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To analyse the imaging findings of papillary glioneuronal tumors (PGNTs), in order to improve the accuracy of preoperative diagnosis of this tumor. The clinical and imaging manifestations of 36 cases of PGNT confirmed by pathology were analyzed retrospectively. A total of 17 males and 19 females, averaging 22.47 (± 11.23) years. Initial symptoms included epilepsy in ten, headache in seven, and others in 19 cases. 97.2% (35/36) of the lesions were located in the supratentorial area, and 80.5% (29/36) in the intraventricular or deep white matter adjacent to the lateral ventricles. Twenty-four of the lesions (66.7%) were mixed cystic and solid, four (11.1%) were cystic with mural nodules, four (11.1%) were cystic, and four (11.1%) were solid. Four cases of PGNT of cystic imaging showed a "T2-FLAIR mismatch" sign. 69.4% (25/36) had septations. Nine lesions (25%) were accompanied by edema, and 9 (25%) of the mixed cystic and solid lesions were accompanied by hemorrhage. Among the 18 patients who underwent computed tomography (CT) or susceptibility-weighted imaging (SWI), nine had lesions with calcification. PGNTs mostly manifest as cystic mass with mural nodules or mixed cystic and solid mass in the white matter around the supratentorial ventricle, and the cystic part of the lesion is mostly accompanied by septations. Pure cystic lesions may exhibit the sign of "T2-FLAIR mismatch". PGNT is rarely accompanied by edema but sometimes by calcification and hemorrhage. Patients often present with seizures, headaches, and mass effect symptoms. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumor (PGNT) is a low-grade biphasic tumor that is composed of glial fibrillary acidic protein (GFAP)-positive glial cells and synaptophysin-positive neurons. We report a case of PGNT occurring in the right occipital lobe of a 48-year-old woman who presented with acute headache and left homonymous hemianopsia, the latter of which was difficult to distinguish from malignant brain tumors because of peritumoral brain edema, intratumoral hemorrhage, and intraoperative fluorescence staining. PGNT should be included as one of the differential diagnoses in cases where the tumor shows hemorrhagic change despite decreased perfusion in arterial spin labeling MRI. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumors are rare neoplasm, accounting only <0.02% of all intracranial tumors. They are generally low grade usually occur in the temporal lobe near the third ventricle. We report an extremely rare case of intraventricular tumor with a high proliferation index. CD 117 expression found in our case is the first study to the best of our knowledge to be described in these tumors. The clinical and diagnostic significance of this finding is subject to further studies. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumor is a recently known entity in central nervous system tumors. These benign WHO grade I tumors are mostly seen in young adults. Pediatric PGNT is rare and there is no report of these tumors in toddlers. Headache, nausea/vomiting and seizure are most common clinical symptoms. Acute presentation with focal neurological deficits or loss of consciousness are not amongst the expected presentations. These tumors are typically cystic with enhancing mural nodule. Although case with chronic intermittent microhemorrhages are reported in the literature but overt intra-tumoral hemorrhage is an odd radiological presentation with just one reported case in the literature. We present an extremely rare case of PGNT presenting with sudden onset hemiparesis and impaired consciousness due to acute intra-tumoral hemorrhage in a toddler which was surgically treated with favorable outcome. PGNTs can also be seen in very young children even in toddlers. Also, it should be kept in mind that these tumors have potential for overt intra-tumoral hemorrhage and acute presentation with focal neurological deficits mimicking more common pathologies which should be considered to plan optimal patient management. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumor (PGNT) is a rare central nervous system neoplasm. Of reported cases, the vast majority are located in the frontal and temporal lobes. We present the case of a 39-year-old male who presented with a one day history of gait disturbance following chemotherapy treatment for metastatic rectal adenocarcinoma. Following MRI of the head showed a tectal mass. Following an occipital interhemispheric craniotomy for tumor resection, final pathology was diagnostic of a papillary neuroglial tumor, WHO grade I. To the best or out knowledge this is the only report of it arising from the tectal plate. [ABSTRACT FROM AUTHOR]

Glioneuronal tumors are very rare CNS neoplasms that demonstrate neuronal differentiation, composed of mixed glial and neuronal cells. The majority of these lesions are low grade and their correct classification is crucial in order to avoid misidentification as 'ordinary' gliomas and prevent inappropriate aggressive treatment; nevertheless, precise diagnosis is a challenge due to phenotypic overlap across different histologic subtype. Surgery is the standard of therapeutic approach; literature concerning the benefit of adjuvant treatments is inconclusive and a globally accepted treatment of recurrence does not exist. Targetable mutations in the genes BRAF and FGFR1/2 are recurrently found in these tumors and could take a promising role in future treatment management. [ABSTRACT FROM AUTHOR]

