Dysembryoplastic neuroepithelial tumor (WHO Grade 1)

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Synonyms
DNET, DNT
ICD-11
XH0H76, 2A00.21

The dysembryoplastic neuroepithelial tumor (abbreviated DNET or DNT) is a rare, benign Brain tumor belonging to the group of gliomas and classified as a WHO Grade 1 tumor[^3].

Epidemiology

The incidence of DNETs is estimated at 0,8% - 5 % of all primary brain tumors[^1], and they account for approximately 30% of all mixed glioneuronal tumors. DNETs typically occur in children and young adults.

Symptoms

DNETs are typically associated with longstanding, medically refractory epileptic seizures. Symptom onset usually occurs before the age of 20[^1].

Location

The tumors are generally located superficially in the cerebrum; however, infratentorial locations have also been described. DNETs are most commonly located in the temporal lobe or frontal lobe. Localization in the parietal or occipital lobe is rare[^1].

Imaging

Dysembryoplastic neuroepithelial tumors typically present as cortical lesions without perifocal Edema and without mass effect or Midline shift. On CT imaging, DNETs appear as sharply demarcated hypodense space-occupying lesions, often with deformity of the adjacent overlying calvarium[^1]. On MRI, DNETs are hypointense on the T1 sequence and hyperintense on T2 weighting. Occasional nodular contrast enhancement may occur[^1]. On PET scans, DNETs are hypometabolic with 18F-fluorodeoxyglucose and show no 11C-methionine uptake[^1].

Histopathology

Histopathologically, two different forms of DNETs are distinguished:

  • Simple form: Glioneuronal elements with axon bundles oriented perpendicular to the cortical surface and oligodendroglial-like cells. These cells are S-100-positive and GFAP-negative. Normal neurons are scattered between these perpendicular columns in a pale eosinophilic matrix that, unlike gangliogliomas, bears no resemblance to ganglion cells[^1].

  • Complex form: Glioneuronal elements as in the simple form, with scattered glial nodules. The glial component may resemble a low-grade fibrillary astrocytoma. Individual foci of cortical dysplasia.

Molecular genetics

DNETs are associated with mutations or duplications of the FGFR1 gene[^2].

Prognosis

The prognosis for DNET is favorable; therefore, DNETs are classified as Grade I according to the WHO classification of tumors of the central nervous system. Epileptic seizures usually improve after surgical resection. The degree of improvement in epileptic seizures correlates with the completeness of resection and is inversely correlated with the duration of medically refractory seizures[^1].

