Early imaging findings in germ cell tumors arising from the basal ganglia

Germinoma of basal ganglia

Basal ganglia germinomas (BGGs) are rare lesions. Because of the atypical features of early-stage clinical symptoms and imaging characteristics, BGGs are easily misdiagnosed with non-tumorous conditions. This article presented cases of 2 young male patients who came to the hospital due to right arm weakness. Brain Magnetic Resonance Imaging (MRI) images in the first case revealed a lobulated mixed component mass on the left basal ganglia. The solid part showed restricted diffusion on diffusion-weighted imaging, heterogeneous strong enhancement, and no signal of calcification or bleeding. The second case in the left putamen showed hypointensity on T2*, mild enhancement, and atrophy of the ipsilateral cerebral peduncle, increased choline, and decreased n-acetyl-aspartate (NAA) on spectroscopy. Follow-up MRI after 6 months showed a mass increase in size and hypointensity part on T2*. BGGs have been confirmed on biopsy in both cases. With isolated chemotherapy application, there is no sign of remission in the first patient. The second patient was treated with chemotherapy and radiotherapy, and MRI images after treatment showed a complete response.

Brain and Spinal Tumors Originating from the Germ Line Cells

Primary central nervous system germ cell tumors (CNS GCTs) are part of the GCTs in children and adults. This tumor entity presents with geographic variation, age, and sex predilection. There are two age peaks of incidence distribution at the first few months of life and in adolescence. CNS GCTs are heterogeneous in histopathological subtypes, locations, and tumor marker (AFP, β-hCG) secretions. In the WHO CNS tumor classification, GCTS are classified as germinoma and nongerminomatous GCT (NGGCT) with different subtypes (including teratoma). Excluding mature teratoma, the remaining NGGCTs are malignant (NGMGCT). In teratoma, growing teratoma syndrome and teratoma with somatic-type malignancy should be highlighted. The common intracranial locations are pineal region, neurohypophysis (NH), bifocal pineal-NH, basal ganglia, and cerebral ventricle. Above 50% of intracranial GCTs (IGCTs) present obstructive hydrocephalus. Spinal tumors are rare. Age, locations, hydrocephalus, and serum/CSF titer of β-hCG correlate with clinical manifestations. Delayed diagnosis is common in tumors arising in neurohypophysis, bifocal, and basal ganglia resulting in the increasing of physical dysfunction and hormonal deficits. Staging work-up includes CSF cytology for tumor cells and contrast-enhanced MRI of brain and spine for macroscopic metastasis before treatment commences. The therapeutic approach of CNS GCTs integrates locations, histopathology, staging, tumor marker level, and therapeutic classification. Treatment strategies include surgical biopsy/excision, chemotherapy, radiotherapy (single or combination). Secreting tumors with consistent imaging may not require histopathological diagnosis. Primary germinomas are highly radiosensitive and the therapeutic aim is to maintain high survival rate using optimal radiotherapy regimen with/without chemotherapy combination. Primary NGNGCTs are less radiosensitive. The therapeutic aim is to increase survival utilizing more intensive chemotherapy and radiotherapy. The negative prognostic factors are residue disease at the end of treatment and serum or CSF AFP level >1000 ng/mL at diagnosis. In refractory or recurrent NMGGCTs, besides high-dose chemotherapy, new therapy is necessary. Molecular profiling and analysis help for translational research. Survivors of pediatric brain tumors frequently experience cancer-related cognitive dysfunction, physical disability, pituitary hormone deficiency, and other CNS complications after cranial radiotherapy. Continuous surveillance and assessment may lead to improvements in treatment protocols, transdisciplinary interventions, after-treatment rehabilitation, and quality of life.

Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group

Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies.

Depression, anxiety and health-related quality of life in paediatric intracranial germ cell tumor survivors

Background

Little is known about depression and anxiety among paediatric intracranial germ cell tumour (iGCT) survivors. We aimed to evaluate the risk factors associated with depression, anxiety and health-related quality of life (HRQoL) in paediatric iGCT survivors.

