title: A peculiar histopathological form of dysembryoplastic neuroepithelial tumor with separated pilocytic astrocytoma and rosette-forming glioneuronal tumor components.
abstract: Dysembryoplastic neuroepithelial tumors (DNTs) mostly display typical clinical, neuroimaging and histopathological features, but sometimes they reveal heterogeneous or non-specific morphology, which results in diagnostic dilemmas. We present a case of a young adult with longstanding, intractable epilepsy associated with a multinodular cystic lesion in the temporal lobe. The lesion consisted of morphologically different components. In particular, a few cortical nodules displayed a specific glioneuronal element with floating neurons typically found in DNT. Two large, well-circumscribed nodules were entirely composed of biphasic, piloid, astroglial patterns that corresponded strictly to a pilocytic astrocytoma. The well-defined areas, which contained numerous distinct neurocytic-like rosettes, were identical with rosette-forming glioneuronal tumors (RGNTs). This type of neurocytic rosette was widespread within the surrounding piloid background. Some solid nodules exhibited increased cellularity, oligodendroglioma-like elements and a focal ribbon cell arrangement. The lesion was associated with advanced reactive gliosis and foci of dysplastic changes in the adjacent cortex. The clinico-radiological and main histopathological features were consistent with a diagnosis of a complex variant of DNT composed of pilocytic and rosette-forming glioneuronal components. Although both piloid tissue and rosette-like formations have been occasionally mentioned in DNT lesions, the present case of DNT was unique in its well-circumscribed, separate pilocytic and RGNT nodules. We concluded that it represented an unusual, mixed pilocytic/RGNT variant of DNT.
authors.affiliation: Department of Experimental and Clinical Neuropathology, M. Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland; Department of Neurosurgery, M. Sklodowska-Curie Memorial Cancer Centre, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Matyja
authors.forename: Wiesława
authors.initials: W
authors.lastname: Grajkowska
authors.forename: Przemysław
authors.initials: P
authors.lastname: Kunert
authors.forename: Andrzej
authors.initials: A
authors.lastname: Marchel
mesh_terms: D000328:Adult; D001254:Astrocytoma / Q000473:pathology; D001932:Brain Neoplasms / Q000473:pathology*; D006801:Humans; D008297:Male; D018193:Neoplasms, Complex and Mixed / Q000473:pathology*; D018302:Neoplasms, Neuroepithelial / Q000473:pathology*; D013702:Temporal Lobe / Q000473:pathology; D055815:Young Adult
keywords: DNT components; dysembryoplastic neuroepithelial tumor; neurocytic rosettes; pilocytic astrocytoma; rosette forming glioneuronal tumor