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Introduction: Papillary Glioneuronal Tumor (PGNT) is a rare tumor with approximately 70 cases reported in the last decade. This tumor is more common in young adults and is the most common clinical manifestation of headaches and seizures. This tumor has an indolent clinical behavior. Regarding gender prevalence there is no detailed epidemiological information available, because of the rarity and newness of this tumor. Case Presentation: A 32-year-old female patient with a sudden headache and blurred vision referred to our hospital. The magnetic resonance imaging (MRI) revealed a heterogeneous mass with dimensions of 35 × 33 × 20 mm in the right frontal lobe. Histologically, a biphasic tumor composed of a glial component arranged in papillary architecture overlaying hyalinized vessels, associated with interpapillary areas, containing monotonous oligodendrocyte-like and ganglion-cells were seen. The immunohistochemical staining indicated glial fibrillary acidic protein (GFAP)-positive glial cells and positive synaptophysin and neuron-specific enolase (NSE) in interpapillary neurocytes. Conclusions: Papillary Glioneuronal tumor is a rare tumor with slow growth and low grade. The possibility of transformation to high-grade tumor, is low. Due to having the structure of pseudopapillary, along with clinical and radiographic characteristics, it must be distinguished from other variants of glioneuronal tumor mix.

Papillary glioneuronal tumors (PGNTs) are rare World Health Organization grade I neoplasms that are characterized by a benign course and excellent response to surgical resection. A few reports exist of tumors with more aggressive clinical and histologic features. In this report we detail the case of an unusually aggressive PGNT in a 67-year-old woman. The patient had a 3-year history of seizures and was diagnosed with a frontoparietal mass on imaging. She underwent subtotal resection with a histologic diagnosis of PGNT. Less than a year after surgery, the patient experienced recurrence of disease and underwent reresection and adjuvant radiation treatment. The patient's disease continued to progress despite radiation treatment, so adjuvant temozolomide was initiated. Molecular testing was performed and revealed a TERT promotor mutation, an FGFR3-TACC3 oncogenic fusion, and a copy number loss in CDKN2A/CDKN2B. PGNTs, while typically benign, can rarely recur after surgery. Molecular testing should be performed on all PGNTs to help possibly identify more aggressive tumors and potentially reveal novel treatment options. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumor (PGNT) is a WHO-defined brain tumor entity that poses a major diagnostic challenge. Recently, SLC44A1–PRKCA fusions have been described in PGNT. We subjected 28 brain tumors from different institutions histologically diagnosed as PGNT to molecular and morphological analysis. Array-based methylation analysis revealed that 17/28 tumors exhibited methylation profiles typical for other tumor entities, mostly dysembryoplastic neuroepithelial tumor and hemispheric pilocytic astrocytoma. Conversely, 11/28 tumors exhibited a unique profile, thus constituting a distinct methylation class PGNT. By screening the extended Heidelberg cohort containing over 25,000 CNS tumors, we identified three additional tumors belonging to this methylation cluster but originally histologically diagnosed otherwise. RNA sequencing for the detection of SLC44A1–PRKCA fusions could be performed on 19 of the tumors, 10 of them belonging to the methylation class PGNT. In two additional cases, SLC44A1–PRKCA fusions were confirmed by FISH. We detected fusions involving PRKCA in all cases of this methylation class with material available for analyses: the canonical SLC44A1–PRKCA fusion was observed in 11/12 tumors, while the remaining case exhibited a NOTCH1-PRKCA fusion. Neither of the fusions was found in the tumors belonging to other methylation classes. Our results point towards a high misclassification rate of the morphological diagnosis PGNT and clearly demonstrate the necessity of molecular analyses. PRKCA fusions are highly diagnostic for PGNT, and detection by RNA sequencing enables the identification of rare fusion partners. Methylation analysis recognizes a unique methylation class PGNT irrespective of the nature of the PRKCA fusion. [ABSTRACT FROM AUTHOR]

