Radiation-induced meningioma: a descriptive study of 253 cases

Multiple meningiomas in a woman irradiated in utero

Meningiomas are a common central nervous system tumour and radiation is a known risk factor for their development. In utero radiation exposure correlates to developmental abnormalities and carcinogenesis in a dose- and gestational age-related manner. Radiation induced meningioma has been reported in detail in the literature in patients who had been irradiated earlier in life. At the time of publication, there was no data on radiation exposure whilst in utero and meningioma. We report on a 42-year-old woman with multiple intracranial meningiomas and no other risk factors except a history of in utero exposure to low dose X-ray radiation at 12weeks gestational age.

Sarcoma-like tumor originating from oligodendroglioma

We present a case of sarcoma occurring at a site of resected oligodendroglioma without preceding radiotherapy or chemotherapy. Oligosarcoma occurring at sites of resected oligodendroglioma or anaplastic oligodendroglioma with sarcomatous components are rare. Although meningioma or sarcoma-like lesions are sometimes reported after glioma-targeted radiotherapy, those without preceding radiotherapy are quite rare. Moreover, cases of sarcoma without oligodendroglial components occurring at a site of resected oligodendroglioma have never been reported. In this case, fluorescent in situ hybridization analysis revealed 1p/19q co-deletion in both the first tumor and second tumors. Additionally, immunohistochemistry revealed mutated isocitrate dehydrogenase 1 in both tumors. Taken together, these findings suggest a monoclonal tumor origin. Consequently, this case may indicate a new mechanism of development of sarcomatous lesions occurring at the site of a resected glioma.

Meningioma after radiotherapy for malignancy

Complications of radiation exposure have gained importance with increasing cancer survivorship. Secondary malignancies have been associated with cranial radiation exposure. We present our experience with intracranial radiation-induced meningioma (RIM) and discuss the implications of its presentation and natural history for patient management. Patients diagnosed with meningioma who had received radiation therapy between 1960 and 2014 were identified. Records were retrospectively reviewed for details of radiation exposure, previous malignancies, meningioma subtypes, multiplicity and pathologic descriptions, treatment and follow-up. Thirty patients were diagnosed with RIM. Initial malignancies included acute lymphocytic leukemia (33.3%), medulloblastoma (26.7%) and glioma (16.7%) at a mean age of 8.1years (range 0.04-33years). The mean radiation dose was 34Gy (range 16-60Gy) and latency time to meningioma was 26years (range 8-51years). Twenty-one patients (70%) underwent surgery. Of these, 57.1% of tumors were World Health Organization (WHO) grade I while 42.9% were WHO II (atypical). The mean MIB-1 labeling index for patients with WHO I tumors was 5.44%, with 33.3% exhibiting at least 5% staining. Mean follow-up after meningioma diagnosis was 5.8years. Mortality was zero during the follow-up period. Meningioma is an important long-term complication of therapeutic radiation. While more aggressive pathology occurs more frequently in RIM than in sporadic meningioma, it remains unclear whether this translates into an effect on survival. Further study should be aimed at delineating the risks and benefits of routine surveillance for the development of secondary neoplasms after radiation therapy.

An unusual radiological presentation of optic nerve sheath meningioma

Our report describes an unusual radiological presentation of optic nerve sheath meningioma. The classic radiological appearance of optic nerve thickening with enhancement and calcification within the tumor was not seen; instead, an elongating gadolinium enhancing band-like area adjacent to the superomedial aspect of the left optic nerve sheath was identified. The diagnosis was confirmed on histopathology. Our report adds to the spectrum of presentations of this relatively common clinical entity.

Fluoroscopy-free Atrial Transseptal Puncture

Introduction

Fluoroscopy is traditionally used in atrial transseptal puncture (TSP); however fluoroscopy exposes patient and physician to excess radiation. Here, we describe a feasibility study of a zero-fluoroscopy transseptal puncture (ZFTSP) technique utilising electroanatomical mapping (EAM) and intracardiac echo (ICE) in a small case series of patients undergoing ablation for atrial fibrillation (AF). We then compare this technique to other established ZFTSP techniques for paroxysmal AF ablation.

Methods

Seven patients received ZFTSP. An Acunav™ ICE catheter (Biosense Webster Inc., California, US) was placed in the right atrium, then an Agilis™ sheath (St. Jude Medical, Saint Paul, Minnesota, US) was established into the inferior vena cava. A ThermoCool^® SmartTouch™ catheter (Biosense Webster Inc., California, US) was inserted through the Agilis to map the fossa ovalis. Mapping catheter exchange for dilator and needle allowed for facile ZFTSP. AF outcome, fluoroscopy times, and procedure times were compared with eight age-matched control patients.

Results

There were no significant differences in age, body mass index (BMI) or AF duration between the two groups and no immediate complications. ZFTSP procedure time was 183.9±33.7 minutes versus 293.13±129.9 minutes for TSP-only controls (p=0.05). Fluoroscopy time was 17.5±14.1 minutes in ZFTSP patients versus 73.4±50.3 minutes in controls (p=0.01). AF recurrence in ZFTSP patients was 14% versus 25% in controls.

