Evaluation of the effect of high-energy proton irradiation treatment on meningiomas by means of 11C-L-methionine PET

A remnant meningioma of WHO grade I that is located at the base of the skull and is treated with radiotherapy has to be followed up for at least 5-10 years to evaluate the treatment effect and detect recurrence. The tumour has to grow considerably to show detectable volume increase on computed tomography (CT) or magnetic resonance imaging (MRI). Owing to the location at the base of the skull, a small increase in tumour volume may be hazardous. It is thus important to find a method to evaluate treatment effects earlier and potentially detect those tumours that have a tendency to grow. Nineteen patients with intracranial meningiomas were given irradiation with the 180-MeV proton beam at the Svedberg Laboratory, Uppsala, Sweden. The fractionation schedule used was in general a total dose of 24 Gy in four consecutive daily 6-Gy fractions. Serial ¹¹C-L-methionine PET examinations were used to evaluate the effect of stereotactic proton beam treatment. The radioactivity uptake in the tumour was evaluated as the ratio to the uptake in normal brain tissue. The follow-up period thus far is 36 months. In 15 of the 19 patients, ¹¹C-L-methionine uptake was reduced 36 months after irradiation compared with the pre-treatment uptake of the tracer. In the total patient group the average reduction was 19.4%. Our results reveal that proton beam irradiation of meningiomas had an inhibitory effect on the methionine uptake in the meningiomas, although tumour size remained unchanged. The combination of unchanged tumour morphology and a reduction in methionine uptake after irradiation suggests that ¹¹C-L-methionine PET might enable earlier evaluation of the treatment effect than is possible with CT or MRI.     

颅内血管周细胞瘤与脑膜瘤的MRI表现及鉴别分析

目的探讨颅内血管周细胞瘤(HPC)MR影像特点并与脑膜瘤影像表现进行对比分析。方法回顾性分析6例2015—2017年经中国医科大学附属第一医院确诊的HPC病人[年龄26～75岁,平均(46.33±16.88)岁]及40例颅内脑膜瘤病人[年龄27～78岁,平均(56.12±12.19)岁]的临床及影像资料。所有病人均进行MRI扫描检查,采用χ~2检验对2组病人的影像表现进行比较。结果 HPC与脑膜瘤病人MRI表现相似,常规MRI可表现为肿瘤分叶、瘤体内有囊变坏死、血管流空影、窄基底连接及骨质破坏,且HPC的发生率均高于脑膜瘤(P0.05)。但脑膜瘤增强MRI上脑膜尾征的发生率高于HPC(P0.05)。结论 HPC与脑膜瘤存在的影像差异有助于两者的鉴别诊断。