Gangliogliomas: experience with 34 patients and review of the literature

Diagnosis and Therapeutic Management of Ventricular Gangliogliomas: An Illustrated Review

BACKGROUND

Gangliogliomas (GGs) are extremely rare benign neoplasms frequently located within the temporal lobe that usually present with seizures. GGs growing predominantly within the ventricular system (VGGs) are even more infrequent, so definite conclusions concerning their diagnosis and therapeutic management are lacking.

METHODS

A retrospective review of case reports of VGGs was performed from the introduction of modern imaging techniques, including 4 new illustrative cases treated in our department.

RESULTS

Thirty-four cases were collected. Ages ranged from 10 to 71 years (mean, 26.62 years), and 55.9% were male. Most patients developed symptoms related to high intracranial pressure. The lateral ventricles were predominantly involved (58.8%). Obstructive hydrocephalus was observed in 54.5% of patients. Cystic degeneration and calcification were frequently observed. Surgical treatment was carried out in all cases. Morbidity and mortality were 17.6% and 2.9%, respectively. Gross total tumor resection was achieved in 64.5% of patients. Four patients experienced tumor dissemination along the neural axis. More than 90% of patients maintained a good functional status at last follow-up.

CONCLUSIONS

Despite their low incidence, a diagnosis of VGGs should be considered in young male adults who progressively develop intracranial hypertension, caused by a ventricular mass showing signs of cystic degeneration and calcification. Maximal and safe surgical resection represents the gold standard for the treatment of symptomatic VGGs, although total removal is frequently precluded by difficulties in defining appropriate tumor boundaries. Adjuvant radiotherapy should be considered if an incomplete resection was carried out, especially in World Health Organization grade III neoplasms.

Giant Cerebellar Ganglioglioma Mimicking a Pilocytic Astrocytoma

A benign brain tumor, called a ganglioglioma (GG), can sometimes be found in the cerebrum. We describe an unusual pediatric case of GG in the cerebellum in this article. An 11-year-old male patient had a headache and epilepsy disorder. The head magnetic resonance imaging results revealed a giant cyst with an enhancing mural nodule in the right cerebellar hemisphere that flattened the fourth ventricle. Pilocytic astrocytoma was the provisional diagnosis based on clinical and imaging details. After radical mass eradication, a GG was demonstrated through histopathological analysis. Even though GG is an uncommon tumor, it should be included in the differential diagnosis for a cerebellar mass with both cystic and solid components in children.

Glioneuronal tumors: clinicopathological findings and treatment options

Glioneuronal tumors are very rare CNS neoplasms that demonstrate neuronal differentiation, composed of mixed glial and neuronal cells. The majority of these lesions are low grade and their correct classification is crucial in order to avoid misidentification as ‘ordinary’ gliomas and prevent inappropriate aggressive treatment; nevertheless, precise diagnosis is a challenge due to phenotypic overlap across different histologic subtype. Surgery is the standard of therapeutic approach; literature concerning the benefit of adjuvant treatments is inconclusive and a globally accepted treatment of recurrence does not exist. Targetable mutations in the genes BRAF and FGFR1/2 are recurrently found in these tumors and could take a promising role in future treatment management.

Glioneuronal Tumor With Features of Ganglioglioma and Neurocytoma Arising in the Fourth Ventricle: A Report of 2 Unusual Cases and a Review of Infratentorial Gangliogliomas

Infratentorial glioneuronal neoplasms are overall quite rare and are more commonly low-grade with surgical excision usually being curative. Multiple distinct histologic entities have been described including rosette-forming glioneuronal tumor, papillary glioneuronal tumor, neurocytoma, dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease), cerebellar liponeurocytoma, and ganglioglioma. While each of these entities has distinct findings, in some instances a tumor may demonstrate overlapping histologic features with mixed components. Herein, we report 2 unusual adult cases of a fourth ventricular glioneuronal tumor with features of ganglioglioma and neurocytoma, with one coming from a surgical resection and one found incidentally at autopsy. To the best of our knowledge, this specific histologic combination has not previously been described. As such, the clinical significance is unknown although in both cases the neoplasms were circumscribed and appeared to be low grade. The presence of the gangliogliomatous component was of particular interest since these are extremely rare occurrences in the fourth ventricle and we provide a comprehensive review of infratentorial gangliogliomas.

Ganglioglioma Progression to Combined Anaplastic Ganglioglioma and Anaplastic Pleomorphic Xanthoastrocytoma. Case Report and Literature Review

BACKGROUND

Composite ganglioma and pleomorphic xanthoastrocytoma with anaplastic features in both components is an extremely rare glioneuronal tumor. Five cases of anaplastic progression in the glioma component have been reported. These tumors generally affect young patients who have brain tumor-related epilepsy, which are usually located in the temporal lobe or in the cerebellum and may have associated leptomeningeal spreading. Its current optimal treatment consists of maximal safe surgical resection and adjuvant chemoradiotherapy. Overall survival at 5 years is 33% in anaplastic pleomorphic xanthoastrocytoma and 53% in anaplastic ganglioglioma.

CASE DESCRIPTION

We describe a progression from ganglioglioma to this composite anaplastic entity after 32 months of follow-up, with apparently nontumoral parenchyma separating the 2 components. Polymerase chain reaction showed a wild-type BRAF gene. Seven months after concomitant chemoradiotherapy, radiologic progression led to a second line of chemotherapy, and a third line of chemotherapy was initiated after a subsequent progression at 11 months.

