Germinomas in the basal ganglia: magnetic resonance imaging classification and the prognosis

Germ cell tumors of the central nervous system: A brief review and site-specific considerations

Germ cell tumors of the central nervous system (GCT-CNS) arise predominantly in midline locations of the CNS and affect young patients in their first to third decades of life. Involvement of the CNS is thought to be a sequelae of residual primordial germ cells with incomplete embryologic migration. Clinically, GCT-CNS present with symptoms of ventricular obstruction or compression of affected brain structures. Histologically, these tumors are analogous to their gonadal and extra-gonadal counterparts. Diagnosis relies heavily on morphology and immunohistochemical findings, and can be complicated by limited tumor sampling. There is currently only a limited role for molecular studies. Treatment of these lesions is made difficult by their involvement of deep and vital brain structures and accurate pathologic diagnosis is essential for appropriate therapy. Diagnosis should involve review of the clinical history, imaging studies, and assessment of serum and cerebrospinal fluid tumor markers. Current therapeutic strategies involving radiation therapy with or without chemotherapy are quite effective, in spite of the locational difficulties that often prevent gross total resection.

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.

[Clinical analysis of 30 cases of basal ganglia germinoma in children]

OBJECTIVE

To summarize and analyze the clinical characteristics of children with basal ganglia germinoma and to improve the level of early clinical diagnosis.

METHODS

The clinical data of children diagnosed with basal ganglia germinoma admitted to the Pediatric Surgery Ward of Peking University First Hospital from January 2013 to December 2020 were retrospectively analyzed, and descriptive statistics were used to analyze the clinical characteristics of children with basal ganglia germinoma.

RESULTS

A total of 30 patients were included in the study, 28 were male, 2 were female, the mean age at onset was (9.7±2.2) years, the median disease duration was 7 months, 27 had unilateral disease, and 3 had bilateral disease. The clinical manifestations were decreased limb muscle strength, cognitive function disorders, polydipsia, precocious puberty, intracranial hypertension, dysphonia and swallowing dysfunction. The serum and cerebrospinal fluid tumor marker alpha-fetoprotein (AFP) were normal in the 30 patients, and the serum and cerebrospinal fluid tumor marker β-human chorionic gonadotropin (β-HCG) were normal in 8 patients.The serum β-HCG was normal in 11 patients but the cerebrospinal fluid β-HCG was slightly elevated, and the serum and cerebrospinal fluid β-HCG were slightly elevated in 11 patients. A total of 33 lesions with irregular shapes were found by imaging examination, including 15 (45.5%) patchy lesions, 10 (30.3%) patchy lesions, and 8 (24.2%) round-like high-density lesions. Tumors showed obvious high-density shadows on computed tomography (CT) scan. Magnetic resonance imaging (MRI) scan of the tumors showed low or isointensity on T1WI and isointensity on T2WI, accompanied by mild peritumoral edema, hemispheric atrophy, cerebral peduncle atrophy, calcification, cystic degeneration, ventricular dilatation and wallerian degeneration. On contrast-enhanced scans, the tumor showed no enhancement or heterogeneous enhancement.

CONCLUSION

The main age of onset of germ cell tumors in the basal ganglia in children is about 10 years old, and males are absolutely dominant. The clinical features and imaging manifestations have certain characteristics. With both combined, the early diagnosis of germ cell tumors in the basal ganglia can be improved.

Long-Term Outcomes and Sequelae Analysis of Intracranial Germinoma: Need to Reduce the Extended-Field Radiotherapy Volume and Dose to Minimize Late Sequelae

PURPOSE

We aimed to refine the radiotherapy (RT) volume and dose for intracranial germinoma considering recurrences and long-term toxicities.

MATERIALS AND METHODS

Total 189 patients with intracranial germinoma were treated with RT alone (n=50) and RT with upfront chemotherapy (CRT) (n=139). All cases were confirmed histologically. RT fields comprised the extended-field and involved-field only for primary site. The extended-field, including craniospinal, whole brain (WB), and whole ventricle (WV) for cranial field, is followed by involved-field boost. The median follow-up duration was 115 months.

