Clinical heterogeneity of desmoplastic infantile ganglioglioma: a case series and literature review

Imaging of pediatric glioneuronal and neuronal tumors

Glioneuronal tumors (GNTs) are an expanding group of primary CNS neoplasms, commonly affecting children, adolescents and young adults. Most GNTs are relatively indolent, low-grade, WHO grade I lesions. In the pediatric age group, GNTs have their epicenter in the cerebral cortex and present with seizures. Alterations in the mitogen-activated protein kinase (MAPK) pathway, which regulates cell growth, are implicated in tumorigenesis. Imaging not only plays a key role in the characterization and pre-surgical evaluation of GNTs but is also crucial role in follow-up, especially with the increasing use of targeted inhibitors and immunotherapies. In this chapter, we review the clinical and imaging perspectives of common pediatric GNTs.

Other Less Prevalent Tumors of the Central Nervous System

The presented tumors in this chapter are somewhat very rare, and their management is still debated due to the scarcity of information about their cell of origin, behavior, and biology. Treatment options are still limited, but we are confident that in the near future by discovering the genetic and biological mechanisms that drive tumor growth we will be able to offer new target therapies that should be flanked by surgery, radiotherapy, and chemotherapeutic agents actually in use. The purpose of this chapter is to highlight the most important known characteristics of these tumors offering the chance to recognize the disease and then offer the best opportunity for treatment to patients. The 5th WHO Classification Central Nervous System features substantial changes by moving further to advance the role of molecular diagnostics in CNS tumor classification, but remaining rooted in other established approaches to tumor characterization, including histology and immunohistochemistry, and probably, the category of many tumors will change. Here, the most important characteristics of each neoplasm are summarized focusing on genetic mechanisms and molecular pathways, their histopathologic footprints, signs and symptoms, radiologic features, therapeutic approaches, and prognosis as well as follow-up protocols. Schematic classifications are also presented to offer a better understanding of the pathology.

Establishment and Characterization of Brain Cancer Primary Cell Cultures From Patients to Enable Phenotypic Screening for New Drugs

Aim: Desmoplastic infantile ganglioglioma (DIG), is a rare tumor arising mainly during the first 2 years of life. Molecular characterization of these benign yet rapidly proliferating tumors has been limited to evaluating a few mutations in few genes. Our aim was to establish a live cell culture to enable the understanding of the cellular processes driving the non-malignant growth of these tumors.

Methods: Tumor tissue from a rare non-infantile 8-year-old female DIG patient was dissociated and digested using collagenase to establish live cultures. Both 2D monolayer and 3D neurospheres were successfully cultured and characterized for proliferative potential, intrinsic plasticity, presence of cancer stem cells and the expression of stem cell markers. Cells cultured as 3D were embedded as tissue blocks. Immunohistochemistry was performed in both tissue and 3D sections for markers including synaptophysin, vimentin, neurofilament and MIB-1. Mutation analysis by NGS was performed using a-100 gene panel.

Results: Using immunohistochemistry, the 3D cultures were shown to express markers as in the original DIG tumor tissue indicating that the spheroid cultures were able to maintain the heterogeneity found in the original tumor. Cells continued proliferating past passage 10 indicative of immortalization. Enrichment of cancer stem cells was observed in neurospheres by FACS using CD133 antibody and RT-PCR. Mutation analysis indicated the presence of germline mutations in three genes and somatic mutations in two other genes.

Conclusion: A spontaneous cell line-like cell culture with high percentage of stem cells has been established from a DIG tumor for the first time.

The molecular characteristics of low-grade and high-grade areas in desmoplastic infantile astrocytoma/ganglioglioma

AIMS

Desmoplastic infantile astrocytomas and gangliogliomas (DIA/DIGs) are rare brain tumours of infancy. A distinctive feature of their histopathology is a combination of low-grade and high-grade features. Most DIA/DIGs can be surgically resected and have a good prognosis. However, high-grade features often dominate recurrent tumours, some of which have a poor outcome. In this study, we test the hypothesis that low-grade and high-grade areas in DIA/DIGs have distinct molecular characteristics.

METHODS

Tissue samples from microdissected low-grade and high-grade areas in 12 DIA/DIGs were analysed by DNA methylation profiling, whole exome sequencing, RNA sequencing and immunohistochemistry to search for potential differences at multiple molecular levels.