Methods

We recruited 200 iGCT patients (and their parents) from Beijing Tiantan Hospital and assessed their HRQoL using the Paediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales. The Children’s Depression Inventory, Screen for Child Anxiety Related Emotional Disorders, and Symptom Checklist 90 were used to evaluate depression and anxiety. The results were analysed based on disease recurrence, tumour location and treatment strategies.

Results

Survivors with recurrent tumours had worse HRQoL scores than those with non-recurrent tumours. Patients with tumours involving both the suprasellar and basal ganglia regions had the worst HRQoL scores. A large proportion of survivors had depression or anxiety. Both depression and anxiety scores were highly correlated with the HRQoL emotional functioning scores. The parent proxy-reports (PPR) and child self-reports were highly correlated in all domains.

Conclusions

This study demonstrated the clinical factors affecting paediatric iGCT survivors’ depression, anxiety, and HRQoL. Therefore, psychological interventions should be implemented. It also suggests that the PedsQL PPR would be helpful for routine screening.

Intracranial germ cell tumours (iGCT) are relatively rare brain tumours that predominantly occur in paediatric patients. Since the survival rate of patients with iGCT has been improving and the burden of long-term morbidity is substantial, promoting the health-related quality of life (HRQoL) and reducing depression and anxiety among its survivors is of critical concern. Although many studies have been published on factors related to the HRQoL of iGCT survivors, little is known about their long-term emotional function. This study demonstrated the clinical factors that affect depression, anxiety, and the HRQoL and the associations between the HRQoL and depression/anxiety in 200 paediatric iGCT patients. We found that patients with recurrent tumours had a worse HRQoL. Tumour locations also played a critical role in that tumour involving the basal ganglia were associated with worse outcomes. A large proportion of paediatric iGCT survivors had depression or anxiety in all the groups. Depression/anxiety scores were highly correlated with the HRQoL emotional functioning scores. In addition, we found that the PedsQL parent proxy report is appropriate in most cases when it is not possible to obtain child self-reports. These findings provide evidence to support the optimization of treatment strategies for iGCTs, such as the provision of psychological interventions.

Ectopic Germinoma: A Delayed Diagnosis With Serial Magnetic Resonance Imaging Features

Germinoma arising from intracranial off-midline structures is considered ectopic. Although basal ganglia germinoma is a rare occurrence, it is more commonly seen in the Asian population, particularly among boys. Here, we report a case of an adolescent boy who presented with hemiplegia and delayed diagnosis of basal ganglia germinoma with progression on serial magnetic resonance imaging (MRI). Several signal changes have been described during the early stage of the disease such as T2-weighted patchy hyperintense signal, cerebral hemiatrophy, and signal change on susceptibility-weighted imaging. ¹¹C-methionine positron emission tomography is an additional imaging technique that can reveal ectopic germinoma. Follow-up MRI revealed small cystic changes, and the latest imaging showed progression into a large multicystic lesion with mass effect. The patient underwent surgery, and histopathological examination revealed basal ganglia germinoma. We highlight the serial MRI changes that were suggestive of basal ganglia germinoma in this case.

Imaging diagnosis of basal ganglia germ cell tumors: subtype features subtype imaging features of GCTs

OBJECTIVES

To evaluate the subtype imaging features of basal ganglia germ cell tumors (GCTs).

METHODS

Clinical and imaging data of 33 basal ganglia GCTs were retrospectively analyzed, including 17 germinomas and 16 mixed germ cell tumors (MGCTs).

RESULTS

The cyst/mass ratio of germinomas (0.53 ± 0.32) was higher than that of MGCTs (0.28 ± 0.19, p = 0.030). CT density of the solid part of germinomas (41.47 ± 5.22 Hu) was significantly higher than that of MGCTs (33.64 ± 3.75 Hu, p < 0.001), while apparent diffusion coefficients (ADC, ×^10-3 mm²/s) value of the solid part was significantly lower in geminomas (0.86 ± 0.27 ×^10-3 mm²/s) than in MGCTs (1.42 ± 0.39 ×^10-3 mm²/s, p < 0.001). MGCTs were more common with intratumoral hemorrhage (68.75% vs 11.76%, p = 0.01), T1 hyperintense foci (68.75% vs 5.88%, p < 0.001) and calcification (64.29% vs 20.00%, p = 0.025) than germinomas. There was no significant difference in internal capsule involvement between the two subtypes (p = 0.303), but Wallerian degeneration was more common in germinomas than in MGCTs (70.59% vs 25.00%, p = 0.015).