Conclusion

ZFTSP utilising ICE and EAM is safe, effective, and time-efficient. There is a small but significant reduction in radiation exposure to patient and physician by the use of this technique.

Complications from radiotherapy

Radiotherapy (RT) of the brain is associated with significant stigma in the neuro-oncology community. This is primarily because of the potentially severe complications with which it may be associated. These complications, especially in subacute and latent settings, are often unpredictable, potentially progressive, and irreversible. The onset of complications may start from the first fraction of 2 Gy, continuing over several months after end of RT with persistent drowsiness and apathy. It may also extend over many years with progressive onset of neurocognitive impairments such as memory decline, and diminished focus/attention. For long-term survivors, such as young patients irradiated for a favorable low-grade glioma, quality of life can be seriously impacted by RT. It is essential, as in the pediatric field, to propose patient-specific regimens from the very outset of therapy. The use of molecular biomarkers to better predict survival, control of comorbidities along with judicious use of medications such as steroids and antiepileptics, improved targeting with the help of modern imaging and RT techniques, modulation of the dose, and fractionation aimed at limiting integral dose to the healthy brain all have the potential to minimize treatment-related complications while maintaining the therapeutic efficacy for which RT is known. Sparing "radiosensitive" areas such as hippocampi could have a modest but measurable impact with regard to cognitive preservation, an effect that can possibly be enhanced when used in conjunction with memantine and/or donepezil.

[Our experience of intracranial meningioma in Dakar: about 50 cases]

Les méningiomes sont des tumeurs bénignes extra parenchymateuses développées aux dépens des villosités arachnoïdiennes. Ils tirent leur gravité de leur localisation dans des zones hyperfonctionnelles. Le but de cette étude est d’évaluer la prise en charge des méningiomes intracrâniens depuis la réhabilitation du service de neurochirurgie en 2007. Les auteurs rapportent une série rétrospective portant sur 50 patients admis et opérés d'un méningiome intracrânien d'octobre 2007 à Juin 2013 dans leur service. Ont été inclus les patients ayant un dossier complet. Les patients étaient âgés de 08 à 70 ans avec une moyenne d’âge de 47,3 ans, 68% avaient plus de 40 ans. La sex-ratio était de 0,76. Les manifestations cliniques étaient essentiellement l'hypertension intracrânienne (46%), le déficit moteur (30%) et la comitialité (48%). La tomodensitométrie cérébrale était réalisée chez 41 patients et l'IRM chez 23. Le méningiome était localisé sur la convexité chez 24 patients. L'imagerie postopératoire immédiate était réalisée chez 15 patients. L'exérèse a consisté dans 44% des cas à un Sympson II, et dans 30% des cas à un Sympson III. L'anatomopathologie a conclu à une prédominance du type méningothélial (38%) et 60% des méningiomes étaient de grade I selon la classification de l'O.M.S. Aucun patient n'a bénéficié d'une radiothérapie. La mortalité était de 16%. Les pays d'Afrique subsaharienne continuent d'accuser un retard malgré les efforts réalisés dans les domaines diagnostic et thérapeutique des méningiomes intracrâniens. Le pronostic s'est considérablement amélioré à mesure de l'amélioration du plateau technique dans notre pays.

Meningiomas after cranial radiotherapy for childhood cancer: a single institution experience

PURPOSE

Childhood cancer survivors (CCS) treated with cranial radiation therapy (CRT) are at risk of developing meningiomas. The aim of this study was to evaluate the cumulative incidence of meningiomas in a cohort of CCS who previously underwent CRT.

METHODS

We considered all CCS who received CRT and were followed up at the "Transition Unit for Childhood Cancer Survivors" in Turin. Even though asymptomatic, they had at least one brain computed tomography or magnetic resonance imaging performed at a minimum interval of 10 years after treatment for pediatric cancer.

RESULTS

We identified 90 patients (median follow-up 24.6 years). Fifteen patients developed meningioma (median time from pediatric cancer, 22.5 years). In four patients, it was suspected on the basis of neurological symptoms (i.e., headache or seizures), whereas all other cases, including five giant meningiomas, were discovered in otherwise asymptomatic patients. Multiple meningiomas were discovered in four CCS. Ten patients underwent surgical resection. An atypical meningioma (grade II WHO) was reported in four patients. One patient with multiple meningiomas died for a rapid growth of the intracranial lesions. A second neoplasm (SN) other than meningioma was diagnosed in five out of the 15 patients with meningioma and in ten out of the 75 CCS without meningioma. Cox multivariate analysis showed that the occurrence of meningioma was associated with the development of other SNs, whereas age, sex, or CRT dose had no influence.

CONCLUSIONS

CCS at risk of the development of meningioma deserve close clinical follow-up, especially those affected by other SNs.

