The effectiveness of diffusion kurtosis imaging metrics for distinguishing between brainstem glioma and cerebellar medulloblastoma.

Background: In some clinical situations, distinguishing between cerebellar medulloblastoma and brainstem glioma is important. We assessed whether diffusion kurtosis imaging (DKI) metrics could be used to distinguish cerebellar medulloblastomas from brainstem gliomas in children. Patients and methods: This prospective study was approved by the institutional review board. Seventy patients were separated into two groups according to eventual diagnosis: brainstem glioma (n = 30) and cerebellar medulloblastoma (n = 40). Both groups underwent brain magnetic resonance imaging (MRI), including DKI. The Kurtosis value for the tumor region and the ratio between Kurtosis values between the tumor and the normal parenchyma (rKurtosis) were compared between groups using the Mann-Whitney U test. Receiver operating characteristic curve analysis and the Youden's Index were applied to identify a cutoff value for distinguishing between the two tumor types, and the area under the curve (AUC), sensitivity, and specificity for the selected cutoff value were calculated. Results: Compared with brainstem gliomas, cerebellar medulloblastomas had significantly higher Kurtosis and rKurtosis values (p < 0.05). Medulloblastoma could be differentiated from brainstem gliomas using a Kurtosis value of 0.91 or an rKurtosis value of 0.90, both of which achieved 100% sensitivity, 96.7% specificity, and AUC values of 0.990. Conclusions: DKI measurements can contribute to distinguishing between cerebellar medulloblastoma and brainstem glioma in children.

The Role of Apparent Diffusion Coefficient in the Differentiation between Cerebellar Medulloblastoma and Brainstem Glioma.

For certain clinical circumstances, the differentiation between cerebellar medulloblastoma and brainstem glioma is essential. We aimed to evaluate the role played by the apparent diffusion coefficient (ADC) values in the differentiation between cerebellar medulloblastomas and brainstem gliomas in children. The institutional review board approved this prospective study. Brain magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) and ADC, was assessed in 32 patients (median age: 7.0 years), divided into two groups, a medulloblastoma group (group 1, n = 22) and a brainstem glioma group (group 2, n = 10). The Mann-Whitney U test was utilized to compare tumor ADCmax, ADCmin, ADCmean, and ADCsd values, and their ratios with the parenchyma values between the two groups. Receiver operating characteristic (ROC) curve analysis and the Youden index were used to calculate the cut-off value, along with the area under the curve (AUC), sensitivity, and specificity. The median ADCmax, ADCmin, and ADCmean values were significantly higher in group 2 than in group 1 (p < 0.05). The median ratios of ADCmin and ADCmean to the parenchyma were significantly higher in group 2 than in group 1 (p < 0.05). The ROC analysis showed that the AUC for the ADCmean ratio was the highest among these parameters, at 98.2%. The ADCmean tumor to parenchyma ratio was a significant and effective parameter for the differentiation between pediatric medulloblastomas and brainstem gliomas.

A clinical case of presumed cerebellar medulloblastoma in a Japanese Black calf with increased neuron-specific enolase in cerebrospinal fluid.

A 2-day-old Japanese Black male calf that presented with opisthotonos with spastic extension of all four limbs and nystagmus was presented. Evaluation of cranial neurology revealed a horizontal slow nystagmus and absence of menace response in the left eye. Necropsy revealed a mass located between the posterior margin of the cerebrum and anterior margin of the cerebellum, and continuously with the cerebellar lesion. The brainstem was severely compressed by those lesions. Original structures of the cerebellum were mostly replaced by grayish-white and brownish tissues. Those lesions were diagnosed as presumed cerebellar medulloblastoma by histopathological and immunohistochemical examination. As neuron-specific enolase in the cerebrospinal fluid which is a biomarker for neuronal damage was increased compared with healthy calves.

The role of diffusion tensor imaging metrics in the discrimination between cerebellar medulloblastoma and brainstem glioma.

BACKGROUND: Differentiation between cerebellar medulloblastoma and brainstem glioma is necessary for certain clinical circumstances. We aimed to evaluate the function of diffusion tensor imaging (DTI) metrics in the differentiation between cerebellar medulloblastomas and brainstem gliomas in children. PROCEDURE: The institutional review board approved this prospective study. Brain magnetic resonance imaging (MRI), including DTI, was assessed in 40 patients, who were divided into two groups: a medulloblastoma group (group 1, n = 25) and a brainstem glioma group (group 2, n = 15). The Mann-Whitney U test was utilized to compare tumoral fractional anisotropy (FA) and diffusivity (MD) values and tumor-to-parenchyma ratios for these values (rFA and rMD, respectively) between the two groups. Receiver-operating characteristic (ROC) curve analysis and the Youden index were exploited to calculate the cutoff value, along with the area under the curve (AUC), sensitivity, and specificity. RESULTS: The FA value for medulloblastomas was significantly higher than that for brainstem gliomas (P < 0.05). In contrast, the MD and rMD values for medulloblastoma were significantly lower than those for brainstem gliomas (P < 0.05). A cutoff MD value of 0.97 was identified as the most effective factor for the differential diagnosis between medulloblastomas and brainstem gliomas, which reached a sensitivity of 96%, a specificity of 100%, and an AUC of 99.5%. CONCLUSION: DTI metrics play a significant role in the differentiation between medulloblastoma and brainstem glioma in pediatric patients.

