Outcomes of radiation-induced meningiomas treated with stereotactic radiosurgery.

PURPOSE: Data on the efficacy and safety of stereotactic radiosurgery (SRS) for treatment of radiation-induced meningiomas (RIMs) are limited. METHODS: A single institution database of Cobalt-60 SRS cases from 08/1999 to 10/2020 was reviewed. Radiation-induced meningiomas were identified using Cahan's criteria. Endpoints included overall survival (OS), progression free survival (PFS), local control (LC), treatment failure, and treatment toxicity. Univariate and multivariate analyses were performed using cox proportional hazard models. RESULTS: A total of 29 patients with 86 RIM lesions were identified. Median follow-up after SRS was 59 months. The median dose prescribed to the 50% isodose line was 14 Gy (range 12-20 Gy). The actuarial 5-yr OS and PFS were 96% and 68%, respectively. Patients treated for recurrent RIMs had a significantly lower PFS (45% vs 94% at 3 yr, p < 0.005) than patients treated in the upfront setting. Patients with presumed or WHO grade I RIMs had a significantly greater PFS (3-year PFS 96% vs 20%) than patients with WHO grade II RIMs (p < 0.005). On a per-lesion basis, local control (LC) at 1-, 3-, and 5-yrs was 82%, 76%, 74%, respectively. On multivariate analysis, female gender was associated with improved LC (p < 0.001), while marginal doses > 14 Gy were associated with worse local control (p < 0.001). Grade I-III toxicity following treatment was 9.0%. CONCLUSIONS: Stereotactic radiosurgery is a safe and effective treatment option for radiographic RIMs, WHO grade I RIMs, or lesions treated in the upfront setting. WHO grade II lesions and recurrent lesions are at increased risk for disease progression.

Evaluation of the growth rates and related prognostic factors in radiation-induced meningiomas.

PURPOSE: Literature dedicated to growth patterns and growth rate influencing factors of radiation-induced meningiomas (RIMs) is limited. To deliver new insights into the topic, a volumetric growth analysis of RIMs was performed. METHODS: This single-center, retrospective cohort study included patients diagnosed with intracranial meningioma who received radiation treatment at least > 5 years before the RIM diagnosis. Volumetric analysis of individual RIMs was performed using 3D volumetry at the time of RIM diagnosis and during follow-up. RIM growth was determined by calculating absolute (AGR), and relative (RGR) growth rates. Prognostic factors associated with RIM growth were evaluated. RESULTS: A total of 26 patients with 33 meningiomas were enrolled in the study and radiologically/clinically followed up during a median duration of 5.6 years (IQR 3.9-8.8 years). Median AGR was 0.19 cm3 per year and the median RGR was 34.5% per year. Surgically managed RIMs were more likely fast-growing compared to observed ones based on the AGR (p < 0.002). The recurrence rate after total resection was 14.3%. Younger age at RIM diagnosis was associated with higher tumor growth (RGR ≥ 30%, p = 0.040). A significant correlation was found between the length of latency period and the RGR (p = 0.005). CONCLUSION: To diagnose RIM as early as possible comprehensive MRI surveillance is required. Younger patients with shorter latency periods may profit from shortened MRI intervals, with further management being dependent on the growth rate and eventual symptomatology.

Reconstruction of Moderately and Severely Atrophic Scalp-A Multicentric Experience in Surgical Treatment of Patients Irradiated for Tinea Capitis in Childhood and Surgical Algorithm.

Background and Objectives: Before the introduction of griseofluvin, the use of X-ray radiation was the treatment of choice for tinea capitis. More than half a century later various types of tumors have been found to be associated with childhood irradiation due to tinea capitis, most commonly cancers of the head and neck, as well as brain tumors. The often unusually aggressive and recurrent nature of these tumors necessitates the need for repeated surgeries, while the atrophic skin with an impaired vascular supply due to radiation often poses an additional challenge for defect reconstruction. We present our experience in the surgical treatment of such patients. Materials and Methods: This is a retrospective cohort study. In this study, 37 patients treated for acquired defects of the scalp with a history of irradiation therapy due to tinea capitis in childhood were included in this study, 24 male and 13 female patients. The mean age at the first appointment was 60.6 ± 7.8, with the youngest included patient being 46 and the oldest being 75 years old. Patients' characteristics, surgical treatment, and complications were analyzed and a reconstructive algorithm was developed. Results: Local flaps were used for reconstruction in 34 patients, direct sutures were used in 10 patients and 20 patients received split-thickness skin grafts for coverage of both primary and secondary defects for reconstruction of flap donor sites. One regional flap and one dermal substitute covered by an autologous skin graft were also used for reconstruction. Complications occurred in 43.2% of patients and were significantly associated with the presence of comorbidities (p = 0.001), aseptic bone necrosis (p = 0.001), as well as skin atrophy in frontal, occipital, and parietal region (p = 0.001, p = 0.042 and p = 0.001, respectively). A significant correlation between major complications and moderate skin atrophy was found only in the parietal region (p = 0.026). Conclusions: Unfortunately, many protocols developed for scalp reconstruction are not applicable in the setting of severe or diffuse scalp skin atrophy associated with high tumor recurrence rate and radiation-induced vascular impairment, such as in tinea capitis patients in Serbia. An algorithm has been developed based on the authors' experience in managing these patients.

