Diagnosis Of Dysembryoplastic Neuroepithelial Tumor Research Articles

Association between features of intraoperative ultrasound and magnetic resonance imaging in the diagnosis of dysembryoplastic neuroepithelial tumor.

To analyze the characteristics of images from intraoperative ultrasound (IoUS) and preoperative magnetic resonance imaging (MRI) and their relationship with pathological components of dysembryoplastic neuroepithelial tumor (DNT) and to discuss the role of IoUS in detecting tumor residues. The clinical and image data of 24 patients with postoperative pathology-confirmed DNT were analyzed retrospectively. Baseline characteristics, imaging features, and intraoperative residues were recorded for further analysis. Cohen's kappa consistency evaluation was performed on the echo and signal characteristics of the lesions. Cohen's kappa coefficient between the echo and signal of the lesion was 0.832. The characteristics of IoUS were gyrus or mass hyperechoic solid nodules located under the cortex, insufficient blood flow signals, and clear boundaries, in addition to mixed cystic and solid echo nodules. The solid part of the lesion consisted of pathologically nodular specific glioneuronal element (SGE) or was combined with glial nodules and focal cortical dysplasia (FCD), which was characterized by a high echo or long T1 long T2 signal and uniform or uneven distribution. The cystic part consisted of a mucinous matrix, showing echoless or long T1 long T2 on fluid attenuated inversion recovery (FLAIR), which was higher than that in cerebrospinal fluid but lower than that in the cerebral cortex. The residual lesion discovered using IoUS was confirmed with postoperative MRI. The IoUS characteristics of DNT are strongly consistent with MRI, and its imaging features are related to pathological components. IoUS can assist the operator to judge the mode and scope of tumor resection, detect residual tumor, and improve the rate of total tumor resection.

Clinical and histopathological profile of dysembryoplastic neuroepithelial tumor: An experience from a tertiary care center.

Dysembryoplastic neuroepithelial tumor (DNT) is a rare benign brain tumor predominantly involving children and young adults. Histologically, it corresponds to WHO Grade I tumors; however, it may masquerade aggressive neural tumors such as oligodendroglioma, oligoastrocytoma, pilocytic astrocytoma, and ganglioglioma. The literature on clinical, radiological, and pathological spectrum of DNT is described mostly in the form of case reports, with only a few case series reported till date. A retrospective review of files with diagnosis of DNT (2016 to 2018) was made in the Department of Pathology, National Institute of Pathology, New Delhi. A total of ten cases were retrieved, and their clinical, radiological, and histopathological features were reviewed and studied. Special stains and immunohistochemistry were done, wherever required. The mean age was 14.8 (±7.9) years, with a male-to-female ratio of 1.5:1. The most common mode of presentation was recurrent, intractable seizures. The most common site of lesion was parietal lobe followed by temporal and frontal lobes of the brain. On histology, mucoid matrix admixed with floating neurons and oligodendrocyte-like cells was a consistent feature; however, the presence of specific glioneuronal elements was observed in only a few cases. DNT is a benign, low-grade, nonrecurrent neuroepithelial neoplasm. It is important to differentiate this rare entity from other mimickers, as it is surgically curable and carries an excellent prognosis without the need for adjuvant chemotherapy and radiotherapy. The study helps to enrich the clinicopathological aspects of this rare but important entity.

LGG-02. A BRAIN TUMOR DIAGNOSED AFTER TRANSITION TO THE DEPARTMENT OF ADULT NEUROSURGERY FROM THE DEPARTMENT OF PEDIATRICS