RESULTS

The relapses developed in 13 patients (6.9%). For the extended-field, cranial RT dose down to 18 Gy exhibited no cranial recurrence in 34 patients. In CRT, 74 patients (56.5%) showed complete response to chemotherapy and no involved-field recurrence with low-dose RT of 30 Gy. WV RT with chemotherapy for the basal ganglia or thalamus germinoma showed no recurrence. Secondary malignancy developed in 10 patients (5.3%) with a latency of 20 years (range, 4 to 26 years) and caused mortalities in six. WB or craniospinal field rather than WV or involved-field significantly increased the rate of hormone deficiencies, and secondary malignancy. RT dose for extended-field correlated significantly with the rate of hormone deficiencies, secondary malignancy, and neurocognitive dysfunction.

CONCLUSION

De-intensifying extended-field rather than involved-field or total scheme of RT will be critical to decrease the late toxicities. Upfront chemotherapy could be beneficial for the patients with complete response to minimize the RT dose down to 30 Gy. Prospective trials focused on de-intensification of the extended-field RT are warranted.

Molecular Pathology and Targeted Therapies for Personalized Management of Central Nervous System Germinoma

Intracranial germinomas are rare tumours, usually affecting male paediatric patients. They frequently develop in the pineal and suprasellar regions, causing endocrinological disturbances, visual deficits, and increased intracranial pressure. The diagnosis is established on magnetic resonance imaging (MRI), serum and cerebrospinal fluid (CSF) markers, and tumour stereotactic biopsy. Imaging techniques, such as susceptibility-weighted imaging (SWI), T2* (T2-star) gradient echo (GRE) or arterial spin labelling based perfusion-weighted MRI (ASL-PWI) facilitate the diagnosis. Germinomas are highly radiosensitive tumours, with survival rates >90% in the context of chemoradiotherapy. However, patients with resistant disease have limited therapeutic options and poor survival. The aim of this review is to highlight the genetic, epigenetic, and immunologic features, which could provide the basis for targeted therapy. Intracranial germinomas present genetic and epigenetic alterations (chromosomal aberrations, KIT, MAPK and PI3K pathways mutations, DNA hypomethylation, miRNA dysregulation) that may represent targets for therapy. Tyrosine kinase and mTOR inhibitors warrant further investigation in these cases. Immune markers, PD-1 (programmed cell death protein 1) and PD-L1 (programmed death-ligand 1), are expressed in germinomas, representing potential targets for immune checkpoint inhibitors. Resistant cases should benefit from a personalized management: genetic and immunological testing and enrolment in trials evaluating targeted therapies in intracranial germinomas.

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.

An Unusual Case of Primary Intracranial Germinoma with Diffuse Subarachnoid Spread Masquerading as Tuberculous Meningitis

Central nervous system (CNS) germinomas often extend or disseminate into the ventricular and subarachnoid space. We present a case of primary CNS germinoma consisting mainly of meningeal dissemination, which is extremely unusual and must be kept in the differential diagnosis.

Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review

The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.

A single-center study of treatment outcomes of pediatric basal ganglia germinoma in Taiwan

PURPOSE

A basal ganglia (BG) germinoma is a rare tumor, and the optimal treatment remains unknown. We evaluated the clinical outcomes of treatment of BG germinoma in pediatric patients in Taiwan.

METHODS

We retrospectively reviewed the medical records of 34 children with BG germinoma who were treated with radiotherapy (RT) at Taipei Veterans General Hospital between 1989 and 2016. The median follow-up time is 8.3 years (1.8-25.2 years). Survival was analyzed using the Kaplan-Meier estimate. Univariate Cox proportional-hazards models were used to identify the potential risk factors.