Biology and clinical management challenges in meningioma

Meningiomas are the most frequently occurring intracranial tumors. They are characterized by a broad spectrum of histopathologic appearance. Molecular alterations driving meningioma development, which affect the NF2 gene, are found in roughly 50% of patients. Rare genetic events in benign meningiomas are mutations in TRAF7, KLF4, AKT1, and SMO; all of these mutations are exclusive of NF2 alterations. Progression to a clinically aggressive meningioma is linked to inactivation of CDKN2A/B genes, and a plethora of signaling molecules have been described as activated in meningiomas, which supports the concept of successful clinical use of specific inhibitors. Established treatments include surgical resection with or without radiotherapy delivered in a single fraction, a few large fractions (radiosurgery), or multiple fractions (fractionated radiotherapy). For recurrent and aggressive tumors, inhibitors of the vascular endothelial growth factor (VEGF) pathway, such as vatalinib, bevacizumab, and sunitinib, showed signs of activity in small, uncontrolled studies, and prospective clinical studies will test the efficacy of the tetrahydroisoquinoline trabectedin and of SMO and AKT1 inhibitors.

The incidence of second brain tumors related to cranial irradiation

Secondary brain tumor (SBT) is a devastating complication of cranial irradiation (CI). We reviewed the literature to determine the incidence of SBT as related to specific radiation therapy (RT) treatment modalities. The relative risk of radiation-associated SBT after conventional and conformal RT is well established and ranges from 5.65 to 10.9; latent time to develop second tumor ranges from 5.8 to 22.4 years, depending on radiation dose and primary disease. Theories and dosimetric models suggest that intensity-modulated radiation therapy may result in an increased risk of SBT, but clinical evidence is limited. The incidence of stereotactic radiosurgery-related SBT is low. Initial data suggest that no increased risk from proton therapy and dosimetric models predict a lower incidence of SBT compared with photons. In conclusion, the incidence of SBT related to CI is low. Longer follow-up is needed to clarify the impact of intensity-modulated radiation therapy, proton therapy and other developing technologies.

Incidental detection of late subsequent intracranial neoplasms with magnetic resonance imaging among adult survivors of childhood cancer

PURPOSE

Survivors of childhood cancer are at an increased risk of developing subsequent neoplasms. In long-term survivors of childhood malignancies treated with and without cranial radiation therapy (CRT), undergoing unenhanced magnetic resonance imaging (MRI) of the brain, we estimated detection of intracranial neoplasms.

METHODS

To investigate neurocognitive outcomes, 219 survivors of childhood cancer underwent unenhanced screening MRI of the brain. Of the survivors, 164 had been treated for acute lymphoblastic leukemia (ALL) (125 received CRT) and 55 for Hodgkin lymphoma (HL) (none received CRT). MRI examinations were reviewed and systematically coded by a single neuroradiologist. Demographic and treatment characteristics were compared for survivors with and without subsequent neoplasms.

RESULTS

Nineteen of the 219 survivors (8.7 %) had a total of 31 subsequent intracranial neoplasms identified by neuroimaging at a median time of 25 years (range 12-46 years) from diagnosis. All neoplasms occurred after CRT, except for a single vestibular schwannoma within the cervical radiation field in a HL survivor. The prevalence of subsequent neoplasms after CRT exposure was 14.4 % (18 of 125). By noncontrast MRI, intracranial neoplasms were most suggestive of meningiomas. Most patients presented with no specific, localizing neurological complaints. In addition to the schwannoma, six tumors were resected based on results of MRI screening, all of which were meningiomas on histologic review.

CONCLUSION

Unenhanced brain MRI of long-term survivors of childhood cancer detected a substantial number of intracranial neoplasms. Screening for early detection of intracranial neoplasms among aging survivors of childhood cancer who received CRT should be evaluated.

IMPLICATIONS FOR CANCER SURVIVORS

The high prevalence of incidentally detected subsequent intracranial neoplasms after CRT in long-term survivors of childhood cancer and the minimal symptoms reported by those with intracranial tumors in our study indicate that brain MRI screening of long-term survivors who received CRT may be warranted. Prospective studies of such screening are needed.

Proteomic analysis of meningiomas

Meningiomas represent one-third of all primary brain tumors and cause 35,000 new cases each year. Because of this high incidence, we sought to determine if there are proteomic differences between meningiomas and neighboring tissues. Two-dimensional gel electrophoresis and mass spectrometry were used to detect differentially expressed proteins in tumor samples, using arachnoid tissue as a control. Western blot analysis was used to validate the identified candidate proteins. We obtained quantitative data on 112 proteins, 17 of which were down-regulated and 26 of which were up-regulated in meningiomas relative to normal arachnoid tissue. Our analysis showed that the expression of galectin-3, vimentin, and endoplasmin was decreased significantly in meningiomas. The expression of 40S ribosomal protein S12, glutathione S-transferase P, and hypoxia up-regulated protein 1 was increased significantly (P < 0.05). The six above-mentioned differentially expressed proteins might be closely involved with the development of meningiomas. The results of this study provide basic insights into the proteome of meningiomas and provide a preliminary database for further research to enhance understanding of meningioma development.