Objective: Papillary glioneuronal tumors (PGNT) are a rare and recently recognized tumor entity. The neuroimaging findings were reviewed to determine if any specific findings emerge to assist a preoperative diagnosis of PGNT.Materials and Methods: Seven histologically confirmed cases of PGNT were evaluated from 2004 to 2014. Clinical, neuroimaging and histological findings were reviewed and tabulated.Results: Headache and seizures were observed in 4 patients (57.1%) each. The majority (n=5, 71.4%) of lesions were periventricular and located in temporal lobe with 57.1% cases being solid cystic (n=4), and 42.9% being purely solid (n=3). Calcification and hemorrhage were noted in 3 cases (42.9%) and 5 cases (71.4%) respectively. The most frequent imaging feature was the presence of septations in the cystic component that enhanced on contrast which correlated with long pseudopapillary projections into the cyst cavity on histopathology. The solid inner component demonstrated heterogeneous enhancement. One case with tumor recurrence demonstrated hemorrhage with superficial siderosis, patchy diffusion restriction, raised choline and focal areas of raised perfusion which correlated on histopathology with increased cellularity and anaplasia.Conclusion: Presence of cystic mass in periventricular location with septations and a solid inner component should raise a suspicion of PGNT on neuroimaging. [ABSTRACT FROM AUTHOR]

Background Although the World Health Organization classifies papillary glioneuronal tumor (PGNT) as a grade I tumor, several malignant cases have been reported. In this study, we examined the clinical and prognostic characteristics of PGNT. Methods PubMed, Embase, and institutional databases were queried for patient-level reports of PGNT, resulting in identification of 138 cases. Descriptive and Kaplan–Meier survival analyses were conducted. The threshold of significance was 0.05. Results The mean age at presentation was 26.9 ± 16.3 years, and the incidence was higher in males (1.42:1). Tumors with a high Ki-67 index (≥5) were more likely to exhibit perilesional edema and ring enhancement on magnetic resonance imaging, trending toward significance ( P = 0.114 and 0.113, respectively). Compared with tumors with a low Ki-67 index (<5), those with a high Ki-67 index were more likely to be treated with subtotal resection (STR) than with gross total resection (GTR) (Kruskal–Wallis test, P = 0.006) and with radiation therapy (χ 2 test, P = 0.010). At 5 years post-treatment, PGNT had a mean progression-free survival (PFS) of 85.9 ± 3.9%. Males had a better 5-year PFS than females (94.0 ± 3.4% vs. 74.8 ± 7.8%; Mantel–Cox test, P = 0.002). Two-year PFS was higher after GTR than after STR (91.9 ± 3.6% vs. 46.7 ± 21.4%; Mantel–Cox test, P < 0.001). A low Ki-67 index was associated with a higher 5-year PFS compared with a high Ki-67 index (94.8 ± 3.6% vs. 55.6 ± 12.9%; Mantel–Cox test, P < 0.001). Conclusions PGNT is a benign tumor of young adults, but can present atypically as high grade. Male sex, low cellular proliferation, and maximal surgical resection are positive prognostic indicators for PGNT. [ABSTRACT FROM AUTHOR]

Background: Papillary glioneuronal tumor (PGNT) is a rare, recently described distinct low-grade brain neoplasm. This study was performed to characterize the clinicopathologic and neuroradiologic features of PGNTs. Methods: We reviewed the medical records of 16 patients with PGNT who underwent surgery, including 11 males and five females (median age 27 years). The clinical, neuroradiologic, histopathologic, and immunohistochemical findings were documented. Results: Headache was the principal presentation. Neuroimaging showed contrast-enhancing, cystic-solid or cystic masses with a mural nodule, mostly involved the frontal or parietal lobes. Histologically, the tumors were characterized by glial fibrillary acidic protein (GFAP)-positive small cuboidal cells lining hyalinized vascular pseudopapillae and synaptophysin and/or NeuN-positive interpapillary neuronal elements. Other findings included small angiomatous areas in ten, small islands of neuropil and rosettes in seven, and microvascular proliferation and/or nuclear atypia in six. Mitoses or necrosis were absent. All lacked isocitrate dehydrogenase 1 (IDH1) R132H protein expression. Low expression of p53 was observed in three cases. Ki67 labeling index ranged from less than 1 to 3 %. All but one was totally resected. Median follow-up was 65 months, and one patient had tumor recurrence. Conclusions: PGNTs display distinct clinicopathologic and imaging characteristics and indicate a favorable prognosis. However, recurrences sometimes occur. Immunohistochemistry facilitates the appropriate diagnosis of these tumors. Complete resection of the tumor is important for a favorable outcome. [ABSTRACT FROM AUTHOR]

