Angiocentric Neuroepithelial Tumor (ANET): A New Epilepsy‐Related Clinicopathological Entity with Distinctive MRI

Abstract

Several types of glioneuronal tumors are known to induce intractable partial seizures in children and adults. The most frequent are dysembryoplastic neuroepithelial tumors (DNETs) and gangliogliomas. We report here a new clinicopathological entity within the spectrum of glioneuronal tumors observed in 10 children who underwent surgery for refractory epilepsy. These tumors demonstrate a unique, pathognomonic histological pattern and a specific appearance at magnetic resonance imaging (MRI). The most striking neuropathological feature is an angiocentric polarity of the tumor with gliofibrillary acidic protein (GFAP) positive fusiform and bipolar astrocytic cells arranged around blood vessels (perivascular cuffing with tumoral astrocytes). Characteristic MRI findings include involvement of cortical gray and white matter, intrinsically high signal on T1-weighted images, as well as a stalk like extension to the ventricle. Immunohistochemical neuronal markers (neurofilament protein, synaptophysin and chromogranin) confirm the presence of a neuronal cell component. Therefore, the term angiocentric neuroepithelial tumor (ANET) is proposed.

“Unusual brain stone”: heavily calcified primary neoplasm with some features suggestive of angiocentric glioma

“…An infiltrative pattern is not usual, but has previously been described with angiocentric glioma. 6 This tumor is typically located superficially in the parietal or temporal cortex.…”

“…8,13,19 Its cell of origin is uncertain, but it may derive from astrocytic, ependymal, radial glial, or neuronal elements. 6 It is not usually associated with dense calcification. It has very rarely been described as part of a mixed glioneuronal neoplasm, 6 although whether the neuronal population represents residual cortical "trapped" neurons is uncertain.…”

“…6 It is not usually associated with dense calcification. It has very rarely been described as part of a mixed glioneuronal neoplasm, 6 although whether the neuronal population represents residual cortical "trapped" neurons is uncertain. In the case reported here, the patient presented with seizures at the age of 24 years, and the radiological finding at that time was a small speck of calcification in his brain; his seizures were fully controlled with medication.…”

“…13 However, Lellouch-Tubiana et al reported a series with a neuronal cell component in all cases, similar to our case, and thus classified the lesions as mixed glioneuronal neoplasms and proposed the term angiocentric neuroepithelial tumor. 6 Wang et al proposed the term monomorphous angiocentric glioma for lesions lacking a neuronal component. 19 Isocitrate dehydrogenase mutation (IDH1 R132H), is absent in diffuse angiocentric glioma.…”

Central Nerve System Malignant Tumors

“…They grade III when the endothelial cell area explosion and mitosis happens in this tumor nonstop. They will be grade II in absence of lesions [33].…”