Cranial Irradiation for Childhood Cancers and Adult Risk of Meningioma.

INTRODUCTION: Following cranial irradiation, there is an increased risk of developing secondary neoplasms, especially meningiomas. Despite childhood cancer survivors who have undergone cranial irradiation having an increased risk of acquiring radiation-induced meningioma (RIM), there is no widely used standard guideline for meningioma screening. METHODS: At a single institution, we reviewed three adult survivors of childhood cancer who were treated for RIM between 2010 and 2020. We recorded age at diagnosis for the primary lesion, the radiation dose, age at RIM diagnosis, and tumor characteristics including treatment, pathology, and outcome. Two had had T-cell acute lymphocytic leukemia and one a rhabdomyosarcoma. The age of diagnosis of the RIM ranged from 20 to 40 years, with latencies ranging from 18 to 33 years. All lesions were classified as WHO Grade I meningiomas, and only 1 patient had a subsequent recurrence. A literature search identified articles that address RIM: a total of 684 cases were identified in 36 publications. RESULTS: Mean radiation doses ranged from 1.4 gray to 70 gray. Mean age of diagnosis for secondary meningioma ranged from 8 to 53.4 years old, with latency periods ranging from 2.8 to 44 years. Given variability in the way that investigators have published their results, it is difficult to make a single recommendation for RIM screening. Using our experience and the literature, we devised two different screening protocols and calculated their expense. CONCLUSIONS: We recommend that data be standardized in a registry to provide greater insight into the clinical and resource allocation questions, especially as long-term survival of children with pediatric cancer into full adulthood becomes more commonplace worldwide.

The growth rate and clinical outcomes of radiation induced meningioma undergoing treatment or active monitoring.

INTRODUCTION: Radiation induced meningioma (RIM) incidence is increasing in line with improved childhood cancer survival. No optimal management strategy consensus exists. This study aimed to delineate meningioma growth rates from tumor discovery and correlate with clinical outcomes. METHODS: Retrospective study of patients with a RIM, managed at a specialist tertiary neuroscience center (2007-2019). Tumor volume was measured from diagnosis and at subsequent interval scans. Meningioma growth rate was determined using a linear mixed-effects model. Clinical outcomes were correlated with growth rates accounting for imaging and clinical prognostic factors. RESULTS: Fifty-four patients (110 meningiomas) were included. Median duration of follow-up was 74 months (interquartile range [IQR], 41-102 months). Mean radiation dose was 41 Gy (standard deviation [SD] = 14.9) with a latency period of 34.4 years (SD = 13.7). Median absolute growth rate was 0.62 cm3/year and the median relative growth rate was 72%/year. Forty meningiomas (between 27 patients) underwent surgical intervention after a median follow-up duration of 4 months (IQR 2-35). Operated RIMs were clinically aggressive, likely to be WHO grade 2 at first resection (43.6%) and to progress after surgery (41%). Median time to progression was 28 months (IQR 13-60.5). A larger meningioma at discovery was associated with growth (HR 1.2 [95% CI 1.0-1.5], P = 0.039) but not progression after surgery (HR 2.2 [95% CI 0.7-6.6], P = 0.181). Twenty-seven (50%) patients had multiple meningiomas by the end of the study. CONCLUSION: RIMs exhibit high absolute and relative growth rates after discovery. Surgery is recommended for symptomatic or rapidly growing meningiomas only. Recurrence risk after surgery is high.

Efficacy of stereotactic radiosurgery for radiation-induced meningiomas.