The evolving role of radiosurgery in the management of radiation-induced meningiomas: a review of current advances and future directions

Meningiomas are among the most common primary adult brain tumors, which arise either spontaneously or secondary to environmental factors such as ionizing radiation. The latter are referred to as radiation-induced meningiomas (RIMs) which, while much less common than their spontaneous counterparts, are challenging from a management point of view. Similar to spontaneous meningiomas, the optimal management of RIMs is complete surgical resection. However, given their high grade, multiplicity, tendency to invade bone and venous sinuses, and high recurrence rate, this cannot always be accomplished safely. Therefore, other therapeutic modalities, such as stereotactic radiosurgery, have emerged. In the current review, we provide an overview of the historical outcomes achieved for RIMs through radiosurgery and microsurgical resection. Furthermore, we provide a discussion of clinical and radiological parameters that affect the decision-making process with regard to the management of RIMs. We also provide an outline of recent changes in our understanding of RIMs, based on molecular and genetic markers, and how these will change our management perspective. We conclude the review by summarizing some of the current obstacles in the management of RIMs with SRS and how current and future research can address these challenges.

Risk of malignancy associated with head and neck CT in children: a systematic review

OBJECTIVE

To perform a systematic review to evaluate the risk of malignancy associated with computed tomography (CT) of the head and/or neck in infants, children, and adolescents.

DATA SOURCES

Pubmed, EMBASE, and the Cochrane Library were assessed from the date of their inception to January 2014. Additionally, manual searches of bibliographies were performed and topic experts were contacted.

REVIEW METHODS

Data were obtained from studies measuring or estimating the risks of malignancy associated with radiation from head and/or neck CT in pediatric populations according to an a priori protocol. Two independent evaluators corroborated the extracted data.

RESULTS

There were 16 criterion-meeting studies that included data from n = 858,815 patients. The radiation-related risk of malignancy was estimated using primary patient data for both the exposure and outcome in a minority of studies, with most analyses utilizing mathematical modeling techniques. The data regarding otolaryngology-specific studies were limited and suggested a borderline significant increase in the risk of all combined cancers after facial CT (incidence rate ratio [IRR] = 1.14; 95% CI, 1.01-1.28) and neck/spine CT (IRR = 1.13; 95% CI, 1.00-1.28). Cohort data suggest that 1 excess brain malignancy occurred after 4000 brain CTs (40 mSv per scan) and that the estimated risk in the 10 years following CT exposure was 1 brain tumor per 10,000 patients exposed to a 10 mGy scan at less than 10 years of age.

CONCLUSION

Detailed understanding of any potential malignancy risk associated with pediatric imaging of the head and neck furthers our ability to engage in rational, shared, informed decision making with families considering CT scan.

Meningiomas occurring during long-term survival after treatment for childhood cancer

Childhood cancer is rare but improvements in treatment over the past five decades have resulted in a cohort of more than 30,000 long-term survivors of childhood cancer in the UK with more added annually. These long-term survivors are at risk of late effects of cancer treatment which replace original tumour recurrence as the leading cause of premature death. Second neoplasms are a particular risk and in the central nervous system meningiomas occur increasingly with increased radiation dose to central nervous system tissue and length of time after exposure, resulting in a 500-fold increase above that expected in the normal population by 40 years of follow up. This multidisciplinary author group and others met to discuss the issue. Our pooled information, and consensus that screening should only follow symptoms, was published online by the Royal College of Radiologists in 2013. We outline here the current knowledge and management of these neoplasms secondary to childhood cancer treatment.

Radiation-associated secondary brain tumors after conventional radiotherapy and radiosurgery

Although there is not enough strong molecular evidence for radiation to be a causal factor for the development of secondary brain tumors, a relationship has still been found. There is a slight but significant 2-2.7% increased risk of secondary brain tumors after conventional radiotherapy. However, this risk is small and should not preclude the use of radiotherapy as an effective treatment for uncontrolled pituitary tumors. The risk of radiosurgery-associated secondary brain tumors has not been precisely determined. Taking into account the considerable number of patients who received radiosurgery worldwide and the small number of secondary brain tumors, radiosurgery seems to be a safe treatment modality. This review summarizes the pathogenesis, prevalence and characteristics of secondary brain tumors after conventional radiotherapy and stereotactic radiosurgery for pituitary adenomas.

Radiation-induced intracranial meningioma and multiple cavernomas

Brain irradiation has several well-known long-term side effects, including radiation-induced neoplasms and vasculopathy. In this case report, we describe an extremely rare case of meningioma and 15 cavernomas developing in a 29-year-old man, 19 years after cranial irradiation for posterior cranial fossa medulloblastoma. To our knowledge, this is the first case of a radiation-induced meningioma accompanied by this many radiation-induced cavernous angiomas.

