Papillary meningioma. Clinicopathologic study of seven cases and review of the literature

Primary intracranial papillary meningioma: Analysis of factors of prognosis and systematic review

OBJECTIVE

Papillary meningioma is rare and displays an aggressive clinical behavior with poor prognosis. Therefore, we performed an extensive literature review to evaluate the adverse factors and treatment strategy of survival.

METHOD

We performed Ovid, Medline, Embase, Pubmed, Web of Science and Cochrane database queries for articles published between 1938 and 2019 with the search term "WHO grade III meningioma" or "papillary meningioma" and "central nervous system", "cerebral", or "intracranial".

RESULTS

After a careful evaluation, a total of 19 studies were included. The entire cohort included the 67 patients, 34 (50.7%) were male and 33 (49.3%) were female with a mean age of 32.6 ± 2.1 years ranging from 4.5 months to 74 years. Gross total resection was achieved in 48 (71.6%) cases, and 29 (51.8%) patients received postoperative radiation. The mean follow-up period was 42.3 ± 4.4 months (range, 2-197 months). Thirty-six (53.7%) patients happened to recurrences, 11 (16.4%) patients happened to extracranial metastasis and 25 (37.3%) patients died. Univariate analysis revealed that the MIB > 5% trended toward a shorter time to recurrence (p = 0.084). Gross total resection was associated with favorable progression-free survival (p = 0.007) and overall survival (p = 0.001). Postoperative radiation was associated with favorable progression-free survival (p = 0.001).

CONCLUSIONS

Gross total resection and adjuvant radiation were recommended as the initial treatment option for patients with papillary meningioma.

Intraventricular cystic papillary meningioma: A case report and literature review

INTRODUCTION

Papillary meningioma is an extremely rare malignant lesion with high degree of invasiveness, high recurrence rate, and perivascular pseudopapillary structure. The incidence of cystic degeneration in papillary meningiomas is relatively low, and cystic papillary meningiomas growing in the ventricle are even rarer. Here, we present a case of cystic meningioma and review the literature to propose the diagnosis, treatment, immunohistochemical features, and prognosis of the same.

PATIENT CONCERNS

In July 2013, a 35-year-old male Chinese patient presented with dizziness that lasted for a week, without relief. Magnetic resonance imaging (MRI) revealed a 2.0 cm × 1.5 cm × 3.0 cm-sized mass located in the left lateral ventricle trigone. The tumor was small and likely non-malignant. Therefore, the patient received conservative treatment and regular follow-ups. In June 2017, the patient experienced sudden severe headache, dizziness, and vomiting.

DIAGNOSIS AND INTERVENTION

MRI revealed that the mass in the left lateral ventricle trigone had increased to 5.0 cm × 7.0 cm × 8.0 cm over 4 years. The patient underwent surgical resection via the left parietal-occipital approach. Two months postoperatively, the patient received 60 Gy local radiotherapy. The postoperative histopathology suggested that the mass was a cystic papillary meningioma.

OUTCOMES

Two years after the operation, the patient was asymptomatic, and no recurrence of the lesion was noted on MRI.

CONCLUSION

The diagnosis of intraventricular cystic papillary meningioma depends mainly on its histology and imaging features. Total resection and adjuvant radiotherapy can result in a relatively good prognosis of patients with intraventricular cystic papillary meningiomas.

Pathology of meningiomas

Meningiomas are a diverse group of neoplasms that exhibit a wide range of morphologies and clinical behavior. They are generally accepted to originate from arachnoid cap cells within the leptomeninges. Classic histologic features include whorl formations, psammoma bodies, nuclear holes, and nuclear pseudoinclusions. Meningiomas are classified as benign, atypical, or anaplastic (grades I, II, or III) based on histologic features including mitotic activity, brain invasion, and presence of other minor criteria. There are numerous histologic variants of meningiomas, and some are associated with worse clinical outcomes and therefore are assigned a higher grade. The majority of meningiomas show diffuse positivity for vimentin and epithelial membrane antigen, supporting the dual mesenchymal and epithelial nature of meningothelial cells. The presence of an elevated proliferation index (as measured by Ki-67 immunohistochemical stain) and loss of progesterone receptor expression are associated with the higher grade. Pathologic features including histologic variants, grading criteria, and ancillary tests such as special and immunohistochemical stains are discussed.

Infiltration of Benign Meningioma into Sagittal Sinus and Subsequent Metastasis to Lung: Case Report and Literature Review

BACKGROUND

Meningioma is an intracranial tumor frequently encountered in the neurosurgical setting. Extracranial disease is a rare occurrence, with a reported incidence in 0.1% of cases. Metastasis is associated with previous craniotomy, venous sinus invasion, local recurrence, and World Health Organization (WHO) grade III tumor. Metastasis of a benign, grade I meningioma is extraordinarily rare.

CASE DESCRIPTION

We report a case of a 41-year-old with a WHO grade I intracranial meningioma that had invaded and occluded the superior sagittal sinus. Chest computed tomography (CT) scan revealed pulmonary nodules, which were biopsied and confirmed benign meningioma. The metastatic meningiomas were found before resection of the primary tumor, suggesting direct seeding through the venous system versus iatrogenic seeding. Thirteen years later, an additional lung mass was found incidentally on abdominal CT scan for workup of a sarcoidosis. Biopsy and subsequent resection confirmed benign meningioma. A retrospective review of earlier chest CT scans revealed a small lesion that corresponded to the larger lesion found 13 years later.

CONCLUSIONS

This a rare case of a WHO grade I meningioma involving the sagittal sinus with direct seeding of the pulmonary vascular bed leading to multiple meningioma metastases. The report highlights an increased risk of distant metastases for a benign meningioma with invasion of dural sinuses.

Rare Intracranial Recurrent Meningioma with Unique Coexisting Atypical, Papillary and Lipomatous Component: Case Report and Review of Literature

BACKGROUND

Meningiomas are common central nervous system tumors with a wide range of morphologic variants, the pathogenesis being their complex embryogenesis. Intracranial meningiomas with heterogenous histopathology in the same lesion are common in low-grade meningiomas but less frequent in recurrent and high-grade variants.