Biallelic loss of GNAS in a patient with pediatric medulloblastoma.

Genome sequencing was performed on matched normal and tumor tissue from a 6.5-yr-old boy with a diagnosis of recurrent medulloblastoma. A pathogenic heterozygous c.432+1G>A canonical splice donor site variant in GNAS was detected on analysis of blood DNA. Analysis of tumor DNA showed the same splice variant along with copy-neutral loss of heterozygosity on Chromosome 20 encompassing GNAS, consistent with predicted biallelic loss of GNAS in the tumor specimen. This case strengthens the evidence implicating GNAS as a tumor-suppressor gene in medulloblastoma and highlights a scenario in which therapeutics targeting the cAMP pathway may be of great utility.

Germline POLE mutation in a child with hypermutated medulloblastoma and features of constitutional mismatch repair deficiency.

Ultra-hypermutation (>100 mutations/Mb) is rare in childhood cancer genomes and has been primarily reported in patients with constitutional mismatch repair deficiency (CMMRD) caused by biallelic germline mismatch repair (MMR) gene mutations. We report a 5-yr-old child with classic clinical features of CMMRD and an ultra-hypermutated medulloblastoma with retained MMR protein expression and absence of germline MMR mutations. Mutational signature analysis of tumor panel sequencing data revealed a canonical DNA polymerase-deficiency-associated signature, prompting further genetic testing that uncovered a germline POLE p.A456P missense variant, which has previously been reported as a recurrent somatic driver mutation in cancers. This represents the earliest known onset of malignancy in a patient with a germline mutation in the POLE proofreading polymerase. The clinical features in this child, virtually indistinguishable from those of CMMRD, suggest that polymerase-proofreading deficiency should be considered in the differential diagnosis of CMMRD patients with retained MMR function.

Meduloblastoma cerebeloso durante el embarazo: Reporte de caso / Cerebellar meduloblastoma during pregnancy: A case report

Maternal malignancies complicate approximately one of every 1 000 pregnancies. These neoplasms arise more frequently from the breasts, cervix and hematopoietic system. Brain tumors in pregnancy are extremely rare. Cerebellar medulloblastomas are the most common malignant brain tumors in childhood. They are considered as embryonic tumors and represent 4% of all intracranial neoplasms; they are extremely rare during pregnancy. We present the case of a 21-year-old patient with a 16-week pregnancy who suffered of intense headache in the occipital region, accompanied by photophobia, slight alteration of coordination, unstable gaits and vomiting. Neurological evaluation was normal but for positive Romberg sign and ataxic gait. Cerebral magnetic resonance imaging showed a complex, ill-defined tumor occupying the cerebellar space. The patient underwent surgical reduction of the tumor. Histopathological analysis revealed grade IV cerebellar medulloblastoma. Adjuvant radiotherapy was administered. Cesarean section was performed at 34 weeks of gestation with live newborn. Following delivery, treatment was completed with external radiation therapy to the craniospinal axis.

Las neoplasias malignas maternas complican aproximadamente uno de cada 1 000 embarazos. Estas neoplasias surgen con mayor frecuencia de las mamas, cuello uterino o sistema hematopoyético. Los tumores cerebrales en el embarazo son extremadamente raros. Los meduloblastomas cerebelosos son los tumores cerebrales malignos más comunes de la infancia. Se les clasifica como tumor embrionario y representan el 4% de todas las neoplasias intracraneales; es extremadamente raro que aparezcan durante el embarazo. Se presenta un caso de una paciente de 21 años con embarazo de 16 semanas quien consultó por presentar cefalea intensa en la región occipital, acompañada de fotofobia, alteración ligera de la coordinación, marcha inestable y vómitos. El examen neurológico fue normal, aparte del signo de Romberg positivo y marcha atáxica. La resonancia magnética cerebral mostró tumoración compleja, mal definida, que ocupaba el espacio cerebeloso. La paciente fue sometida a reducción quirúrgica. El análisis histopatológico reveló meduloblastoma cerebeloso de grado IV. Se administró radioterapia adyuvante. La cesárea fue realizada a las 34 semanas de gestación, obteniendo un recién nacido vivo. Después del parto, la radioterapia externa hacia el eje craneoespinal completó el tratamiento.