Generalizability of "GWAS Hits" in Clinical Populations: Lessons from Childhood Cancer Survivors.

With mounting interest in translating genome-wide association study (GWAS) hits from large meta-analyses (meta-GWAS) in diverse clinical settings, evaluating their generalizability in target populations is crucial. Here, we consider long-term survivors of childhood cancers from the St. Jude Lifetime Cohort Study, and we show the limited generalizability of 1,376 robust SNP associations reported in the general population across 12 complex anthropometric and cardiometabolic phenotypes (n = 2,231; observed-to-expected replication ratio = 0.70, p = 6.2 × 10-8). An examination of five comparable phenotypes in a second independent cohort of survivors from the Childhood Cancer Survivor Study corroborated the overall limited generalizability of meta-GWAS hits to survivors (n = 4,212; observed-to-expected replication ratio = 0.55, p = 5.6 × 10-15). Finally, in direct comparisons of survivor samples against independent equivalently powered general population samples from the UK Biobank, we consistently observed lower meta-GWAS hit replication rates and poorer polygenic risk score predictive performance in survivor samples for multiple phenotypes. As a possible explanation, we found that meta-GWAS hits were less likely to be replicated in survivors who had been exposed to cancer therapies that are associated with phenotype risk. Examination of complementary DNA methylation data in a subset of survivors revealed that treatment-related methylation patterns at genomic sites linked to meta-GWAS hits may disrupt established genetic signals in survivors.

Endoscopic Transsphenoidal Surgery for an Adult Patient With Giant Exophytic Chiasmatic/Hypothalamic Glioma.

Optic pathway hypothalamic gliomas are intrinsic low-grade gliomas involving the optic nerve, chiasm, optic tract, and hypothalamus. The rarity of these tumors and their unpredictable course make assessment and standardization of treatment modalities difficult. Tumor debulking via various transcranial approaches was considered to be effective at controlling tumor growth, but with high rates of severe surgery-related complications. In the present case, endoscopic transsphenoidal surgery was initiated to debulk the exophytic chiasmatic/hypothalamic glioma with good preservation of hypothalamic and endocrine functions. The authors suggest transsphenoidal surgery with tumor debulking could be an effective and safe treatment for patients with chiasmatic/hypothalamic gliomas.

Neurofibromatosis type 1: A neuro-psycho-cutaneous syndrome?

Neurofibromatosis type 1 (NF1) is an inherited disorder often associated with optic nerve gliomas, low-grade brain tumors, and readily visible signs. Though these features are frequently emphasized, the psychosocial and emotional morbidities are often overlooked. We present a patient with depressive disorder resulting in suicide in a patient with NF1.

[SCT perfusion in the diagnosis of sellar and parasellar tumors].

UNLABELLED: The study is devoted to the use of a minimally invasive method of SCT perfusion for the differential diagnosis of sellar and pаrаsellar tumors. Given a wide differential diagnostic range of tumors occurring in this area, the tumor perfusion indicators were used as an auxiliary diagnostic criterion. MATERIAL AND METHODS: The study analyzed outcomes in 115 patients with various tumors of the sellar area who underwent surgery or biopsy for histological verification of the diagnosis. RESULTS: The statistically significant differences were obtained for certain groups of tumors based on the values of hemodynamic parameters (p<0.05) that enable, with a high confidence, making a conclusion on the histologic type of most tumors. CONCLUSION: These findings demonstrated that SCT perfusion is a highly informative method of the preoperative differential diagnosis of these tumors. The sensitivity and specificity of SCT perfusion in the study were 100% and 81.2%, respectively.

Outcomes of pediatric low-grade gliomas treated with radiation therapy: a single-institution study.

Radiation therapy is often considered the treatment of choice for low-grade gliomas. However, given the long-term effects of radiation on the developing brain, the appropriate use of radiation therapy in pediatric patients remains controversial. The purpose of this study was to evaluate progression-free survival (PFS) of pediatric low-grade glioma patients treated with radiation therapy. Data were obtained through a retrospective chart review of patients treated between 1991 and 2008 from a single tertiary care center in the midwest. The study population consisted of 17 patients, of whom 8 (47%) had tumor recurrence after radiation therapy. The median follow-up time was 8.2 years, with a range of 2.3 to 17.2 years. The median age at diagnosis was 5.4 years, and the median age at radiation therapy was 9.4 years. The 3- and the 10-year PFS were 69%± 11.7% and 46%± 13.3%, respectively. A significant difference in PFS was seen when comparing brainstem tumors with hypothalamic/optic pathway tumors (P=0.019). Differences in PFS based on the age at diagnosis, the extent of initial surgery, and indication for radiation therapy were not significant. A larger multicenter study is needed to better assess PFS in these patients.

