Aggressive variant of a papillary glioneuronal tumor. Report of 2 cases

Uncommon Glioneuronal Tumors: A Radiologic and Pathologic Synopsis

Glioneuronal tumors are characterized exclusively by neurocytic elements (neuronal tumors) or a combination of neuronal and glial features (mixed neuronal-glial tumors). Most of these tumors occur in young patients and are related to epilepsy. While ganglioglioma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile tumor are common glioneuronal tumors, anaplastic ganglioglioma, papillary glioneuronal tumor, rosette-forming glioneuronal tumor, gangliocytoma, and central neurocytoma are less frequent. Advances in immunohistochemical and molecular diagnostics have improved the characterization of these tumors and favored the description of variants and new subtypes, some not yet classified by the World Health Organization. Not infrequently, the histologic findings of biopsies of glioneuronal tumors simulate low-grade glial neoplasms; however, some imaging findings favor the correct diagnosis, making neuroimaging essential for proper management. Therefore, the aim of this review was to present key imaging, histopathology, immunohistochemistry, and molecular findings of glioneuronal tumors and their variants.

Acute presentation of papillary glioneuronal tumor due to intra-tumoral hemorrhage in a toddler: an odd presentation of a rare pathology

BACKGROUND AND IMPORTANCE

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.

CLINICAL PRESENTATION

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.

CONCLUSION

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.

Primary diffuse leptomeningeal glioneuronal tumors of the central nervous system: Report of three cases and review of literature

Primary diffuse leptomeningeal glioneuronal tumors (DLGNT) are rare tumors, recently recognized as a unique entity based on their unique pathologic and clinical characteristics. We report three cases of DLGNT and compare their clinical characteristics and presentation with other reported cases, and with primary leptomeningeal gliomatosis. Because their prognosis is better than that of diffuse leptomeningeal gliomatosis, and pathologic diagnosis may be difficult, clinicians should consider this diagnosis in patients who present with new neurological symptoms, hydrocephalus and diffuse leptomeningeal enhancement on MRI. Further studies are required to better understand the unique biological characteristics of these tumors and to improve therapy.

Papillary Glioneuronal Tumour: A Case Report

Only a few cases of papillary glioneuronal tumour (PGNT) with predominantly focal symptomatology are described in the literature. We report on the clinical, radiological, and histopathological features of PGNT. The intraoperative pathology revealed no tumour in the walls of the cyst, thus surgical resection of the nodule was performed leaving the cyst wall intact. There was no recurrence of tumour at the three-year follow-up, although a long-term follow-up is necessary.

Surgical Resection and Cellular Proliferation Index Predict Prognosis for Patients with Papillary Glioneuronal Tumor: Systematic Review and Pooled Analysis

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 (χ2 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.

Papillary glioneuronal tumors: A radiopathologic correlation

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.

Clinicopathologic and neuroradiologic studies of papillary glioneuronal tumors

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.

Rare glial tumors

This chapter describes the epidemiology, pathology, molecular characteristics, clinical and neuroimaging features, treatment, outcome, and prognostic factors of the rare glial tumors. This category includes subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma, astroblastoma, chordoid glioma of the third ventricle, angiocentric glioma, ganglioglioma, desmoplastic infantile astrocytoma and ganglioma, dysembryoplastic neuroepithelial tumor, papillary glioneuronal tumor, and rosette-forming glioneuronal tumor of the fourth ventricle. Many of these tumors, in particular glioneuronal tumors, prevail in children and young adults, are characterized by pharmacoresistant seizures, and have an indolent course, and long survival following surgical resection. Radiotherapy and chemotherapy are reserved for recurrent and/or aggressive forms. New molecular alterations are increasingly recognized.

Papillary glioneuronal tumors: histological and molecular characteristics and diagnostic value of SLC44A1-PRKCA fusion

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.

Neuroradiological features of papillary glioneuronal tumor: a study of 8 cases

OBJECTIVE

The purpose of this study was to characterize the magnetic resonance imaging (MRI), and computed tomographic (CT) findings in a series of 8 patients with papillary glioneuronal tumor (PGNT).