PURPOSE: Stereotactic radiosurgery is an established treatment option for sporadic meningiomas, though limited data exists for radiation-induced lesions. METHODS: Patients treated with cobalt-60 radiosurgery between October 2005 and December 2018 in an institutional registry were reviewed. Single fraction treatments were prescribed to the 50% isodose line. Lesions were deemed to be radiation-induced according to standard criteria previously established by Cahan et al. RESULTS: A total of 37 patients with 72 lesions were analysed. Median follow up per patient was 44 months (range, 1.4-150.7 months). Median age at initial radiotherapy was 5 years (4 months-48 years), and at radiosurgery was 38 years. Of the 72 lesions, 62 were grade 1 (n = 4) or radiologically-diagnosed (n = 58), six were grade 2 and four were grade 3. Median lesion volume was 2.13 cc (0.04-13.8 cc), while the median radiosurgery margin dose was 13 Gy. Local control, on a per lesion basis, was 88.6% at 5 years (95% confidence interval [CI] 72.3-95.6). For grade 1 or radiologically-diagnosed lesions, local control was 96.6% at 5 years (95% CI 77.9-99.5), whereas those with grade 2 or higher lesions had a local control of 40% at 5 years (95% CI 5.2-75.3, p = 0.005). Radiologic oedema developed in 17 lesions (23.6%) and was symptomatic in 12 patients (16.7%). Doses above 12 Gy were not associated with local control probability (p = 0.292). CONCLUSION: Radiosurgery is an effective treatment option for grade 1 or radiologically-diagnosed radiation-induced meningiomas, with 12 Gy appearing to be a sufficient dose.

Purely endoscopic removal of a parasagittal/falx meningioma.

BACKGROUND: Endoscopic techniques are an integral part of the neurosurgical armamentarium with a growing list of indications. We describe the purely endoscopic removal of an atypical parasagittal meningioma in a patient who could not undergo standard craniotomy due to severe scalp atrophy following childhood irradiation for tinea capitis. METHODS: A 68-year-old man in good general health presented with a parasagittal meningioma that recurred following subtotal removal and adjuvant fractionated stereotactic radiosurgery (FSR). The scalp above the tumor location was very diseased and precluded a regular craniotomy for tumor removal. A 4-cm craniotomy was made in the midline forehead, where the skin was normal. A rigid endoscope was advanced under neuronavigation through the interhemispheric fissure, which provided good access with limited retraction, until the tumor was encountered at a depth of 7-8 cm. Two surgeons performed the surgery using a "four-hands technique". The tumor was removed and the insertion area was resected and coagulated. RESULTS: The surgery was uneventful, with no coagulation or transection of major veins. A subtotal resection was achieved, and the patient recovered with no neurological deficit. CONCLUSIONS: Safe resection of parasagittal meningiomas with a purely endoscopic technique is feasible. This option needs further exploration as an alternative strategy in patients with severely atrophic scalp skin that greatly increases the risk of significant healing complications with calvarian craniotomy.

Case report: Low-dose radiation-induced meningioma with a short latency period.

Patients with radiation-induced meningioma (RIM), most of whom had received head radiation therapy or had been exposed to ionizing radiation during childhood or adolescence, are at risk of developing cranial meningiomas throughout their lifetimes because of the long latency period. Although intermediate-to-high-dose ionizing radiation exposure is an established risk factor for RIM, risk factors for low-dose RIM remain incompletely defined. This study presents the case of a 56-year-old woman diagnosed with radiation-induced giant meningioma 2.5 years after undergoing an interventional embolization procedure for a brain aneurysm. This is the first report of RIM attributable to a brain intervention with an extremely short latency period. The total radiation dose received by the patient during the operation was 1367.3 mGy, representing a low dose. Our case report strengthens the evidence that even low radiation doses can increase the risk of RIM. These findings provide a realistic basis for the theoretical study of RIM and suggest some new ideas for RIM treatment. The need for caution in the use of radioactive treatments and optimization of interventional procedures is highlighted.

Favourable outcomes with an initial active surveillance strategy for asymptomatic radiation-induced meningiomas in long-term survivors of paediatric and young adult malignancies.