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Edit · Alaric Steinmetz · (+282 −38)
  • Text added: “Epidemiology”
  • Text added: “The incidence of DNETs is estimated at 0,8% - 5 % of all primary brain tumors[^1], and they account for approximately 30% of all mixed glioneuronal tumors. DNETs typically occur in children and young adults.”
  • Text added: “Symptoms”
  • Text added: “DNETs are typically associated with longstanding, medically refractory epileptic seizures. Symptom onset usually occurs before the age of 20[^1].”
  • Text added: “Location”
  • Text added: “The tumors are generally located superficially in the cerebrum; however, infratentorial locations have also been described. DNETs are most commonly located in the temporal lobe or frontal lobe . Localization in the parietal or occipital lobe is rare[^1].”
  • Text added: “Imaging”
  • Text added: “Dysembryoplastic neuroepithelial tumors typically present as cortical lesions without perifocal Edema and without mass effect or Midline shift . On CT imaging , DNETs appear as sharply demarcated hypodense space-occupying lesions, often with deformity of the adjacent overlying calvarium[^1]. On MRI, DNETs are hypointense on the T1 sequence and hyperintense on T2 weighting . Occasional nodular contrast enhancement may occur[^1]. On PET scans, DNETs are hypometabolic with 18F-fluorodeoxyglucose and show no 11C-methionine uptake[^1].”
  • Text added: “Histopathology”
  • Text added: “Histopathologically, two different forms of DNETs are distinguished:”
  • Text added: “Molecular genetics”
  • Text added: “DNETs are associated with mutations or duplications of the FGFR1 gene[^2].”
  • Text added: “Prognosis”
  • Text added: “The prognosis for DNET is favorable; therefore, DNETs are classified as Grade I according to the WHO classification of tumors of the central nervous system. Epileptic seizures usually improve after surgical resection. The degree of improvement in epileptic seizures correlates with the completeness of resection and is inversely correlated with the duration of medically refractory seizures[^1].”
  • Text removed: “## Epidemiology {#epidemiologie} The incidence of DNETs is estimated at 0.8% - 5 % of all primary brain tumors[^1] and accounts for approximately 30% of all mixed glioneuronal tumors. DNETs typically occur in children and young adults.”
  • Text removed: “## Symptoms {#symptome} DNETs are typically associated with long-standing, drug-resistant epileptic seizures. Symptom onset usually occurs before the age of 20[^1].”
  • Text removed: “## Location {#lokalisation} The tumors are generally located superficially in the cerebrum; however, [infratentorial](\/lexikon\/infratentoriell) locations have also been described. DNETs are most commonly located in the [temporal lobe](\/lexikon\/lobus-temporalis) or [frontal lobe](\/lexikon\/lobus-frontalis-frontallappen). Localization in the [parietal lobe](\/lexikon\/lobus-parietalis-parietallappen) or [occipital lobe](\/lexikon\/lobus-occipitalis) is rare[^1].”
  • Text removed: “## Imaging {#bildgebung} Dysembryoplastic neuroepithelial tumors typically appear as cortical lesions without perifocal edema and without mass effect or [midline shift](\/lexikon\/mittellinienverlagerung). On CT imaging, DNETs appear as hypodense masses with sharp margins and frequent deformity of the overlying calvaria[^1]. On MRI, DNETs are hypointense on T1-weighted sequences and hyperintense on T2-weighted images. Nodular contrast enhancement may occasionally occur[^1]. On PET scans, DNETs are hypometabolic with 18F-fluorodeoxyglucose and show no 11C-methionine uptake[^1].”
  • Text removed: “## Histopathology {#histopathologie} Histopathologically, two different forms of DNETs are distinguished:”
  • Text removed: “* Simple form: Glioneuronal elements with axon bundles perpendicular to the cortical surface and oligodendroglial-like cells. These cells are [S-100](\/lexikon\/s-100-protein) positive and [GFAP](\/lexikon\/saures-gliafaserprotein) negative. Normal neurons are scattered between these perpendicular columns in a pale eosinophilic matrix, which, unlike gangliogliomas, shows no resemblance to ganglion cells[^1].”
  • Text removed: “* Complex form: Glioneuronal elements as in the simple form with scattered glial nodules. The glial component may resemble a low-grade fibrillary astrocytoma. Individual foci of cortical dysplasia.”
  • Text removed: “## Molecular Genetics {#molekulargenetik} DNETs are associated with mutations or duplications of the FGFR1 gene[^2].”
  • Text removed: “## Prognosis {#prognose} The prognosis of DNET is favorable, which is why DNETs are classified as Grade I according to the WHO classification of tumors of the central nervous system. Epileptic seizures usually improve after surgical resection. The degree of improvement in epileptic seizures correlates with the completeness of resection and is inversely correlated with the duration of drug-resistant seizures[^1].”
  • Text removed: “**References**”
  • Text removed: “[^1]: Handbook of Neurosurgery. Greenberg M, ed. 9th Edition. New York: Thieme; 2019. [^2]: [Rivera, Barbara, et al. "Germline and somatic FGFR1 abnormalities in dysembryoplastic neuroepithelial tumors." Acta neuropathologica 131 (2016): 847-863.](https:\/\/doi.org\/10.1007\/s00401-016-1549-x)”
  • Text changed: “The dysembryoplastic neuroepithelial tumor (abbreviated DNET or DNT) is a rare, benign brain tumor belonging to the group of gliomas.”“The dysembryoplastic neuroepithelial tumor (abbreviated DNET or DNT) is a rare, benign Brain tumor belonging to the group of gliomas and classified as a WHO Grade 1 tumor[^3].”
  • Citation added: “Rivera, Barbara, et al. "Germline and somatic FGFR1 abnormalities in dysembryoplastic neuroepithelial tumors." Acta neuropathologica 131 (2016): 847-863”
  • Citation added: “Louis, David N., et al. "The 2021 WHO classification of tumors of the central nervous system: a summary." Neuro-oncology 23.8 (2021): 1231-1251.”
  • Citation removed: “Handbook of Neurosurgery. Greenberg M, ed. 9th Edition. New York: Thieme; 2019.”
  • Citation removed: “Rivera, Barbara, et al. "Germline and somatic FGFR1 abnormalities in dysembryoplastic neuroepithelial tumors." Acta neuropathologica 131 (2016): 847-863.”
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