RESULTS

Copy number variants among tumours and between the two morphologically distinct areas were infrequent. No recurrent genetic alterations were identified across the tumour series, and high-grade areas did not have additional genetic alterations to explain their distinct morphology or biological behaviour. However, high-grade areas showed relative hypomethylation in genes downstream of the transcription factors SOX9 and LEF1 and evidence of a core SOX9 transcription network alongside activation of the BMP, WNT, and MAPK signalling pathways.

CONCLUSIONS

This study contributes to our knowledge of molecular genetic alterations in DIA/DIGs, uncovers molecular differences between the two distinct cell populations in these tumours, and suggests potential therapeutic targets among the more proliferative cell population in DIA/DIGs.

Predictors of mortality and tumor recurrence in desmoplastic infantile ganglioglioma and astrocytoma-and individual participant data meta-analysis (IPDMA)

PURPOSE

Desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma (DIG) are classified together as grade I neuronal and mixed neuronal-glial tumor of the central nervous system by the World Health Organization (WHO). These tumors are rare and have not been well characterized in terms of clinical outcomes. We aimed to identify clinical predictors of mortality and tumor recurrence/progression by performing an individual patient data meta-analysis (IPDMA) of the literature.

METHODS

A systematic literature review from 1970 to 2020 was performed, and individualized clinical data for patients diagnosed with DIA/DIG were extracted. Aggregated data were excluded from collection. Outcome measures of interest were mortality and tumor recurrence/progression, as well as time-to-event (TTE) for each of these. Participants without information on these outcome measures were excluded. Cox regression survival analyses were performed to determine predictors of mortality and tumor recurrence / progression.

RESULTS

We identified 98 articles and extracted individual patient data from 188 patients. The cohort consisted of 58.9% males with a median age of 7 months. The majority (68.1%) were DIGs, while 24.5% were DIAs and 7.5% were non-specific desmoplastic infantile tumors; DIAs presented more commonly in deep locations (p = 0.001), with leptomeningeal metastasis (p = 0.001), and was associated with decreased probability of gross total resection (GTR; p = 0.001). Gender, age, and tumor pathology were not statistically significant predictors of either mortality or tumor recurrence/progression. On multivariate survival analysis, GTR was a predictor of survival (HR = 0.058; p = 0.007) while leptomeningeal metastasis at presentation was a predictor of mortality (HR = 3.27; p = 0.025). Deep tumor location (HR = 2.93; p = 0.001) and chemotherapy administration (HR = 2.02; p = 0.017) were associated with tumor recurrence/progression.

CONCLUSION

Our IPDMA of DIA/DIG cases reported in the literature revealed that GTR was a predictor of survival while leptomeningeal metastasis at presentation was associated with mortality. Deep tumor location and chemotherapy were associated with tumor recurrence / progression.

Desmoplastic infantile astrocytoma and ganglioglioma: a series of 12 patients treated at a single institution

BACKGROUND

Desmoplastic infantile astrocytomas and gangliogliomas (DIA/DIG) usually present with a large size, large cystic component, large dural implant, encasement of big vessels, clinical presentation within 18 months of life, high incidence of seizures and overall good prognosis, even if tumour surgery can be very challenging at first procedure.

METHODS

We retrospectively reviewed clinical and radiological data of patients diagnosed with desmoplastic infantile tumours who were surgically treated between 2008 and 2019.

RESULTS

The series included 12 patients. The median age at surgery was 91 days. The average tumour volume was 212 cm³. Cystic components were predominant ranging from 0 to 295 cm³. Active hydrocephalus was pre-operatively evident in 5 cases. Eight patients (66.6%) received total or subtotal removal, three of them (25%) underwent partial removal, and one patient (8.3%) received a biopsy. One patient died within 24 h after surgery due to severe hypotension, as a consequence of significant intraoperative blood loss. Overall, seven (58.3%) patients were reoperated on the tumour after the first procedure: 4 patients were operated twice; 3 patients were operated 3 times. Two patients presented remote localizations and underwent chemotherapy. At last follow-up, 7 patients were tumour-free, 2 are alive with stable disease, and 2 are alive with progressive disease (leptomeningeal seeding).

CONCLUSION

Desmoplastic infantile tumours are rare giant neonatal tumours. Total removal is the goal of treatment, but prognosis remains good even if total removal is not achieved. In case of tumour progression or epilepsy from residual tumour, reoperation is the first option, with chemotherapy reserved to unresectable or disseminated cases with mixed results, while, to date, radiotherapy still plays no role.

Infantile and Noninfantile Desmoplastic Astrocytoma and Ganglioglioma: Only Different Age of Onset?