PURPOSE: Radiation-induced meningiomas (RIM) are the most common secondary neoplasm post cranial radiotherapy, yet optimal surveillance and treatment strategies remain contentious. Herein, we report the clinical outcomes and radiological growth rate of RIM, diagnosed in a cohort of survivors undergoing MRI screening, with the objective of informing clinical guidelines and practice. MATERIALS AND METHODS: Long-term survivors of paediatric or young-adult malignancies, diagnosed with RIM between 1990 and 2015, were identified. Absolute (AGR) and relative (RGR) volumetric growth rates were calculated. Rapid growth was defined as AGR > 2 cm3/year or AGR > 1 cm3/year and RGR ≥ 30% RESULTS: Fifty-two patients (87 RIM) were included. Median age at first RIM diagnosis was 33.9 (range,13.8-54.1) years. Seventy-seven (88%) RIM were asymptomatic at detection. Median follow-up time from first RIM detection was 11 (range, 0.6-28) years. Median absolute and relative volumetric growth rates were 0.05 (IQR 0.01-0.11) cm3 and 26 (IQR 7-79) % per year, respectively. Two (3.3%) RIM demonstrated rapid growth. Active surveillance was adopted for 67 (77%) RIM in 40 patients. Neurological sequelae due to RIM progression were reported in 5% of patients on active surveillance. Surgery was performed for 33 RIM (30 patients): 18 (54.5%) at diagnosis and 15 (45.5%) after active surveillance. Histopathology was WHO Grade 1 (85.2%), 2 (11.1%), 3 (3.7%). Following resection, 10-year local recurrence rate was 12%. During follow-up, 19 (37%) survivors developed multiple RIM. CONCLUSIONS: Asymptomatic RIM are typically low-grade tumours which exhibit slow growth. Active surveillance appears to be a safe initial strategy for asymptomatic RIM, associated with a low rate of neurological morbidity.

Radiation-induced meningiomas (RIM) in adults: A single-centre retrospective experience.

Introduction: Radiotherapy of central nervous system (CNS) is treatment against many paediatric cancers, even if it is a well-recognized risk factor for meningioma formation. An increased risk of developing secondary brain tumors like radiation-induced meningiomas (RIM) is related to irradiated patients. Research question: This retrospective study aims to present RIM cases treated in a single tertiary-hospital in Greece and compare the results with international literature and cases of sporadic meningiomas. Materials and methods: A single-centre retrospective study of all patients diagnosed between January 2012 and September 2022 with RIM after having been irradiated in CNS for paediatric cancer was undertaken through hospital's electronic record and clinical notes, identifying baseline demographics and latency period. Results: Thirteen patients were identified with RIM diagnosis after receiving irradiation for Acute Lymphoblastic Leukaemia (69.2%), Premature Neuro-Ectodermal Tumour (23.1%), and Astrocytoma (7.7%). Median age at irradiation was 5 years old and 32 years old at RIM's presentation. The latent period from irradiation to meningioma diagnosis was 26.23 â€‹± â€‹5.96 years. After surgical excision, histopathologic results showed grade I meningiomas in 12 out of thirteen cases, while only one atypical meningioma was diagnosed. Conclusion: Patients who underwent CNS-radiotherapy in childhood for any condition have an increased risk of developing secondary brain tumors such as radiation-induced meningiomas. RIMs resemble sporadic meningiomas in symptomatology, location, treatment, and histologic grade. However, long-term follow-up and regular check-ups are recommended in irradiated patients due to short latency period from irradiation to RIM development, which means younger age patients than those with sporadic meningiomas cases.

A Case of Suspected Radiation-Induced Meningioma That Developed 36 Years after Radiotherapy for a Suprasellar Tumor.

Recently, the improvements in the prognosis of childhood brain tumors have made it necessary to consider the risk of radiation-induced brain tumor development in long-term survivors. In this report, we describe a case of radiation-induced meningioma (RIM) treated surgically 36 years after radiotherapy. A 46-year-old woman, who underwent craniotomy for suprasellar germ cell tumor at 10 years of age with additional postoperative radiotherapy, was admitted to the emergency room with consciousness disturbance and right hemiplegia. One year earlier, magnetic resonance imaging (MRI) revealed a 1-cm diameter tumor in the left middle cranial fossa. This MRI showed an enlarged brain tumor in same lesion with clearly enhanced by gadolinium. A RIM located on a left sphenoid ridge with a fast growth rate was diagnosed, and the gross total removal was achieved by a left frontotemporal craniotomy. Histological diagnosis of atypical meningioma (World Health Organization grade II) was made. RIMs are frequently atypical, anaplastic meningiomas that have already been treated with radiotherapy, making additional postoperative radiotherapy difficult; the removal rate must be increased to achieve a good prognosis. In the case of long-term survivors after childhood radiotherapy, a strict follow-up with the occurrence of RIM in mind is necessary.