CONCLUSION

The subtypes of GCT have different imaging features. Tumoral cystic-solidity, heterogeneity, ADC value, CT density, and Wallerian degeneration are helpful to differentiate germinomas and MGCTs in basal ganglia.

ADVANCES IN KNOWLEDGE

The subtypes of GCT have different histological characteristics, leading to various imaging findings. The imaging features of GCT subtypes in basal ganglia may aid clinical diagnosis and treatment.

Imaging of brain tumors in children: the basics-a narrative review

Primary pediatric brain tumors comprise a broad group of neoplasm subtypes that can be categorized based on their histological and molecular features according to the 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors. The majority of the pediatric brain tumors demonstrate a singular preference for this age group and have a unique molecular profile. The separation of certain tumor entities, including different types of embryonal tumors, low-grade gliomas, and high-grade gliomas, may have a significant impact by guiding appropriate treatment for these children and potentially changing their outcomes. Currently, the focus of the imaging diagnostic studies is to follow the molecular updates, searching for potential imaging patterns that translate this information in molecular profile results, therefore helping the final diagnosis. Due to the high impact of accurate diagnosis in this context, the scientific community has presented extensive research on imaging pediatric tumors in recent years. This article summarizes the key characteristics of the imaging features of the most common primary childhood brain tumors, categorizing them according to the recent WHO classification update, which is based on each of their molecular profiles. The purpose of this review article is to familiarize radiologists with their key imaging features and thereby improve diagnostic accuracy.

Basal Ganglia Germ Cell Tumors With or Without Sellar Involvement: A Long-Term Follow-Up in a Single Medical Center and a Systematic Literature Review

BACKGROUND

Basal ganglia germ cell tumors (BGGCTs) represent an extremely rare subset of tumors about which little is known. Some patients suffer from tumor dissemination, such as sellar involvement. This study aimed to evaluate the independent prognostic risk factors of patients with BGGCTs with or without sellar involvement.

METHODS

Sixteen patients were diagnosed with BGGCTs at Peking Union Medical College Hospital from January 2000 to December 2020. A literature review was performed on the online databases Medline and PubMed, and 76 cases in the 19 retrieved articles were identified at the same time. The data regarding biochemical tests, radiological examinations, and outcomes during follow-up were analyzed.

RESULTS

Of 92 patients in this study, seven patients were clinically diagnosed as germinomas, with the remaining 85 patients receiving surgery. Fifty-two patients suffered from multifocal lesions or tumor dissemination. The patients with BGGCTs demonstrated a significant male predilection. The patients with delayed diagnosis more likely had cognitive disturbance (p = 0.028), mental disturbance (p = 0.047), and diabetes insipidus (p = 0.02). Multivariate analysis demonstrated that the independent poor prognostic risk factors of patients with BGGCTs were delayed diagnosis [odd ratio (OR) 2.33; 95% CI 1.02-5.31], focal radiotherapy (OR 4.00; 95% CI 1.69-9.49), and non-pure germinoma (OR 4.64; 95% CI 1.76-12.22).

CONCLUSIONS

The delayed diagnosis, focal radiotherapy, and non-pure germinoma were associated with a poorer prognosis for patients with BGGCTs with or without sellar involvement.

Clinico-radiological approach to cerebral hemiatrophy

INTRODUCTION

Cerebral hemiatrophy is an uncommon neuroimaging finding of diverse etiologies, conventionally classified into two broad categories: congenital and acquired. The authors propose an alternative pragmatic clinical approach to cerebral hemiatrophy, classifying its diverse etiologies into a single event insult such as an in utero stroke, or a progressive disorder from an inflammatory or neoplastic process, the latter of which needs urgent intervention and will be the focus of our review paper. Illustrative cases will also be presented to facilitate the understanding of the discussed disorders.

CONCLUSION

A systematic approach, linking both clinical and neuroimaging features, is important to facilitate the diagnostic workup of cerebral hemiatrophy. This may potentially help avoid large-scale investigations. Determining the underlying aetiology of cerebral hemiatrophy may impact treatment and prognostication as some conditions such as Rasmussen encephalitis and Parry-Romberg syndrome may benefit from timely implementation of immunomodulatory therapy.

