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Dysembryoplastic Neuroepithelial Tumors.

Suh YL - J Pathol Transl Med (2015)

Bottom Line: Histologically, the recognition of a unique, specific glioneuronal element in brain tumor samples from patients with medically intractable, chronic epilepsy serves as a diagnostic feature for complex or simple DNT types.However, nonspecific DNT has diagnostic difficulty because its histology is indistinguishable from conventional gliomas and because a specific glioneuronal element and/or multinodularity are absent.The histological and cytological differential diagnoses for this lesion, especially the nonspecific variant, will be discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

ABSTRACT
Dysembryoplastic neuroepithelial tumor (DNT) is a benign glioneuronal neoplasm that most commonly occurs in children and young adults and may present with medically intractable, chronic seizures. Radiologically, this tumor is characterized by a cortical topography and lack of mass effect or perilesional edema. Partial complex seizures are the most common presentation. Three histologic subtypes of DNTs have been described. Histologically, the recognition of a unique, specific glioneuronal element in brain tumor samples from patients with medically intractable, chronic epilepsy serves as a diagnostic feature for complex or simple DNT types. However, nonspecific DNT has diagnostic difficulty because its histology is indistinguishable from conventional gliomas and because a specific glioneuronal element and/or multinodularity are absent. This review will focus on the clinical, radiographic, histopathological, and immunohistochemical features as well as the molecular genetics of all three variants of DNTs. The histological and cytological differential diagnoses for this lesion, especially the nonspecific variant, will be discussed.

No MeSH data available.


Related in: MedlinePlus

Immunohistochemical findings of dysembryoplastic neuroepithelial tumors (DNTs). (A, B) Floating neurons are positive for synaptophysin (A) and phosphorylated neurofilament (B). (C, D) The oligodendroglioma-like cells (OLCs) are diffusely positive for S-100 (C) but negative for glial fibrillary acidic protein (D). (E) Nonspecific DNTs show slightly decreased synaptophysin granular staining compared with that seen in the adjacent normal cortex. (F) In the specific glioneuronal element, CD34 is expressed along the perikarya and in membrane of the floating neurons, pericellular stroma, and cytoplasm of OLCs. (G, H) The specific glioneuronal element shows cluster staining pattern of CD34 (G), while diffuse CD34 immunoreactivity in glial nodules of complex DNTs (H).
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f4-jptm-2015-10-05: Immunohistochemical findings of dysembryoplastic neuroepithelial tumors (DNTs). (A, B) Floating neurons are positive for synaptophysin (A) and phosphorylated neurofilament (B). (C, D) The oligodendroglioma-like cells (OLCs) are diffusely positive for S-100 (C) but negative for glial fibrillary acidic protein (D). (E) Nonspecific DNTs show slightly decreased synaptophysin granular staining compared with that seen in the adjacent normal cortex. (F) In the specific glioneuronal element, CD34 is expressed along the perikarya and in membrane of the floating neurons, pericellular stroma, and cytoplasm of OLCs. (G, H) The specific glioneuronal element shows cluster staining pattern of CD34 (G), while diffuse CD34 immunoreactivity in glial nodules of complex DNTs (H).

Mentions: In specific GN elements, floating neurons have expressed neuronal markers including synaptophysin neurofilament, NeuN, neuron specific enolase, MAP2, and class-III beta-tubulin (Fig. 4A, B). The majority of OLCs are strongly positive for S-100 protein and Oligo-2 but generally negative for glial fibrillary acidic protein (GFAP) (Fig. 4C, D). Rarely, OLCs may show immunoexpression of NeuN. Glial nodules contain variable numbers of GFAP-positive astrocytes. In the nonspecific type of DNTs, synaptophysin granular staining is slightly decreased in the lesion compared with that seen in the adjacent normal cortex (Fig. 4E). Other neuronal markers except MAP2 are negative in nonspecific DNTs, but MAP2 is frequently expressed [8]. The expression of CD34 has been reported in 25% to 61% of cases [6-8]. In our study, CD34 expression was more frequently observed in nonspecific types (83.3%) than in simple (10%) and complex types (30.8%). CD34 was positive in the neuronal cell membrane, pericellular stroma, and cytoplasm of OLCs and stellate cells with astroglial morphology (Fig. 4F). CD34 positive cells were focally identified in specific GN elements, whereas most nonspecific tumors and glial nodules of some complex DNTs showed a focal, multifocal, or diffuse pattern of CD34 immunoreactivity (Fig. 4G, H). CD34 was expressed in the peritumoral cortex (Fig. 5A–C), which is more frequent in nonspecific (94.4%) than in classic (26.1%) DNTs. Different expression patterns of nestin and MAP2 in three subtypes of DNTs have also been demonstrated [8,30]. Combined analysis of CD34 and MAP2 is useful in differential diagnosis between nonspecific DNTs and diagnostically challenging mimickers, which will be discussed in the section on differential diagnosis. The Ki-67 labeling index is generally low, below 1% or 2%. The immunohistochemical detection of BRAFV600E has been described in 30% of DNTs, including specific and nonspecific tumors [31]. BRAFV600E immunostaining is diffusely and strongly positive in glial nodules and usually negative in the floating neurons. However, dysplastic neurons show strong BRAFV600E immunoreactivity in complex DNTs associated with FCD.