The patient was a 17-year-old boy with a history of 4 non-febrile convulsions at 15 and 16 years of age. He visited the Department of Pediatrics at a pediatric hospital. An electroencephalogram showed right frontal spike discharge. MRI was performed and judged to show no abnormality. The pediatric doctor diagnosed him with epilepsy. At 17 years old, he was referred to our Department of Adult Neurosurgery for transition. Physical and neurological examinations showed no abnormalities. Brain MRI showed right frontal cortical small tumor, with T1 low, T2 high, diffusion-weighted imaging low, and partial contrast enhancement. We diagnosed him with a brain tumor and symptomatic epilepsy. We surgically removed a right frontal cortical tumor. A pathological examination finalized the diagnosis of dysembryoplastic neuroepithelial tumor. MRI confirmed the total removal of the tumor. Anticonvulsant was started before surgery. No epileptic seizure was observed, so the anticonvulsant medication was gradually tapered and stopped at two years after the surgery. No epilepsy nor recurrence has been observed thus far. The problem with the initial management of this case at the Department of Pediatrics in the pediatric hospital was that the brain tumor was missed despite an MRI examination. Had the transition not happened, this brain tumor might not have been diagnosed. A brain tumor is a rare disease, and epilepsy is a common disease. However, in cases of non-febrile convulsion, a brain tumor should be considered. Collaboration within a single department, hospital and local area should be established.

Germline and somatic FGFR1 abnormalities in dysembryoplastic neuroepithelial tumors.

Dysembryoplastic neuroepithelial tumor (DNET) is a benign brain tumor associated with intractable drug-resistant epilepsy. In order to identify underlying genetic alterations and molecular mechanisms, we examined three family members affected by multinodular DNETs as well as 100 sporadic tumors from 96 patients, which had been referred to us as DNETs. We performed whole-exome sequencing on 46 tumors and targeted sequencing for hotspot FGFR1 mutations and BRAF p.V600E was used on the remaining samples. FISH, copy number variation assays and Sanger sequencing were used to validate the findings. By whole-exome sequencing of the familial cases, we identified a novel germline FGFR1 mutation, p.R661P. Somatic activating FGFR1 mutations (p.N546K or p.K656E) were observed in the tumor samples and further evidence for functional relevance was obtained by in silico modeling. The FGFR1 p.K656E mutation was confirmed to be in cis with the germline p.R661P variant. In 43 sporadic cases, in which the diagnosis of DNET could be confirmed on central blinded neuropathology review, FGFR1 alterations were also frequent and mainly comprised intragenic tyrosine kinase FGFR1 duplication and multiple mutants in cis (25/43; 58.1%) while BRAF p.V600E alterations were absent (0/43). In contrast, in 53 cases, in which the diagnosis of DNET was not confirmed, FGFR1 alterations were less common (10/53; 19%; p<0.0001) and hotspot BRAF p.V600E (12/53; 22.6%) (p<0.001) prevailed. We observed overexpression of phospho-ERK in FGFR1 p.R661P and p.N546K mutant expressing HEK293 cells as well as FGFR1 mutated tumor samples, supporting enhanced MAP kinase pathway activation under these conditions. In conclusion, constitutional and somatic FGFR1 alterations and MAP kinase pathway activation are key events in the pathogenesis of DNET. These findings point the way towards existing targeted therapies.

Magnetic resonance imaging diagnosis of dysembryoplastic neuroepithelial tumor in children