Pilomyxoid astrocytoma presenting as diencephalic syndrome.

We report the case of a child who presented with diencephalic syndrome. During diagnostic work- up, he was found to have a supra-sellar hypothalamic tumour. Histopathological examination of the tumour revealed it to be pilomyxoid astrocytoma, which is a WHO grade-II tumour, previously considered to be part of the spectrum of WHO grade-I pilocytic astrocytomas. However, because of its characteristic histopathology and behaviour, it was later segregated from pilocytic astrocytomas. In this case report, we discuss the cytological and histopathological features of this tumor with the aim of increasing awareness of this tumour amongst general histopathologists, to highlight the importance of its differentiation from pilocytic astrocytomas in view of its different behaviour, treatment and prognosis and that it should be included in the differential diagnosis of diencephalic syndrome.

The Role of Tumor-Associated Hypothalamic Involvement in Surgical Treatment and Long-Term Outcome in Adult Patients with Craniopharyngioma.

INTRODUCTION: Hypothalamic invasion in pediatric patients with craniopharyngioma negatively influences clinical outcomes. It has been shown that radiologic classification of hypothalamic invasion can effectively predict surgical strategies to minimize postoperative comorbidities in pediatric patients. However, no comparative analysis has been performed in adult patients with craniopharyngioma. This study implements the previously established radiologic classification to characterize postoperative morbidity, surgical outcome, and distress in adult patients with craniopharyngioma. METHODS: Electronic medical records of 22 adult patients with craniopharyngioma were used to analyze patient demographics, surgical data, endocrinologic and ophthalmologic status, and histopathology in a retrospective single-center study. Questionnaires regarding postoperative distress (National Comprehensive Cancer Network Distress Thermometer and Problem List), comorbidities (Charlson Comorbidity Index), employment status, and need for supportive care were distributed. Magnetic resonance imaging scans were categorized according to Puget et al. RESULTS: Patients with hypothalamic involvement show significantly higher rates of postoperative diabetes insipidus and higher scores on the National Comprehensive Cancer Network Distress Thermometer. This significant difference was lost when considering postoperative Puget grades. Puget grades 1 and 2 were found to be associated with the use of a subfrontal surgical approach (hazard ratio, 4.080; confidence interval, 1.153-14.431; P = 0.029). CONCLUSIONS: Our results point toward a possible predictive role of preoperative hypothalamic invasion for postoperative diabetes insipidus as well as higher perceived levels of distress after surgery, which may be established in larger patient cohorts. Furthermore, a subfrontal surgical approach seems to be predicted by tumors with hypothalamic invasion. In this case, preoperative magnetic resonance imaging grading may help guide the planning of an optimal surgical strategy for adults with craniopharyngioma to reduce postoperative morbidity.

Magnetic Resonance Imaging Features of Sporadic Optic Chiasmatic-Hypothalamic Gliomas and Correlation with Histopathology and BRAF Gene Alterations.

OBJECTIVE: Sporadic optic chiasmatic-hypothalamic gliomas (OCHGs), though histologically low-grade tumors, manifest as aggressive neoplasms radiologically, leading to difficulty in diagnosis. Molecular alterations of the BRAF gene are detectable in a majority of sporadic OCHGs. The purpose of our study was to elucidate the characteristic imaging features of sporadic OCHGs and to investigate whether imaging phenotypes could potentially correlate with specific BRAF gene alterations associated with these tumors. METHODS: We retrospectively reviewed baseline magnetic resonance (MR) images and medical records of 26 patients with histopathologically proven sporadic OCHGs. MR imaging (MRI) features were systematically evaluated. Statistical analysis was performed to determine whether there was a significant association between imaging findings and BRAF molecular alterations. RESULTS: Twenty-two cases (84.6%) presented with solid-cystic masses, while four (15.4%) presented with purely solid lesions. In all 26 cases, the solid component revealed central necrosis; there was minimal necrosis in 11 cases (42.3%), moderate in 8 (30.7%), and marked in 7 (26.9%). The presence of multiple cysts (>4) and minimal necrosis showed a significant association with BRAFV600E mutation (P < 0.005). Marked necrosis in the solid component significantly correlated with BRAF wild genotype (P < 0.001). The presence of a single peripheral cyst significantly correlated with BRAF fusion (P = 0.04). CONCLUSION: Sporadic OCHGs have a distinctive appearance on imaging. The solid-cystic composition coupled with varying degrees of central necrosis are clues to the radiological diagnosis of this entity and can facilitate early recognition in clinical practice. Imaging could potentially serve as a non-invasive predictor of the BRAF alteration status, thereby serving as a prognostic marker and guiding personalized management.