T2*-based MR imaging (gradient echo or susceptibility-weighted imaging) in midline and off-midline intracranial germ cell tumors: a pilot study

PURPOSE

The role of T2*-based MR imaging in intracranial germ cell tumors (GCTs) has not been fully elucidated. The aim of this study was to evaluate the susceptibility-weighted imaging (SWI) or T2* gradient echo (GRE) features of germinomas and non-germinomatous germ cell tumors (NGGCTs) in midline and off-midline locations.

METHODS

We retrospectively evaluated all consecutive pediatric patients referred to our institution between 2005 and 2016, for newly diagnosed, treatment-naïve intracranial GCT, who underwent MRI, including T2*-based MR imaging (T2* GRE sequences or SWI). Standard pre- and post-contrast T1- and T2-weighted imaging characteristics along with T2*-based MR imaging features of all lesions were evaluated. Diagnosis was performed in accordance with the SIOP CNS GCT protocol criteria.

RESULTS

Twenty-four subjects met the inclusion criteria (17 males and 7 females). There were 17 patients with germinomas, including 5 basal ganglia primaries, and 7 patients with secreting NGGCT. All off-midline germinomas presented with SWI or GRE hypointensity; among midline GCT, all NGGCTs showed SWI or GRE hypointensity whereas all but one pure germinoma were isointense or hyperintense to normal parenchyma. A significant difference emerged on T2*-based MR imaging among midline germinomas, NGGCTs, and off-midline germinomas (p < 0.001).

CONCLUSION

Assessment of the SWI or GRE characteristics of intracranial GCT may potentially assist in differentiating pure germinomas from NGGCT and in the characterization of basal ganglia involvement. T2*-based MR imaging is recommended in case of suspected intracranial GCT.

MRI features of pediatric intracranial germ cell tumor subtypes

Intracranial germ cell tumors differ in histology and location, and require different clinical management strategies. We characterized the imaging features that may aid pre-operative differentiation of intracranial germinomas and non-germinomatous germ cell tumors (NGGCTs). This retrospective study analyzed 85 patients with intracranial germ cell tumors and adequate preoperative or pretreatment MRIs between 2000 and 2013 at our institution. Pretreatment MRI characteristics, apparent diffusion coefficient (ADC) values, tumor histopathology, and patient outcomes were compared. NGGCTs occurred in the pineal region and cerebral hemispheres more often than germinomas; all bifocal lesions were germinomas. NGGCTs (36.6 ± 17.0 mm) were significantly larger than germinomas (25.7 ± 11.6 mm; P = 0.002). The presence of pure solid tumor (45.5 vs. 20.0%, P = 0.033) and an infiltrative margin (20.0 vs. 3.3%, P = 0.035) were significantly more common in germinomas than NGGCTs. The presence of intratumoral T1 hyperintense foci (66.7 vs. 10.9%, P < 0.001) and moderate/marked enhancement (86.7 vs. 50.9%, P < 0.001) were significantly more common in NGGCTs than in germinomas. Mean ADC_mean values (×10^-3 mm²/s) were significantly lower in germinomas (1.113 ± 0.415) than in NGGCTs (2.011 ± 0.694, P = 0.001). Combined a lack of T1 hyperintense foci and an ADC_mean threshold value (1.143 × 10^-3 mm²/s) had the highest specificity (91.3%) and positive predictive value (92.3%), while the combination of lack of a T1 hyperintensense foci, no/mild enhancement, and an ADC_mean threshold value had 100% sensitivity and 100% negative-predictive value for discriminating germinomas from NGGCTs. Pre-operative conventional MRI characteristics and diffusion-weighted MRI help clinicians to assess patients with intracranial germ cell tumors. Tumor size, location, T1 hyperintense foci, intratumoral cystic components, tumor margin and enhancing patterns demonstrate contrast between germinomas and NGGCTs. Serum tumor markers and adjunctive combination with T1 hyperintensity and/or enhancing pattern with ADC offer potential in preoperative differentiating intracranial germinomas and NGGCTs.