Desmoplastic infantile and non-infantile ganglioglioma. Review of the literature

Desmoplastic infantile astrocytoma/ ganglioglioma in a pediatric onset multiple sclerosis patient: A case report

Here we present a co-occurrence of a non-typical presentation of DIG/DIA and multiple sclerosis in a 13-year-old female. Our case highlights how a thorough investigation prior to treatment is needed in patients with such condition to choose proper management for better prognosis.

Low-grade glioma of the temporal lobe and tumor-related epilepsy in children

PURPOSE

Low-grade glioma is the most common brain tumor among children and adolescents. When these tumors arise in the temporal lobe, patients frequently present with seizures that are poorly controlled with antiepileptic drugs. Here we summarize the clinical features, pathophysiology, preoperative evaluation, surgical treatment, and outcomes of pediatric patients with low-grade gliomas in the temporal lobe.

METHODS

We reviewed the literature on pediatric low-grade gliomas in the temporal lobe, focusing on cohort studies and systematic reviews that described surgical treatment strategies and reported both oncologic and epilepsy outcomes.

RESULTS

The differential diagnoses of pediatric low-grade gliomas in the temporal lobe include ganglioglioma, dysembryoplastic neuroepithelial tumor, desmoplastic infantile ganglioglioma, papillary glioneuronal tumor, pilocytic astrocytoma, pleomorphic xanthoastrocytoma, angiocentric glioma, and polymorphous low-grade neuroepithelial tumor of the young. There is no consensus on the optimal surgical approach for these tumors: lesionectomy alone, or extended lesionectomy with anterior temporal lobectomy, with or without removal of mesial temporal structures. Gross total resection and shorter preoperative duration of epilepsy are strongly associated with favorable seizure outcomes, defined as Engel Class I or Class II, approaching 90% in most series. The risk of surgical complications ranges from 4 to 17%, outweighing the lifetime risks of medically refractory epilepsy.

CONCLUSION

Pediatric patients with temporal low-grade glioma and tumor-related epilepsy are best managed by a multidisciplinary epilepsy surgery team. Early and appropriate surgery leads to prolonged survival and a greater likelihood of seizure freedom, improving their overall quality of life.

High-grade desmoplastic infantile astrocytoma in a 1-year-old child with Down’s syndrome: a case report

Background

Down’s syndrome is the most common chromosomal abnormality in humans. It has been associated with central nervous system tumors such as primary acute lymphoblastic leukemia and germinomas, but desmoplastic infantile astrocytoma has not yet been reported with Down’s syndrome. Desmoplastic infantile astrocytoma is a rare intracranial tumor that mostly occurs in the first 2 years of life. It usually presents as a large, aggressive tumor with both solid and cystic components. Genetically, it has been linked to the BRAF V600E mutation. Despite the rapid growth pattern, it usually has a favorable prognosis after neurosurgical excision. The presence of this extremely rare, genetically linked tumor, and its combination with Down’s syndrome, the most common human genetic defect, makes this a very novel clinical presentation. It also raises a very research-worthy question of an undiscovered link between these two genetic disorders.

Case presentation

In this case, we report a 1-year-old Pakistani origin male child with Down’s syndrome, who presented with progressive macrocephaly and developmental regression over the last 2 months. He was unable to sit by himself, and had lost his handgrip bilaterally. Down’s Syndrome was diagnosed soon after birth, based on typical facial features and presence of palmar crease, and later confirmed karyotypically for Trisomy 21. Upon presentation, initial blood tests did not show any abnormality. Magnetic resonance imaging of the brain was done, and showed a mixed intensity cystic mass with solid dural component posteriorly in the right parieto temporo occipital region. Craniotomy was performed, and about 85% of the tumor mass was excised. Histological examination and immunochemistry confirmed the suspected radiological diagnosis of desmoplastic infantile astrocytoma. After surgical excision, our patient gradually reacquired his previously regressed developmental milestones. Unfortunately, the remaining mass, which could not be excised due to its attachment to the highly vascular dura mater, showed regrowth on repeat brain magnetic resonance imaging. As his parents did not consent to further surgery, chemotherapy was offered as the next treatment option to prevent tumor regrowth.