CONCLUSIONS

This case may add some evidence in favor of the glioneuronal maldevelopment hypothesis to explain the oncogenesis of these neuroepithelial tumors.

[MRI-characteristics of epileptogenic supratentorial brain tumors in children]

OBJECTIVE

To analyze MR-images in patients with symptomatic epilepsy associated with the brain tumor.

MATERIAL AND METHODS

MRI results of 52 patients with symptomatic epilepsy operated for tumors of supratentorial localization were analyzed. The most epileptogenic tumors with atypical MRI signs and subtle clinical presentation were identified. All patients with tumors were operated using different methods of surgical intervention.

RESULTS

Dysembryoplastic neuroepithelial tumors (DNET), diffuse astrocytomas (DA) and gangliogliomas (GG) were the most frequent epileptogenic tumors. In all the cases of DNET and in 4 patients with GG, epileptic seizures were the first, and in 4 of 5 cases of DIO were the only clinical sign of tumor presence. In DNET, DA and GG, there was an iso- or hypointensive signal on T1 WI and a signal varying in intensity from moderate to hyperintense in T2 and FLAIR WI, while in cases with DNET and GG, no mass effect and perifocal edema was practically seen. The so-called «spume-like» (multicystic) structure was most clearly observed in FLAIR WI. No significant changes in the dimensions of the DNET and GG were identified. The combination of DNET with focal cortical dysplasia was noted in one case. In DA, it was difficult to distinguish the perifocal edema from tumorous tissue and normal brain tissues, and the growth potential of malformation was slow.

CONCLUSION

Epileptogenic tumors can imitate the x-ray characteristics of each other, and mimicry to gangliogliomas, oligodendrogliomas and astrocytomas Gr I, II, and others. They are the most frequent causes of symptomatic focal epilepsy. The presence of these malformations is necessary to exclude first of all in all cases of pharmacoresistant epilepsy.

Bilateral internal auditory canal gangliogliomas mimicking neurofibromatosis Type II

Background:

Gangliogliomas are rare low grade, typically well-differentiated, tumors that are composed of mature ganglion cells and neoplastic glial cells. These tumors can appear at virtually any location along the neuroaxis but classically occur in the temporal lobe of young patients. In a small number of cases, gangliogliomas have presented as masses in the brainstem or involving cranial nerves. With the exception of vestibular schwannomas, bilateral tumors in the region of the internal auditory canal (IAC) or cerebellopontine angle (CPA) are exceedingly rare.

Case Description:

We report a case of a 58-year-old male who presented with hearing loss, tinnitus, and vertigo. Initial magnetic resonance imaging revealed bilateral nonenhancing IAC/CPA tumors. Based on this finding, a presumptive diagnosis of neurofibromatosis Type II was made, which was initially managed conservatively with close observation. He returned for follow-up with worsening vertigo and tinnitus, thus prompting the decision to proceed with surgical resection of the symptomatic mass. Intriguingly, pathological study demonstrated a WHO Grade I ganglioglioma.

Description:

We report a case of a 58-year-old male who presented with hearing loss, tinnitus, and vertigo. Initial magnetic resonance imaging revealed bilateral nonenhancing IAC/CPA tumors. Based on this finding, a presumptive diagnosis of neurofibromatosis Type II was made, which was initially managed conservatively with close observation. He returned for follow-up with worsening vertigo and tinnitus, thus prompting the decision to proceed with surgical resection of the symptomatic mass. Intriguingly, pathological study demonstrated a WHO Grade I ganglioglioma.

Conclusion:

This is the first reported case of bilateral IAC/CPA gangliogliomas. When evaluating bilateral IAC/CPA lesions with unusual imaging characteristics, ganglioglioma should be included in the differential diagnosis.

A national perspective of adult gangliogliomas

Gangliogliomas (GG) are rare tumors of the nervous system. Patient characteristics and clinical outcomes of low and high-grade GG have been difficult to elucidate in the adult population. This study aims to further elaborate on GG treatment and overall survival utilizing a larger cohort than previously published. The USA National Cancer Database was utilized to evaluate adult (age 18years and older) patients diagnosed with GG between 2004 and 2006. Descriptive statistics and Kaplan-Meier overall survival estimates were provided. A total of 198 adult GG patients were diagnosed between 2004 and 2006. Of these, 181 (91.4%) were low-grade and 17 (8.6%) high-grade GG. Overall, the median age was 36years; approximately 50% of patients were female, and 86.5% Caucasian. Most patients (59%) had near/gross total resection. Radiation and chemotherapy were prescribed in 18 (9.1%) and 11 (5.7%) patients, respectively. Radiation (64.7% versus 3.9%, p<.0001) and chemotherapy (47.1% versus 1.7%, p<.0001) were more frequently given to patients with high-grade tumors than low-grade. The median overall survival of high-grade GG was 44.4months (95% confidence interval [CI]: 10.5-92.5) while the corresponding estimate for low-grade tumors was not reached. Older age (hazard ratio [HR] 1.72, 95% CI: 1.26-2.34) and high tumor grade (HR 3.91, 95% CI: 1.43-10.8) were found to be associated with poor survival. Adult GG have a temporal lobe predilection and overall gross total resection rate of 59%. Older patients with high-grade tumors had an increased hazard of mortality. High-grade GG were significantly more likely to be treated with radiation therapy and chemotherapy.