RESULTS

Only four patients (11.8%) experienced recurrence and all successfully underwent salvage therapy. One patient (2.97%) died due to suspected radiotherapy (RT)-related sarcoma in the scalp. The 2-, 3-, and 5-year DFS rates were 91.2%, 88.2%, and 79.4%, respectively; the 2-, 3-, and 5-year OS rates were 97.1%, 94.1%, and 82.4%, respectively. Focal RT showed low DFS in the Kaplan-Meier survival curves (P = .028) compared with non-focal RT (whole ventricle, whole brain, or cranial spinal area). In the univariate Cox proportional-hazards model, there was a significant difference in DFS between focal and non-focal RT (P = .03). There is no difference in DFS and OS between BG germinoma patients and non-BG germinoma patients.

CONCLUSIONS

We found an excellent DFS and OS in pediatric patients with BG germinoma treated with RT. Whole ventricle irradiation is recommended for good tumor control and low treatment-related toxicity. BG germinoma patients showed similar treatment results as germinoma patients in other common sites.

Clinical and neuropsychological outcome of pediatric non-midline central nervous system germinoma treated with chemotherapy and reduced dose/volume irradiation: The Children's Hospital Los Angeles experience

BACKGROUND

Germ cell tumors (GCT) arising from non-midline structures (basal ganglia, thalamus, and posterior fossa) are rare. Although patients with midline (pineal and suprasellar) germinoma have excellent survival with chemotherapy and whole ventricular irradiation (WVI), germinoma in non-midline locations have traditionally been treated with craniospinal irradiation (CSI) or whole brain irradiation (WBI) to achieve similar outcomes. However, CSI and WBI are associated with significant long-term neuropsychological sequelae.

METHODS

We describe the clinical and neuropsychological outcomes of patients with non-midline germinoma treated at the Children's Hospital Los Angeles between 1990 and 2015.

RESULTS

Nine patients had basal ganglia/thalamic germinoma and one patient had a cerebellar primary. Eight patients received chemotherapy followed by reduced dose/volume irradiation, whereas two patients received chemotherapy alone as upfront therapy. One patient in the chemotherapy alone group relapsed after 4.3 years and was salvaged with CSI plus boost. The overall survival for the entire cohort was 100% at a median follow-up of 8.5 years. Neuropsychological data were available for six patients at a median of five months (baseline) and 4.2 years (follow-up) post-diagnosis. At four-year follow-up, data available revealed intact overall cognitive ability, verbal memory, and executive functioning, but persistent deficits in fine motor function. Comparison of baseline to follow-up suggests a downward trend in working memory, planning/problem-solving, verbal memory, and visuospatial integration.

CONCLUSION

Chemotherapy followed by reduced dose/volume of irradiation is an effective strategy resulting in long-term survival in patients with non-midline germinoma. Neuropsychological data suggest relatively minimal morbidity over time.

Treatment outcomes based on radiation therapy fields for bifocal germinoma: Synchronous or disseminated disease?

Intracranial germinoma sometimes present as bifocal germinoma, and whether bifocal germinoma should be treated as a synchronous or disseminated disease remains unclear. This study aimed to determine the optimal treatment modality for bifocal germinoma. Patients with bifocal germinoma who received radiotherapy (RT) from March 1990 to August 2017 were included for analysis. A total of 21 patients were included. The median follow-up period was 76.2 months (range, 6.2-305.4 months). There were 17 patients who received cranio-spinal irradiation (CSI) with local RT; 3, whole ventricular RT (WVRT) with local RT; and 1, local RT only. Three recurrences occurred (1 patient each among those who underwent CSI, WVRT, and local RT). Recurrence in the patient who received CSI and who received WVRT occurred in the right thalamus and right frontal convexity, respectively. Meanwhile, the patient who received local RT showed not only a recurred lesion in the hypothalamus, but also cerebrospinal fluid seeding. For this patient, salvage CSI was performed and complete response was achieved after treatment. However, after 9 years and 6 months, he was diagnosed with glioblastoma and expired. As for toxicity, although 17 patients showed decrease in complete blood count levels during treatment, all patients recovered soon after treatment completion. Our findings suggest that bifocal germinoma may be considered as a disseminated disease when considering the patterns of failure according to RT fields. In addition, patients who received CSI showed low acute toxicity rates. However, further studies are necessary to confirm these findings.

