Answer for BIR CoW 04 Dec 2022
Complex Dysembryoplastic Neuro Epithelial Tumour (DNET) with Type 3 Focal Cortical Dysplasia (FCD).
Findings
MRI shows a well-defined, well-marginated, T1 isointense/ T2 hyperintense intraaxial lesion in the left post-central gyrus with cyst-like spaces within. There was partial suppression of the signal of cyst-like spaces on the FLAIR sequence. There was no diffusion restriction and no significant enhancement on post-contrast images. There were no areas of blooming. There was no perilesional edema or no mass effect. There was associated mild adjacent bony scalloping indicating chronicity of the lesion. There was a focal expansion of the cortex noted adjacent to the lesion. Awake craniotomy was performed in view of the tumor's location in the eloquent cortex and gross total resection of the tumor was achieved. Histopathology showed the specific glioneuronal elements; small oligodendrocyte-like cells arranged in columns with S-100 positivity and few normal (floating) neurons between tumor cells and extracellular mucin. The surrounding cortex shows disturbed lamination and architectural disarray. The final diagnosis was Complex Dysembryoplastic Neuro Epithelial Tumour (DNET) with Type 3 Focal Cortical Dysplasia (FCD).
Discussion
DNET is a benign, slow-growing, supratentorial, cortical-based, low-grade glioma associated with chronic drug-resistant epilepsy in children and adolescents. Long-term epilepsy-associated tumors (LEATs) include DNET, ganglioglioma, and pleomorphic xanthoastrocytoma. The most common location is the temporal lobe although any part of the cerebral cortex can be involved. DNETs are of two types. 1. Complex type: surrounded by dysplastic cortex; which is highly epileptogenic. 2. Simple type: epileptogenic zone is localized within the tumor. CT can show a low attenuation lesion and MRI they have swollen gyri with a typical bubbly or popcorn-like multinodular lesion with T1 hypointensity and T2/FLAIR hyperintensity. Bright rim sign- well-defined hyperintense ring surrounding the DNET on FLAIR. They do not usually enhance or show diffusion restriction. They can sometimes have an elevated lactate peak. Multigyral involvement, tumor location in the eloquent cortex, and satellite lesions are associated with a higher chance of seizure and tumor recurrence. Focal cortical dysplasia is a congenital condition of abnormal cortical development, characterized by a thickened cortex with the blurring of grey-white matter junction. Most commonly seen in the temporal lobe, followed by the frontal and then the parietal lobe. Transmantle sign: Focal signal intensity extending from the cortex to the adjacent ventricle is a characteristic MRI sign described. They are of three types according to Blumcke’s classification, when associated with 1. Abnormal cortical lamination 2. Dysplastic neurons and balloon cells 3. Architectural distortion; adjacent to a) Hippocampal sclerosis/atrophy b) Glial or glioneuronal tumour c) Vascular malformation d) Early childhood insults (gliosis)
References:
1. Phi JH, Kim SH. Dysembryoplastic Neuroepithelial Tumor: A Benign but Complex Tumor of the Cerebral Cortex. Brain Tumor Res Treat. 2022;10(3):144-150. doi:10.14791/btrt.2022.0015
2. Makola, Monwabisi & Cecil, Kim. Dysembryoplastic neuroepithelial tumor (DNET) and focal cortical dysplasia: Case report of two pediatric patients with imaging features. International Journal of Diagnostic Imaging. 2017;4(31). doi:10.5430/ijdi.v4n2p31.
Findings
MRI shows a well-defined, well-marginated, T1 isointense/ T2 hyperintense intraaxial lesion in the left post-central gyrus with cyst-like spaces within. There was partial suppression of the signal of cyst-like spaces on the FLAIR sequence. There was no diffusion restriction and no significant enhancement on post-contrast images. There were no areas of blooming. There was no perilesional edema or no mass effect. There was associated mild adjacent bony scalloping indicating chronicity of the lesion. There was a focal expansion of the cortex noted adjacent to the lesion. Awake craniotomy was performed in view of the tumor's location in the eloquent cortex and gross total resection of the tumor was achieved. Histopathology showed the specific glioneuronal elements; small oligodendrocyte-like cells arranged in columns with S-100 positivity and few normal (floating) neurons between tumor cells and extracellular mucin. The surrounding cortex shows disturbed lamination and architectural disarray. The final diagnosis was Complex Dysembryoplastic Neuro Epithelial Tumour (DNET) with Type 3 Focal Cortical Dysplasia (FCD).
Discussion
DNET is a benign, slow-growing, supratentorial, cortical-based, low-grade glioma associated with chronic drug-resistant epilepsy in children and adolescents. Long-term epilepsy-associated tumors (LEATs) include DNET, ganglioglioma, and pleomorphic xanthoastrocytoma. The most common location is the temporal lobe although any part of the cerebral cortex can be involved. DNETs are of two types. 1. Complex type: surrounded by dysplastic cortex; which is highly epileptogenic. 2. Simple type: epileptogenic zone is localized within the tumor. CT can show a low attenuation lesion and MRI they have swollen gyri with a typical bubbly or popcorn-like multinodular lesion with T1 hypointensity and T2/FLAIR hyperintensity. Bright rim sign- well-defined hyperintense ring surrounding the DNET on FLAIR. They do not usually enhance or show diffusion restriction. They can sometimes have an elevated lactate peak. Multigyral involvement, tumor location in the eloquent cortex, and satellite lesions are associated with a higher chance of seizure and tumor recurrence. Focal cortical dysplasia is a congenital condition of abnormal cortical development, characterized by a thickened cortex with the blurring of grey-white matter junction. Most commonly seen in the temporal lobe, followed by the frontal and then the parietal lobe. Transmantle sign: Focal signal intensity extending from the cortex to the adjacent ventricle is a characteristic MRI sign described. They are of three types according to Blumcke’s classification, when associated with 1. Abnormal cortical lamination 2. Dysplastic neurons and balloon cells 3. Architectural distortion; adjacent to a) Hippocampal sclerosis/atrophy b) Glial or glioneuronal tumour c) Vascular malformation d) Early childhood insults (gliosis)
References:
1. Phi JH, Kim SH. Dysembryoplastic Neuroepithelial Tumor: A Benign but Complex Tumor of the Cerebral Cortex. Brain Tumor Res Treat. 2022;10(3):144-150. doi:10.14791/btrt.2022.0015
2. Makola, Monwabisi & Cecil, Kim. Dysembryoplastic neuroepithelial tumor (DNET) and focal cortical dysplasia: Case report of two pediatric patients with imaging features. International Journal of Diagnostic Imaging. 2017;4(31). doi:10.5430/ijdi.v4n2p31.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!