CASE DESCRIPTION

A 75-year-old male presented elsewhere a year ago with complaints of slurred speech. Magnetic resonance imaging revealed a left frontotemporal, dural-based, extraaxial, solid cystic lesion with doubtful infiltration into the adjacent brain parenchyma. A subtotal excision was done. A diagnosis of meningioma with an aggressive biological behavior was rendered on histology, but the grade was deferred, in view of a single focus of small cell formation and no adjacent brain parenchyma to comment on invasion. The patient presented here with recurrence of his original symptoms. Magnetic resonance imaging of the brain with contrast revealed 2 dural-based, solid cystic enhancing lesions of sizes 29 mm × 25 mm × 24 mm and 25 mm × 16 mm seen at the left frontal region, indenting the adjacent brain parenchyma with diffuse meningeal thickening in the postoperative bed. Microscopy revealed a hypercellular meningeal neoplasm with increased mitosis and a pseudopapillary pattern with lipomatous changes.

CONCLUSIONS

To date there are no case reports in current literature with such rare combinations in a recurrent meningioma. This highlights the multipotency of phenotypic transformation of primary meningothelial cells. The presence of papillary features, even if focal, should be quantified in the diagnosis. This is of importance because the most current literature suggests that meningioma harboring a papillary component has an increased risk of recurrence and progression to aggressive behavior.

Papillary meningioma: Diagnosis by intraoperative crush smear cytology

Papillary meningioma is a rare, aggressive variant of meningioma. It accounts for less than 1% of all meningiomas. It is categorized as WHO grade III due to high rate of recurrence and metastasis. Histopathologic features of papillary meningioma are well described, but cytomorphology is rarely been described. We report a case of papillary meningioma, diagnosed on intraoperative crush cytology and later confirmed on histopathology. Papillary meningioma possesses characteristic cytological features. Along with the cellular meningothelial features, radial arrangement of cells around thin and thick walled hyalinised blood vessels gives the diagnostic clue. In addition, knowledge of clinical and radiological features is extremely helpful to arrive at the correct diagnosis and to differentiate it from other papillary lesions involving central nervous system. Due to aggressive clinical course and poor prognosis of papillary meningioma, a timely recognition of the diagnosis is desirable and helpful for rationalizing approaches to therapy.

Diagnostic challenges in meningioma

Advances in molecular profiling and the application of advanced imaging techniques are currently refreshing diagnostic considerations in meningioma patients. Not only technical refinements but also sophisticated histopathological and molecular studies have the potential to overcome some of the challenges during meningioma management. Exact tumor delineation, assessment of tumor growth, and pathophysiological parameters were recently addressed by "advanced" MRI and PET. In the field of neuropathology, high-throughput sequencing and DNA methylation analysis of meningioma tissue has greatly advanced the knowledge of molecular aberrations in meningioma patients. These techniques allow for more reliable prediction of the biological behavior and clinical course of meningiomas and subsequently have the potential to guide individualized meningioma therapy. However, higher costs and longer duration of full molecular work-up compared with histological assessment may delay the implementation into clinical routine.This review highlights the diagnostic challenges of meningiomas from both the neuroimaging as well as the neuropathological side and presents the latest scientific achievements and studies potentially helping in overcoming these challenges. It complements the recently proposed European Association of Neuro-Oncology guidelines on treatment and diagnosis of meningiomas by integrating data on nonstandard imaging and molecular assessments most likely impacting the future.

Papillary meningioma of the jugular foramen: A case report

Papillary meningioma (PM) is a rare histological variant of intracranial meningioma, which displays an aggressive behavior and its management is difficult. The present study reported the case of a 21-year-old male patient, who presented with headaches and dizziness. Upon neurological examination, left hypoglossal nerve palsy and left cerebellar signs were observed. Computed tomography and magnetic resonance imaging scans of the brain revealed a high-density mass in the left jugular foramen area. Following an uneventful complete surgical resection of the tumor, a definitive diagnosis of Grade III PM was determined based on the histopathological findings, according to the World Health Organization classification. CT scanning one day after surgery confirmed that the tumor had been completely resected, and after four years of follow-up, no evidence of transformation or recurrence was observed.

Systematic Analysis of Outcomes for Surgical Resection and Radiotherapy in Patients with Papillary Meningioma

Introduction Papillary meningiomas (PMs) are characterized by their aggressive nature and high rate of recurrence. Due to their rarity, studies examining the relationship between treatment and clinical outcomes for this disease are limited. Gross total resection (GTR) with or without radiotherapy (RT) is considered the standard treatment; however, when GTR is not feasible, subtotal resection (STR) followed by RT may be an effective alternative. In this study, we analyzed the clinical outcomes in patients who either underwent GTR alone, GTR followed by RT, STR alone, or STR followed by RT. Methods A systematic analysis was performed to identify PM patients with sufficient follow-up and outcome data, as measured by recurrence. Patient data lacking extent of resection, follow-up, or recurrence information were excluded. Results A total of 29 patients with PM were treated with resections (23 GTRs and 6 STRs).The mean age and mean follow-up of patients in this study were 32.3 years and 42.1 months, respectively. Of these patients, 58.6% experienced recurrence. Overall, 47.8% of patients who underwent GTR experienced recurrence. These patients also demonstrated improved survival compared with STR. Among patients whose tumors were only partially excised, a recurrence rate of 83% was observed. Conclusion Our results confirm that GTR results in fewer recurrences compared with STR, supporting GTR as the treatment of choice for PM. Furthermore, GTR in conjunction with RT resulted in improved survival compared with GTR alone. When GTR was not feasible, STR with RT was associated with improved survival compared with STR alone. Future studies with more outcome data are needed to elucidate the optimal treatment for this rare disease.

Magnetic resonance imaging findings of intracranial papillary meningioma: a study on eight cases

OBJECTIVES

To increase the awareness on intracranial papillary meningiomas (PMs) by presenting magnetic resonance imaging (MRI) findings on this disease.

MATERIALS AND METHODS

The MRI findings and clinical presentations of nine discrete lesions in eight patients with pathologically documented PMs were retrospectively analyzed.

RESULTS

Most tumors occurred in young adults. The tumors originated from the convexity meninges in five cases and from the parasagittal regions in four cases. The tumor shape was irregular in six cases, lobulated in two cases, and round in one case. By MRI, nine masses were primarily isointense (n=5) or mildly hypointense (n=4) to gray matter on T1-weighted images and inhomogeneous hyperintense (n=3) or isointense (n=6) to the cortex on T2-weighted and fluid-attenuated inversion recovery images. On diffusion-weighted imaging, the signal intensity of the tumor was increased in all lesions compared with the adjacent parenchyma. Tumor and brain interfaces were unclear in seven cases, cyst formation was observed in eight tumors, scattered hemorrhage was observed in three tumors, signal voids due to vessels were visible in four cases, and eight tumors had moderate or marked irregular peritumoral edema. Enhancement was homogeneous (n=2) or heterogeneous (n=7), an area of focal nodular enhancement was observed in three lesions, and the dural tail sign was visible in seven cases.