Occurrence and distribution of pilomyxoid astrocytoma.

PURPOSE: To know the occurrence and distribution of Pilomyxoid Astrocytomas amongst tumours previously diagnosed histologically as Pilocytic Astrocytoma and to assess the clinical impact of this new entity. METHODS: Retrospective Diagnostic review of all cases histologically diagnosed as WHO Grade I Astrocytoma at a single Neurosurgical unit between 1990 and 2003. RESULTS: Of a total of 91 cases identified, 9 were found to have Pilomyxoid histology. Of these, 8 were children (mean age 3.33 years) and 1 adult. 6 tumours were hypothalamochiasmatic in location. The clinical course of Pilomyxoid tumours was aggressive marked by maturation, multiple recurrences and disease control was rarely achieved with single treatment modality as opposed to typical pilocytics. The overall survival of the pilomyxoid group was not statistically different from the pilocytic tumours. CONCLUSIONS: Encompassing all age-groups and locations, Pilomyxoid Astrocytomas constitute about 10% of all tumours previously diagnosed as Pilocytic Astrocytoma. Nearly two-thirds are hypothalamo-chiasmatic in location. Knowledge of this entity is essential for appropriate aggressive treatment and follow-up.

A novel rodent model that mimics the metabolic sequelae of obese craniopharyngioma patients.

Patients with craniopharyngioma (CP), a tumor located in the pituitary and/or hypothalamus, are susceptible to developing obesity and many metabolic complications. The study aim was to create a rodent model that mimics the complex neuroanatomical and metabolic disturbances commonly seen in obese CP patients. We compared the metabolic phenotype of animals with three distinct types of hypothalamic lesions: 1) destruction of the arcuate nucleus (ARC) induced by monosodium glutamate (MSG), 2) electrolytic lesion of the adjacent ventromedial nucleus (VMN) alone, 3) both the VMN and dorsomedial nucleus (DMN), or a 4) combined medial hypothalamic lesion (CMHL) affecting the VMN, DMN, and the ARC. Only the CMHL model exhibited all key features observed in patients with hypothalamic obesity induced by CP. These features included excessive weight gain due to increased adiposity, increased food intake, and pronounced hyperinsulinemia and hyperleptinemia. Similar to characteristics of patients with CP, CMHL animals exhibited reduced plasma levels of alpha-melanocyte stimulating hormone and reduced ambulatory activity compared with weight-matched controls. Therefore, the CMHL model best mimics the complex metabolic abnormalities observed in obese CP patients compared with lesions to other hypothalamic areas and provides a foundation for future pharmacological approaches to treat obesity in children with hypothalamic damage.

Hypothalamic Cavernomas: Pediatric Case Report with 8.5-Year Follow-up and Review of the Literature.

BACKGROUND: Cavernous malformations (cavernomas) are angiographically occult vascular lesions that can present symptomatically or be discovered incidentally. Rarely, they present in the hypothalamus or in children. CASE DESCRIPTION: We describe the case of a 14-year-old male patient who presented with headaches and fever and was found to have a hypothalamic cavernoma that hemorrhaged. It was managed expectantly, with 1 rehemorrhage 21 months later, and the patient remains asymptomatic to this day aside from headaches. CONCLUSIONS: This is to our knowledge the youngest case of a hypothalamic cavernoma to be reported and includes 8.5 years of follow-up and imaging. In addition, a literature review is performed that summarizes the 11 previously reported cases of hypothalamic cavernomas, including associated symptoms, management options, and outcomes.

Feasibility of neuroendoscopic biopsy of pediatric brain tumors.

PURPOSE: The purpose of this study was to investigate the potential value of neuroendoscopic biopsies in pediatric patients with peri- or intraventricular tumors. METHODS: From 2001 to 2008, 49 pediatric patients (mean age, 12.16 years) with tumors located in the intraventricular or paraventricular areas underwent neuroendoscopic biopsy, with or without simultaneous endoscopic third ventriculostomy. Neuroendoscopic biopsies were performed to verify the histological diagnosis of neoplasms and to establish pathological diagnoses necessary for planning appropriate treatment strategies. RESULTS: In 45 of 49 patients (91.8%) neuroendoscopic biopsy specimens were appropriate for diagnosis and revealed 27 germinomas, 11 astrocytomas, and one ependymoma, etc. The tumor location included the pineal gland (n = 28), thalamus (n = 7), intraventricle (n = 3), hypothalamus (n = 3), suprasellar area (n = 2), and diffuse multifocal area (n = 3). In two patients (4.1%) biopsy specimens were informative but not diagnostic. Tumor tissue specimens were undiagnostic in two patients (4.1%). There were eight transient morbidities, including four EOM limitations, two central DI, one EVD infection, and one CSF leakage. One patient experienced postoperative tumor bleeding requiring emergent operation. There was no case of operative mortality. CONCLUSION: Neuroendoscopic biopsy can be considered as the first choice for tissue sampling of periventricular and intraventricular tumors with acceptable risks.