Introduction: Papillary Glioneuronal Tumor (PGNT) is a grade I tumor which was classified as a separate entity in the World Health Organization Classification of the Central Nervous System 2007 in the group of mixed glioneuronal tumors. This tumor is rare and subclassifying PGNT represents a challenge. Recently, a fusion between SLC44A1 and PRKCA which encodes a protein kinase C involved in MAPK signaling pathway has been described in two studies (five cases). The current study aimed at raising the cytogenetic, histological and molecular profiles of PGNT and to determine if SLC44A1-PRKCA fusion represented a specific diagnostic marker to distinguish it from other glioneuronal tumors. Results: We report on four pediatric cases of PGNT, along with clinico-radiologic and immunohistological features for which SLC44A1-PRKCA fusion assessment by fluorescence in situ hybridization, BRAF V600E and FGFR1 mutation by immunohistochemistry and direct DNA sequencing and KIAA1549-BRAF fusion by RT-PCR were performed. MAPK signaling pathway activation was investigated using phospho-ERK immunohistochemistry and western blot. We analyzed fifteen cases of tumors with challenging histological or clinical differential diagnoses showing respectively a papillary architecture or periventricular location (PGNT mimics). fluorescence in situ hybridization analysis revealed a constant SLC44A1-PRKCA fusion signal in all PGNTs. None of PGNT mimics showed the SLC44A1-PRKCA fusion signal pattern. All PGNTs were negative for BRAF V600E and FGFR1 mutation, and KIAA1549-BRAF fusion. Phospho-ERK analysis provides arguments for the activation of the MAPK signaling pathway in these tumors. Conclusions: Here we confirmed and extended the molecular data on PGNT. These results suggest that PGNT belong to low grade glioma with MAPK signaling pathway deregulation. SLC44A1-PRKCA fusion seems to be a specific characteristic of PGNT with a high diagnostic value and detectable by FISH. [ABSTRACT FROM AUTHOR]

We report a case of a young female patient with a rare and recently described form of brain tumor. This patient had a history of headache, hemiparesis and motor simple partial seizures. Her investigation revealed a brain tumor involving the left frontal and parietal lobes. The radiological images showed a cystic mass with multiple nodular masses and a rim of contrast enhancement extending from the right parietal cortex to the ipsilateral ventricle and corpus callosum. The patient underwent gross resection of the lesion and the histological analysis of the surgical specimen revealed a pseudopapillary structure formed by delicate vessels intermixed with a fibrillary pattern and bordered by intense astrocytic reaction with Rosenthal fibers. These features correspond to the recently described mixed neuronal-glial neoplasm, the papillary glioneuronal tumor. The patient has been followed for five years since the surgical treatment, without evidence of tumor recurrence, confirming the indolent behavior of this type of tumor.Relatamos o caso de uma jovem paciente com um tumor cerebral raro e recentemente descrito. Essa paciente apresentou-se com queixas de cefaléia, hemiparesia e crises epiléticas parciais simples. Sua investigação revelou um tumor cerebral envolvendo os lobos frontal e parietal esquerdos. As imagens radiológicas mostraram uma massa cística com massas nodulares múltiplas e reforço anelar de contraste estendendo do córtex parietal direito aos ventrículo lateral e corpo caloso ipsilaterais. A paciente se submeteu à ressecção do tumor e a análise histológica da lesão revelou uma estrutura pseudopapilar formada por vasos delicados entremeados com um padrão fibrilar e emoldurada por intensa reação astrocítica com fibras de Rosenthal. Essas características correspondem a uma forma de neoplasia mista glial-neuronal recentemente descrita, o tumor papilar glioneuronal. A paciente está em seguimento desde a cirurgia sem evidência de recorrência tumoral, confirmando o comportamento benigno desse tipo de tumor.