CONCLUSION

Although PM is rare, it should be considered in the differential diagnosis when evaluating intracranial neoplasms. Younger patient age, as well as imaging features such as unclear tumor-brain interface, internal heterogeneity including cyst formation, irregular enhancement, signal voids of vessels, and marked peritumoral edema can help distinguish PM from typical benign meningiomas.

[Papillary meningioma: a very rare and aggressive variant of meningioma]

Papillary meningioma (MP) is a rare and aggressive variant of meningioma, occurring preferentially in young subjects. Histopathological features of papillary meningiomas are characterized by papillary or perivascular pseudorosette patterns. We report the case of a right frontal MP in a 16-year-old boy. Differential diagnosis included other primitive or secondary intracranial papillary neoplasms. MP diagnosis should not be missed due to its aggressive behavior with brain invasion, local recurrence and metastases.

Anaplastic meningioma with papillary, rhabdoid, and epithelial features: a case report

A 74-year-old man manifested disturbed consciousness and right hemiparesis. Computed tomography revealed a left frontal parasagittal meningeal tumor with extensive peritumoral brain edema and skull invasion. Subtotal removal was performed. Five years later, he underwent two more operations of massive recurrences. Pathological studies revealed anaplastic meningioma with two different histological areas. One was an epithelial and meningothelial area, and the other was a papillary and rhabdoid area. In the papillary and rhabdoid area, small tumor cells with a high nucleus/cytoplasm ratio proliferated densely around the dilated central capillaries with a pseudopapillary pattern. Many rhabdoid cells (vimentin ++, cytokeratin AE1/AE3 +, epithelial membrane antigen [EMA] + +) tended to be distributed far from the central capillaries. There were many mitotic figures near the central vessels. Dense MIB1-positive nuclei were also observed near the central vessels. The trabecular pattern of the tumor cells in the epithelial area was quite different from the histological features of chordoid meningioma.

Papillary (malignant) meningioma of the foramen magnum presenting as a posterior neck mass

Meningiomas and neurofibromas are the most common extramedullary tumors in the region of the foramen magnum. The clinical symptoms are variable, including headache, occipitocervical pain, and hoarseness. Neurological symptoms are present only in 40% of cases. The age group ranges from 4 to 56 years. A number of patients are misdiagnosed as multiple sclerosis, syringomyelia, and cervical disc disease. The overall incidence of these tumors vary from 1.6 to 2.4%. The majority of meningiomas are histologically benign. Papillary (malignant) meningiomas are even rarer in this location. The present report is that of a 46-year-old man who developed a painless mass in the nape of his neck, without any neurological symptoms. Following initial biopsy at another hospital, a definitive resection was undertaken at Loyola University Medical Center. The diagnosis of a malignant meningioma was made after extensive immunohistochemical and electron microscopic studies. The patient developed a positive cervical lymph node 1 year later, which was excised and showed identical histopathologic features.

Papillary meningioma with leptomeningeal seeding

A 43-year-old male presenting with headache and dizziness underwent craniotomy and gross total resection of an extraaxial tumor was achieved via left occipital interhemispheric approach. The tumor was diagnosed as papillary meningioma arising from the left falcotentorium with such pathologic characteristics of bronchoalveolar adenocarcinoma. At postoperative day 40, he developed generalized tonic clonic seizure and then progressed to a status epilepticus pattern. Brain magnetic resonance imaging showed irregular leptomeningeal enhancement with a significant peritumoral area. Through a cerebrospinal fluid (CSF) study, we identified the meningioma cells of the papillary type from the CSF. At the postoperative day 60, he fell into semicomatose state, and the computed tomography imaging showed low density on both cerebral hemispheres, except the basal ganglia and cerebellum, with overall brain swelling and an increased intracranial pressure. He died on the following day. We experienced a rare case of a papillary meningioma with leptomeningeal seeding.

Diffuse craniospinal metastases of intraventricular rhabdoid papillary meningioma with glial fibrillary acidic protein expression: a case report

Rhabdoid papillary meningioma is a recently described clinically aggressive variant of meningiomas with a high recurrence rate. Additionally, only one case of intraventricular rhabdoid meningioma has been reported so far. We present a case of a 50-year-old man who developed an intracranial tumor of the left lateral ventricle at the trigone, for which he underwent total tumor resection followed by gamma knife radiosurgery for recurrence of the tumor. The histological diagnosis was rhabdoid papillary meningioma. Five years after surgery, diffuse craniospinal leptomeningeal metastases developed and subtotal removal of the spinal tumor was performed. The spinal tumor was considered to have metastasized via cerebrospinal fluid (CSF) in view of its histological features that were identical to those of the primary tumor. Immunohistochemistry revealed the unusual cytoplasmic expression of glial fibrillary acidic protein (GFAP) of tumor cells. To our knowledge, this is the first reported case of diffuse craniospinal metastases of intraventricular rhabdoid papillary meningioma with GFAP expression and the second reported case of the rhabdoid subtype amongst intraventricular meningiomas.

Spinal drop metastases from a papillary meningioma: a case report and review of the literature: utility of CSF sampling

In this paper, we report a rare case of a 29-year-old boy who presented with papillary meningioma originating from the posterior fossa meninges. After a long, disease-free period, however, spinal drop metastases occurred 32 months after resection of the primary tumor. The primary and metastatic lesions had a similar histological appearance, meaning that multiple spinal metastatic lesions occurred through CSF route even after a gross total resection of the tumor. Tumor seeding during surgery is the evident reason for spinal metastasis, although we strictly adhered to the standard precautions for operations for malignant tumors such as obstruction of the cisterna magna with cotton paddies, and changing surgical gloves and instruments during the operation. In this report, we briefly discuss an exceedingly rare variant of meningioma, the papillary variant, and suggest a new approach, a CSF sampling, in the management of both malignant and benign meningiomas. CSF sampling allows for the early detection of metastasis and of tumor cells before metastasis has occurred, thus allowing treatment to begin as soon as possible. This early detection and management is possibly associated with longer survival. Furthermore, we discussed that meningiomas are tumors that are not as benign as initially thought.