OBJECTIVE

The purpose of this study was to investigate clinical, pathological, and prognostic discrepancies between infantile and noninfantile desmoplastic astrocytoma/ganglioglioma patients.

METHODS

From January 2012 to December 2019, we retrospectively reviewed patients aged <18 years who underwent craniotomies at Beijing Tiantan Hospital. Patients diagnosed with desmoplastic infantile astrocytoma and ganglioglioma (DIA/DIG) were included.

RESULTS

The group consisted of 9 infantile patients and 8 noninfantile patients. The mean age of onset was 30.11 months in infantile patients and 103.75 months in noninfantile patients. Comparing with infantile patients, noninfantile patients had a mild female predominance (P = 0.335). The most common presentation in noninfantile patients was seizure (n = 4, 50%), whereas abnormal head circumference (n = 3, 33.3%) was the most common presentation in the infantile group. All cases showed a ki-67 index <2%. Preoperative tumor volume in infantile patients (213.98 cm³) was larger than that in noninfantile patients (21.99 cm³) (P = 0.043). Gross total resection was achieved in 5 (55.6%) infantile patients and 6 (75%) noninfantile patients (P = 0.62). All patients are alive by last follow-up visit, and 1 infantile patient recurred 8 months postoperative.

CONCLUSIONS

Infantile and noninfantile patients with DIA/DIGs share similar clinical and histopathological features. Compared with infantile patients, noninfantile patients tend to have different symptom predominance. Lesions in noninfantile patients are prone to present with different cystic-solid patterns and smaller volume. Patients with DIA/DIGs have favorable prognosis regardless of extent of resection.

Desmoplastic Infantile Ganglioglioma: A MAPK Pathway-Driven and Microglia/Macrophage-Rich Neuroepithelial Tumor

MAPK pathway activation has been recurrently observed in desmoplastic infantile ganglioglioma/astrocytoma (DIG/DIA) with reported disproportionally low mutation allele frequencies relative to the apparent high tumor content, suggesting that MAPK pathway alterations may be subclonal. We sought to expand the number of molecularly profiled cases and investigate if tumor cell composition could account for the observed low mutation allele frequencies. Molecular (targeted neuro-oncology next-generation sequencing/RNA sequencing and OncoScan microarray) and immunohistochemical (CD68-PGM1/CD163/CD14/CD11c/lysozyme/CD3/CD20/CD34/PD-L1) studies were performed in 7 DIG. Activating MAPK pathway alterations were identified in 4 (57%) cases: 3 had a BRAF mutation (V600E/V600D/V600_W604delinsDQTDG, at 8%–27% variant allele frequency) and 1 showed a TPM3-NTRK1 fusion. Copy number changes were infrequent and nonrecurrent. All tumors had at least 30% of cells morphologically and immunophenotypically consistent with microglial/macrophage lineage. Two subtotally resected tumors regrew; 1 was re-excised and received adjuvant treatment (chemotherapy/targeted therapy), with clinical response to targeted therapy only. Even with residual tumor, all patients are alive (median follow-up, 83 months; 19–139). This study further supports DIG as another MAPK pathway-driven neuroepithelial tumor, thus expanding potential treatment options for tumors not amenable to surgical cure, and suggests that DIG is a microglia/macrophage-rich neuroepithelial tumor with frequent low driver mutation allele frequencies.

The great neurosurgical masquerader: 3 cases of desmoplastic infantile ganglioglioma

Desmoplastic infantile ganglioglioma (DIG) is a rare, distinctive, supratentorial neoplasm with a generally favorable prognosis. Clinical, radiographic, and pathologic features can sometimes mimic those of a malignant tumor and other serious intracranial disorders. The author describes his experience with 3 cases of DIG, each of which initially masqueraded as another neurological disease with a very different prognosis. Case 1 was an infant boy referred for evaluation of a hemorrhagic infarction at birth. Case 2 was an infant girl referred for evaluation of a holohemispheric malignant neoplasm. Case 3 was an infant girl referred for evaluation of an intracranial mass believed to be a subdural empyema or possible sarcoma. In each case the lesion was resected and found to be a WHO grade I DIG. Each child has had a benign postoperative course. DIG can be mistaken for other serious neurological conditions including malignant neoplasm, cerebral infarction, and infection. It is prudent to consider this rare, low-grade resectable tumor in the differential diagnosis of atypical intracranial masses of childhood, as the impact on prognosis can be profound. The author discusses management strategies for DIG, including a role for molecular sequencing.