Radiation-Induced Papillary Meningioma: A Case Report.

Meningiomas are the most common tumors that develop following cranial radiotherapy. They have a shorter latency period and an aggressive behavior when compared with spontaneously occurring meningiomas. We report a 69-year-old male who underwent high-dose radiotherapy for recurrent pituitary adenoma and later developed temporal high-grade meningioma which was excised. Patient developed tumor bed bleed twice in the postoperative period and succumbed subsequently to the disease. After a thorough review of literature, this may be the second case of radiation-induced grade III papillary meningioma which has been reported.

Microsurgical Resection of Radiation-Induced Cervical Spinal Intradural Extramedullary Meningioma: Dural Splitting Resection.

Spinal meningiomas constitute 10% of all meningiomas. They most commonly rise in the thoracic spine and are most common in middle aged women; symptoms include progressive myelopathy.1,2 Radiation induced/radiotherapy-associated cranial meningiomas are well described with aggressive behavior; however, radiation-induced spinal meningiomas are extremely rare in the literature.3-7 Our patient had a history of Hodgkin lymphoma treated with neck radiation, and thyroid cancer treated with radioactive iodine/thyroidectomy. He presented with neck pain and myelopathy from a large intradural, extramedullary tumor compressing the spinal cord (C3-C5). He had a prevertebral phlegmon that was resolved with antibiotics prior to surgery. Intraoperative neurophysiological electrodes were placed for somatosensory-evoked potential and motor-evoked potential monitoring. C3-C5 bilateral laminectomies were performed (Video 1); dura was incised over the tumor. Tumor attachments to the dura were coagulated and divided. The tumor was dissected microsurgically from the spinal cord and nerve roots. The dural layer involved by the tumor was split and resected from the uninvolved dura, achieving tumor resection. Postoperatively, the patient's myelopathy resolved. He has been followed for a 1 year now with mangetic resonance imaging scans of the cervical spine ± contrast every 6 months. To our knowledge, this is the first operative video describing resection of a spinal meningioma, which happens to be radiation-induced, using a dural splitting technique to achieve better resection and prevent tumor recurrence. The alternative treatment would be to leaving the inner layer of dura, coagulation, or excising both layers and performing duraplasty. Both alternative options, however, would increase the risk of recurrence and spinal fluid leak. Cervical spine meningiomas with spinal cord compression and myelopathy should be resected to prevent further neurological decline. Dural splitting can be utilized to achieve "radical" tumor resection to prevent recurrence, which is particularly important if the tumor is aggressive and recurrent, as is the case in radiation-induced/radiotherapy-associated meningiomas. Upon dural closure, we applied autologous fat tissue along with fibrin glue to avoid spinal fluid leak as we published earlier.8 The patient consented to the procedure and publication of his image.

Stereotactic radiosurgery for treatment of radiation-induced meningiomas: a multiinstitutional study.

OBJECTIVE: Radiation-induced meningiomas (RIMs) are associated with aggressive clinical behavior. Stereotactic radiosurgery (SRS) is sometimes considered for selected RIMs. The authors investigated the effectiveness and safety of SRS for the management of RIMs. METHODS: From 12 institutions participating in the International Radiosurgery Research Foundation, the authors pooled patients who had prior cranial irradiation and were subsequently clinically diagnosed with WHO grade I meningiomas that were managed with SRS. RESULTS: Fifty-two patients underwent 60 SRS procedures for histologically confirmed or radiologically suspected WHO grade I RIMs. The median ages at initial cranial radiation therapy and SRS for RIM were 5.5 years and 39 years, respectively. The most common reasons for cranial radiation therapy were leukemia (21%) and medulloblastoma (17%). There were 39 multiple RIMs (35%), the mean target volume was 8.61 ± 7.80 cm3, and the median prescription dose was 14 Gy. The median imaging follow-up duration was 48 months (range 4-195 months). RIM progressed in 9 patients (17%) at a median duration of 30 months (range 3-45 months) after SRS. Progression-free survival at 5 years post-SRS was 83%. Treatment volume ≥ 5 cm3 predicted progression (HR 8.226, 95% CI 1.028-65.857, p = 0.047). Seven patients (14%) developed new neurological symptoms or experienced SRS-related complications or T2 signal change from 1 to 72 months after SRS. CONCLUSIONS: SRS is associated with durable local control of RIMs in the majority of patients and has an acceptable safety profile. SRS can be considered for patients and tumors that are deemed suboptimal, poor surgical candidates, and those whose tumor again progresses after removal.

