Dysembryoplastic neuroepithelial tumor
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Synonyms and Keywords: DNT; DNET; Dysembryoplastic neuroepithelial tumors; Dysembryoplastic neuroepithelial tumour; Dysembryoplastic neuroepithelial tumours
Dysembryoplastic neuroepithelial tumor (also known as DNT or DNET) is a type of benign glioneuronal brain tumor that arises from the oligodendrocyte, which is normally involved in the production of myelin in the central nervous system. Dysembryoplastic neuroepithelial tumor is most commonly found in the temporal lobe (supratentorial cortex). Dysembryoplastic neuroepithelial tumor was first discovered by Dumas-Duport in 1988. Dysembryoplastic neuroepithelial tumors are glioneuronal tumors comprised of both glial and neuron cells and often have ties to focal cortical dysplasia. According to the World Health Organization is classified as benign brain tumors (WHO Grade I). Dysembryoplastic neuroepithelial tumors may be classified according to the World Health Organization into 3 groups: complex, simple, and unspecific. Dysembryoplastic neuroepithelial tumor is more commonly observed among patients aged between 8 and 19 years old. The majority of patients with dysembryoplastic neuroepithelial tumor remain asymptomatic and are undiagnosed until they become symptomatic at the time of diagnosis. Early clinical features include seizures, headaches, and personality changes. Common complications of dysembryoplastic neuroepithelial tumor include status epilepticus and severe memory loss. Surgical excision is the most common approach to the treatment of dysembryoplastic neuroepithelial tumor.
In 1988, Dumas-Duport was the first who described dysembryoplastic neuroepithelial tumor. It was primarily identified in autopsies or when the patient was undergoing a brain surgery for another reason. However, these days due to technological progress, it can be identified with imaging techniques during early stages. It was determined to name this tumor as “dysembryoplastic neuroepithelial tumor” due to unique clinicopathological features of this tumor, including:
- Deformity of the overlying skull
- Early onset of seizure
- Presence of focal cortoical dysplasia in the adjacent cortex
Dysembryonic neuroepithelial tumors are classified as benign brain tumors (WHO Grade I). Dysembryoplastic neuroepithelial tumors may be classified into 3 groups:
- Specific glioneuronal element (SGNE) only
The IDH1 gene mutations have been associated with the development of dysembryoplastic neuroepithelial tumor.
On gross pathology, characteristic findings of dysembryoplastic neuroepithelial tumor may appear as a cortical mass.
- On microscopic histopathological analysis, characteristic findings of dysembryoplastic neuroepithelial tumor may include:
- Axonal columns oriented to the surface
- Floating neurons in eosinophilic matrix
- Lined by cells similar to oligodendrocytes
- Large central nuclei with indentations
- Multiple small nucleoli (common)
- Clear cytoplasm
- Few stellated astrocytes
On immunohistochemical analysis, characteristic findings of dysembryoplastic neuroepithelial tumor may include:
- Positive MAP2
- Positive CD34
- Positive calbindin
- Positive nestin
- Positive MIB-1 (Ki-67)
- Positive synaptophysin
- Positive neuron-specific enolase
There are no established causes for dysembryoplastic neuroepithelial tumor.
Differentiating Dysembryoplastic Neuroepithelial Tumor from Other Diseases
Dysembryoplastic neuroepithelial tumor must be differentiated from other tumors that cause seizures, such as:
Epidemiology and Demographics
The prevalence of dysembryoplastic neuroepithelial tumor remains unknown.
Dysembryoplastic neuroepithelial tumor is more commonly observed among patients aged between 8 and 19 years old.
Dysembryoplastic neuroepithelial tumor affects men and women equally.
There is no racial predilection for dysembryoplastic neuroepithelial tumor.
There are no associated risk factors in the development of dysembryoplastic neuroepithelial tumor.
Natural History, Complications and Prognosis
- The majority of patients with dysembryoplastic neuroepithelial tumor remain asymptomatic and only become symptomatic at the time of diagnosis.
- Early clinical features include seizures, headaches, and personality changes.
- If left untreated, the majority of patients with dysembryoplastic neuroepithelial tumor may progress to develop severe cognitive dysfunction.
Common complications of dysembryoplastic neuroepithelial tumor include:
- Status epilepticus
- Severe memory loss
The prognosis of dysembryoplastic neuroepithelial tumor is generally good; the 5-year survival rate of patients with dysembryoplastic neuroepithelial tumor is approximately 80%.
Patients with dysembryoplastic neuroepithelial tumor are commonly well-appearing. Physical examination may be remarkable for:
There are no specific laboratory findings associated with dysembryoplastic neuroepithelial tumor.
MRI is the imaging modality of choice for dysembryoplastic neuroepithelial tumor.
- Solid component iso- to hypointense
T1 C+ (Gd)
- Solid component variable contrast enhancement
- Hyperintense solid component
- Variable signal in the cystic component depending on quantity proteinaceous material or presence of blood products
- Peri-tumoral FLAIR/T2 edema is distinctly uncommon
- Calcified areas (common) will show blooming signal loss
On CT scan, findings of dysembryoplastic neuroepithelial tumor may include:
- Tumors with cortical location may scallop the inner table of the skull vault (44-60%) but no erosion
- The cranial fossa can be minimally enlarged at times
- Calcification in approximately 30% (more common histologically)
- Low density
- No enhancement
Other Diagnostic Studies
- Repetitive spikes
- Burst of polyspikes
There is no treatment for dysembryoplastic neuroepithelial tumor; the mainstay of therapy is surgery.
Surgery is the mainstay of therapy for dysembryoplastic neuroepithelial tumor. Surgical excision is the most common approach to the treatment of dysembryoplastic neuroepithelial tumor.
There are no known primary preventive measures for dysembryoplastic neuroepithelial tumor.
- Daumas-Duport C, Scheithauer BW, Chodkiewicz JP, Laws ER, Vedrenne C (November 1988). "Dysembryoplastic neuroepithelial tumor: a surgically curable tumor of young patients with intractable partial seizures. Report of thirty-nine cases". Neurosurgery. 23 (5): 545–56. doi:10.1227/00006123-198811000-00002. PMID 3143922.
- Burneo JG, Tellez-Zenteno J, Steven DA, Niaz N, Hader W, Pillay N, Wiebe S (September 2008). "Adult-onset epilepsy associated with dysembryoplastic neuroepithelial tumors". Seizure. 17 (6): 498–504. doi:10.1016/j.seizure.2008.01.006. PMID 18316209.
- Dysembryoplastic neuroepithelial tumour. Wikipedia. https://en.wikipedia.org/wiki/Dysembryoplastic_neuroepithelial_tumour Accessed on May 2, 2016
- Suh, Yeon-Lim (2015-11-01). "Dysembryoplastic Neuroepithelial Tumors". Journal of Pathology and Translational Medicine. 49 (6): 438 449. doi:10.4132/jptm.2015.10.05. ISSN 2383-7837. PMC 4696533. PMID 26493957.
- Suh YL (November 2015). "Dysembryoplastic Neuroepithelial Tumors". J Pathol Transl Med. 49 (6): 438–49. doi:10.4132/jptm.2015.10.05. PMC 4696533. PMID 26493957.
- Dysembryoplastic neuroepithelial tumour. Libre Pathology https://librepathology.org/wiki/Dysembryoplastic_neuroepithelial_tumour Accessed on May 2, 2016