Inflammatory myofibroblastic lung tumor transforming into intracranial desmoplastic noninfantile ganglioglioma: A case report and literature review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) of the lung often arises from excessive inflammatory response. It is one of the rare benign tumors of the lung, while desmoplastic noninfant gangliogliomas (DNIG), on the contrary, are rare intracranial benign tumors often seen in children within the first one and a half years of life.

PATIENT CONCERNS

We present a 12-year-old girl with 2 months history of none productive cough and right-sided chest pain.

DIAGNOSES

Computer tomography scan of the chest revealed a soft tissue mass at the right upper lobe which was consistent with IMT. Histopathologic examination confirmed the diagnosis of IMT.

INTERVENTIONS

Thoracic surgery was successfully carried out and she further received radiotherapy. The patient recovered initially.

OUTCOMES

Two years later, she complained of seizures during follow-up. Magnetic resonance imaging of the head revealed DNIG. We achieved total resection of the major lesions and she was further treated with radiotherapy. She is currently well and in school. Histopathologic examination confirmed the diagnosis of DNIG.

LESIONS

We speculate that IMT might have transformed into intracranial DNIG through metastatic process or as a result of genetic mutations or chromosomal abrasions.

Novel suprasellar location of desmoplastic infantile astrocytoma and ganglioglioma: a single institution's experience

OBJECTIVE

The aim of this study was to describe the clinical presentation, imaging appearance, and differential outcomes based on tumor location in 7 patients with desmoplastic infantile astrocytoma and desmoplastic infantile gangliogliomas (DIA/DIG).

METHODS

Data of 7 patients with histopathology-proven DIA/DIGs and preoperative imaging were retrospectively reviewed, and age, sex, clinical presentation, imaging characteristics, tumor location, surgical procedure, postoperative morbidity, and overall mortality were recorded.

RESULTS

Two subgroups of patients with DIA/DIGs were found to exist based on whether their tumor was located in the cerebral hemispheres or suprasellar region. Nearly all patients presented with rapidly enlarging head circumference regardless of tumor location. However, ocular abnormalities, including nystagmus and preference for downward gaze, were specific for patients with suprasellar disease. These patients experienced significant postoperative complications and had poor long-term outcomes. In contrast, patients with hemispheric tumors underwent more extensive resection than patients with suprasellar tumors, had uneventful postoperative courses, and had no documented long-term comorbidities.

CONCLUSIONS

Postoperative course and long-term outcome for patients with DIA/DIGs were correlated to the anatomical location and radiographic appearance of their tumor at presentation, despite having histologically and molecularly indistinguishable, WHO grade I tumors.

Desmoplastic infantile astrocytoma/ganglioglioma with rare BRAF V600D mutation

BACKGROUND

Desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile gangliogliomas (DIGs) are rare, massive, cystic and solid tumors of infants usually found in superficial cerebral hemispheres. They manifest prominent desmoplastic stroma, admixed neoplastic astrocytes, primitive-appearing small cells, and additional neoplastic ganglion cells in the case of DIGs. While v-Raf murine sarcoma viral oncogene homolog B (BRAF) mutation is found in up to 50% of pediatric gangliogliomas, two recent studies found that it was rare in DIA/DIGs; we sought to assess BRAF status in DIA/DIGs from our institution.

PROCEDURE

Departmental files from 2000 to 2016 were reviewed to identify cases. Clinical, neuroimaging, histological, and immunohistochemistry (IHC) features were assessed; the latter included IHC for astrocytic and neuronal markers and BRAF VE1. BRAF mutational assessment by Sanger and next-generation sequencing was attempted in all cases.

RESULTS

All six identified cases (four males-two females; three DIA-three DIG) occurred in children <1-year old, were large, cerebral-hemispheric, cystic and solid, and enhancing tumors. Only one case, a DIG with prominent aggregates of neoplastic ganglion cells, showed either BRAF VE1 IHC positivity or mutation by Sanger and next-generation sequencing (rare c. 1799_1800delinsAT; p. V600D). Four of six archival cases were BRAF VE1 IHC negative, but failed mutational sequencing.

CONCLUSION

Five of six classic DIA/DIGs were negative for BRAF mutation; previous series have identified BRAF mutation in two of 18 and one of 14 cases, although all were the more common BRAF V600E. We were unable to find other examples of glial tumors in public databases with this rare BRAF V600D mutation. Identification of BRAF mutational opens the possibility of BRAF-targeted therapies for the subset of DIA/DIG that clinically progress postresection.