An Unusual Case of Constitutional Mismatch Repair Deficiency Syndrome With Anaplastic Ganglioglioma, Colonic Adenocarcinoma, Osteosarcoma, Acute Myeloid Leukemia, and Signs of Neurofibromatosis Type 1: Case Report

BACKGROUND AND IMPORTANCE

Constitutional mismatch repair deficiency (CMMRD) syndrome is a disorder with recessive inheritance caused by biallelic mismatch repair gene mutations, in which mismatch repair defects are inherited from both parents. This syndrome is associated with multiple cancers occurring in childhood. The most common tumors observed with CMMRD include brain tumors, digestive tract tumors, and hematological malignancies. The aim of this study was to report new phenotypic expressions of CMMRD syndrome and add new insight to the existing knowledge about this disease. A review of the literature was conducted and recommendation for surveillance and follow-up in patients with CMMRD are proposed.

CLINICAL PRESENTATION

We report for the first time in the literature, the case of a 22-year-old female patient who was diagnosed with CMMRD syndrome, with the development of 2 unusual tumors: an anaplastic ganglioglioma and an osteosarcoma. She presented initially with an anaplastic ganglioglioma and later developed several malignancies including colonic adenocarcinoma, osteosarcoma, and acute myeloid leukemia. The patient had an atypical course of her disease with development of the initial malignancy at an older age and a remarkably long survival period despite developing aggressive tumors.

CONCLUSION

Many aspects of this disease are still unknown. We identified a case of CMMRD in a patient presenting with an anaplastic ganglioglioma, who underwent successful surgical resection, chemotherapy, and radiotherapy and has had one of the longest survival periods known with this disease. This case broadens the tumor spectrum observed with CMMRD syndrome with anaplastic ganglioglioma and osteosarcoma as new phenotypic expressions of this genetic defect.

Principles of radiation therapy

Although resection remains the mainstay in the treatment of gliomas, microscopically complete resection of most central nervous system tumors remains challenging, and is, in fact, rarely accomplished. Considering their invasive nature, gross total resections to clearly negative margins often do or would require removal or transection of functional brain, with likely serious neurologic deficits. Consequently, radiotherapy has emerged as an indispensable component of therapy. It is delivered primarily by external-beam radiotherapy or brachytherapy techniques. Herein, we present the biologic principles, techniques, and applications of radiotherapy in glioma treatment today.

Anaplastic ganglioglioma: a report of three cases and review of the literature

Gangliogliomas are rare tumors of the central nervous system that are thought to arise from a glioneuronal precursor and consist of both neuronal and glial elements. Grade III, or anaplastic ganglioglioma (AGG), most commonly affects children and young adults, generally arises in a supratentorial location, is highly epileptogenic, and often results in diffuse local and distant failure within the craniospinal axis. Pathologically, these tumors are graded by the degree of malignancy in their glial portion and radiologic diagnosis is difficult due to the wide variation in its degree of solid and cystic components, contrast uptake, and calcification patterns. This report presents three cases of AGG, with initial treatment including subtotal resection followed by conformal radiotherapy. In the case where the AGG developed in the setting of an existent low-grade astrocytoma, the patient received no chemotherapy. Both of the other de novo cases were managed with adjuvant chemoradiotherapy with temozolomide. Recurrence occurred at 6, 16, and 20 months following therapy. Two of the three patients experienced symptomatic decline at recurrence, but experienced Karnofsky performance status (KPS) improvement after salvage therapy, including the reduction of cranial neuropathy and balance. All patients had a significant reduction in presenting symptoms following salvage therapy. Patients died at 23, 20, and 22 months following initial surgical management, respectively. A review of anaplastic and malignant gangliogliomas is presented in the context of these three cases.

Rare primary central nervous system tumors

There are close to 70,000 new cases of primary central nervous system tumors diagnosed annually in the United States. Meningiomas, gliomas, nerve sheath tumors and pituitary tumors account for 85% of them. There is abundant literature on these commonly occurring tumors but data from the literature on infrequently encountered tumors such as atypical teratoid/rhabdoid tumor, choroid plexus carcinoma, ganglioglioma, hemangiopericytoma, and pleomorphic xanthoastrocytoma are limited. This review provides an overview of the clinicopathologic and therapeutic aspects of these rare primary central nervous system tumors.

Intraventricular ganglioglioma prognosis and hydrocephalus: the largest case series and systematic literature review

BACKGROUND

Ganglioglioma is mostly found in cerebral parenchymal, and it is rarely located in the ventricular system. To date, ganglioglioma within the ventricular system has been reported in only 10 cases. Its prognosis and relationship with complicating hydrocephalus are unclear.

METHODS

A total of 7 cases with intraventricular ganglioglioma diagnosed by the surgical pathology examination from June 2004 to April 2011 in our center were retrospectively analyzed. The clinical data were collected from the clinical medical records, and the tumor site, size and basement of tumor were analyzed. Follow up was performed to obtain the clinical outcomes.

RESULTS

The 7 cases included 5 males and 2 females, with disease onset at 23.6 ± 14.9 years old. Epilepsy as the initial symptom was observed in 1 case. Reduced hearing, dizziness and weakness of both lower limbs were found in 1 case. Intracranial hypertension were detected in 5 cases, including 1 case complicating by decreased visual acuity. Tumors were located in the lateral ventricle in 5 cases, while 2 cases in the third ventricle. Hydrocephalus was observed in 5 cases, including 2 cases with severe hydrocephalus, and both underwent ventriculoperitoneal shunting. Total resection of tumors was performed in 5 cases, and 2 cases underwent gross total resection. The mean duration of follow-up was 28.7 months (8-90 months). Intracranial hypertension in all cases disappeared. Even radiotherapy post-surgery, one case with GTR relapsed 1 year later. However, the other 6 cases didn't relapse.