Brain and neck tumors among physicians performing interventional procedures

Physicians performing interventional procedures are chronically exposed to ionizing radiation, which is known to pose increased cancer risks. We recently reported 9 cases of brain cancer in interventional cardiologists. Subsequently, we received 22 additional cases from around the world, comprising an expanded 31 case cohort. Data were transmitted to us during the past few months. For all cases, where possible, we endeavored to obtain the baseline data, including age, gender, tumor type, and side involved, specialty (cardiologist vs radiologist), and number of years in practice. These data were obtained from the medical records, interviews with patients, when possible, or with family members and/or colleagues. The present report documented brain and neck tumors occurring in 31 physicians: 23 interventional cardiologists, 2 electrophysiologists, and 6 interventional radiologists. All physicians had worked for prolonged periods (latency period 12 to 32 years, mean 23.5 ± 5.9) in active interventional practice with exposure to ionizing radiation in the catheterization laboratory. The tumors included 17 cases (55%) of glioblastoma multiforme (GBM), 2 astrocytomas (7%), and 5 meningiomas (16%). In 26 of 31 cases, data were available regarding the side of the brain involved. The malignancy was left sided in 22 (85%), midline in 1, and right sided in 3 operators. In conclusion, these results raise additional concerns regarding brain cancer developing in physicians performing interventional procedures. Given that the brain is relatively unprotected and the left side of the head is known to be more exposed to radiation than the right, these findings of disproportionate reports of left-sided tumors suggest the possibility of a causal relation to occupational radiation exposure.

Radiation-induced tumours of meninges. Report on eight cases and review of the literature

BACKGROUND AND PURPOSE

Despite their rarity, post-radiation meningeal tumours seem to be a growing problem due to the increasing application of radiation therapy. The aim of the study was to ascertain the specific features of these tumours.

MATERIAL AND METHODS

Among 433 intracranial meningeal tumours treated from 2000 to 2008, eight cases (2%) have been presumed to be associated with high-dose therapeutic radiation for previous neoplasm of the head (7) or neck (1). On average, tumours were diagnosed 24 years after irradiation. All patients had a solitary meningeal tumour, but two of them also developed other neoplasms in the irradiated area.

RESULTS

All tumours were microsurgically removed. The post-operative course was uncomplicated in two cases only. In the remaining 6 (75%), complications included liquorrhoea (2), brain oedema (1), venous thrombosis (1), bleeding into the tumour bed (1) and focal deficit due to manipulation (3). Most tumours (5) were WHO grade I meningiomas. These benign meningiomas exhibited some peculiar histological features, including focal increase of cellularity, focal enhancement of proliferation index, pleomorphism of nuclei, occasional mitotic figures and, in one case, evidence of brain invasion. One meningioma was assigned to WHO grade II, one to WHO grade III and one appeared to be meningeal fibrosarcoma. The event-free survival and overall survival rate at 4.4 years of follow-up were 63% and 75%, respectively.

CONCLUSIONS

Radiation-induced tumours of the meninges show certain characteristic histopathological features, which may promote invasiveness of the tumour and higher risk of malignancy.

Intracranial meningiomas managed at Memfys hospital for neurosurgery in Enugu, Nigeria

Introduction:

The epidemiology and pathology of meningioma in Nigeria are still evolving and little has been published about this tumor in Nigeria, especially in the southeast region. The aim of this paper is to compare the characteristics of intracranial meningioma managed in our center with the pattern reported in the literature worldwide.

Materials and Methods:

Retrospective analysis of prospectively recorded data of patients managed for intracranial meningioma between January 2002 and December 2010 at a Private neurosurgery Hospital in Enugu, Nigeria. We excluded patients whose histology results were inconclusive.

Results:

Meningiomas constituted 23.8% of all intracranial tumors seen in the period. The male to female ratio was 1:1.1. The peak age range for males and females were in the fifth and sixth decades, respectively. The most common location is the Olfactory groove in 26.5% of patients followed by convexity in 23.5%. Presentation varied with anatomical location of tumor. Patients with olfactory groove meningioma (OGM) mostly presented late with personality changes and evidence of raised ICP. Tuberculum sellar and sphenoid region tumors presented earlier with visual impairment with or without hormonal abnormalities. Seizures occurred in 30.9% of all patients and in 45% of those with convexity meningiomas. Only 57.4% of the patients were managed surgically and there was no gender difference in this group. WHO grade1 tumors were the most common histological types occurring in 84.6%. One patient had atypical meningioma and two had anaplastic tumors.

Conclusion:

The pattern of meningioma in our area may have geographical differences in location and histology. Childhood meningioma was rare.

Ionizing radiation and the risk of brain and central nervous system tumors: a systematic review

Although exposure to moderate-to-high doses of ionizing radiation is the only established environmental risk factor for brain and CNS tumors, it is not clear whether this relationship differs across tumor subtypes, by sex or age at exposure, or at the low-to-moderate range of exposure. This systematic review summarizes the epidemiologic evidence on the association between ionizing radiation exposure and risk of brain/CNS tumors. Articles included in this review estimated radiation exposure doses to the brain and reported excess relative risk (ERR) estimates for brain/CNS tumors. Eight cohorts were eligible for inclusion in the analysis. Average age at exposure ranged from 8 months to 26 years. Mean dose to the brain ranged from 0.07 to 10 Gy. Elevated risks for brain/CNS tumors were consistently observed in relation to ionizing radiation exposure, but the strength of this association varied across cohorts. Generally, ionizing radiation was more strongly associated with risk for meningioma compared with glioma. The positive association between ionizing radiation exposure and risk for glioma was stronger for younger vs older ages at exposure. We did not observe an effect modification on the risk for meningioma by sex, age at exposure, time since exposure, or attained age. The etiologic role of ionizing radiation in the development of brain/CNS tumors needs to be clarified further through additional studies that quantify the association between ionizing radiation and risk for brain/CNS tumors at low-to-moderate doses, examine risks across tumor subtypes, and account for potential effect modifiers.