Radiation-induced meningiomas.

Radiation-induced meningiomas (RIMs) became more common as the use of ionizing radiation was adopted in the treatment of medical conditions, both benign and malignant. Currently, RIMs represent the most common radiation-induced tumors. They are heterogeneous in terms of patient characteristics, radiographic appearance, genetics, pathology, symptoms, and management strategies. They tend to occur in a younger population and are generally more aggressive in nature than their spontaneous counterparts. Their characteristics also vary based on the dose of radiation received, which is most commonly separated into low dose (<10Gy) and high dose (>10Gy). The importance of the dosing classification is that it can provide insight into the nature and biologic behavior of the tumor. Given their heterogeneity, RIMs pose significant challenges in management. While surgical resection remains the preferred treatment when feasible, recent data supports stereotactic radiosurgery (SRS) as a comparable alternative. Although there is more knowledge about the molecular pathways leading to RIMs, targeted drug therapy is still limited and is the focus of current research.

Supracerebellar Transtentorial Approach for Occipital Meningioma to Maximize Visual Preservation: Technical Note.

BACKGROUND AND IMPORTANCE: Surgery for resection of tentorial meningiomas compressing primary visual cortex carries a significant risk of worsening vision. This concern is especially acute in patients with a preexisting visual deficit. Approaches that involve mechanical retraction of the occipital lobe further threaten visual function. The supracerebellar transtentorial (SCTT) approach, which does not carry a risk of occipital retraction injury, should be considered for patients with occipital tentorial meningiomas to maximize functional visual outcomes. CLINICAL PRESENTATION: A 54-yr-old woman underwent 2 resections and radiation therapy for a right occipital oligodendroglioma as a teenager. She was left with a complete left homonymous hemianopsia. The patient now presented with progressive vision loss in her remaining right visual field. Imaging revealed a left occipital superiorly projecting tentorial meningioma. To preserve her remaining visual function the SCTT approach was chosen for resection. A Simpson grade 1 removal was achieved without disrupting the occipital lobe pia or requiring mechanical cerebellar retraction. A diagnosis of a WHO grade II meningioma (presumably radiation induced) was made. The patient's vision returned to premorbid baseline 1 wk after surgery. CONCLUSION: The SCTT approach should be considered for the surgical management of patients with occipital tentorial meningiomas when visual preservation is at risk. This approach avoids transgression of visual cortex and minimizes the risk of venous infarction or contusions from retraction injury.

Management of multiple meningiomas.

OBJECTIVE Multiple meningiomas account for 1%-10% of meningiomas. This study describes epidemiological aspects of the disease and its management, which is more challenging than for single tumors. METHODS A consecutive series of adult patients with ≥ 2 spatially separated meningiomas was reviewed. Patients with neurofibromatosis Type 2 were excluded. The authors collected clinical, imaging, histological, and treatment data to obtain information on epidemiology, management options, and outcomes of active treatment and surveillance. RESULTS A total of 133 consecutive patients were included over 25 years, with a total of 395 synchronous and 53 metachronous meningiomas, and a median of 2 tumors per patient. One hundred six patients had sporadic disease, 26 had radiation-induced disease, and 1 had familial meningiomatosis. At presentation, half of the patients were asymptomatic. In terms of their maximum cross-sectional diameter, the tumors were small (≤ 2 cm) in 67% and large (> 4 cm) in 11% of the meningiomas. Fifty-four patients had upfront treatment, and 31 had delayed treatment after an observation period (mean 4 years). One in 4 patients had ≥ 2 meningiomas treated. Overall, 64% of patients had treatment for 142 tumors-67 with surgery and 18 with radiotherapy alone. The mean follow-up was 7 years, with 13% of treated patients receiving salvage therapy. Approximately 1 in 4 patients who underwent surgery had ≥ 1 WHO Grade II or III meningioma. Meningiomas of different histological subtypes and grades in the same patient were not uncommon. CONCLUSIONS Multiple meningiomas are often asymptomatic, probably because the majority are small and a significant proportion are induced by radiation. Approximately two-thirds of patients with multiple meningiomas require therapy, but only one-third of all meningiomas need active treatment. The authors recommend surveillance for stable and asymptomatic meningiomas and therapy for those that are symptomatic or growing.