Frequent Clinical and Radiological Progression of Optic Pathway/Hypothalamic Pilocytic Astrocytoma in Adolescents and Young Adults.

Most cases of optic hypothalamic pilocytic astrocytoma (OHPA) develop during childhood, so few cases of histologically verified OHPA have been described in adolescents and young adults (AYA). To elucidate the clinical features of OHPA with histological verification in AYA, we reviewed the clinical and radiological finding of OHPA treated at our institute from January 1997 and July 2017. AYA are aged between 15 and 39 years. The clinical courses of 11 AYA patients with optic hypothalamic glioma (OHG) without neurofibromatosis type 1 were retrospectively reviewed. About six patients were diagnosed in childhood and followed up after 15 years of age, and five patients developed OHPA during AYA. Histological diagnosis, verified at initial presentation or recurrence, was pilocytic astrocytoma in 10 and pilomyxoid astrocytoma in one. After initial treatment including debulking surgery and/or chemotherapy, tumor progression occurred 16 times in seven patients as cyst formation, tumor growth, and intratumoral hemorrhage. Five of 10 patients suffered deterioration of visual function during AYA. One of 10 cases had endocrinopathies requiring hormone replacement at last follow-up examination. In conclusion, histological diagnoses of OHG before and in AYA were pilocytic astrocytoma or pilomyxoid astrocytoma. Both pediatric and AYA-onset OHPA demonstrate high incidences of tumor progression and visual dysfunctions in AYA, so that long-term follow up is essential after the completion of treatment for pediatric and AYA-onset OHPA. The optimal timing of debulking surgery and radiation therapy should be established to achieve the long-term tumor control and to preserve the visual function.

Tumor stabilization under treatment with imatinib in progressive hypothalamic-chiasmatic glioma.

BACKGROUND: Hypothalamic-chiasmatic gliomas (HCG) account for up to 20% of tumors in patients under the age of 3 years. While most children respond to chemotherapy, alternative treatment approaches are needed for those with progressive disease refractory to chemotherapy. PROCEDURE: Six patients (median age: 5.5 years) with progressive HCG were treated with imatinib for 3-29 months at a median daily oral dose of 270 mg/m(2). All patients initially presented with extensive tumors during infancy and had undergone two to three surgical resections and two to three prior chemotherapies with multiple agents. RESULTS: The best response achieved was stable disease in all six patients. Disease control lasted from 5 to 46 months and was sustained longer in comparison to their last prior chemotherapy. Toxicities possibly related to imatinib included edema, elevated liver enzymes and bowel problems. Immunohistochemistry in our patients' tumor cells revealed focal expression of arg and PDGFR-alpha in one patient, in the remaining five patients no expression of any of the five known targets of imatinib could be detected. Expression of PDGFR-alpha and PDGFR-beta was detected in endothelial cells of tumor capillaries of all six patients. CONCLUSIONS: We conclude that imatinib has possible activity in progressive HCG and may present an additional therapeutic option for patients who are too young or whose tumor is too extensive to receive radiotherapy. However, the optimal use of imatinib in this disease, its mechanism of action, and possible long-term effects remain unclear and will require additional study.

Bilateral gonadoblastoma with dysgerminoma and pilocytic astrocytoma with WT1 GT-IVS9 mutation: A 46 XY phenotypic female with Frasier syndrome.

Frasier syndrome is characterized by a 46 XY disorder of sex development, nephropathy, and increased risk for gonadoblastoma due to Wilms tumor 1(WT1) mutation in the donor splice site of intron-9, resulting in the splice form +KTS. Germ cell tumors and gonadoblastomas have been reported previously in Frasier syndrome. We present the clinical, radiological, and genetic (WT1 mutation analysis) of a 46 XY phenotypic female with Frasier syndrome with bilateral gonadoblastoma with dysgerminoma who developed pilocytic astrocytoma.

Chemotherapy with cisplatin and vincristine for optic pathway/hypothalamic astrocytoma in young children.