Boron neutron capture therapy for recurrent malignant meningioma. Case report

Malignant meningioma is a rare brain tumor with a high risk of recurrence. If this tumor recurs after complete resection and adjuvant radiotherapy, there is no optimal treatment to control it. The authors report the first case of recurrent malignant meningioma treated using boron neutron capture therapy (BNCT). This 25-year-old pregnant woman presented with a large frontal tumor. After her baby was born, she underwent gross-total resection of the tumor. A second resection and three Gamma Knife surgeries could not control progression of the enhancing mass; therefore, the authors applied BNCT based on their experience with it in the treatment of malignant gliomas. The minimum tumor dose and maximum brain tissue dose were estimated as 39.7 Gy-Eq and less than 9.0 Gy-Eq, respectively. Before BNCT the patient was mobile by wheelchair only, whereas 1 week after therapy she was able to walk. Twenty-two weeks later she underwent a second BNCT for tumor regrowth on the contralateral side, and the lesion was subsequently reduced. The tumor volume was markedly decreased from 65.6 cm3 at the time of the first BNCT to 31.8 cm3 at 26 weeks thereafter. The treatment of recurrent malignant meningioma is difficult and has been discouraging thus far. Data in the present case indicate that BNCT may be a promising treatment option for this challenging tumor.

Papillary meningioma: a rare but distinct variant of malignant meningioma

Background

Papillary meningiomas are rare meningeal tumors and are associated with aggressive clinical behavior as compared with other meningiomas. Because of their rare occurrence, they may pose a diagnostic dilemma to the unwary pathologist. We report a case of papillary meningioma in a 16-year-old boy.

Case Presentation

A 16-year-old boy presented with complaints of headache, progressively diminishing vision and more recently generalized seizures. MRI revealed a large bifrontal meningioma which showed presence of a predominantly papillary pattern with areas of focal necrosis, frequent mitoses and bone invasion. He underwent radical excision of the tumor and is free from recurrence or metastasis at 15 months follow-up.

Conclusion

Papillary meningiomas are rare but well recognized variants of meningioma. They need to be differentiated from other intracranial tumors with a papillary pattern. They are malignant, frequently show bone and parenchymatous invasion and have the potential for extracranial metastasis. Their timely recognition could prevent local and distant metastasis and the mortality or morbidity associated with it.

Histological classification and molecular genetics of meningiomas

Meningiomas account for up to 30% of all primary intracranial tumours. They are histologically classified according to the World Health Organization (WHO) classification of tumours of the nervous system. Most meningiomas are benign lesions of WHO grade I, whereas some meningioma variants correspond with WHO grades II and III and are associated with a higher risk of recurrence and shorter survival times. Mutations in the NF2 gene and loss of chromosome 22q are the most common genetic alterations associated with the initiation of meningiomas. With increase in tumour grade, additional progression-associated molecular aberrations can be found; however, most of the relevant genes are yet to be identified. High-throughput techniques of global genome and transcriptome analyses and new meningioma models provide increasing insight into meningioma biology and will help to identify common pathogenic pathways that may be targeted by new therapeutic approaches.

The challenges of revision skull base surgery

Because the skull base is an anatomically complex structure, skull base tumors can hide easily in the crevices that interconnect the intra- and extracranial spaces and intermingle with important neurovascular structures. Often, total surgical resection of these tumors is not possible, and even with postoperative adjuvant radiotherapy, some recurrences after treatment are inevitable. Early detection of recurrent skull base tumors requires clinical vigilance and periodic imaging studies. The management of recurrent skull base tumors presents many challenges beyond those associated with primary procedures. A multidisciplinary setting that includes modern microsurgery and stereotactic radiation therapy provides patients with optimal care.

Psammomatous choroid plexus papilloma

BACKGROUND

Intravertricular papillary neoplasms are derived from choroid plexus epithelium. Although choroid plexus tumors account for 0.4% to 0.6% of all brain tumors, they represent 2% to 4%. Approximately 80% of choroid plexus carcinomas arise in children.

CASES DESCRIPTION

We describe 3 cases of choroid plexus papilloma (CPP) with profuse psammomatous bodies and calcifications that have lost their normal papillary architecture. Immunohistochemistry was positive for glial fibrillary acidic protein in 2 cases, and proliferating cellular nuclear antigen index was higher compared with regular CPPs. All 3 patients were female and were 12, 40, and 48 years old, respectively.

CONCLUSION

We describe psammomatous CPPs and suggest a difference from CPPs because of the more aggressive clinical course, and higher nuclear proliferation index (proliferating cellular nuclear antigen) than the CPPs that lack psammoma bodies.

An atypical spinal meningioma with CSF metastasis: fatal progression despite aggressive treatment. Case report

The authors report the case of a 23-year-old man who presented with a C1-3 spinal mass. Following intraspinal decompression the tumor was histologically classified as an atypical meningioma (World Health Organization grade II). Two further surgical interventions resulted in almost total removal of the meningioma. In addition, radiotherapy was performed. During the 1.5-year follow-up period the diagnostic examinations identified a local tumor recurrence, an intraspinal C-6 metastasis, and a segmental instability with anterior C2-3 slippage and C3-4 kyphosis. The tumor was resected and occipitocervical stabilization was performed. Histological examination showed no change in malignancy. Despite additional hydroxyurea-based chemotherapy, the patient presented 4 months later with a hemiparesis and a massive recurrence of the tumor mass involving the posterior fossa and the upper thoracic spine. Because there were no further therapeutical options, the patient died. The authors discuss more aggressive therapeutic options in addition to surgery in patients with metastatic atypical meningiomas. The results in the reported case indicate that meningiomas associated with cerebrospinal fluid metastasis may represent a higher grade of malignancy.

Meningiomas of the jugular foramen

Primary meningiomas of the jugular foramen are extremely rare. There is controversy regarding the management of these tumors. The objective of this article is to analyze the treatment and results in a series of ten cases. From a series of 107 patients that had been operated on for jugular foramen tumors between 1987 and 2005, ten had meningiomas. The clinical, histological and imaging findings, as well as the outcome of these cases, were reviewed. A high incidence of malignant or aggressive tumors (six cases) was found. Gross total resection (Simpson I and II) was achieved in five patients. Four patients with meningotheliomatous meningiomas are alive, with a mean follow-up time of 71.8 months (6.5 years). Two patients (one with anaplastic type and one with papillary type) died in the immediate postoperative period. Four patients (two with papillary type, one with microcystic type and one with anaplastic type) died because of disease progression, with a mean survival time of 35 months. Radical removal of benign jugular foramen meningiomas is possible. The incidence of postoperative deficit of cranial nerves is higher than in other benign tumors of the jugular foramen. A high incidence of aggressive (malignant) tumors was observed in this series.