METHODS

The routine MRI (n = 8), DWI (n = 7), and CT (n = 4) of 8 PGNTs verified by pathologic examination were reviewed. The location, internal architecture, calcification, attenuation value on CT; and signal features and degree of enhancement of the lesions on MRI were evaluated.

RESULTS

Papillary glioneuronal tumor showed relatively characteristic imaging features as well-demarcated masses with cystic degeneration, calcification, and inhomogeneous enhancement. Six of the 8 cases were located in the periventricular area. The solid part of the lesion was isointense (n = 5/8) or hypointense (n = 3/8) to gray matter on T1-weighted imaging. Diffusion-weighted imaging presented heterogeneous hypointensity and isointensity (n = 4/7) or homogeneous hypointensity (n = 3/7) in the solid part of the lesion.

CONCLUSIONS

The location adjacent to lateral ventricle, isointensity on T1-weighted imaging, and low signal on DWI may be of some specificity to PGNT.

An individual patient data meta-analysis on characteristics and outcome of patients with papillary glioneuronal tumor, rosette glioneuronal tumor with neuropil-like islands and rosette forming glioneuronal tumor of the fourth ventricle

Background and Purpose

In 2007, the WHO classification of brain tumors was extended by three new entities of glioneuronal tumors: papillary glioneuronal tumor (PGNT), rosette-forming glioneuronal tumor of the fourth ventricle (RGNT) and glioneuronal tumor with neuropil-like islands (GNTNI). Focusing on clinical characteristics and outcome, the authors performed a comprehensive individual patient data (IPD) meta-analysis of the cases reported in literature until December 2012.

Methods

PubMed, Embase and Web of Science were searched for peer-reviewed articles reporting on PGNT, RGNT, and GNTNI using predefined keywords.

Results

95 publications reported on 182 patients (PGNT, 71; GNTNI, 26; RGNT, 85). Median age at diagnosis was 23 years (range 4–75) for PGNT, 27 years (range 6–79) for RGNT, and 40 years (range 2–65) for GNTNI. Ninety-seven percent of PGNT and 69% of GNTNI were located in the supratentorial region, 23% of GNTNI were in the spinal cord, and 80% of RGNT were localized in the posterior fossa. Complete resection was reported in 52 PGNT (73%), 36 RGNT (42%), and 7 GNTNI (27%) patients. Eight PGNT, 3 RGNT, and 12 GNTNI patients were treated with chemo- and/or radiotherapy as the primary postoperative treatment. Follow-up data were available for 132 cases. After a median follow-up time of 1.5 years (range 0.2–25) across all patients, 1.5-year progression-free survival rates were 52±12% for GNTNI, 86±5% for PGNT, and 100% for RGNT. The 1.5-year overall-survival were 95±5%, 98±2%, and 100%, respectively.

Conclusions

The clinical understanding of the three new entities of glioneuronal tumors, PGNT, RGNT and GNTNI, is currently emerging. The present meta-analysis will hopefully contribute to a delineation of their diagnostic, therapeutic, and prognostic profiles. However, the available data do not provide a solid basis to define the optimum treatment approach. Hence, a central register should be established.

Clinical, radiological, and pathological features of 16 papillary glioneuronal tumors

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.

Malignant papillary glioneuronal tumor of the pineal gland: Case presentation and literature review of a distinct entity

Patient:

Male, 58

Final Diagnosis:

Papillary glioneuronal tumor of the pineal gland

Symptoms:

Headache • loss of memory • hydrocephalus

Medication:

—

Clinical Procedure:

—

Specialty:

Oncology • neurology • neurosurgery

Objective:

Rare disease

Background:

The authors report the third case of a rare papillary glioneuronal tumor of the pineal gland and only the second case reported with anaplastic features in this particular location. The authors also review the literature of papillary glioneuronal tumors.