Conclusions

This case report highlights the need for more case data and research to understand desmoplastic infantile astrocytoma, and their genetic correlation with Down’s syndrome. From a clinical standpoint, since desmoplastic infantile astrocytoma has a good postresection prognosis in a majority of early-diagnosed clinical cases, pediatricians, radiologists, and pathologists should consider desmoplastic infantile astrocytoma in their initial differential diagnosis in Down’s syndrome patients with macrocephaly and developmental regression during the first 2 years of life.

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.

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.

Infant High-Grade Gliomas Comprise Multiple Subgroups Characterized by Novel Targetable Gene Fusions and Favorable Outcomes

Infant high-grade gliomas appear clinically distinct from their counterparts in older children, indicating that histopathologic grading may not accurately reflect the biology of these tumors. We have collected 241 cases under 4 years of age, and carried out histologic review, methylation profiling, and custom panel, genome, or exome sequencing. After excluding tumors representing other established entities or subgroups, we identified 130 cases to be part of an "intrinsic" spectrum of disease specific to the infant population. These included those with targetable MAPK alterations, and a large proportion of remaining cases harboring gene fusions targeting ALK (n = 31), NTRK1/2/3 (n = 21), ROS1 (n = 9), and MET (n = 4) as their driving alterations, with evidence of efficacy of targeted agents in the clinic. These data strongly support the concept that infant gliomas require a change in diagnostic practice and management. SIGNIFICANCE: Infant high-grade gliomas in the cerebral hemispheres comprise novel subgroups, with a prevalence of ALK, NTRK1/2/3, ROS1, or MET gene fusions. Kinase fusion-positive tumors have better outcome and respond to targeted therapy clinically. Other subgroups have poor outcome, with fusion-negative cases possibly representing an epigenetically driven pluripotent stem cell phenotype.See related commentary by Szulzewsky and Cimino, p. 904.This article is highlighted in the In This Issue feature, p. 890.

Uncommon low-grade brain tumors

The 2016 World Health Organization (WHO) classification of primary central nervous system (CNS) tumors includes numerous uncommon (representing ≤1% of tumors) low-grade (grades I-II) brain neoplasms with varying clinical behaviors and outcomes. Generally, gross tumor or maximal safe resection is the primary treatment. Adjuvant treatments, though their exact role is unknown, may be considered individually based on pathological subtypes and a proper assessment of risks and benefits. Targetable mutations such as BRAF (proto-oncogene B-Raf), TRAIL (tumor necrosis factor apoptosis inducing ligand), and PDGFR (platelet derived growth factor receptor) have promising roles in future management.

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.

Mixed Solid and Cystic Mass in an Infant

Desmoplastic infantile tumors are rare supratentorial brain tumors that occur in pediatric patients. Desmoplastic infantile tumors are made up of 2 subtypes: desmoplastic infantile gangliogliomas and desmoplastic infantile astrocytomas. Desmoplastic infantile tumors are often identifiable on imaging on the basis of multiple characteristics. Nevertheless, pathologic analysis is required to confirm the diagnosis, particularly when the imaging features are atypical. Here, the radiology findings, surgical approach and subsequent management, and pathology of a desmoplastic infantile ganglioglioma are described.

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.

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.

Atypical imaging in a desmoplastic non-infantile astrocytoma

INTRODUCTION

Desmoplastic infantile tumors, especially desmoplastic astrocytomas, are uncommon neoplasms that are generally seen within first 2 years of life. Their occurrence in slightly older children is very rare. The typical radiological appearance is a large cystic lesion with small enhancing solid part.

CASE

In the present report, we describe a 10-year-old child with atypical appearance of desmoplastic non-infantile astrocytoma which was predominantly solid on imaging.

CONCLUSION

Although rare, desmoplastic astrocytomas may present even in older children and should be considered in the differential diagnoses. These tumors may present as predominantly solid enhancing lesions and add to the radiological dilemma.

Progressive Disordered Movements in an Infant Leads to Rare Diagnosis

Desmoplastic infantile ganglioglioma (DIG) is a supratentorial superficially-located cystic neuroepithelial tumor. It is an exceedingly rare tumor with an incidence of <0.1% of central nervous tumors; approximately 60 cases have been reported in the literature. We present a case of a three-month-old infant with progressive disordered movements described as intermittent upper body stiffening with associated eye blinking, drooling, and change in level of alertness. A seizure was witnessed in the emergency department, after which the child was sent for imaging studies. Magnetic resonance imaging (MRI) revealed a large solid and cystic mass in the temporal region measuring 8.6cm × 7.9cm × 5.1cm. The infant underwent complete surgical resection, and post-surgical pathology revealed a diagnosis of DIG. The patient had an excellent post-operative course in the months following discharge. At his last well-child visit, no neurological deficits were appreciated and the infant was meeting expected milestones for his age.