Radiation-induced meningiomas after high-dose cranial irradiation

Radiation-induced meningiomas (RIM) are known to occur after high and low dose cranial radiation therapy. Currently, RIM are the most common form of radiation-induced neoplasm reported. We present the largest series of RIM induced by high dose radiation reported thus far and review the literature. Radiation therapy was most commonly given for childhood malignancy. We compared our group of 26 patients with RIM with previously published reports of RIM, and also with 364 patients with spontaneous meningioma (SM) treated at The Royal Melbourne Hospital between 2007 and 2011 with regard to age, gender, and histopathology. In our group of patients with RIM, the mean age at presentation was 38.5 years, in comparison to 60.1 years for patients with SM. The female-to-male ratio was 1.88:1 in RIM compared to 2.37:1 for SM. Of the RIM, 86.5% were World Health Organization (WHO) grade I and 11.5% were grade II (atypical) meningiomas. There were no anaplastic or malignant RIM. Of the SM, 91.5% were WHO grade I, 7.1% WHO grade II, and 1.4% WHO grade III meningiomas. The characteristics of RIM induced by low dose radiation therapy have been well described. It is timely to consider RIM due to high dose radiation, which is now frequently employed in the management of various childhood and other malignancies.

Occurrence of symptomatic meningioma as a second neoplasm in patients with differentiated thyroid cancer treated with radioiodine

Occurrence of second tumors has been seen in patients with papillary and follicular thyroid cancer. We studied the occurrence of meningioma as a second neoplasm in patients with differentiated thyroid cancer treated with radioiodine at our institution.

Fatty acid synthase is a predictive marker for aggressiveness in meningiomas

Meningiomas are the most frequent intracranial tumors. Although most are benign WHO grade I tumors, grade II and III tumors are aggressive and survival is poor. Treatment options for grade II and III meningiomas are limited, and molecular targets are few. The re-programming of metabolic pathways including glycolysis, lipogenesis, and nucleotide synthesis is a hallmark of the physiological changes in cancer cells. Because fatty acid synthase (FAS), the enzyme responsible for the de-novo synthesis of fatty acids, has emerged as a potential therapeutic target for several cancers, we investigated its involvement in meningiomas. We subjected 92 paraffin-embedded samples from 57 patients with grade I, 18 with grade II and III, and six with radiation-induced tumors to immunohistochemical study of FAS. Whereas its expression was increased in grade II and III meningiomas (62.9 %) compared with grade I tumors (29.8 %) (chi-squared test: p < 0.001), FAS was expressed in grade I tumors with a high MIB-1 index and infiltration into surrounded tissues. All radiation-induced meningiomas expressed FAS and its expression was positively correlated with the MIB-1 index (p < 0.005). Our findings suggest that increased FAS expression reflects the aggressiveness of meningiomas and that it may be a novel therapeutic target for treatment of unresectable or malignant tumors.

Meningiomas, nerve sheath tumors, and pituitary tumors: diagnosis and treatment

This article gives an overview of meningiomas, pituitary tumors, and intracranial nerve sheath tumors as regards epidemiology, diagnosis, and treatment. Discussion includes the definition of these tumors and their symptomatology, diagnostic procedures, treatment options, surgical techniques, and outcomes.

The relationship between urinary bisphenol A levels and meningioma in Chinese adults

BACKGROUND

Estrogen has been implicated as a risk factor for meningioma. Bisphenol A (BPA), a widely used synthetic xenoestrogen, has already been reported to be associated with several estrogen-sensitive tumors.

METHOD

An exploratory association study of 243 meningioma cases and 258 frequency-matched healthy controls was conducted, using subjects from a hospital-based study to demonstrate the association of urine BPA concentration and the risk of meningioma. The specimens and data of patients were collected at Union Hospital, Wuhan, China, from 2009 to 2010.

RESULTS

A positive association between increasing levels of urinary BPA and meningioma was observed, independent of confounding factors such as gender, age, race, body mass index, HRT use, BMI, and family history of cancer. Compared to quartile 1 (referent), the multivariate-adjusted odds ratio of meningioma associated with quartile 4 was 1.45 (95 % CI, 1.02-1.98) (P trend = 0.03).

CONCLUSION

In this case-control study from China, a clear association between urinary BPA concentrations and diagnosis of meningioma was detected.