Upfront chemotherapy followed by response adaptive radiotherapy for intracranial germinoma: Prospective multicenter cohort study

PURPOSE

To assess the efficacy of upfront chemotherapy followed by response-adapted reduced-dose/reduced-volume radiotherapy (RT) for intracranial germinoma.

MATERIALS AND METHODS

Ninety-one patients from five institutions were registered in the KSPNO G051/G081 Protocol. Germinomas were classified as solitary or multiple/disseminated diseases, and upfront chemotherapy was administered. For all patients with multiple or disseminated disease, and patients with partial response after chemotherapy, 19.5-24 Gy of craniospinal irradiation plus 10.8-19.8 Gy of tumor bed boost were planned. For patients with complete response (CR), reduced-dose RT (30.6 Gy) was planned, along with a reduced field for solitary lesions.

RESULTS

The median patient age was 14 (range, 3-30) years. Sixty-five patients (71.4%) had a solitary lesion. The median follow-up duration was 67.9 (range, 6.6-119.3) months. Recurrence was not observed in 32 patients in the protocol compliant group. Four patients (4.4%) in the protocol non-compliant group experienced relapse after CR and one patient died of the disease. The 5-year and 7-year overall survival rates were 98.8% and 98.8%, while the corresponding event-free survival rates were 96.6% and 93.8%, respectively. All three patients with basal ganglia germinomas who were treated with local RT experienced recurrence outside the RT field. Among the 23 patients with pineal or suprasellar lesions who received whole-ventricle RT, there was no recurrence.

CONCLUSIONS

Currently used upfront chemotherapy followed by reduced-dose, reduced-volume RT appears acceptable, when whole-ventricle RT for pineal or suprasellar tumors and, at minimum, whole-brain RT for basal ganglia/thalamus lesions are applied.

Fast-developing fatal diffuse leptomeningeal dissemination of a pineal germinoma in a young child: a case report and literature review

BACKGROUND

Intracranial germinomas are uncommon and constitute less than 1% of all intracranial tumors. They usually arise in the midline of the brain, most commonly in the pineal region. Pineal germinomas tend to spread through the cerebrospinal fluid (CSF). However, pineal germinomas with fast-developing diffuse subarachnoid/leptomeningeal dissemination are extremely rare, especially in young children.

METHODS

The case of a 4-year-old boy with a pineal germinoma who died of diffuse subarachnoid/leptomeningeal dissemination 1 month after radiotherapy is reported. A PubMed search with specific key terms was used to review cases of pineal germinomas with metastasis.

RESULTS

The patient presented with a two-week history of worsening headache, visual disturbances and nonprojectile vomiting. Parinaud's sign was positive on physical examination. Head computed tomography (CT)/magnetic resonance imaging (MRI) revealed a lesion in the pineal region with eccentric calcification and obvious supratentorial hydrocephalus. Pineal germinoma was suspected. A ventriculoperitoneal (VP) shunt followed by focal radiotherapy ameliorated the headaches and visual disturbances. The patient was discharged home without further treatment due to financial difficulties. One month after discharge, he was readmitted due to worsening headache, vomiting and lethargy. MRI showed a decrease in the size of the pineal lesion but revealed a diffuse leptomeningeal enhancement including the sulcus, basal cistern, prepontine cistern, and supravermian cistern. The patient's condition deteriorated rapidly, and he died 26 hours after readmission. The characteristics of pineal germinomas with metastasis are reported based on a review of the literature.

CONCLUSIONS

Metastases in pineal germinomas predominately occur in adolescents or young adults, most commonly as spinal "drop metastases." Dissemination usually develops several years after the initial tumor diagnosis and has a relatively good clinical prognosis. However, fast widespread subarachnoid/leptomeningeal dissemination and sudden death may occur in a young child before salvage treatment, as in the presented case.