CONCLUSIONS

Ganglioglioma in ventricular system is extremely rare, mainly with the symptoms of intracranial hypertension or seizure. The degree of hydrocephalus is closely related to the site of tumor's basement. The prognosis is good after total resection. The patients with GTR should be followed-up.

Brainstem ganglioglioma in an infant: Case report and review of literature

Gangliogliomas are well differentiated, usually low grade, neuroepithelial tumors that comprise of neoplastic ganglion cells in combination with neoplastic glial cells. Occasionally, glial cells may show anaplastic features and are then labeled as anaplastic gangliogliomas. Most of the reported gangliogliomas are supratentorial tumors, predominantly in the temporal lobe. Brainstem location has been reported infrequently. As with cortically based gangliogliomas, though the primary treatment is resection, this is often not possible due to the eloquence of surrounding involved parenchyma. Here, we report a case of brainstem tumor in an 8-month-old child that was substantially resected and was histopathologically Grade 1 ganglioglioma. As per review of English literature, there has been no case of brainstem ganglioglioma reported in an infant (less than 1 year age). We discuss the surgical difficulties in the radical excision of such benign tumors and review literature on pediatric brainstem gangliogliomas.

Pediatric primary anaplastic ganglioglioma: a case report and review of the literature

Gangliogliomas with anaplastic features are classified as grade III tumors by the World Health Organization. The clinical course and optimal treatment of anaplastic gangliogliomas have not been well understood to date. We report a case of a primary pure anaplastic ganglioglioma in a 14-year-old male treated with surgery and radiotherapy, who is disease-free 6 years after the diagnosis. A review of primary pure anaplastic gangliogliomas in children (between 3 and 21 years of age) is presented. Gross total removal and focal radiotherapy with a total dose of 54 Gy are recommended. The addition of chemotherapy should be evaluated. Prospective studies are needed to identify an appropriate chemotherapy schedule and to define biological factors in order to select those patients with a poor prognosis, who are to be treated with a more aggressive therapy.

Occipital ganglioglioma in an older adult

Gangliogliomas are rare benign tumors of the central nervous system that typically involve the temporal lobe in younger patients. We present a 63-year-old man with an unusual occipital ganglioma with new seizures resolving after resection. A search of the literature revealed only three reports of occipital ganglioma in adults over 30 years old. Therefore, ganglioglioma of the occipital lobe in older patients is rare, but is a diagnostic consideration.

Intraventricular ganglioglioma: a short illustrated review

The following review of the literature describes the ganglioglioma, an uncommon mixed glioneuronal neoplasm, most often of low-grade histology, with a small, albeit well-documented, malignant potential. These tumors exhibit a strong epileptogenic propensity and most often present as new onset seizures or are discovered after a long history of refractory epilepsy. Despite their indolent course, the importance of gross total resection is well recognized to prevent anaplastic and malignant degeneration. Morphologically, the neoplasm is often cystic with an enhancing mural nodule, but can also be entirely solid. They are most often found in the temporal lobe but have been found throughout the neuraxis. An exceedingly rare location of the ganglioglioma is within the lateral ventricle. A systematic literature search revealed only eight reports documenting the occurrence of a ganglioglioma within the lateral ventricle. We describe an illustrative case of an intraventricular ganglioglioma with a prominent cystic component and enhancing mural nodule, which represents the classic radiographic appearance of gangliogliomas described in other locations. A superior parietal lobule approach offered excellent surgical access for tumor removal and the patient has remained free of neurological deficits following surgery. Regardless of location within the central nervous system, ganglioglioma should be on the differential diagnosis for any cystic mass with a mural nodule, particularly in the setting of epilepsy.

Minimum apparent diffusion coefficient for the differential diagnosis of ganglioglioma

OBJECTIVES

The utility of apparent diffusion coefficient (ADC) values was evaluated for the differential diagnosis of ganglioglioma.

METHODS

Ten consecutive patients, five men and five women, aged from 14 to 67 years, with histologically proven supratentorial gangliogliomas, underwent diffusion-weighted magnetic resonance imaging with echo planar imaging technique. The minimum ADC (minADC) of each tumor was pre-operatively determined from several regions of interest. The minADC of ganglioglioma was compared with that of low- or high-grade astrocytomas (astrocytoma, anaplastic astrocytoma and glioblastoma). Tumor cellularity of gangliogliomas was compared with the minADC.

RESULTS

The mean minADC of the gangliogliomas (1.45 +/- 0.20 x 10(-3) mm(2)/s) was significantly higher than that of the low- or high-grade astrocytomas. Tumor cellularity of ganglioglioma was inversely correlated with the minADC value.

DISCUSSION

The minADC value reflects in the low tumor cellularity of gangliogliomas and may provide a method for the differential diagnosis of ganglioglioma.

Factors contributing to resectability and seizure outcomes in 44 patients with ganglioglioma

OBJECTIVES

The purpose of this retrospective study was to evaluate causes contributing to surgical resectability and seizure outcomes depending on various clinical and surgical factors.

PATIENTS AND METHODS

The records of 44 patients with gangliogliomas surgically treated between April 1986 and March 2007, were retrospectively reviewed to assess presenting symptoms, resectability and seizure outcomes.

RESULTS

Tumors were located in the supratentorial areas in 33 cases, the infratentorial area in 9 cases and the spinal cord in 2 cases. Thirty-five cases underwent gross total removal and 9 cases underwent subtotal resection. Only 2 cases underwent postoperative radiotherapy and 2 cases underwent gamma knife surgery. Twenty-six patients presented seizure symptoms of which 22 cases were located in temporal lobe and 4 cases were located in the extratemporal lobe. Twenty-three patients (88.5%) were seizure-free after surgery. Two patients were Engel class II and another was Engel class III.

