Papillary glioneuronal tumor

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.

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.

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.

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

Papillary glioneuronal tumors are a newly recognized type of brain neoplasm characterized by prominent pseudopapillary structures and glioneuronal elements. All prior cases have shown that these tumors have an indolent course. The authors present 2 patients with an aggressive variant of the tumor. The first patient had dissemination of her tumor and the second had local spreading. Therefore, the authors conclude that papillary glioneuronal tumors do not always behave in a strictly benign fashion.

Genetic alterations in a papillary glioneuronal tumor

Papillary glioneuronal tumors (PGNTs) are rare lesions of the central nervous system, and no information exists on the genetic alterations in these neoplasms. The authors report on such a case in a child. Genetic studies revealed that the tumor was characterized by gains and structural alterations involving only chromosome 7 with breakpoints at 7p22. By using comparative genomic hybridization, the authors observed a high-level amplification region at 7p14~q12. Fluorescence in situ hybridization with a probe for EGFR revealed that this gene was not amplified. Similar to other patients with PGNTs, the patient in the present case fared well. From a genetic point of view the data in the present case are in accordance with previous findings of EGFR amplifications as uncommon in low-grade gliomas and gangliogliomas. Recurrent rearrangements of chromosome 7 have been noted in other mixed glioneuronal tumors. The data in this case suggest that genes located at chromosome 7 can also be involved in the pathogenesis of PGNT. In clinical terms it will be especially important to corroborate, through the analysis of further cases, the involvement of the chromosome 7p22 locus, a region where glial and neuronal linked genes (RAC1 and NXPH1) are known to be located.

The 2007 WHO Classification of Nervous System Tumors: newly recognized members of the mixed glioneuronal group

The clinical and pathologic features of two glioneuronal neoplasms newly incorporated in the 2007 revision of the WHO classification of nervous system tumors are reviewed. These are the papillary glioneuronal tumor and the rosette-forming glioneuronal tumor of the fourth ventricle.

Papillary glioneuronal tumour: a report of a rare case and review of literature

INTRODUCTION

Amongst the mixed glioneuronal tumours, 'papillary glioneuronal tumour', a new variant, has been described recently.

CASE REPORT

We report a case of papillary glioneuronal tumour in a 4-year-old boy who presented with fever, weakness of left upper and lower limbs and headache for the last 2.5 month. Radiologic examination showed a cystic space-occupying lesion with mural nodule in the right frontal lobe with extension into white matter. Surgical excision of a large cystic mass with small solid nodule was done. Pathological examination revealed a well-circumscribed tumour showing predominantly papillary architecture with focal aggregates of cells in sheets. The papillae were composed of hyalinised blood vessels lined by single to multi-layered cells. The tumour cells showed mild pleomorphism without any necrosis. The individual tumour cells had scant eosinophilic cytoplasm, round to oval hyperchromatic nucleus with occasional mitoses. The tumour cells were immunopositive for glial fibrillary acidic protein, synaptophysin, vimentin, and S-100 protein, but negative for neurofilament, epithelial membrane antigen, cytokeratin and CD34. MIB-1 labelling index was approximately 12% in the highest proliferating areas. In view of subtotal excision of the tumour and high MIB-1 labelling index (LI), the patient was given chemotherapy and he is doing well at 1-year follow-up.

DISCUSSION

This report supports the existence of this rare tumour. Some of its rare clinicopathological features like young age, cyst with mural nodule, presence of mitoses and raised MIB-1 LI need to be documented.

Atypical papillary glioneuronal tumor

We describe a 34-year-old man who presented with headaches for about 3 months. Magnetic Resonance Imaging (MRI) revealed a large cystic tumor, involving the right frontoparietal lobe region. Pathological study revealed a papillary glioneuronal tumor (PGNT) with mitotic activity and a Ki-67 labeling index of approximately 15%. Five years after radical surgery and radiotherapy, the patient is symptom-free, without tumor recurrence or residual tumor. This case supports the existence of an atypical variant of PGNT, with mitotic activity and high proliferative index, and suggests that in these tumors, histological findings of malignity not necessarily indicate a short-term unfavorable behavior.