Papillary glioneuronal tumor ( PGNT) is a rare type of primary brain tumor. Although PGNT has traditionally been defined as a clinically indolent neoplasm, several cases with high proliferative activity and tumor recurrence have recently been reported. We report a case of PGNT in a 12-year-old boy who presented with epilepsy and harbored a 64 mm cystic tumor with a high proliferative component in the right temporal lobe. 11C-methionine positron emission tomography ( PET) showed high uptake in the solid mass. Gross total resection of the tumor mass was achieved and the patient became seizure-free without any neurological deficits. Histologically, the tumor contained two distinct areas of a vasocentric papilliform structure and a desmoplastic component. Minigemistocytic cells and small necrotic regions were observed adjacent to the pseudopapillae. Immunohistochemical analyses revealed both glial and neuronal differentiation. The Ki-67 proliferation index was high (14%) in the area corresponding to the high uptake region in the 11C-methionine PET. No tumor recurrence was observed 20 months after surgery. High proliferative PGNTs are rare and to our knowledge this is only the third pediatric case of PGNT with atypical features reported in the literature. Hence, we here review the reported cases of PGNT and discuss the clinical, radiological and histological features of this malignancy. [ABSTRACT FROM AUTHOR]

Background: Papillary glioneuronal tumors (PGNTs) are a novel distinct intracranial neoplastic entity. In this study, the authors aimed to analyze the clinical, radiological, and pathological features of PGNT. Methods: Clinical charts and radiographs of 16 cases of PGNT surgically treated between 2006 and 2013 were retrospectively reviewed. Follow-up evaluations and a literature review were performed. Results: The study included nine males and seven females with a mean age of 23.8 years. The most common preoperative symptom was headache (68.8 %, 11 of 16 patients). Radiological results showed that the frontal lobe (25.0 %) was the most common portion of the brain involved, and 13 lesions (81.3 %) presented with cystic appearance with or without solid elements. All patients were misdiagnosed as non-PGNT tumors. Complete resection was achieved in 12 patients (75.0 %). Ki67 staining was positive in <1 % of cells present in eight lesions and varied in the other eight lesions, with a range of 1 % to 13 %. The mean follow-up duration was 56.2 months, and no recurrence was observed. Seventy-seven PGNTs (40 males, 51.9 %) have been reported, and 49 patients stained positive for Ki67/MIB-1. Of these cases, 28 (57.1 %) had positive staining rates of ≥1 %. In 51 patients for whom outcome information was available, six (11.8 %) exhibited recurrence, and the recurrence rates for complete resection and incomplete resection were 5.1 % and 33.3 %, respectively. Conclusions: PGNTs displayed a wide spectrum of clinical and radiological phenotypes, and they were more frequently observed in the frontal lobe and in young patients without sex predilection. Fair outcomes could be achieved by complete resection. Although PGNT displayed indolent pathobiology, atypical appearances were observed. More patients and longer follow-up periods are needed to further elucidate the biological features of PGNTs. [ABSTRACT FROM AUTHOR]

Glioneuronal tumors ( GNTs) are rare neoplasms consisting of both glial and neuronal components. Among the GNTs, dysembryoplastic neuroepithelial tumors ( DNTs), papillary glioneuronal tumors ( PGNTs), and rosette-forming glioneuronal tumors of the fourth ventricle ( RGNTs) share the character of being mainly composed of small round Olig2-positive tumor cells. Using immunohistochemistry and fluorescence in situ hybridization, we examined a series of 35 GNT cases (11 DNTs, 15 PGNTs and 9 RGNTs) on the characteristics of Olig2-positive tumor cells. Histologically, Olig2-positive cells showed small round forms in most GNTs; however, there were a small number of Olig2-positive cells with neuronal morphology only in a PGNT case. These cells expressed both glial and neuronal markers by double immunostaining. With regard to labeling indices and intensity, only PGNT cells expressed neuronal markers, including α-internexin and neurofilament. These findings also suggest that some Olig2-positive PGNT cells may show neuronal differentiation. In GNTs, a considerable number of Olig2-positive cells showed immunopositivity for cyclin D1 and/or platelet-derived growth factor receptor alpha ( PDGFRα), which are markers for oligodendrocyte progenitor cells. These immunostainings were particularly strong in DNTs. In RGNTs, Olig2-positive cells formed 'neurocytic rosettes'. Furthermore, they were also immunopositive for glial markers, including GFAP, PDGFRα and cyclin D1. These findings indicate the heterogeneous characteristics of Olig2-positive cells in GNTs, and some of them also exhibited neuronal features. So it is possible that a part of Olig2-positive GNT cells have characteristics similar to those of progenitor cells. [ABSTRACT FROM AUTHOR]