Jugular foramen papillary meningioma: A case report

Jugular foramen meningioma is very rare. Papillary meningioma, the histological aspects and clinical behavior of which are highly malignant, is also very rare. Only 55 cases of jugular foramen meningioma have been reported in the literature. To our knowledge, this is the first report of a jugular foramen papillary meningioma. A 25-year-old woman presented with hoarseness and right hearing disturbance. Neurological examination showed deficits of the right hypoglossal and vagus nerves with palsy. Magnetic resonance imaging (MRI) revealed a mass on the right jugular foramen extending intracranially and extracranially, with weak contrast enhancement. The intracranial tumor was removed via the right lateral suboccipital approach. Histopathological examination confirmed the diagnosis of papillary meningioma. We report here the first case of jugular foramen papillary meningioma. No completely effective treatment for papillary meningiomas exists at present, with the exception of surgery.

Recurrent Meningioma With Metastasis to the Skin Incision-Case Report-

A 70-year-old woman presented with meningioma with metastasis to the skin incision. Neuroimaging demonstrated a tumor of the falx extending to the frontal bone. The tumor was grossly totally resected through a coronal skin incision. The histological diagnosis was meningotheliomatous meningioma. The tumor recurred in the ethmoid sinus 2 years later, and was resected through the transfacial approach. One year later, the tumor recurred in the ethmoid sinus and orbit, and was resected through the transcranial approach. Six months later, she noticed an isolated small mass under the skin incision, distant from a further recurrence of the tumor. Both tumors were resected. The histological diagnosis was atypical meningioma. Resection of atypical meningioma carries the risk of iatrogenic metastasis. Surgeons should wash out the operative field carefully and change surgical tools frequently.

Ultrastructural examination is essential for diagnosis of papillary meningioma

AIMS

Papillary meningioma is a rare meningeal tumour. To date only a few cases have been reported and their immunohistochemical features have not been fully documented.

METHODS AND RESULTS

A 49-year-old woman presented with a 2-month history of headaches and memory disturbance. CT and MRI imaging showed an enhancing pineal mass with extension into the occipital lobes and invasion of the splenium. At surgery, the tumour was found to be tough and vascular with a well-defined capsule. No recurrence was noted 19 months after the operation. In another case a 44-year-old woman was admitted with 1-month history of headaches, poor memory, imbalance and diplopia. CT scan showed a large hyperdense, uniformly, enhancing mass within the middle cranial fossa at the petrous ridge. The tumour recurred 19 and 25 months after first resection. The histology of both tumours was similar. The neoplasms contained polygonal cells with a moderate amount of cytoplasm, rounded regular nuclei and distinct cell borders. The cells were arranged radially around the blood vessels (perivascular pattern) and a papillary pattern was seen only focally. Mitotic figures were moderately frequent. Immunohistochemistry showed that both tumours were immunoreactive to vimentin and NSE, whereas GFAP, CAM5.2, EMA, S100 protein and synaptophysin were negative. Electron microscopy revealed interdigitating cell processes, desmosomes and intermediate filaments.

CONCLUSIONS

The histological and immunohistochemical features of these two tumours are complex and difficult to interpret. Although papillary meningiomas were considered in our initial differential diagnosis, the final conclusion was possible only when the ultrastructural features were revealed.

Prognostic significance of p53 and p21WAF1/CIP1 immunoreactivity and tumor micronecrosis for recurrence of meningiomas

Recurrence is an important factor for prognosis of meningioma patients, this also occurring with some lesions diagnosed histopathologically as benign. To analyze their relationships with clinicopathological factors, p53 and p21WAF1/CIP1 immunoreactivity, 80 meningiomas were classified into four groups with regard to the World Health Organization (WHO) histological classification and recurrence: 40 cases of Group I (typical type)-NR (no recurrence); five cases of Group I-R (recurrence); 20 cases of Group II (atypical or anaplastic type)-NR and 15 cases of Group II-R. Micronecrosis was detected in 25% of Group II-NR and 73.3% of Group II-R (P = 0.007, odds ratio (OR) = 8.25, 95% confidence interval (CI) = 1.79-38.01). Patients receiving radiation therapy had a lower risk of recurrence (P = 0.041, OR = 0.20, 95% CI = 0.05-0.85). Immunoreactivity for p53 protein was positive in 22% of Group I and 54% or Group II (P = 0.005), and in 80% of Group I-R and 15% of Group I-NR (P = 0.006, OR = 22.7, 95% CI = 2.15-239.4). p21WAF1/CIP1 protein was detected in 22% of Group I and 48% of Group II (P = 0.017), but with no link to recurrence. Multivariate analysis also showed p53 immunoreactivity in Group I (benign lesions) and micronecrosis in Group II (atypical/anaplastic meningiomas) to be strong prognostic factors for recurrence (P < 0.05). These results indicate that p53 immunoreactivity and micronecrosis can help predicting recurrence of meningiomas.

Papillary meningioma in the dog: a clinicopathological study of two cases

Two cases of canine papillary meningioma are reported. The first animal, an 11-year-old male Boxer, presented with vestibular ataxia and the tumour was located in the left pontomedullary region. The second animal, a 15-year-old female cross-bred Miniature Poodle, presented with dementia, truncal ataxia and hypermetria, and the tumour was located in the right semilunar ganglion of Gasser. In the first case, histopathological examination showed that the papillary pattern merged with a typical syncytial meningioma, with extensive areas of necrosis. In the second case, the multilobular tumour had lobules with a purely syncytial, fibrous or transitional histological pattern, and lobules with intermingling papillary and secretory histological patterns. Both tumours exhibited histological features of malignancy, but evidence of remote metastasis was not found.

Papillary meningioma in the cerebellum of a cat

An unusual papillary meningioma in a cat with progressive cerebellar ataxia is described. Computed tomography revealed the presence of a primary tumour. Microscopically, the tumour was seen to arise from the cerebellar pia mater, forming perivascular structures composed of a single layer of cuboidal to columnar epithelial cells. By immunolabelling, the neoplastic cells appeared positive for cytokeratin, vimentin and S-100 protein. Ultrastructural examination, together with the immunocytochemical findings, indicated the mesenchymal and epithelial nature of the tumour.