Radiation-Induced Meningiomas: An Exhaustive Review of the Literature.

OBJECTIVE: Radiation-induced meningioma (RIM) is an uncommon late risk of cranial irradiation. We conducted an exhaustive review of individual patient data to characterize RIM. METHODS: Using a systematic search of the PubMed database, we performed a comprehensive literature review to characterize and investigate RIM. Student t tests were used to evaluate differences between variables. A Kaplan-Meier analysis was used to assess survival. Statistical significance was assessed using a log-rank test. RESULTS: Our analysis included 251 cases of RIM. The average age at onset for the primary lesion was 13.0 ± 13.5 years, and the average radiation dose delivered to this lesion was 38.8 ± 16.8 Gy. Secondary meningiomas could be divided into grades I (140), II (55), and III (10) tumors. Thirty patients (11.9%) had multiple lesions, and 46 (18.3%) had recurrent meningiomas. The latency period between radiotherapy for primary lesions and the onset of meningiomas was 22.9 ± 11.4 years. The latency period was shorter for patients with grade III meningioma and for those in the high-dose and intermediate-dose radiation groups who received systemic chemotherapy. Aggressive meningiomas and multiple meningiomas were more common in the high-dose and intermediate-dose groups than in the low-dose group. The 5-year and 10-year survival rates for all patients with meningioma were 77.7% and 66.1%, respectively. CONCLUSIONS: For patients treated with cranial radiotherapy, the risk of secondary meningioma warrants a longer follow-up period beyond the standard time frame typically designated for determining the risk of primary tumor relapse.

Sphenoid wing en plaque meningioma development following craniopharyngioma surgery and radiotherapy: Radiation-induced after three decades.

Radiation therapy is widely used as adjuvant or primary treatment modality of neoplastic lesions. Radiation therapy may cause an acute adverse effect such as brain edema, radiation necrosis, or delayed, for example, panhypopituitarism, vasculitis, and rare de-novo neoplasm development. However, radiation-induced meningioma (RIM) occurrence is extremely rare. A detailed PubMed and Medline search yielded only three isolated Case-reports of RIM development in craniopharyngioma cases receiving radiotherapy after surgery. All cases occurred in patients < 13-year age, with male preponderance, detected after a mean interval of 23-year, the range being 2-44 years. Two had solitary while the third had multiple meningiomas. Authors report an 8-year-old female, who was operated for craniopharyngioma and received adjuvant therapy, was asymptomatic for next 30 years, met a road traffic accident and magnetic resonance imaging brain revealed incidental right sphenoid wing en plaque meningioma. She was planned for gamma-knife therapy as unwilling for surgical intervention. Management of RIM development after radiotherapy of craniopharyngioma along with pertinent literature is reviewed briefly.

Quadruple Neoplasms following Radiation Therapy for Congenital Bilateral Retinoblastoma.

PURPOSE: The aim of this study was to describe a 34-year-old male with hereditary bilateral retinoblastoma treated with radiotherapy as a child who developed 4 distinct tumors within the radiation field. METHODS: A 34-year-old male with bilateral retinoblastoma status postradiation therapy and recurrence requiring enucleation presented with left-eye visual acuity changes. Magnetic resonance imaging demonstrated a left orbital mass and a right parasellar complex lobulated mass (right sphenoid and right cavernous sinus). Two weeks later, the patient underwent excision of the orbital mass and biopsy of an upper-lid nodule. This was followed by craniotomy for removal of the complex mass. RESULTS: Histology revealed 4 distinct tumors, including an undifferentiated pleomorphic sarcoma (left orbit), a radiation-induced meningioma (right sphenoid), a schwannoma (right cavernous sinus), and a basal-cell carcinoma (left lid). CONCLUSION: Although occurrence of a second neoplasm is a well-known outcome following radiation treatment in patients with hereditary retinoblastoma, the diagnosis of 4 additional neoplasms is rare. Pleomorphic sarcoma, radiation-induced meningioma, and schwannoma are uncommon tumors and not well represented in the literature describing irradiated retinoblastoma patients. Secondary malignancies are a leading cause of early death in retinoblastoma survivors, and long-term follow-up is crucial for patient care.