Mixed neuronal-glial tumors are rare and challenging to subclassify. One recently recognized variant, papillary glioneuronal tumor ( PGNT), is characterized by prominent pseudopapillary structures and glioneuronal elements. We identified a novel translocation, t(9;17)(q31;q24), as the sole karyotypic anomaly in two PGNTs. A fluorescence in situ hybridization ( FISH)-based positional cloning strategy revealed SLC44A1, a member of the choline transporter-like protein family, and PRKCA, a protein kinase C family member of serine/threonine-specific protein kinases, as the 9q31 and 17q24 breakpoint candidate genes, respectively. Reverse transcription-polymerase chain reaction ( RT-PCR) analysis using a forward primer from SLC44A1 exon 5 and a reverse primer from PRKCA exon 10 confirmed the presence of a SLC44A1-PRKCA fusion product in both tumors. Sequencing of each chimeric transcript uncovered an identical fusion cDNA junction occurring between SLC44A1 exon 15 and PRKCA exon 9. A dual-color breakpoint-spanning probe set custom-designed for interphase cell recognition of the translocation event identified the fusion in a third PGNT. These results suggest that the t(9;17)(q31;q24) with the resultant novel fusion oncogene SLC44A1-PRKCA is the defining molecular feature of PGNT that may be responsible for its pathogenesis. The FISH and RT-PCR assays developed in this study can serve as valuable diagnostic adjuncts for this rare disease entity. [ABSTRACT FROM AUTHOR]

The article describes the case of a 74-year-old-woman who presented with two months history of episodic positional vertigo associated with headache and nausea. Right occipital periventricular heterogenous lesion composed of a polycystic mass and nodular portion enhanced by Gadolinium was revealed by cerebral magnetic resonance imaging (MRI). Right frontal craniotomy was conducted on the patient.

Purpose: Papillary glioneuronal tumors (PGNT) have been recently included as a distinct entity in the WHO classification of tumors of the central nervous system. Their molecular pathogenesis is not clear. In the current study, we present the morphological, immunohistochemical, and molecular features of four cases of PGNT reported over the past 11 years. Methods: Over a period of 11 years (January 2000-February 2010), there were four cases of PGNT, which were reviewed for histomorphological features. TP53 and IDH1 mutations were assessed using antibodies against p53 protein and for mutant IDH1 protein, respectively. Immunohistochemistry was also performed for epidermal growth factor receptor (EGFR) protein. Fluorescence in situ hybridization assay was used for analyzing 1p/19q deletion status. Results: All the tumors showed the characteristic biphasic morphology. Rare findings included minigemistocyte-like cells in one, angiomatous areas in three, focal necrosis in one, and a high MIB-1 labeling index of 12 and 13 %, respectively, in two of the cases. All lacked EGFR, IDH1 expression, and 1p/19q deletions. Interestingly, antibody for p53 labeled the tumor cells, mainly those showing glial differentiation, in two cases. At a mean follow-up of 30 months, there was no evidence of disease progression except in one case which recurred after 24 months. Conclusion: PGNT are rare CNS neoplasms. Despite showing focal morphological features reminiscent of oligodendroglial tumors and presence of astrocytic component, they usually lack the common genetic alterations involved in the pathogenesis of gliomas. Multi-institutional pooling of cases may aid in elucidating their oncogenetic pathway. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumors represent a new and rare entity of an uncommon morphologic subtype of low-grade mixed neuronal-glial neoplasms with an unclear etiology. They are described as benign lesions with extraventricular localization. We report the second case of papillary glioneuronal tumor with recurrent nature after gross-total resection, and the third case of this tumor with intraventricular localization. While conventionalmagnetic resonance imaging of papillary glioneuronal tumors is well described in literature, there are no data based on advanced magnetic resonance techniques. The present article represents a review of clinicopathological and both conventional and advanced magnetic resonance imaging characteristics of papillary glioneuronal tumors, with focus on 2 cases with atypical course and localization. [ABSTRACT FROM AUTHOR]

BSTRACT OBJECTIVE [ABSTRACT FROM AUTHOR]