CONCLUSION

We concluded that tumor location and seizure-presenting symptoms are good predictors of gross total removal. Gross total removal of ganglioglioma had a better chance of leaving the patient seizure free after surgery rather incomplete resection. Our data do not support the concept that surgical methods, invasive monitoring and surrounding cortical malformation correlated with seizure-free outcome.

Cerebellar ganglioglioma

The location of ganglioglioma (GG) within the infratentorial compartment is unusual. The authors report a rare case of GG in the cerebellar hemisphere. A 12-year-old boy suffered from headache and gait disturbance. Neuroimaging studies demonstrated a large enhancing cerebellar mass with cystic components compressing the forth ventricle. After complete resection of the tumor, the patient became symptom free. Histological examination on the tumor disclosed glial cells and dysplastic ganglion cells. Although it is a rare tumor, in the appropriate clinical setting, a GG should be considered in the presence of a cerebellar mass with both solid and cystic components on magnetic resonance images in children.

Intracranial ganglioglioma: clinicopathological and MRI findings in 16 patients

AIM

To record the clinical findings and magnetic resonance imaging (MRI) characteristics of intracranial gangliogliomas in 16 patients.

MATERIALS AND METHODS

Sixteen patients were imaged using unenhanced and contrast-enhanced MRI. Eight patients underwent unenhanced CT and of these, three underwent contrast-enhanced CT. Two radiologists read the images retrospectively. The images were studied with regard to location, size, margin, signal intensity, enhancement characteristics, cystic changes, and presence of calcifications. Clinical data, such as presenting signs and symptoms, physical findings, and medical histories, were collected. Histopathological and immunohistochemical studies were performed and analysed by two pathologists.

RESULTS

In 12 cases the tumours were located in one of the cerebral hemispheres; in the other cases they were located in the brainstem, cerebellum, suprasellar area or the thalamus. The tumour dimension varied from 1-7 cm, with a mean of 3.6 cm+/-1.8 cm. The MRI features of ganglioglioma in the present cohort can be divided into three patterns: cystic (n=2), cystic-solid (n=6), and solid (n=8). Solid lesions had a predilection for the temporal lobe; cystic and cystic-solid tumours had a wide anatomical distribution. Cystic lesions were significantly smaller than both cystic-solid and solid lesions (F=4.28, P<0.05). Cystic changes in the cystic-solid tumours showed one of the following patterns: those with walls showing contrast enhancement, those containing an enhancing nodule, or cysts without an obvious wall. The solid portion of cystic-solid gangliogliomas and the entire tumour in solid tumours showed homogeneous enhancement of variable degrees on T1-weighted (T1W) spin-echo (SE) images. Five tumours had mild or moderate oedema. In one patient two separate gangliogliomas were found, each lesion exhibiting different MRI features: solid and cystic-solid. One case of cortical ganglioglioma was found, causing bone erosion due to pressure. One tumour with chronic haemorrhage was found in the study.

CONCLUSION

MRI features of gangliogliomas are non-specific. A ganglioglioma should be suspected when a tumour shows the following features: (1) a solid lesion located in the temporal lobes with mild or no oedema and homogeneous enhancement on SE T1W images; or (2) a small cystic lesion or cystic-solid mixed mass with a wall enhancement or a markedly enhanced nodule. We report a patient with two separate gangliogliomas and a case with bone erosion.

Pediatric infratentorial gangliogliomas: a retrospective series

OBJECT

The aim of this study was to retrospectively review the clinical presentation, the roles of surgery and adjuvant therapy, and the treatment-related morbidity in children with a ganglioglioma in the posterior fossa and to try and determine the prognostic factors.

METHODS

Between 1991 and 2006, 10 children were treated for a posterior fossa ganglioglioma at the authors' institution. The mean age of the children, the duration of symptoms prior to diagnosis, and the follow-up were 8.2, 2.4, and 3.9 years, respectively. Nine of the children presented with symptoms of raised intracranial pressure. Preoperative imaging showed enhancement in all patients; in eight it was in a patchy distribution. The operations consisted of radical resection (> 75%) in seven children, biopsy in two, and a total macroscopic excision in one.

RESULTS

The surgical procedure did not cause deterioration in the neurological condition in any of the children. There was no recurrence in the child who underwent total macroscopic excision of the tumor, and there has been no tumor progression in three children, two of whom have had no evidence of enhancement of the postoperative residual tumor. The tumor has progressed in six children, requiring further surgery in three, chemotherapy in four, and radiotherapy and second-line chemotherapy in one child to control the tumor.

CONCLUSIONS

The imaging of gangliogliomas in the posterior fossa showed patchy enhancement. The patients in whom it was possible to achieve a radical resection, aimed at removing at least the enhancing portion of the tumor, have not required further treatment. A second excision, for progressive tumors, is an effective adjuvant therapy.