Immunohistochemical analysis of LRIG proteins in meningiomas: correlation between estrogen receptor status and LRIG expression

The leucine-rich repeats and immunoglobulin-like domains (LRIG) protein family is comprised of three integral membrane proteins: LRIG1, LRIG2, and LRIG3. LRIG1 is a negative regulator of growth factor signaling. The expression and subcellular localization of LRIG proteins have prognostic implications in primary brain tumors, such as oligodendrogliomas and astrocytomas. The expression of LRIG proteins has not previously been studied in meningiomas. In this study, the expression of LRIG1, LRIG2, and LRIG3 was analyzed in 409 meningiomas by immunohistochemistry, and potential associations between LRIG protein expression and tumor grade, gender, progesterone receptor status, and estrogen receptor (ER) status were investigated. The LRIG proteins were most often expressed in the cytoplasm, though LRIG1 also showed prominent nuclear expression. Cytoplasmic expression of LRIG1 and LRIG2 correlated with histological subtypes of meningiomas (p = 0.038 and 0.013, respectively). Nuclear and cytoplasmic expression of LRIG1 was correlated with ER status (p = 0.003 and 0.004, respectively), as was cytoplasmic expression of LRIG2 (p = 0.006). This study is the first to examine the expression of LRIG proteins in meningiomas, and it shows a correlation between ER status and the expression of LRIG1 and LRIG2, which suggests a possible role for LRIG proteins in meningioma pathogenesis.

Meningioma as second malignant neoplasm after oncological treatment during childhood

A total of 38 patients (18 female/20 male) with childhood meningioma were recruited from the German registry HIT-Endo (1989-2009). In 5 cases meningioma occurred as second malignant neoplasm (SMN). Histologies were confirmed by reference assessment in all cases (SMN: 2 WHO I, 1 WHO II, 2 WHO III). The SMNs were diagnosed at a median age of 12.4 years with a median latency of 10.2 years after primary malignancy (PMN; 4 brain tumors, 1 lymphoblastic leukemia; median age at diagnosis 2.7 years). Meningioma occurred as SMN in the irradiated field of PMN (range 12-54 Gy). The outcome after treatment of SMN meningioma (surgery/irradiation) was favorable in terms of psychosocial status and functional capacity in 4 of 5 patients (1 death). We conclude that survivors of childhood cancer who were exposed to radiation therapy at young age harbor the risk of developing meningioma as a SMN at a particularly short latency period in case of high dose exposure.

Glioblastoma following radiosurgery for meningioma

We report a patient who underwent gamma knife radiosurgery to treat recurrent meningioma after microsurgery and thereafter developed secondary malignancy adjacent to the original tumor. A 47-year-old woman had underwent resection of the olfactory groove meningioma. Then radiosurgery was done three times over 4 year period for the recurrent tumor. After 58 months from the initial radiosurgery, she presented with headache and progressive mental dullness. Huge tumor in bifrontal location was revealed in MRI. Subsequent operation and pathological examination confirmed diagnosis of glioblastoma. This case fits the criteria of radiation-induced tumor and the clinical implication of the issue is discussed.

Emergence of a high-grade sarcoma in a recurrent meningioma: malignant progression or collision tumor?

Anaplastic meningiomas that resemble sarcomas often reveal clues to their meningothelial differentiation or develop in a plausible setting that confirms their meningothelial origin. Malignant mesenchymal neoplasms without obvious evidence of meningothelial differentiation or origin are more likely to be true primary or metastatic sarcomas. Because of their clinical and biological differences, it is important to distinguish anaplastic meningioma from a sarcoma. We present a 67-year-old woman with multiple meningiomas, who developed a high-grade spindle cell tumor 6 months after the resection of a World Health Organization grade I meningioma. It was not clear whether this tumor represented a malignant transformation of meningioma or a primary sarcoma. Malignant transformation of a meningioma is exceptional within this short period and a coexisting sarcoma and meningioma are equally uncommon. Even though these malignant neoplasms are rare in general, they appear to be more prevalent in patients with multiple meningiomas including those with neurofibromatosis type 2.

Modeling Intracranial Second Tumor Risk and Estimates of Clinical Toxicity with Various Radiation Therapy Techniques for Patients with Pituitary Adenoma

This study was designed to estimate the risk of radiation-associated tumors and clinical toxicity in the brain following fractionated radiation treatment of pituitary adenoma. A standard case of a patient with a pituitary adenoma was planned using 8 different dosimetric techniques. Total dose was 50.4 Gy (GyE) at daily fractionation of 1.8 Gy (GyE). All methods utilized the same CT simulation scan with designated target and normal tissue volumes. The excess risk of radiation-associated second tumors in the brain was calculated using the corresponding dose-volume histograms for the whole brain and based on the data published by the United Nation Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and a risk model proposed by Schneider. The excess number of second tumor cases per 10,000 patients per year following radiation is 9.8 for 2-field photons, 18.4 with 3-field photons, 20.4 with photon intensity modulated radiation therapy (IMRT), and 25 with photon stereotactic radiotherapy (SRT). Proton radiation resulted in the following excess second tumor risks: 2-field = 5.1, 3-field = 12, 4-field = 15, 5-field = 16. Temporal lobe toxicity was highest for the 2-field photon plan. Proton radiation therapy achieves the best therapeutic ratio when evaluating plans for the treatment of pituitary adenoma. Temporal lobe toxicity can be reduced through the use of multiple fields but is achieved at the expense of exposing a larger volume of normal brain to radiation. Limiting the irradiated volume of normal brain by reducing the number of treatment fields is desirable to minimize excess risk of radiation-associated second tumors.