Dysembryoplastic Neuroepithelial Tumors.

Suh YL - J Pathol Transl Med (2015)

Immunohistochemical findings of dysembryoplastic neuroepithelial tumors (DNTs). (A, B) Floating neurons are positive for synaptophysin (A) and phosphorylated neurofilament (B). (C, D) The oligodendroglioma-like cells (OLCs) are diffusely positive for S-100 (C) but negative for glial fibrillary acidic protein (D). (E) Nonspecific DNTs show slightly decreased synaptophysin granular staining compared with that seen in the adjacent normal cortex. (F) In the specific glioneuronal element, CD34 is expressed along the perikarya and in membrane of the floating neurons, pericellular stroma, and cytoplasm of OLCs. (G, H) The specific glioneuronal element shows cluster staining pattern of CD34 (G), while diffuse CD34 immunoreactivity in glial nodules of complex DNTs (H).
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f4-jptm-2015-10-05: Immunohistochemical findings of dysembryoplastic neuroepithelial tumors (DNTs). (A, B) Floating neurons are positive for synaptophysin (A) and phosphorylated neurofilament (B). (C, D) The oligodendroglioma-like cells (OLCs) are diffusely positive for S-100 (C) but negative for glial fibrillary acidic protein (D). (E) Nonspecific DNTs show slightly decreased synaptophysin granular staining compared with that seen in the adjacent normal cortex. (F) In the specific glioneuronal element, CD34 is expressed along the perikarya and in membrane of the floating neurons, pericellular stroma, and cytoplasm of OLCs. (G, H) The specific glioneuronal element shows cluster staining pattern of CD34 (G), while diffuse CD34 immunoreactivity in glial nodules of complex DNTs (H).
Mentions: In specific GN elements, floating neurons have expressed neuronal markers including synaptophysin neurofilament, NeuN, neuron specific enolase, MAP2, and class-III beta-tubulin (Fig. 4A, B). The majority of OLCs are strongly positive for S-100 protein and Oligo-2 but generally negative for glial fibrillary acidic protein (GFAP) (Fig. 4C, D). Rarely, OLCs may show immunoexpression of NeuN. Glial nodules contain variable numbers of GFAP-positive astrocytes. In the nonspecific type of DNTs, synaptophysin granular staining is slightly decreased in the lesion compared with that seen in the adjacent normal cortex (Fig. 4E). Other neuronal markers except MAP2 are negative in nonspecific DNTs, but MAP2 is frequently expressed [8]. The expression of CD34 has been reported in 25% to 61% of cases [6-8]. In our study, CD34 expression was more frequently observed in nonspecific types (83.3%) than in simple (10%) and complex types (30.8%). CD34 was positive in the neuronal cell membrane, pericellular stroma, and cytoplasm of OLCs and stellate cells with astroglial morphology (Fig. 4F). CD34 positive cells were focally identified in specific GN elements, whereas most nonspecific tumors and glial nodules of some complex DNTs showed a focal, multifocal, or diffuse pattern of CD34 immunoreactivity (Fig. 4G, H). CD34 was expressed in the peritumoral cortex (Fig. 5A–C), which is more frequent in nonspecific (94.4%) than in classic (26.1%) DNTs. Different expression patterns of nestin and MAP2 in three subtypes of DNTs have also been demonstrated [8,30]. Combined analysis of CD34 and MAP2 is useful in differential diagnosis between nonspecific DNTs and diagnostically challenging mimickers, which will be discussed in the section on differential diagnosis. The Ki-67 labeling index is generally low, below 1% or 2%. The immunohistochemical detection of BRAFV600E has been described in 30% of DNTs, including specific and nonspecific tumors [31]. BRAFV600E immunostaining is diffusely and strongly positive in glial nodules and usually negative in the floating neurons. However, dysplastic neurons show strong BRAFV600E immunoreactivity in complex DNTs associated with FCD.

Bottom Line: Histologically, the recognition of a unique, specific glioneuronal element in brain tumor samples from patients with medically intractable, chronic epilepsy serves as a diagnostic feature for complex or simple DNT types.However, nonspecific DNT has diagnostic difficulty because its histology is indistinguishable from conventional gliomas and because a specific glioneuronal element and/or multinodularity are absent.The histological and cytological differential diagnoses for this lesion, especially the nonspecific variant, will be discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

ABSTRACT
Dysembryoplastic neuroepithelial tumor (DNT) is a benign glioneuronal neoplasm that most commonly occurs in children and young adults and may present with medically intractable, chronic seizures. Radiologically, this tumor is characterized by a cortical topography and lack of mass effect or perilesional edema. Partial complex seizures are the most common presentation. Three histologic subtypes of DNTs have been described. Histologically, the recognition of a unique, specific glioneuronal element in brain tumor samples from patients with medically intractable, chronic epilepsy serves as a diagnostic feature for complex or simple DNT types. However, nonspecific DNT has diagnostic difficulty because its histology is indistinguishable from conventional gliomas and because a specific glioneuronal element and/or multinodularity are absent. This review will focus on the clinical, radiographic, histopathological, and immunohistochemical features as well as the molecular genetics of all three variants of DNTs. The histological and cytological differential diagnoses for this lesion, especially the nonspecific variant, will be discussed.

No MeSH data available.


Related in: MedlinePlus