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.

Desmoplastic infantile ganglioglioma with focal cortical dysplasia: A rare double pathology in an infant with history of seizures

We describe an extremely rare case of double pathology arising in an infant girl presenting with a history of intractable seizures, delayed milestones and enlarging head. The pathology included desmoplastic infantile ganglioglioma (DIG) and extensive focal cortical dysplasia in the overlying cortex. While tumors such as ganglioglioma have been commonly described to occur as concomitant pathology with cortical dysplasia, DIG in such an association has not been described in the literature. As DIG are voluminous supratentorial tumors, awareness about such an association is pertinent for correct diagnosis.

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.

Non-infantile variant of desmoplastic ganglioglioma: Conventional and advanced MR imaging characteristics

Desmoplastic infantile ganglioglioma is a paediatric brain tumor that is commonly seen in the infantile age group. Literature on the non-infantile variant of this low-grade supratentorial neoplasm is very scarce, except for a few case reports. Herein, we report a case of desmoplastic non-infantile ganglioglioma occurring at the age of 6 years and describe its conventional and advanced magnetic resonance imaging characteristics.

BRAF V600E expression and distribution in desmoplastic infantile astrocytoma/ganglioglioma

AIMS

Desmoplastic infantile astrocytoma/ganglioglioma (DIA/DIG) is a rare primary neuroepithelial brain tumour typically affecting paediatric patients younger than 24 months. Knowledge about genetic alterations in DIA/DIG is limited. However, a previous study on BRAF V600E mutation in paediatric glioma revealed a BRAF mutation in one of two tested DIAs/DIGs. The limited number of cases in that study did not allow any conclusion about mutation frequency of BRAF in this tumour entity.

METHODS

We collected a series of 18 DIAs/DIGs for testing BRAF V600E mutational status by BRAF V600E immunohistochemistry (clone VE1). Cases with sufficient DNA were tested for BRAF V600E mutation by pyrosequencing.

RESULTS

Three out of 18 DIAs/DIGs presented with VE1 binding. A considerable proportion of BRAF V600E mutated tumour cells was detected in the cortical tumour component, whereas the pronounced leptomeningeal tumoural stroma was predominantly negative for VE1 binding. Pyrosequencing confirmed BRAF V600E mutation in two of three VE1-positive cases.

CONCLUSION

BRAF V600E mutation affects a subset of DIAs/DIGs and offers new therapeutic opportunities.

Desmoplastic infantile ganglioglioma with late presentation. A clinical, radiological and histopathological analysis

Desmoplastic infantile ganglioglioma (DIG) is a rare supratentorial tumor in the central nervous system. Definitive diagnosis of this neoplasm is based on histopathologic analysis evaluating distinctive findings such as the fibroblastic differentiation. Here we present a clinical case of DIG with a long follow-up in an eight-year-old boy with a six-month history of recurrent emesis, psychomotor hyperactivity and generalized tonic-clonic seizures. Computed tomography scan and magnetic resonance imaging (MRI) showed a cystic, heterogeneous, mass on the right temporal uncus. A histopathological diagnosis of late presentation DIG was made. We documented the immunohistochemical expression of a molecular soft tissue / muscle differentiation marker (h-CaD) in addition to a low proliferative index (Ki-67) in this case. After surgical intervention, a control MRI showed changes of right frontal-temporal craniotomy and a persistent mass in the anterior and medial temporal lobe with basal extension. Further surgical intervention was performed, completely removing the tumor, which had the same characteristics. The patient is asymptomatic while receiving anticonvulsant therapy (phenytoin) with no evidence of tumor recurrence on MRI after a follow-up of five years. The low grade and soft tissue appearance in images are correlated with the histopathologic and immunohistochemical profile of this tumor, but the rarity of this tumor makes a presumptive diagnosis by images a challenge. The above-mentioned molecular markers or new ones could be used as molecular targets for molecular imaging studies to increase the probability of a pre-operative diagnosis based on molecular features through images.

Mixed neuronal-glial tumor in the temporal lobe of an infant: a case report

Background

Tumors that arise in the temporal lobes of infants and spread to the neural system are limited to several diagnoses. Herein, we present an infantile case of a temporal tumor showing neuronal and glial differentiation.