A contemporary review of stereotactic radiotherapy: inherent dosimetric complexities and the potential for detriment

OBJECTIVE

The advantages of highly localised, conformal treatments achievable with stereotactic radiotherapy (SRT) are increasingly being extended to extracranial sites as stereotactic body radiotherapy with advancements in imaging and beam collimation. One of the challenges in stereotactic treatment lies in the significant complexities associated with small field dosimetry and dose calculation. This review provides a comprehensive overview of the complexities associated with stereotactic radiotherapy and the potential for detriment.

METHODS

This study is based on a comprehensive review of literature accessible via PubMed and other sources, covering stereotactic radiotherapy, small-field dosimetry and dose calculation.

FINDINGS

Several key issues were identified in the literature. They pertain to dose prescription, dose measurement and dose calculation within and beyond the treatment field. Field-edge regions and penumbrae occupy a significant portion of the total field size. Spectral and dosimetric characteristics are difficult to determine and are compounded by effects of tissue inhomogeneity. Measurement of small-fields is made difficult by detector volume averaging and energy response. Available dosimeters are compared, and emphasis is given to gel dosimetry which offers the greatest potential for three-dimensional small-field dosimetry. The limitations of treatment planning system algorithms as applied to small-fields (particularly in the presence of heterogeneities) is explained, and a review of Monte Carlo dose calculation is provided, including simplified treatment planning implementations. Not incorporated into treatment planning, there is evidence that far from the primary field, doses to patients (and corresponding risks of radiocarcinogenesis) from leakage/scatter in SRT are similar to large fields.

CONCLUSIONS

Improved knowledge of dosimetric issues is essential to the accurate measurement and calculation of dose as well as the interpretation and assessment of planned and delivered treatments. This review highlights such issues and the potential benefit that may be gained from Monte Carlo dose calculation and verification via three-dimensional dosimetric methods (such as gel dosimetry) being introduced into routine clinical practice.

Meningioma of the conus medullaris mimicking neurofibroma--possibly radiation induced

BACKGROUND CONTEXT

Radiation-induced meningiomas (RIMs) of the brain are the most common RIMs. However, there has been no report in the literature of an RIM of the spine. Conus medullaris is a favorite site for ependymomas, whereas it is an extremely rare location for meningiomas. Dumbbell-shaped configuration is typical for nerve sheath tumors; however, it is very rarely seen in meningiomas.

PURPOSE

To describe imaging findings of a possibly RIM at the level of the conus medullaris mimicking a neurofibroma.

STUDY DESIGN

A 60-year-old male with 6-year history of irradiated urinary bladder cancer presented with paraparesis.

METHODS

Radiography, computed tomography, and magnetic resonance imaging of the thoracolumbar spine were undertaken.

RESULTS

Radiography showed widening of intervertebral foramina at T12-L1 level. Computed tomography and magnetic resonance imaging disclosed a lobulated intradural mass at the level of the conus medullaris causing widening and scalloping of adjacent bony structures, with dumbbell-shaped configuration. Surgical biopsy of the mass was consistent with fibroblastic meningioma.

CONCLUSIONS

The reported tumor might have developed secondary to irradiation for urinary bladder cancer because meningiomas are the most common radiation-induced central nervous system tumors. Although location at the level of the conus medullaris is atypical for meningioma, and dumbbell-shaped configuration is rather characteristic for neurogenic tumors, they should not exclude a diagnosis of meningioma.

Intraventricular meningioma after cranial irradiation for childhood leukemia

Meningiomas are among the most common brain tumors in adults. They are most commonly located over the cerebral convexities and are infrequently found in an intraventricular location. Ionizing cranial radiation is a risk factor for late occurrence of meningiomas within the radiation field. While pathologic grading of meningiomas is straightforward, significant variability often exists between pathologists in applying standard grading criteria. This has implications for prognosis. Radiation-induced meningiomas may also have predilection to recur. The authors describe a case of an intraventricular meningioma occurring 23 years after cranial irradiation for childhood acute lymphoblastic leukemia.

Epidemiology and etiology of meningioma

Although most meningiomas are encapsulated and benign tumors with limited numbers of genetic aberrations, their intracranial location often leads to serious and potentially lethal consequences. They are the most frequently diagnosed primary brain tumor accounting for 33.8% of all primary brain and central nervous system tumors reported in the United States between 2002 and 2006. Inherited susceptibility to meningioma is suggested both by family history and candidate gene studies in DNA repair genes. People with certain mutations in the neurofibromatosis gene (NF2) have a very substantial increased risk for meningioma. High dose ionizing radiation exposure is an established risk factor for meningioma, and lower doses may also increase risk, but which types and doses are controversial or understudied. Because women are twice as likely as men to develop meningiomas and these tumors harbor hormone receptors, an etiologic role for hormones (both endogenous and exogenous) has been hypothesized. The extent to which immunologic factors influence meningioma etiology has been largely unexplored. Growing emphasis on brain tumor research coupled with the advent of new genetic and molecular epidemiologic tools in genetic and molecular epidemiology promise hope for advancing knowledge about the causes of intra-cranial meningioma. In this review, we highlight current knowledge about meningioma epidemiology and etiology and suggest future research directions.