Prognostic value of proliferation index and expression of the RNA component of human telomerase (hTR) in papillary meningiomas

Papillary meningioma is a rare subtype of meningioma that often behaves aggressively. In order to characterize factors that may influence this behavior, we chose to compare MIB-1 labeling index (LI) and telomerase RNA localization (hTR) in papillary meningiomas, meningiomas, and atypical meningiomas. LI is now often used to supplement histologic grade in the evaluation of these lesions. More recent studies indicate that increased expression of hTR is detected in many neoplastic cells, and may play an essential role in cell immortalization. The study group consisted of five papillary meningiomas (and a recurrence in one case), 11 conventional meningiomas, and eight atypical meningiomas. Conventional meningiomas showed either negative or 1 + hTR. Atypical meningiomas showed 1 + hTR. Papillary meningiomas showed the highest hTR (five of six, including recurrence, 2-3+ and one 1+). Generally, the LI was very low for conventional meningiomas (< 2%). The LI of atypical meningiomas ranged from 3-19%, mean 12%, and from 5.5-17.5%, mean 11.75% for papillary meningiomas. LI differentiated between meningiomas, and papillary or atypical meningiomas. hTR further delineated papillary (moderate to high) from atypical meningiomas (low). The combined variable of LI and hTR expression could be a useful independent prognostic indicator in patients with papillary meningioma.

Intracranial meningeal tumours in childhood: a clinicopathologic study including MIB-1 immunohistochemistry

Primary tumours of the meninges with a relatively high tendency for malignant behaviour are uncommon in childhood. This study concerns 18 cases of meningeal tumours in children under the age of 16, of which 13 were meningiomas and five were other tumours arising in the meninges. Meningiomas showed a preponderance in females as in adult series, and the majority were supratentorial in localisation. The percentage of meningeal tumours and meningiomas among all brain tumours in our centre were 3.72% and 2.69%, respectively. Four out of 13 meningiomas were fibroblastic, four were transitional, one was meningothelial, two were psammomatous and two were papillary meningiomas. Seven (38.8%) out of 18 tumours showed anaplastic features, including two papillary meningiomas, two hemangiopericytomas, one mesenchymal chondrosarcoma, one pleomorphic sarcoma and one anaplastic meningeal tumour. Papillary meningiomas with hemangiopericytoma-like solid areas were seen frequently in our cases (15.3%). Meningoangiomatosis was associated with two meningeal tumours. MIB1 (Ki-67) labelling indices (LIs) ranged between 0% and 13.6% (mean 1.83%) in benign, and between 1% and 20% (mean 7.2%) in malignant tumour, including papillary meningiomas. Mean MIB-1 LIs were 5.61% and 1.14% in non-recurrent and recurrent cases, respectively. MIB-1 LIs showed significant differences between benign and malignant meningeal tumours but no significant correlation either with prognosis or recurrence. Despite the fact that brain tumours are among the most common neoplasms of childhood, meningeal tumours are rare lesions, accounting for less than 2% of published series of intracranial neoplasms in childhood [5, 8, 18, 24, 30, 32]. It has been suggested that the clinical and pathological characteristics of meningiomas in this age group differ from those of adults [14, 18, 24, 45]. Besides meningiomas, there are a few reports of other meningeal tumours in childhood and difficulties in differential diagnosis may arise within this group, especially in anaplastic tumours [11, 13, 32, 44, 46]. One of the major problems in meningiomas and some tumours arising in the meninges is the discordance that arises between the histologic appearance of the tumour and behaviour [4]. Several studies have attempted to determine the proliferation potential of meningiomas, including immunohistochemical labelling with monoclonal antibodies to Ki-67, proliferating cell nuclear antigen (PCNA), and bromodeoxyuridine (BUdR); flow cytometric DNA analysis; or argyrophilic nucleolar organizer regions (AgNORs) counting [9, 10, 15, 19, 22, 26, 31, 35, 53]. The studies concerning proliferation markers have contradictory results [9, 10, 15, 26, 31, 42, 53]. MIB-1 detects the same or a similar epitope as the original antibody Ki-67 and reacts with a proliferation associated antigen expressed in all active parts of the cell cycle, G1, S, G2 and M (mitosis), but not in the G0 or quiescent phases [7]. In this study we examined the clinicopathological characteristics and MIB1 values of 18 meningeal tumours in children under the age of 16 years within the last 25 years (from 1970 to 1995).

Meningioma metastatic to the lung

Meningiomas constitute 15% to 18% of all primary intracranial and intraspinal tumors. Distant extracranial metastases are reported to occur in fewer than 1 in 1000 cases. Of 1992 primary intracranial meningiomas seen at Mayo Clinic Rochester from 1972 through 1994, we identified 3 (0.15%) with documented extracranial metastasis. A review of the literature suggests that previous craniotomy, venous sinus invasion, local recurrences, histological malignancy, and papillary morphology may be risk factors for systemic spread, as demonstrated in our cases. Although rare, metastatic meningioma should be considered in the differential diagnosis of abnormal findings on chest radiography in patients with known or suspected intracranial meningioma.

Cerebellar papillary meningioma in a 3-year-old boy: the usefulness of electron microscopy for diagnosis

We report one case of papillary meningioma located in the posterior fossa in a 3-year-old boy. Despite a gross total resection, a major recurrence occurred 6 months later that was operated on. Eight months later, another recurrence was observed with intracranial metastases and dissemination throughout the cerebrospinal fluid. The tumor had a papillary architecture more obvious in the recurrence. Areas of necrosis were numerous. Tumor cells had large clear atypical nuclei. Many mitotic figures were seen and Ki-67 labeling index was high. The tumor cells were immunoreactive for vimentin and polysialylated neural cell adhesion molecule only, ruling out a diagnosis of ependymoma or medulloblastoma. Diagnosis of meningioma was done by electron microscopy, which showed interdigitating cytoplasmic processes and cell junctions. Cytogenetic study revealed unusual karyotypic abnormalities.

Extracranial metastatic meningioma

Meningiomas rarely metastasize outside the intracranial compartment. We report a case of disseminated metastases from a recurrent intracranial meningioma and review the imaging and pathological literature on metastatic meningioma.

"Malignancy" in meningiomas: a clinicopathologic study of 116 patients, with grading implications

BACKGROUND

Due to the rarity of malignancy in meningiomas, prior studies have been limited to small series. Controversies regarding the definition of malignant meningioma have complicated matters further. Although histologic anaplasia and extracranial metastasis are established criteria, the former is difficult to define and the latter represents a clinical finding. Traditionally, brain invasion has also been accepted, although this has recently been debated. In a prior series, the authors were unable to prove that 23 meningiomas that had invaded the brain were more aggressive than atypical meningiomas.