Case presentation

The patient was a 9-month-old boy with low body weight due to intrauterine growth retardation. At 9 months after birth, he presented partial seizures. Computed tomography scanning revealed a mass (35 * 40 mm) in the left temporal lobe. Isointensity was noted on magnetic resonance T1-weighted images and fluid attenuation inversion recovery images. The tumor was heterogeneously enhanced with gadolinium. Positron emission tomography showed high methionine uptake in the tumor. During surgery, the tumor, which was elastic and soft and bled easily, was gross totally resected. A moderately clear boundary was noted between the tumor and normal brain parenchyma. Histologically, the tumor mainly comprised a ganglioglioma-like portion and short spindle cells at different densities. The former was immunohistochemically positive for some kinds of neuronal markers including synaptophysin. The spindle cells were positive for glial fibrillary acidic protein, but desmoplasia was not observed.

Discussion

The tumor contained both neuronal and glial elements; the former were the main constituents of the tumor and included several ganglion-like cells. Because neuronal elements gradually transited to glial cells, a mixed neuronal-glial tumor was diagnosed.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2045126100982604

Coexpression of glial and neuronal markers in the neurocytic rosettes of rosette-forming glioneuronal tumors

Rosette-forming glioneuronal tumor of the fourth ventricle (RGNT) is a new entity in the WHO 2007 Classification of Tumors of the Central Nervous System. RGNT has two components: neurocytic rosettes and low-grade gliomas. Neurocytic rosettes are conventionally described as consisting of uniform neurocytes. However, some studies have reported rosette-forming tumor cells that expressed glial markers such as Olig2. We indicated the expression of glial markers including Olig2, cyclinD1, glial fibrillary acidic protein (GFAP), and platelet-derived growth factor receptor alpha (PDGFRα) in the neurocytic rosettes in our previous study, and we suggested that these tumor cells had a heterogeneous nature. In this study, we used double and triple immunostaining to demonstrate that these tumor cells have both glial and neuronal characteristics. We found that rosette-forming tumor cells coexpressed Olig2/cyclinD1 and synaptophysin. Furthermore, the cores of the rosettes coexpressed GFAP/PDGFRα in the peripheral zone and synaptophysin in the central zone. These findings imply that rosette-forming tumor cells have a similar nature to neuronal-glial progenitor cells, and we believe that the nomination "neurocytic rosette" may be unsuitable given their heterogeneous nature. Our study appears to clarify some of the properties of RGNT tumor cells and may help elucidate the histogenesis of RGNT.

Strong desmin expression in a congenital desmoplastic infantile ganglioglioma mimicking pleomorphic rhadomyosarcoma: a case report including ultrastructural and cytogenetic evaluation and review of the literature

PURPOSE

Desmoplastic infantile gangliogliomas (DIGs) are rare tumors of infancy. Herein, we describe an unusual case of DIG diagnosed by prenatal ultrasound.

METHODS

This 5-day-old newborn was delivered after a prenatal ultrasound revealed a large cystic mass in the left cerebral hemisphere along with an echogenic solid component.

RESULTS

The tumor revealed a glial and neuronal proliferation in a background of desmoplasia more typical of DIG and a minor component with a more primitive, immature appearance to the glioneuronal elements. A significant component of the tumor was composed of pleomorphic eosinophilic spindle cells in whorls and interlacing fascicles that showed a strong, sharp, and diffuse positivity for desmin, thus mimicking rhabdomyosarcoma. However, the tumor cells were GFAP (+), INI-1 (+), and myogenin (-). Mitoses were seen both in the more spindle cell astroglial areas as well as the more primitive neuroepithelial cells. The MIB-1 proliferation index was brisk, exceeding 15 %, and in areas it was estimated to be as high as 30 %. Such high proliferation index has been described and accepted in the more primitive neuroepithelial areas, but not in the terminally differentiated, spindle cell astroglial areas as in our case. Our patient was incidentally diagnosed prenatally. To our knowledge, this case is the first documented congenital DIG diagnosed prenatally.

CONCLUSIONS

This case highlights the pitfalls in diagnosing DIG, which can mimic a rhabdomyosarcoma. Furthermore, it underscores the importance of re-evaluating the grading of these tumors or at least segregating the variants where the prognosis may be more guarded.