We investigated the fused protein of solute carrier family 44 choline transporter member 1 ( SLC44A1 ) and protein kinase C alpha ( PRKCA ) in three patients with papillary glioneuronal tumors (PGNT). PGNT and rosette-forming glioneuronal tumors (RGNT) are recently identified, unusual glioneuronal tumor variants which were categorized as novel tumor entities in the 2007 World Health Organization classification system. The molecular background of these tumors remains poorly understood due to the paucity of studies. The SLC44A1 – PRKCA fusion was recently detected in three cases of PGNT. We invesitgated for the SLC44A1 – PRKCA fusion protein in the three PGNT patients and a further two with RGNT using fluorescence in situ hybridization. Two out of the three PGNT patients had a fused signal (paired red–green signal) representing a rearrangement on chromosomes 9 and 17. A normal signal pattern was observed in the third PGNT patient. Neither of the two RGNT patients demonstrated a fused signal. This suggests that the SLC44A1 – PRKCA fusion is a characteristic alteration in PGNT but not RGNT. Therefore, it is a potential biomarker of PGNT. The paired red–green signal that was observed in the PGNT patients implies the presence of a different breakpoint than that previously reported in the 9q31 and 17q24 genes. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumor (PGNT) is a rare, recently recognized tumor type histologically characterized by pseudopapillary architecture associated with compact areas composed of neuronal elements in different maturation states. The histogenesis of this tumor type is still unclear. The immunophenotype of PGNT comprises expression of several glial and neuronal proteins. Recently, immunohistochemical expression of Olig2 in a fraction of tumor cells has been reported, suggesting an additional oligodendroglial or at least oligodendroglia-like tumor cell component. We report a further case of papillary glioneuronal tumor in a 12-year-old boy with immunohistochemical expression of PDGFRα, Olig2 and Nestin in support of a postulated origin of this tumor type from common progenitor cells in the subependymal plate. Nevertheless, further studies are needed to clarify the histogenesis of PGNT. [ABSTRACT FROM AUTHOR]

Summary: Papillary glioneuronal tumor is a recently described central nervous system neoplasm that almost always occurs adjacent to the lateral ventricle. We present a case of this rare entity, representing the 21st case of this lesion, which exhibits a mixed astrocytic and neuronal differentiation. This case was an incidental finding in a young woman who presented secondary to a traumatic injury to the left eye. Histologic evaluation after surgical removal showed a cystic tumor consisting of 2 distinct components: a unique pseudopapillary architecture admixed with foci of solid areas. The pseudopapillae were composed of thick hyalinized vessels enclosed by a single layer of glial fibrillary acid protein–positive astrocytes and variously sized synaptophysin-positive and chromogranin-negative neuronal cells in the interpapillary regions. Abundant Rosenthal fibers, foci of calcification, areas of hemosiderin deposition, gliosis, areas of vascular proliferation associated with piloid gliosis, and chronic inflammatory infiltrate were identified. The combination of cytologic benignity, lack of necrosis, and low proliferative index as evidenced by immunohistochemistry using antibody to Ki-67 confirmed the low malignant potential of this tumor. Knowledge and precise classification of this entity are important to avoid unnecessary use of chemo- and/or radiotherapy for treatment. [Copyright &y& Elsevier]

Papillary glioneuronal tumor is a recently identified low-grade brain neoplasm classified as variant of ganglioglioma. Its salient morphological characteristics are the presence of pseudopapillary structures composed of blood vessels, often hyalinized, lined by uniform small astrocytes and a proliferation of neurocytic cells, eventually admixed with ganglioid and ganglion cells. We present a case of papillary glioneuronal tumor occurring in a 15-year-old female with an unusual hemorrhagic onset. The clinical, morphological and immunohistochemical features are discussed and the published literature is reviewed. This article proposes that papillary glioneuronal tumor should be included in the differential diagnosis of patients with tumoral related brain hemorrhage. [ABSTRACT FROM AUTHOR]

Papillary glioneuronal tumor (PGNT) has recently been identified as a new variant of mixed neuronal-glial tumors. We report the clinical and pathological features of PGNT in two Chinese patients. One patient was a 35-year-old man who suffered from intractable seizures for 16 years. Another was a 26-year-old woman who presented with headache for 2 years. In both patients, magnetic resonance imaging showed well demarcated, mixed cystic and solid tumor in the temporal lobe. Histology of the excised tumors revealed a pseudopapillary architecture surrounded by a glial component and intervening areas were occupied by neuronally differentiated cells. No cortical dysplasia was found in the neighboring cortex in one of them. The glial component showed immunoreactivity with glial fibrillary acidic protein and S-100 protein. Neuronally differentiated cells were immunolabeled by antisynaptophysin, NF, NeuN and MAP2 antibodies. Some small cells surrounding the surface of the pseudopapillae and in the compact area were immunopositive for Olig2. The MIB-1 labeling index was <3%. The tumor did not recur within the follow-up periods of 50 months and 13 months, and the patient with temporal lobe epilepsy became seizure-free after surgery. [ABSTRACT FROM AUTHOR]