METHODS

The authors expanded their analysis to include 116 patients diagnosed with "malignant meningioma" due to brain invasion, frank anaplasia (20 mitoses per 10 high-power fields or histology resembling carcinoma, sarcoma, or melanoma), and/or extracranial metastasis. Patients were followed until death or for a median of 3.7 years.

RESULTS

Survival time was highly variable, ranging from 10 days to 24 years. In multivariate analysis, histologic anaplasia (P=0.0035), subtotal resection (P=0.0038), 20 mitoses per 10 high-power fields (P=0.0071), and nuclear atypia (P=0.0068) were associated with poor survival. Of the 89 cases of meningioma that had invaded the brain, 23% were otherwise benign, 61% were otherwise atypical, and 17% were frankly anaplastic. Those without anaplasia behaved similarly to atypical meningiomas from the authors' prior study. In contrast, anaplastic meningiomas were usually fatal, associated with a median survival of 1.5 years.

CONCLUSIONS

Based on these findings, the authors suggest that brain invasion constitutes an additional criterion for the diagnosis of atypical meningioma (World Health Organization [WHO] Grade II), whereas frank anaplasia indicates high grade (WHO Grade III-IV) malignancy.

"Rhabdoid" meningioma: an aggressive variant

It is has been suggested that rhabdoid morphology is associated with a poor prognosis, regardless of tumor histogenesis. We report a series of 15 meningiomas with rhabdoid features. Nine patients had undergone multiple resections. In six, the rhabdoid component was histologically apparent only in recurrences. Rhabdoid morphology was defined as sheets of loosely cohesive cells with eccentric nuclei and hyaline, paranuclear inclusions. Ultrastructurally, the latter consisted of whorls of intermediate filaments often entrapping lysosomes or other organelles. Meningothelial features included whorl formation and nuclear pseudoinclusions, immunohistochemical coexpression of vimentin and epithelial membrane antigen, and the ultrastructural finding of interdigitating cell membranes and intercellular junctions. At the histologic level, a conventional meningioma component was noted in most tumors; only four lesions were entirely rhabdoid. Histologic malignancy (brain invasion or anaplasia) was observed in nine cases, another two tumors being considered malignant on the basis of extracranial metastasis. In the majority, increased cell proliferation was evidenced by a high mitotic rate or MIB-1 LI. At last follow-up, 13 patients (87%) had experienced at least one recurrence and 8 (53%) were dead of disease. Median time to death was 5.8 years after initial surgery and 3.1 years after the first appearance of rhabdoid morphology. Our findings corroborate those from a smaller series recently reported by Kepes et al. on the same entity (Kepes JJ, Moral LA, Wilkinson SB, Abdullah A, Llena JF. Rhabdoid transformation of tumor cells in meningiomas: A histologic indication of increased proliferative activity. Report of four cases. Am J Surg Pathol 1998;22:231-8). They further suggest that rhabdoid meningiomas are highly aggressive tumors and that the rhabdoid phenotype represents a marker of malignant transformation in meningiomas.

Primarily resected meningiomas: outcome and prognostic factors in 581 Mayo Clinic patients, 1978 through 1988

OBJECTIVE

To establish prognostic factors for recurrence and outcome of surgical treatment, with or without postoperative radiation therapy, in patients with meningiomas.

MATERIAL AND METHODS

From 1978 through 1988, 581 patients underwent initial resection of a previously untreated primary meningioma at Mayo Clinic Rochester. In this study cohort, the outcome and prognostic factors associated with radiographic progression-free survival were analyzed.

RESULTS

Gross total resection (GTR) of the meningioma was accomplished in 80% of patients; the other 20% underwent less than GTR. Perioperative mortality within 10 days was 1.6%. Overall survival was significantly decreased from that for an age- and sex-matched cohort from the US white population. Progression-free survival at 5 and 10 years was 88% and 75%, respectively, in patients who underwent GTR and 61% and 39%, respectively, in those who underwent less than GTR. Multivariate analysis showed that age younger than 40 years, male sex, less than GTR, optic nerve involvement, and 4 or more mitotic figures per 10 high-power fields were associated with decreased progression-free survival. The 581 patients had 106 first recurrences. A trend toward improved progression-free survival was noted after first recurrence when irradiation with or without operation was used in comparison with only surgical treatment (P = 0.058).

CONCLUSION

With only operative treatment of meningioma, the 10-year recurrence rate was 25% in patients who had GTR and 61% in those who had less than GTR. These results emphasize the need for long-term follow-up and for consideration of adjuvant radiation therapy. Patients treated at the time of recurrence seem to benefit from radiation therapy with or without surgical resection. Factors associated with recurrence were (1) less than GTR, (2) involvement of the anterior visual pathway, (3) age younger than 40 years, and (4) increased mitotic index.

Proliferation and DNA fragmentation in meningioma subtypes

Atypical meningioma has been introduced as tumour subtype of intermediate biological behaviour between classical and malignant meningiomas. To substantiate this three-step scale of malignancy, we assessed the proliferative activity reflected by Ki-67 (MIB1) labelling index (LI) in a series of 89 meningiomas, including 15 classical, 29 atypical, 35 anaplastic tumours, and 10 haemangiopericytomas and papillary meningiomas. The possible correlation of proliferation with the frequency of apoptosis and their relations to BCL-2 immunoexpression was investigated in seven classical, 10 atypical and 10 malignant meningiomas. Apoptosis was demonstrated by evaluation of the frequency of apoptotic figures, by the enzymatic technique of in situ tailing (IST) which stains apoptotic DNA fragments, and by DNA preparation and gel electrophoresis demonstrating DNA laddering in frozen tissues of five meningiomas. MIB1 LI revealed a highly significant increase from classical through atypical to anaplastic meningiomas (P < 0.0001); haemangiopericytomas and papillary meningiomas were well within the range of atypical meningiomas. IST indices rose with increasing malignancy and correlated with MIB1 LI (P < 0.0001): they showed a weak inverse correlation with BCL-2 immunoexpression (P = 0.05). BCL-2 expression tended to decrease with malignancy grade and was unrelated to MIB1 LI or frequency of apoptosis. Our data show that (i) apoptosis is a feature of meningiomas, significantly correlated with the malignancy scale. (ii) DNA fragmentation shows significant correlation with proliferation and inversely with BCL-2 expression; (iii) proliferation indices and frequencies of apoptosis/DNA fragmentation within meningioma subgroups corroborate the intermediate biological position of the atypical meningioma between classical and malignant meningiomas.