Objective To study magnetic resonance imaging(MRI) features of dysembryoplastic neuroepithelial tumor(DNT) and to improve accurate diagnosis of DNT. Methods The MRI appearance and clinical features of 10 patients with DNT confirmed by surgery and pathology were analyzed retrospectively. Results In 10 cases, 9 tumors located in supratentorial hemisphere cortex, 3 tumors located in the temporal lobe, 5 in the frontal lobe, 1 in the parietal lobe, and 2 of them encroached the adjacent white matter.In 9 tumors located in supratentorial hemisphere cortex, 8 cases had decreased signal intensity on T1-weighted MR images, 1 case iso-decreased mixed signal intensity on T1-weighted MR images, and 9 cases increased signal intensity on T2-weighted images, 9 cases slightly increased signal intensity on fluid attenuated inversion recovery weighted images.The manifestation of tumors was cystic or cystic partially oriented and was seen separate section intratumoral in some cases.Three cases appeared as hyperintense ring sign and internal septation, 2 cases appeared as a triangle in shape, 3 cases appeared as gyrus-like shape, and 1 case as round shape, similar to cyst.Nine tumors had no significant mass effect and peritumoral edema.Enhanced MR imaging showed only 1 case with slight and heterogeneous enhancement, the rest 6 cases showed non enhancement.One case located in cerebellar hemisphere, and appeared cystic-solid mass, the solid part had decreased signal intensity on T1-weighted MR images, and increased signal intensity on T2-weighted images, the cystic part had decreased signal intensity on T1-weighted MR images, and increased signal intensity on T2-weighted images.On enhanced MR imaging, the wall-node obviously contrast enhancement, cyst wall slightly contrast enhancement, cystic part non enhancement.The tumor had peritumoral edema and mass effect.Ten cases had no hemorrhage and calcification. Conclusion The MRI appearance of DNT is characteristic and is helpful for the preoperative diagnosis of DNT. Key words: Dysembryoplastic neuroepithelial tumor; Magnetic resonance imaging; Child

Diagnosis and treatment for dysembryoplastic neuroepithelial tumor

Objective To investigate the clinical characteristics of dysembryoplastic neuroepithelial tumor(DNET) and to improve the comprehension of the lesions.Method The clinical presentation,imaging characteristics,surgical treatment and histopathologic outcomes of fourty-two cases with a confirmed diagnosis of DNET were restrospoctively reviewed.Results The first symptom of DNET was epilepsy in 40 cases (40/42,95%).The characteristics of MRI examination of DNET included decreased signal on the T1-weighted images and a hyper-intense signal on T2-weighted images in 37 cases,and intermix T1 and T2 in 5 patients.Thirty cases were type A and 12 cases were type B.Conclusions Epilepsy is the first and foremost symptom of DNET.CT and MRI are most important diagnostic methods for DNET before operation.Extended resection including mass lesion and epilepsy focus should be performed to relieve seizure attack. Key words: Neoplasms,neuroepithelial; Diagnosis; Surgical procedures,operative; Type

F-18 FDG-PET Imaging of Dysembryoplastic Neuroepithelial Tumor-Like Astrocytoma

Cerebral astrocytoma needs to be distinguished from dysembryoplastic neuroepithelial tumor (DNT) when a well-demarcated, cortically based and pseudo-cystic tumor with minimal mass effect is demonstrated on magnetic resonance imaging. We report an unusual case of DNT-like astrocytoma. 18F fluoro-deoxy-glucose (FDG) positron emission tomography showed a focal increase of FDG uptake in a deep part of the tumor. Histologic examination revealed predominantly microcystic change with oligodendrocyte-like cells, leading to a diagnosis of DNT. However, increased cellularity and nuclear atypia of astrocytes within the tumor were conspicuous as for DNT. Four years after excision, tumor recurrence was detected. FDG-positron emission tomography is useful for identifying the malignant potential of DNT-like astrocytoma.

Electroencephalography-Guided Resection of Dysembryoplastic Neuroepithelial Tumor -Case Report-

A 3-year-old girl presented with a dysembryoplastic neuroepithelial tumor in the right cingulate gyrus manifesting as epilepsy refractory to anticonvulsant medication. Computed tomography and magnetic resonance imaging revealed a cystic tumor in the right cingulate gyrus. The tumor was removed under intraoperative electrocorticography guidance. Abnormal spikes recorded adjacent to the tumor disappeared immediately after total removal. Histological examination showed a multinodular, multicystic structure, satisfying the criteria for the diagnosis of dysembryoplastic neuroepithelial tumor. She has remained seizure-free for more than 4 years without complications. In this case, intraoperative electrocorticography was very useful to identify the possible focus and prevent unnecessary resection of the adjacent tissue. Total removal of the tumor resulted in a dramatic reduction of seizure activity.

