Ganglioglioma arising in a Peutz-Jeghers patient: a case report with molecular implications

The mTOR signaling pathway as a treatment target for intracranial neoplasms

Inhibition of the mammalian target of rapamycin (mTOR) signaling pathway has become an attractive target for human cancer therapy. Hyperactivation of mTOR has been reported in both sporadic and syndromic (hereditary) brain tumors. In contrast to the large number of successful clinical trials employing mTOR inhibitors in different types of epithelial neoplasms, their use to treat intracranial neoplasms is more limited. In this review, we summarize the role of mTOR activation in brain tumor pathogenesis and growth relevant to new human brain tumor trials currently under way using mTOR inhibitors.

Epilepsy related to developmental tumors and malformations of cortical development

Structural abnormalities of the brain are increasingly recognized in patients with neurodevelopmental delay and intractable focal epilepsies. The access to clinically well-characterized neurosurgical material has provided a unique opportunity to better define the neuropathological, neurochemical, and molecular features of epilepsy-associated focal developmental lesions. These studies help to further understand the epileptogenic mechanisms of these lesions. Neuropathological evaluation of surgical specimens from patients with epilepsy-associated developmental lesions reveals two major pathologies: focal cortical dysplasia and low-grade developmental tumors (glioneuronal tumors). In the last few years there have been major advances in the recognition of a wide spectrum of developmental lesions associated with a intractable epilepsy, including cortical tubers in patients with tuberous sclerosis complex and hemimegalencephaly. As an increasing number of entities are identified, the development of a unified and comprehensive classification represents a great challenge and requires continuous updates. The present article reviews current knowledge of molecular pathogenesis and the pathophysiological mechanisms of epileptogenesis in this group of developmental disorders. Both emerging neuropathological and basic science evidence will be analyzed, highlighting the involvement of different, but often converging, pathogenetic and epileptogenic mechanisms, which may create the basis for new therapeutic strategies in these disorders.

BRAF V600E mutation is associated with mTOR signaling activation in glioneuronal tumors

BRAF V600E mutations have been recently reported in glioneuronal tumors (GNTs). To evaluate the expression of the BRAF V600E mutated protein and its association with activation of the mammalian target of rapamycin (mTOR) pathway, immunophenotype and clinical characteristics in GNTs, we investigated a cohort of 174 GNTs. The presence of BRAF V600E mutations was detected by direct DNA sequencing and BRAF V600E immunohistochemical detection. Expression of BRAF-mutated protein was detected in 38/93 (40.8%) gangliogliomas (GGs), 2/4 (50%) desmoplastic infantile gangliogliomas (DIGs) and 23/77 (29.8%) dysembryoplastic neuroepithelial tumors (DNTs) by immunohistochemistry. In both GGs and DNTs, the presence of BRAF V600E mutation was significantly associated with the expression of CD34, phosphorylated ribosomal S6 protein (pS6; marker of mTOR pathway activation) in dysplastic neurons and synaptophysin (P < 0.05). In GGs, the presence of lymphocytic cuffs was more frequent in BRAF-mutated cases (31 vs. 15.8%; P=0.001). The expression of both BRAF V600E and pS6 was associated with a worse postoperative seizure outcome in GNT (P < 0.001). Immunohistochemical detection of BRAF V600E-mutated protein may be valuable in the diagnostic evaluation of these glioneuronal lesions and the observed association with mTOR activation may aid in the development of targeted treatment involving specific pathogenic pathways.

Early surgical intervention in adult patients with ganglioglioma is associated with improved clinical seizure outcomes