Diffusion, Perfusion, and Histopathologic Characteristics of Desmoplastic Infantile Ganglioglioma

We present a case series of a rare tumor, the desmoplastic infantile ganglioglioma (DIG) with MRI diffusion and perfusion imaging quantification as well as histopathologic characterization. Four cases with pathologically-proven DIG had diffusion weighted imaging (DWI) and two of the four had dynamic susceptibility contrast imaging. All four tumors demonstrate DWI findings compatible with low-grade pediatric tumors. For the two cases with perfusion imaging, a higher relative cerebral blood volume was associated with higher proliferation index on histopathology for one of the cases. Our results are discussed in conjunction with a literature review.

Malignant transformation of a desmoplastic infantile ganglioglioma in an infant carrier of a nonsynonymous TP53 mutation

INTRODUCTION

Desmoplastic infantile ganglioglioma is a rare intracranial neoplasm classified as World Health Organization grade I tumor under neuronal and mixed neuronal-glial tumors (2007 World Health Organization brain tumor classification). It is usually a good prognosis, but 40% of patients require further medical, radiation, and/or surgical intervention, and 15% develop leptomeningeal spread or die from desmoplastic infantile ganglioglioma. Transformation to malignant glioblastoma occurs, but the genetic alterations associated with the transformation are generally unknown.

METHODS

We describe a desmoplastic infantile ganglioglioma in a 2-month-old boy, which showed aggressive behavior, requiring debulking at 2.5 months of age and chemotherapy at 10 months of age after tumor progression. At 8.5 years of age he developed malignant transformation to glioblastoma. Chromosome microarray analysis using oligo array and genomic sequencing was performed on the biopsy specimen from 2 months of age and on the subsequent transformed malignant glioblastoma.

RESULTS

After being clinically stable for 7.5-years, transformation to glioblastoma transformation occurred. He did well for 1 year but subsequently died from tumor progression. Chromosome microarray analysis using oligo array performed on the biopsy specimen obtained at 2 months of age did not reveal significant abnormalities; but there were significant genomic deletions and duplications associated with the glioblastoma. These included multiple genomic losses involving 4q and Y, gains of 5q, and amplification of 12q14. Genomic sequencing revealed a single nucleotide variant, p.R248Q in exon 7 of TP53, in the primary desmoplastic infantile ganglioglioma and the glioblastoma multiforme.

CONCLUSIONS

The nonsynonymous variant (p.R248Q in exon 7) of the TP53 gene is predicted to alter the structure of the L2/L3 motif of the DNA binding domain of p53 protein. It was detected in the primary desmoplastic infantile ganglioglioma and glioblastoma multiforme. This child illustrates the rare recurrence of desmoplastic infantile ganglioglioma with malignant transformation to glioblastoma caused by a nonsynonymous TP53 mutation, providing explanation for other rare benign tumor transformations. The TP53 gene is a known primary site of genetic alteration that predisposes to malignant tumors, and this case indicates that it might also be involved in the behavior and outcome of desmoplastic infantile ganglioglioma. Therefore more genetic testing is recommended on desmoplastic infantile ganglioglioma tumors, which may provide biologic prognostic markers.

Genome-wide DNA copy number analysis of desmoplastic infantile astrocytomas and desmoplastic infantile gangliogliomas

Little is known about the molecular features of desmoplastic infantile ganglioglioma (DIG) and desmoplastic infantile astrocytoma (DIA). We performed a genome-wide DNA copy number analysis in combination with a multiplex ligation-dependent probe amplification-based analysis of copy number changes of candidate genes in 4 DIAs and 10 DIGs. Molecular inversion probe (MIP) assay showed that large chromosomal alterations were rare among DIG and DIA. Focal recurrent genomic losses were observed in chromosome regions such as 5q13.3, 21q22.11, and 10q21.3 in both DIA and DIG. Principal component analysis did not show any significant differences between the molecular profiles of DIG and DIA, and a hierarchical cluster analysis did not clearly separate the 2 tumor groups according to their molecular profiles. In 6 cases, gain of genomic material at 7q31 (corresponding to MET gene) was found in multiplex ligation-dependent probe amplification (MLPA) analysis. Furthermore, two cases showed gain at 4q12, and a single case showed BRAF mutation. In agreement with previous analyses, this study demonstrates the absence of consistent recurrent chromosomal alterations in DIA and DIG and overall rarity of the BRAF mutation in these tumors. Notably, these results suggest that DIA and DIG represent a histologic spectrum of the same tumor rather than 2 separate entities.