Dysembryoplastic neuroepithelial tumors: proton MR spectroscopy, diffusion and perfusion characteristics

We describe the magnetic resonance (MR) imaging characteristics of dysembryoplastic neuroepithelial tumors (DNT) and discuss their differential diagnosis. Proton MR spectroscopy (TE 30 and 136 ms), diffusion-weighted and perfusion images were retrospectively evaluated in 22 patients with pathologically proven DNT (17 male and 5 female, mean age 18.7 years) and 14 control subjects (10 male and 4 female, mean age 16.9 years). The results from the DNT patients and from the control subjects were compared using an independent sample t-test and the degree of correlation was tested by Pearson's correlation. All DNTs were solitary and in a supratentorial cortical or subcortical location (ten temporal, eight frontal and four parietal). They had low-signal on T1-weighted images and high-signal on T2-weighted images without a prominent mass effect. Additionally a cystic appearance (six patients, 27.3%), cortical dysplasia (six patients, 27.3%) and contrast enhancement (four patients, 18.2%) were also noted. No significant differences were detected in NAA/Cho, NAA/Cr, NAA/Cho+Cr or Cho/Cr ratios between DNT and normal brain. DNTs had a significantly higher mI/Cr ratio and apparent diffusion coefficient (ADC) values and lower cerebral blood values than normal parenchyma (P < 0.001). ADC had the highest correlation with the diagnosis of DNT (r = 0.996) followed by relative cerebral blood volume (rCBV) (r = -0.883) and mI/Cr ratio (r = 0.663). Proton MR spectroscopy, diffusion-weighted and perfusion imaging characteristics of DNTs provide additional information to their MR imaging findings. The MR spectrum showing a slight increase in mI/Cr ratio, and higher ADC and lower rCBV values than normal parenchyma help to differentiate DNTs from other cortical tumors, which had higher rCBV and lower ADC values than DNTs.

Development of a pilocytic astrocytoma in a dysembryoplastic neuroepithelial tumor

Dysembryoplastic neuroepithelial tumors (DNETs) are benign supratentorial tumors based in the cerebral cortex. They usually are found in children and young adults with seizures that tend to become refractory to medical treatment. In the vast majority of cases resection results in good seizure control, and adjuvant therapy is not required. When tumors thought to be DNETs are not resected due to their proximity to eloquent cortex, lack of change in the clinical and neuroimaging features over time supports the diagnosis of DNET. The authors report on a patient in whom a pilocytic astrocytoma developed within a DNET, raising questions regarding the classification of these lesions and the need for lifelong clinical and imaging surveillance. This paper adds to the growing body of literature about the biological behavior of these lesions.

RAPIDLY GROWING DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOR

During the past 15 years, the concept of dysembryoplastic neuroepithelial tumors has continued to evolve. We present an interesting case of dysembryoplastic neuroepithelial tumor that showed rapid growth during a short period of time. A 9-year-old boy had been experiencing intractable complex partial seizures since the age of 7 years. Magnetic resonance imaging scans demonstrated a well-demarcated 3.5-cm lesion with a 1.5-cm ring-enhanced core in the left temporal lobe. One month later, the lesion had rapidly grown to occupy three times more space than on the first evaluation, with the ring-enhanced core reaching approximately five times its initial volume. A combined tumor removal and epileptogenic focus resection surgery was performed immediately. In the pathological examination, the presence of the specific glioneuronal element with a Ki-67 labeling index of lower than 1%, as well as the glial component with a Ki-67 labeling index of 8%, led to a postoperative diagnosis of dysembryoplastic neuroepithelial tumor, complex form. No adjuvant therapy was performed. Five years after surgery, there is no evidence of any recurrence and the boy continues to be seizure free without antiepileptic drugs. The lesion did not behave as a stable benign entity as it is generally accepted, and is, therefore, presented as an argument in favor of an early and complete resection.