OBJECTIVE: Optic pathway/hypothalamic astrocytomas (OPHA) in young children often show accelerated growth and require rather intensive induction chemotherapy. METHODS: Fifteen children (median age: 3 years) with a large OPHA were treated. All of them presented with progressive disease, and the tumor size was larger than 34 mm. Pilocytic astrocytoma was confirmed histologically in 10 patients. Eleven patients had visual disturbance, six had diencephalic syndrome and four had hydrocephalus. RESULTS: The children received six to eight cycles of cisplatin (20 mg/m(2): days 1-5) and vincristine (1.4 mg/m(2): days 1, 8, 15), every 4 weeks. Objective response was obtained in 11 patients (73%); one complete response, eight partial responses and two minor responses. Although the remaining four cases were evaluated as stable disease, all tumors decreased in volume. All children tolerated the chemotherapy well under careful audiological monitoring. CONCLUSION: Although the present series was small, this chemotherapy is a useful regimen for induction therapy in children with an aggressive deep-seated pilocytic astrocytoma.

The role of leptin, soluble leptin receptor, resistin, and insulin secretory dynamics in the pathogenesis of hypothalamic obesity in children.

INTRODUCTION: In this study, we have investigated the role of leptin, soluble leptin receptor(sOb-R), resistin, and insulin secretory dynamics in the development of hypothalamic obesity. MATERIALS AND METHODS: Children who had hypothalamo-pituitary tumor were divided into two groups. First group included obese-overweight (hypothalamic obese = HOB group, n = 23) and second group included non-obese children (hypothalamic non-obese = HNOB group, n = 16). Exogenously obese-overweight children (OB group, n = 22) were included as controls. Basal and second-hour serum glucose and insulin in oral glucose tolerance test (OGTT), basal serum leptin, sOb-R, resistin levels, and homeostasis model assessment (HOMA) indexes were compared between the groups. RESULTS: Age, sex, and pubertal status were similar in study groups. Median and interquartile ranges of body mass index (BMI) z scores were similar in HOB and OB groups (2.0 (1.5-2.1) and 2.1 (1.8-2.3), respectively). Serum leptin levels corrected for BMI were highest and total leptin/sOb-R ratios (free leptin index (FLI)) tended to be higher in HOB than HNOB and OB groups, indicating leptin resistance (leptin/BMI, 4.0 (1.6-5.2), 1.5 (0.8-3.1), and 2.5 (1.8-3.5); FLI, 2.0 (0.8-3.5), 0.6 (0.3-1.2), and 1.5 (1-2.3) in HOB, HNOB, and OB groups; respectively). Serum resistin levels were similar in groups (2.6 (1.9-3.1), 2.8 (1.7-3.4), and 3.0 (2.2-3.5) ng/ml in HOB, HNOB, and OB groups, respectively). Basal serum glucose, basal and second-hour insulin levels in OGTT, and HOMA index were higher in OB group than the HOB and HNOB groups, indicating insulin resistance in simple obesity; however, increment of insulin to same glycemic load in OGTT was highest in the HOB group indicating insulin dysregulation (p < 0.05). CONCLUSION: Hypothalamic obesity seems to be related to both dysregulated afferent (leptin) and efferent (insulin) neural outputs through the autonomic nervous system resulting in energy storage as fat.

[Clinical and imaging features of hypothalamic hamartoma in children].

OBJECTIVE: To study clinical and imaging features of hypothalamic hamartoma in children. METHODS: Imaging findings and clinical manifestations of 38 children with hypothalamic hamartomas were retrospectively reviewed. The patients included 25 boys and 13 girls, ranging in age of onset from 1 month to 15 years. All the 38 patients were examined with pre-contrast and post-contrast T1 weighted MR imaging and with non-contrast T2 weighted MR imaging. Meanwhile, 10 patients received CT scan. Hypothalamic hamartomas were confimed by pathologic examinations in the 38 patients. RESULTS: Gelastic epilepsy, precocious puberty, other types of epilepsy and disturbance of intelligence were main manifestations in the 38 patients. Gelastic epilepsy was found as an initial clinical symptom in 17 cases, precocious puberty in 13 cases and other types of epilepsy in 8 cases. All masses were located in the suprasellar and interpeduncular cistern. They showed iso-density on CT scan, and homogeneous signal iso-intense to gray matter on T1 and T2 weighted MR images. With contrast MR images, there was no enhancement in the mass. The size or pedunculation of the mass was not correlated with clinical features. CONCLUSIONS: Hypothalamic hamartoma may be characterized by precocious puberty and/or gelastic epilepsy and specific imaging findings mentioned above.