[Meningiomas. Epidemiological and anatomopathological study of 340 cases]

The authors have retrospectively reviewed all tumors of central nervous system (CNS) operated at the most important neurosurgery hospitals of Curitiba in a 5-year period (1990-1994) and found 304 (22.4%) cases of meningioma. Age mean of the patients was 48.5 years, with a range of 3 to 90 years. A marked female preponderance (68.7%) was noted. The most common tumor location was brain (n = 280) and the remaining cases occurred in spinal cord (n = 10), cerebellum (n = 9) and cranial nerves (n = 5). Histologically, there were 294 (96.7%) meningiomas of the classical type, six malignant or anaplastic, three atypical and one papillary. Two hundred and sixty seven classical meningiomas were from the meningotelial subtype, ten psamomatousos, five fibroblastic, five microcystic, five transicional and two angiomatous. The authors conclude that meningiomas are one of the most common group of primary neoplasias of CNS and the definition of malignancy in those tumors is beset by frequent discordance between histologic and biologic features.

Cytogenetic analysis of aggressive meningiomas: possible diagnostic and prognostic implications

BACKGROUND

Published karyotypes from aggressive (atypical and malignant) meningiomas are few, but suggest clonal evolution from benign tumors with monosomy 22 to aggressive forms with additional abnormalities. The goal of this study was to identify the most frequent karyotypic abnormalities associated with aggressive histopathology and biologic behavior.

METHODS

Eight intracranial meningiomas exhibiting histologically atypical features at the time of intraoperative diagnosis were chosen for cytogenetic analysis. The study set was comprised entirely of histologically atypical meningiomas. Four were considered malignant; three on the basis of brain invasion and one due to extracranial metastases. None was histologically anaplastic.

RESULTS

Chromosomal abnormalities were demonstrated in 6 cases (75%), 5 of which were complex (63%). Loss of chromosome 22 was identified in two cases, both of which were associated with additional aberrations. Abnormalities most frequently involved chromosomes 1 (63%), 3 (50%), and 6 (63%). Four cases (50%) had dicentric or ring chromosomes. An additional 47 previously reported karyotypes from atypical and malignant meningiomas were reviewed. Comparison with published karyotypes of 200 histologically benign meningiomas served to underscore the increased frequency of complex karyotypes, chromosome 1, 3, and 6 abnormalities, and telomeric associations in the aggressive tumors. Apparently normal karyotypes as well as monosomy 22 alone were more frequently associated with benign, nonatypical histopathology.

CONCLUSIONS

These findings suggest a possible role for cytogenetic analysis in determining the prognosis and perhaps in refining the diagnosis of atypical or aggressive meningiomas. Further studies are necessary to determine the significance of complex karyotypes, chromosome 1, 3, and 6 abnormalities, and telomeric associations, particularly whether they portend a more aggressive clinical course in meningiomas lacking features of histologic atypia.

Management of posterior cranial fossa meningiomas

Posterior cranial fossa meningiomas are relatively common extra-axial tumors with important relationships to the cochleovestibular system, facial nerve, and/or cranial base. Nevertheless, objective reporting of auditory and vestibular function is rare for this patient population, and a full discussion of the nonsurgical management is all but totally discounted in the otolaryngology literature. Nine cases (8 operative cases) are presented, with the purpose of correlating neurotologic function with precise anatomic tumor location, available by magnetic resonance imaging and computed tomography. The usefulness of this information for diagnosis and meaningful scrutiny of the operative results is discussed. A comprehensive review of posterior fossa meningiomas in terms of epidemiology, etiology, and pathology, as well as nonsurgical treatment alternatives, is provided.

Intracranial meningiomas of the first two decades of life

Meningiomas arising in the first two decades of life are uncommon and their characteristics are controversial. Some authors believe meningiomas in younger patients occur in different locations, have more malignant histological features, and have a worse prognosis than those in adults. To address this controversy, the authors retrospectively reviewed 23 cases of meningiomas in patients under 21 years of age at diagnosis who were operated on at the University of Turin (1948 to 1990) or at the University of California, San Francisco (1970 to 1989). These tumors represented 2.9% of all tumors in this age group and 1.8% of all meningiomas during the study period at the two institutions. There were 14 males and nine females. The mean age at surgery was 13.3 +/- 5.6 years; nine cases occurred in the first decade and 14 in the second. The most common neurological symptoms were a focal neurological deficit (33%) and seizures (25%). Seventy percent of the tumors were supratentorial. A gross total resection was performed in 60% of the cases. Histologically, the majority (74%) of the tumors were meningothelial or mixed. An increased number of mitoses was observed in 33% of the tumors, focal necrosis in 29%, and invasion of adjacent brain in 14%; however, none of the tumors was classified as a Grade III (anaplastic) meningioma. All patients are alive without evidence of recurrent disease 3 to 22 years (mean +/- standard deviation: 10 +/- 7.3 years) after surgery. This study confirms the rarity of meningiomas of the first two decades of life and the absence of the female predominance associated with meningiomas in adults. The location and histological features of these tumors are similar to those in adults; they have a low recurrence rate, and the outcome and survival rate are excellent.

Meningiomas of the cranial base

Treatment objectives for meningiomas of the cranial base include relief of neurologic disability and prevention of clinical progression or recurrence with the least morbidity. Recent advances in skull base surgical techniques, through an appreciation of skull base anatomy and institutional specialization, have contributed major improvements to the outlook for patients with these tumors, and previously inoperable cases may now often be removed completely with acceptable risk. Since significant morbidity may be incurred during surgical resection of these difficult lesions, especially in terms of cranial nerve dysfunction, the value of aggressive surgical resection must be weighted against the often indolent natural history of these lesions, and must be individualized in each patient. Completeness of resection is the major prognostic factor determining the outcome of patients with typical benign meningiomas in terms of length of survival, risk of recurrence, and neurological disability. Various means of prognosticating the growth potential of a given tumor are being investigated, though none have yet been confirmed for their predictive value in typical, histologically benign meningiomas. The role of external beam radiotherapy has not been subjected to adequately controlled, prospective studies, and there is currently insufficient followup to assess the risks and benefits of stereotactic radiosurgery. Advances in the clinical management of tumors of the skull base has had perhaps the greatest impact for patients with meningiomas who constitute a large portion of tumors seen in these locations. Although the majority have benign histological features, skull base meningiomas can present a formidable challenge due to their proximity to vital structures, surgical inaccessibility, and occasional aggressive features. The combination in recent years of advances in skull base surgical techniques, adjuvant therapy, and rehabilitation methods have dramatically improved the outcome for these tumors.