Case Report:

Our patient is a 58-year-old Caucasian male who presented with diffuse headaches and loss of short-term memory. There were no deficits on physical exam. MRI Brain was performed demonstrating a large heterogeneously enhancing mass within the pineal gland causing obstructive hydrocephalus. He was taken to the operating room for supracerebellar-infratentorial approach for biopsy of the mass using neuronavigation. He required an endoscopic third ventriculostomy post-operatively for worsening hydrocephalus. Pathology demonstrated a rare malignant papillary glioneuronal tumor. It was recommended that patient undergo chemotherapy and radiation, however he refused treatment. He died six months after his initial diagnosis due to a condition unrelated to his intracranial tumor.

Conclusions:

This is an unusually rare tumor of the pineal gland, with only one other malignant case noted in this location. We review the literature of this rare entity that should be considered on the differential diagnosis of a pineal gland mass.

Papillary glioneuronal tumor--a rare entity: report of four cases and brief review of literature

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(R132H) 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.

Long-term epilepsy-associated tumors

The term long-term epilepsy associated tumor (LEAT) encompasses lesions identified in patients investigated for long histories (often 2 years or more) of drug-resistant epilepsy. They are generally slowly growing, low grade, cortically based tumors, more often arising in younger age groups and in many cases exhibit neuronal in addition to glial differentiation. Gangliogliomas and dysembryoplastic neuroepithelial tumors predominate in this group. LEATs are further united by cyto-architectural changes that may be present in the adjacent cortex which have some similarities to developmental focal cortical dysplasias (FCD); these are now grouped as FCD type IIIb in the updated International League Against Epilepsy (ILAE) classification. In the majority of cases, surgical treatments are beneficial from both perspectives of managing the seizures and the tumor. However, in a minority, seizures may recur, tumors may show regrowth or recurrence, and rarely undergo anaplastic progression. Predicting and identifying tumors likely to behave less favorably are key objectives of the neuropathologist. With immunohistochemistry and modern molecular pathology, it is becoming increasingly possible to refine diagnostic groups. Despite this, some LEATs remain difficult to classify, particularly tumors with "non-specific" or diffuse growth patterns. Modification of LEAT classification is inevitable with the goal of unifying terminological criteria applied between centers for accurate clinico-pathological-molecular correlative data to emerge. Finally, establishing the epileptogenic components of LEAT, either within the lesion or perilesional cortex, will elucidate the cellular mechanisms of epileptogenesis, which in turn will guide optimal surgical management of these lesions.

Identification of a novel, recurrent SLC44A1-PRKCA fusion in papillary glioneuronal tumor

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.

Intraventricular glioneuronal tumor with disseminated lesions at diagnosis--a case report

A 55-year-old man presented with a large tumor in his lateral ventricles. Magnetic resonance imaging revealed disseminated lesions in the third and fourth ventricles at the time of diagnosis. The patient underwent a partial removal of the tumor in the lateral ventricles. Histologically, the surgical specimens showed glioneuronal differentiation with ganglion or ganglioid cells, Rosenthal fibers, oligodendroglia-like honeycomb appearances, a spongy pattern, perivascular pseudorosettes, and many hyalinized blood vessels. Papillary structure was not observed. The neuronal component showed a moderately high labeling index of Ki-67/MIB-1. We diagnosed this tumor as atypical intraventricular glioneuronal tumor. The disseminated lesions disappeared after chemoradiation therapy with temozolomide, and the residual tumors in the lateral ventricles remained stable for 3 years after the surgery. We discuss the pathological diagnosis, therapy and clinical course with review of the literatures.

Childhood brain tumours due to germline bi-allelic mismatch repair gene mutations

Childhood brain tumours may be due to germline bi-allelic mismatch repair (MMR) gene mutations in MLH1, MSH2, MSH6 or PMS2. These mutations can also lead to colorectal neoplasia and haematological malignancies. Here, we review this syndrome and present siblings with early-onset rectal adenoma and papillary glioneural brain tumour, respectively, due to novel germline bi-allelic PMS2 mutations. Identification of MMR protein defects can lead to early diagnosis of this condition. In addition, assays for these defects may help to classify brain tumours for research protocols aimed at targeted therapies.