Liquid-crystal tunable filter spectral imaging for brain tumor demarcation

Past studies have demonstrated that combined fluorescence and diffuse reflectance spectroscopy can successfully discriminate between normal, tumor core, and tumor margin tissues in the brain. To achieve efficient, real-time surgical resection guidance with optical biopsy, probe-based spectroscopy must be extended to spectral imaging to spatially demarcate the tumor margins. We describe the design and characterization of a combined fluorescence and diffuse reflectance imaging system that uses liquid-crystal tunable filter technology. Experiments were conducted to quantitatively determine the linearity, field of view, spatial and spectral resolution, and wavelength sensitivity of the imaging system. Spectral images were acquired from tissue phantoms, mouse brain in vitro, and human cortex in vivo for functional testing of the system. The spectral imaging system produces measured intensities that are linear with sample emission intensity and integration time and possesses a 1 in. (2.54 cm) field of view for a 7 in. (18 cm) object distance. The spectral resolution is linear with wavelength, and the spatial resolution is pixel-limited. The sensitivity spectra for the imaging system provide a guide for the distribution of total image integration time between wavelengths. Functional tests in vitro demonstrate the capability to spectrally discriminate between brain tissues based on exogenous fluorescence contrast or endogenous tissue composition. In vivo imaging captures adequate fluorescence and diffuse reflectance intensities within a clinically viable 2 min imaging time frame and demonstrates the importance of hemostasis to acquired signal strengths and imaging speed.

Comparison of spectral variation from spectroscopy to spectral imaging

Optical biopsy has been shown to discriminate between normal and diseased tissue with high sensitivity and specificity. Fiber-optic probe-based spectroscopy systems do not provide the necessary spatial information to guide therapy effectively, ultimately requiring a transition from probe-based spectroscopy to spectral imaging. The effect of such a transition on fluorescence and diffuse reflectance line shape is investigated. Inherent differences in spectral line shape between spectroscopy and imaging are characterized and many of these differences may be attributed to a shift in illumination-collection geometry between the two systems. Sensitivity of the line-shape disparity is characterized with respect to changes in sample absorption and scattering as well as to changes in various parameters of the fiber-optic probe design (e.g., fiber diameter, beam steering). Differences in spectral line shape are described in terms of the relative relationship between the light diffusion within the tissue and the distribution of source-detector separation distances for the probe-based and imaging illumination-collection geometries. Monte Carlo simulation is used to determine fiber configurations that minimize the line-shape disparity between the two systems. In conclusion, we predict that fiber-optic probe designs that mimic a spectral imaging geometry and spectral imaging systems designed to emulate a probe-based geometry will be difficult to implement, pointing toward a posteriori correction for illumination-collection geometry to reconcile imaging and probe-based spectral line shapes or independent evaluation of tissue discrimination accuracy for probe-based and spectral imaging systems.

Radiotherapy after subtotally resected or recurrent ganglioglioma

PURPOSE

Gangliogliomas can recur after subtotal resection (STR). The role of postoperative radiation therapy (RT) is undefined.

METHODS AND MATERIALS

Eight consecutive patients with low-grade gangliogliomas (n = 7) or anaplastic gangliogliomas (n = 1) were treated with RT between 1987 and 2004. Median age was 17 years. Five patients received adjuvant RT after STR at a median time of 6 weeks after surgery. Three patients received salvage RT at a median time of 17 months after surgery. The median dose of RT was 54 Gy. Control was defined as no progressive disease on serial imaging. Median follow-up was 8.8 years.

RESULTS

Of the 7 patients with low-grade gangliogliomas, 3 were controlled after RT and 4 recurred locally. Recurrences were controlled with further surgery (n = 2), chemotherapy (n = 1), or re-irradiation (n = 1) (median follow-up, 9 years after salvage therapy). Patients who received adjuvant RT after STR of their low-grade gangliogliomas had an overall local control rate of 75%. All 3 patients who were treated with salvage RT had recurrences in the treated area alone (n = 2) or in the treated area with leptomeningeal spread (n = 1). The patient with an anaplastic ganglioglioma was treated with adjuvant RT, and had recurrence in the radiation field after 4 months, then died 1 month later.

CONCLUSIONS

Adjuvant RT may be indicated to treat select patients with subtotally resected gangliogliomas. Salvage RT for recurrence is probably less effective for long-term control; however, patients who recur may still be candidates for effective salvage therapies in the absence of malignant transformation.

Postoperative radiotherapy in cranial ganglioglioma

We performed an institutional database search for patients with ganglioglioma in order to evaluate postoperative radiotherapy in the light of our experience. This search identified 5 patients with a mean age of 23.3 (range, 9-54 years) treated between April 1994 and April 2003. The latter date was chosen to allow a minimum follow-up of 1 year at the time of our analysis. Median follow up was 7 years (range, 1.5-11 years). Gross total tumor resection could only be achieved in one case, while other four patients had been referred after subtotal tumor excisions. All patients were treated postoperatively with conventionally fractionated (1.8-2 Gy/day) external beam radiotherapy (EBRT) to a total dose of 54-60 Gy. Patients were treated with megavoltage beams using Co(60 )or 6-MV photons. None of the patients were lost to follow up with a median follow up time of 80 months (range, 5.5-122.5 months) and all patients were alive with no evidence of disease at last follow-up. We believe that long term follow-up is necessary to observe the relapse patterns and the significance of postoperative radiotherapy needs to be further evaluated with large patient numbers to remark a conclusive statement.

Less Common Indications for Stereotactic Radiosurgery or Fractionated Radiotherapy for Patients with Benign Brain Tumors

Microsurgical resection remains the mainstay of treatment for truly benign brain tumors that can be safely resected because of the potential for permanent cure with most histologic findings, including most of the histologic findings discussed in this article. Physicians must keep in mind the indolent nature of many of the benign brain tumors and realize that many patients are likely to live out normal life spans if tumor control is achieved. Therefore, it is not sufficient simply to consider local tumor control rates and short-term toxicity risks when choosing between surgery, stereotactic radiosurgery, and fractionated radiotherapy. Patients need to be apprised of all therapeutic options and to make their decisions with all information required to evaluate the risks and benefits. For benign brain tumors, these decisions may have consequences that last for decades.