Gangliogliomas are rare central nervous system tumors, most commonly affecting children and young adults. Chronic seizure and epilepsy are the most frequent presentation of patients with gangliogliomas. In this report, we review the modern literature regarding the effects of early surgical intervention on the clinical outcome of patients with ganglioglioma. A boolean search of PubMed using key words "ganglioglioma", "adult", "seizure control", "treatment", "surgical intervention", and "observation", alone and in combination was performed. The inclusion criteria for articles were that: (i) clinical outcomes were reported specifically for gangliogliomas; (ii) data were reported for adult patients older than the age of 18 years; (iii) treatment data were included for the treatment of gangliogliomas; and (iv) ganglioglioma was the only pathological diagnosis for the evaluation of the tumor. Data were analyzed as a whole then stratified into two groups: early and late treatment intervention. The query identified a total of 99 articles including 1,089 cases of ganglioglioma meeting our inclusion and exclusion criteria. There was a 55% prevalence of males, representing a statistically significant predilection (51-59%, 95% confidence interval). Seizure control was significantly improved when surgical intervention occurred less than 3 years after symptom onset (78% versus 48%; p = 0.0001). Ganglioglioma in adults represents a rare group of tumors, and our systematic analysis suggests a higher prevalence in males. Our findings also support that an early surgical intervention is significantly associated with improved clinical seizure control.

Gangliogliomas: recent advances in classification and treatment

Gangliogliomas are uncommon neoplasms of the CNS and, as a consequence, few randomized, clinical trials have been performed, thereby limiting treatment guidelines. The best management of newly diagnosed gangliogliomas entails a complete resection, corroborated by postoperative contrast-enhanced MRI. If an incomplete resection is documented, a second attempt at gross total resection should be considered, given the prognostic significance of complete resection. Small-volume residual disease is best managed with involved-field radiotherapy. The role of chemotherapy is uncertain and, in general, would be reserved for patients having previously failed surgery and radiotherapy. This article summarizes the most important available up-to-date information on clinical, prognostic, radiological, pathological and therapeutic findings for gangliogliomas in order to provide valuable guidance for the diagnosis and management of such uncommon tumors. This information may be considered as possible background for future studies designed to clarify the complex management of these tumors.

Tumor recurrence and malignant progression of gangliogliomas

BACKGROUND

Most gangliogliomas (GGs) are benign tumors, but tumor recurrence and malignant progression are observed in some patients.

METHODS

The authors analyzed their experience with 4 recurrent/progressive GGs (World Health Organization [WHO] grade I), 21 tumors with atypical features (WHO grade II), and 5 tumors with anaplastic histologic features (WHO grade III). Histopathologic findings (23 patients) were reviewed. The mean follow-up was 5.9 years (median, 4.5 years; range, 0.5-14.7 years).

RESULTS

The 5-year survival rates were only 79% for patients who had tumors with atypical features and 53% for patients who had WHO grade III tumors. Secondary glioblastomas were diagnosed in 5 of 11 patients (45%) who underwent surgery for tumor recurrence. Age at surgery <40 years (P = .007) was associated significantly with better overall survival (OS), but it was not associated with better progression-free survival (PFS). Clinical presentation (drug-resistant epilepsy vs all other patients with seizures vs no seizures) was associated significantly with better OS (P = .005) and PFS (P < .001). Patients who had extratemporal tumors had a significantly shorter PFS (P = .01) but not OS. A complete resection was correlated strongly with both OS (P = .002) and PFS (P = .001). Neuropathologic examination revealed the presence of a gemistocytic cell component (PFS, P = .025), a lack of protein droplets (OS, P = .04; PFS, P = .05), and focal tumor cell-associated CD34 immunolabeling (OS, P = .03) as significant predictors of an adverse clinical course.

CONCLUSIONS

The current data supported a 3-tiered GG histopathologic grading system that included an intermediate diagnostic category (atypical GG, WHO grade II). Careful attention to histopathologic findings and clinical parameters usually will identify patients who are at risk for an adverse clinical course.

Present status and problems in diagnosis and treatment of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disease, which is caused by inactivating germline mutations in LKB1/STK11 and characterized by mucocutaneous pigmentation, multiple gastrointestinal hamartomatous polyps and family history. Life-threatening complications include intestinal obstruction, an increasing risk for developing gastrointestinal malignancies and extraintestinal cancers. PJS more frequently happens to teenagers. Besides susceptibility to malignant cancer, it was characterized by complications associated with polyps, repeated hospitalizations and operations, as well as a high cost of medical cost, which especially brings harm to one-child family in China. This paper focuses on the diagnoses and treatments in PJS, such as clinical use of double-balloon enteroscopy and open surgery combined with intraoperative endoscopy. Also, COX-2 inhibitors and rapamycin for chemoprevention are introduced.