Summary: Papillary glioneuronal tumor (PGNT) is a rare and new type of glioneuronal neoplasm of the central nervous system. It is characterized by pseudopapillary structures composed of hyalinized vessels rimmed by cuboidal glial cells and the proliferation of neuronal cells. We report a peculiar PGNT arising in the parietal lobe of a 67-year-old man, which was characterized by proliferation of minigemistocytic cells as well as typical components. The minigemistocytic cells had eccentric nuclei and plump eosinophilic cytoplasm that was filled with glial filaments. The Ki-67 labeling index was as high as 10% in the minigemistocytic areas. Recently, the presence of oligodendroglial-like component was suggested in PGNT. Considering that oligodendroglioma sometimes accompanies minigemistocytic components, the minigemistocytic cells in PGNT were suggested to be a part of oligodendroglial differentiation. Although PGNT is defined as an indolent glioneuronal tumor, the presence of minigemistocytic components with the high Ki-67 labeling index may indicate more aggressive nature. [Copyright &y& Elsevier]

Abstract: The descriptive term papillary glioneuronal tumor (PGNT) has been repeatedly applied to a morphologic subset of low-grade mixed glial-neuronal neoplasia of juvenile and young adult patients. We report on a 13-year-old boy with PGNT of the left temporal lobe, who presented with headaches and a single generalized seizure. On magnetic resonance imaging, tumor was seen as a large, moderately enhancing paraventricular mass with cyst-mural nodule configuration and slight midline shift. Perifocal edema was virtually absent. Gross total resection could be performed, followed by an uneventful recovery. Histologically, the tumor exhibited similar, if not identical, features as reported previously. These comprised a patterned biphasic mixture of sheets of synaptophysin-expressing small round cells and pseudorosettes of GFAP-positive rudimentary astrocytes along vascular cores. Focally, the latter imprinted a pseudopapillary aspect on this otherwise solid lesion. Both cellular components expressed non-polysialylated neural cell adhesion molecule (NCAM)-L species, and several overlapping areas of synaptophysin and GFAP immunoreactivity were present. The mean MIB-1 labeling index remained below 1%. Signs of anaplasia, in particular mitotic figures, endothelial proliferation, or necrosis were consistently lacking. We perceive PGNT as a clinically and morphologically well-delineated subgroup of extraventricular neurocytic neoplasia, whose paradigmatic presentation may allow for consideration as an entity. [Copyright &y& Elsevier]

Mixed neuronal-glial tumors of the central nervous system display a wide spectrum of differentiation. Among them, the papillary glioneuronal tumor (PGNT) is characterized by pseudopapillary structures composed of astroglial cells covering hyalinized vessels, and by neurocytic, ganglioid and ganglion cells. In addition, a “nonspecific” cell type, not similar to either astrocytes or neurocytes, has been recognized since the initial reports. Recently, minigemistocytic cells and a population immunostained by anti-Olig2 antibody have also been recognized in PGNT. Olig2 is a transcription factor that is specific for the cellular phenotype of oligodendrocytes. The aim of this study was to further investigate the histological diversity of PGNT. We examined six cases of PGNT, each of which showed Olig2 immunopositivity. Minigemistocytes were encountered in three cases at close proximity to the Olig2-positive area. Olig2-positive cells were negative for glial fibrillary acidic protein (GFAP) and neuronal nuclear antigen by double immunostaining, and mainly occupied the interpapillary area laterally adjacent to the GFAP-positive cells. They had relatively small, round and vesicular nuclei, and were formerly regarded as neurocytic cells or nonspecific cellular elements. Fluorescence in situ hybridization targeting chromosome 1p failed to demonstrate any deletion. This study disclosed an additional cellular component of PGNT that is characterized by Olig2 positivity, suggestive of oligodendroglial phenotype, and the results also encourage us to investigate oligodendroglial participation in various glioneuronal tumors. [ABSTRACT FROM AUTHOR]

The papillary glioneuronal tumor (PGNT) was first reported by Komori et al. as a type of mixed neuronalglial tumor. It is characterized by pseudopapillary structures, composed of hyaline vessels and outsheathing glial cells, and by the proliferation of neurocytic cells admixed with ganglioid and ganglion cells. Although it is most common in young adults, it can occur in the elderly. We report a case in a 75-year-old woman, the oldest reported person with PGNT described. [ABSTRACT FROM AUTHOR]