Survivin expression in ganglioglioma

Gangliogliomas are unusual central nervous system (CNS) neoplasms occurring mainly in children and young adults and inducing chronic pharmacoresistant epilepsy. These are usually well differentiated neuroepithelial tumors composed of neurons in association with neoplastic glial cells. Gangliogliomas present with favorable outcome. However, some may recur and/or progress to anaplasia and be associated with a dismal prognosis. Since histopathological features do not consistently correlate with clinical outcome, reliable prognostic factors have yet to be defined in gangliogliomas. Survivin is an anti-apoptotic protein whose expression has been found to be of prognostic significance in many human cancers, including gliomas. The objective of this study was to assess survivin expression using immunohistochemistry in 15 gangliogliomas. Ten lesions were low-grade neoplasms whereas 5 were high-grade tumors. Survivin expression appeared restricted to the neoplastic glial component and was detected in 6/15 gangliogliomas. Two additional tumors expressed survivin upon relapse. Half survivin expressing lesions displayed less than 1% immunoreactive cells. Survivin expression in more than 5% neoplastic glial cells was detected only in malignant and/or recurrent gangliogliomas. Extended lifespan in survivin expressing cells might enhance aggressive behavior in these tumors through accumulation of mutations, thereby allowing progression to malignant phenotypes. Survivin expression may carry a negative prognostic value in gangliogliomas.

Dynamic, three-dimensional optical tracking of an ablative laser beam

Surgical resection remains the treatment of choice for brain tumors with infiltrating margins but is currently limited by visual discrimination between normal and neoplastic marginal tissues during surgery. Imaging modalities such as computed tomography, magnetic resonance, positron emission tomography, and optical techniques can accurately localize tumor margins. We believe coupling the fine resolution of current imaging techniques with the precise cutting of midinfrared lasers through image-guided neurosurgery can greatly enhance tumor margin resection. This paper describes a feasibility study designed to optically track in three-dimensional space the articulated arm delivery of a noncontact ablative laser beam. To enable optical tracking of the laser beam focus, infrared-emitting diodes (IREDs) were attached to a handpiece machined for the distal end of the articulated arm of a surgical carbon dioxide laser. Crosstalk between the ablative laser beam and the tracking diodes was measured. The geometry of the adapted laser handpiece was characterized to track an externally attached passive tip and the laser beam focus. Target localization accuracies were assessed for both instrument points-of-interest and the sources of tracking errors were investigated. Stray infrared laser light did not affect optical tracking accuracy. The mean target registration errors while optically tracking the laser handpiece with a passive tip and the laser beam focus were 1.31+/-0.50 mm and 2.31+/-0.92 mm, respectively, and were equivalent to the errors tracking a 24-IRED pen probe from Northern Digital in a side-by-side comparison. The majority of error during ablation tracking derived from registration accuracy between physical space and the defined space of the ablation phantom and from an inability to freehand align the laser focus with the target in a consistent manner. While their magnitudes depend on spatial details of the tracking setup (e.g., number and distribution of fiducial points, working distance from the camera, etc.), these errors are inherent to any freehand laser surgery.

Surgical resection for patients with benign primary brain tumors and low grade gliomas

'Benign' brain tumors are a heterogeneous group of primary neoplasms representing 40% of primary brain tumors. Amongst neuroepithelial tumors, astrocytic neoplasms predominate, followed by oligodendroglial and mixed glial and glial-neuronal neoplasms. Less common are tumors of the ependyma, choroid plexus and neuroepithelial tumors of unknown origin such as chordoid glioma of the third ventricle. Neurosurgical intervention is indicated in order to establish a diagnosis, alleviate symptoms of mass effect, hydrocephalus, or hemorrhage, remove a seizure focus and decrease the cell pool at risk of malignant degeneration. As the majority of patients survive their tumor for years after initial diagnosis, the benefits of therapy must be carefully weighed against adverse treatment effects. This article, with a particular focus on surgical management, reflects the authors approach to the treatment of low-grade tumors of the brain parenchyma in the adult and reviews the pertinent literature published on this controversial issue.

Conventional MR imaging with simultaneous measurements of cerebral blood volume and vascular permeability in ganglioglioma

The conventional MR imaging appearance of gangliogliomas is often variable and nonspecific. Conventional MR images, relative cerebral blood volume (rCBV) and vascular permeability (K(trans)) measurements were reviewed in 20 patients with pathologically proven grade 1 and 2 gangliogliomas (n = 20) and compared to a group of grade 2 low-grade gliomas (n = 30). The conventional MRI findings demonstrated an average lesion size of 4.1 cm, contrast enhancement (n = 19), variable degree of edema, variable mass effect, necrosis/cystic areas (n = 8), well defined (n = 12), signal heterogeneity (n = 9), calcification (n = 4). The mean rCBV was 3.66 +/- 2.20 (mean +/- std) for grade 1 and 2 gangliogliomas. The mean rCBV in a comparative group of low-grade gliomas (n = 30), was 2.14 +/- 1.67. p Value < 0.05 compared with grade 1 and 2 ganglioglioma. The mean K(trans) was 0.0018 +/- 0.0035. The mean K(trans) in a comparative group of low-grade gliomas (n = 30), was 0.0005 +/- 0.001. p Value = 0.14 compared with grade 1 and 2 ganglioglioma. The rCBV measurements of grade 1 and 2 gangliogliomas are elevated compared with other low-grade gliomas. The K(trans), however, did not demonstrate a significant difference. Gangliogliomas demonstrate higher cerebral blood volume compared with other low-grade gliomas, but the degree of vascular permeability in gangliogliomas is similar to other low-grade gliomas. Higher cerebral blood volume measurements can help differentiate gangliogliomas from other low-grade gliomas.

Genome-wide survey for chromosomal imbalances in ganglioglioma using comparative genomic hybridization

Ganglioglioma is a mixed neuronal and glial tumor first described by Perkin in 1926. Because of its rare occurrence in the central nervous system, the pathogenesis of this neoplasm is still largely unknown. Previous studies of ganglioglioma mainly focused on histologic features, immunohistochemical analysis, clinical treatment, and patient outcome. Very few cytogenetic and molecular genetic studies have been reported on this neoplasm. To better understand the mechanism underlying the development of ganglioglioma, we performed comparative genomic hybridization analysis to investigate chromosomal imbalances across the entire genome in five cases of gangliogliomas. Loss of genetic material on the short arm of chromosome 9 was a common genetic alteration found in three of five cases. Overrepresentation of partial or the whole chromosome 7 was another recurrent chromosomal imbalance, confirmed by fluorescence in situ hybridization. Immunohistochemical analysis was performed; all five cases revealed no reaction or low expression for epidermal growth factor receptor antibody. Our study highlights chromosomal regions for further fine mapping and investigation of candidate tumor suppressor genes involved in the pathogenesis of ganglioglioma.

Nestin expression in ganglioglioma

It has been suggested that gangliogliomas represent a neoplastic transformation of a dysplastic focus or heterotopia. Other theories propose that gangliogliomas arise from multipotent stem cells with the ability to differentiate along glial and neuronal cell lines. Our goal was to characterize the expression of nestin, a neuroepithelial precursor/stem cell antigen, in gangliogliomas along with other pathological and clinical features of this entity. The clinical and operative features of 18 recent cases meeting the histological criteria for ganglioglioma were reviewed. The expression of nestin, microtubule-associated protein 2 (MAP2), neurofilament, and glial fibrillary acidic protein (GFAP) was assessed by immunohistochemistry and confocal scanning laser microscopy. Abundant MAP2- and nestin-positive neuronal cells were found by immunohistochemistry in all 18 gangliogliomas. GFAP staining was found in reactive and lesional astrocytes but not in cells of neuronal morphology. Confocal microscopy demonstrated colocalization of nestin and MAP2 in select neuronal cells. The true lineage of gangliogliomas remains controversial. Our findings confirm the presence of cells within these lesions that harbor a persistent stem cell cytoskeletal protein (nestin). Further insight into the cytoskeletal derangement of nestin-positive neuronal cells may shed further light on the pathogenesis of gangliogliomas and its associated epilepsy.

Malignant transformation of a gangliocytoma/ganglioglioma into a glioblastoma multiforme: a molecular genetic analysis. Case report

A gangliocytoma/ganglioglioma with no atypical or malignant features was subtotally resected from the right temporal lobe of a 16-year-old woman. A second resection was performed 8 years later to treat a locally recurrent lesion with increased cellularity that was diagnosed as a World Health Organization Grade II ganglioglioma on the basis of neuropathological examination. Molecular analysis of the recurrent tumor revealed a TP53 gene mutation, but no amplification of the epidermal growth factor receptor (EGFR) gene. Radiotherapy (60 Gy) was administered after the second resection. The patient returned 1 year later with a second focal recurrence. The specimen obtained during the third resection of tumor exhibited exclusively astrocytic differentiation, cellular pleomorphism with multinucleated cells, high mitotic activity, and endothelial proliferation. Therefore, the tumor was diagnosed to be a glioblastoma multiforme (GBM). Molecular analysis of tumor DNA from the second recurrent tumor demonstrated the presence of the TP53 mutation, which previously had been observed in the first recurrent tumor, but again no evidence of EGFR amplification. Findings demonstrate that the presence of TP53 mutation in progressed gangliogliomas should be interpreted as a progression-associated mutation rather than a consequence of treatment. This is the first report to indicate that the molecular pathways of gangliocytomas/gangliogliomas progressing to become GBMs may parallel those of diffuse astrocytomas progressing to become GBMs.

Treatment of low-grade pediatric gliomas

The prognosis of pediatric low-grade gliomas is relatively favorable, but residual or unresectable tumors remain a challenge. Conventional radiation therapy is effective but may be associated with unacceptable sequelae in young children. Chemotherapy can delay the need for radiation therapy in young children; however, its role in older children has yet to be established. New forms of radiation are being introduced that may be less toxic.

Brain tumor demarcation using optical spectroscopy; an in vitro study

Optical spectroscopy for brain tumor demarcation was investigated in this study. Fluorescence and diffuse reflectance spectra were measured from normal and tumorous human brain tissues in vitro. A fluorescence peak was consistently observed around 460 nm (+/- 10 nm) emission from both normal and tumorous brain tissues using 337 nm excitation. Intensity of this fluorescence peak (F460) from normal brain tissues was greater than that from primary brain tumorous tissues. In addition, diffuse reflectance (Rd) between 650 and 800 nm from white matter was significantly stronger than that from primary and secondary brain tumors. A good separation between gray matter and brain tumors was found using the ratio of F460 and Rd at 460 nm (Rd460). Two empirical discrimination algorithms based on F460, Rd625, and F460/Rd460 were developed. These algorithms yielded an average sensitivity and specificity of 96% and 93%, respectively.