Thalamic germinoma: a challenging diagnosis, case report and literature review

The thalamus and basal ganglia are unusual locations for an intracranial germ cell tumors. We are reporting a rare case of thalamic germinoma in an 18-year-old male. Challenging presentation, radiological appearance and pathological finding after surgical intervention delayed the diagnosis and treatment. Also, we are providing an extensive literature review. Diagnosis of thalamic germinoma is challenging because of non-specific symptoms, rare location and inconclusive radiological findings. An early tissue diagnosis associated with good outcome.

Intracranial Germ Cell Tumor in the Molecular Era

Intracranial germ cell tumors (iGCTs) are a heterogeneous group of tumors with peculiar characteristics clearly distinguished from other brain tumors of neuroepithelial origin. Diverse histology, similarity to gonadal GCT, predilection to one sex, and geographic difference in incidence all present enigmas and fascinating challenges. The treatment of iGCT has advanced for germinoma to date; thus, clinical attention has shifted from survival to long-term quality of life. However, for non-germinomatous GCT, current protocols provide only modest improvement and more innovative therapies are needed. Recently, next-generation sequencing studies have revealed the genomic landscape of iGCT. Novel mutations in the KIT-RAS-MAPK and AKT-MTOR pathways were identified. More importantly, methylation profiling revealed a new method to assess the pathogenesis of iGCT. Molecular research will unleash new knowledge on the origin of iGCT and solve the many mysteries that have lingered on this peculiar neoplasm for a long time.

Intracranial germinoma causing cerebral haemiatrophy and hypopituitarism

A young woman presented with primary amenorrhoea, progressive haemiparesis, visual disturbance, dementia and focal motor seizures. Investigations showed hypopituitarism, unilateral cerebral atrophy and inflamed cerebrospinal fluid. A trans-sphenoidal biopsy gave a unifying diagnosis of a pituitary germinoma.

Capsuloganglionic Germinoma: A Rare Site for Uncommon Childhood Tumor

Germ cell tumors (GCTs) are rare intracranial tumors with a strong predilection for children. Commonly, these tumors arise either in the suprasellar or the pineal region. The basal ganglia-thalamus complex represents a rare site of nonmidline intracranial GCTs. Such basal ganglionic GCTs have been reported to produce certain interesting clinico-radiological features, the knowledge of which may provide important diagnostic clues preoperatively. We present the case of a 9.5-year-old boy who presented with right hemiparesis and precocious puberty. Imaging revealed a heterogeneously enhancing mass involving the left capsuloganglionic region, sparing the thalamus. There was little perilesional edema and midline shift. Because of the deep location of the mass and a lack of mass effect, a neuronavigation-guided tumor biopsy was performed which unraveled a pure germinoma. The child was referred for adjuvant radiotherapy following an uneventful postoperative course. At the time of writing the report, the child was on radiotherapy and doing well.

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.

Progressive hemiparesis in a young man: Hemicerebral atrophy as the initial manifestation of basal ganglia germinoma

Basal ganglia germinomas are rare and patients are classically young Oriental males presenting with gradually progressive hemiparesis. Although early treatment with chemo-radiotherapy can be curative and significantly improve the quality of life, medical attention is often delayed. A young Chinese male experienced a 6-month history of right hemiparesis with magnetic resonance imaging findings of hemicerebral atrophy and lentiform nucleus microhemorrhage, highly suggestive and early signs of basal ganglia germinomas. No further imaging was performed until 2 years later when he was admitted for acute neurological deterioration and a repeat scan revealed a large infiltrative tumor pathologically confirmed to be a pure germinoma.

Germinoma with Diffuse Subependymal Spread: A Case Report

A 19-year-old Caucasian male presented with complaints of headaches and syncope. Suspicion of hydrocephalus prompted computed tomography (CT) and magnetic resonance imaging (MRI), which revealed pineal and suprasellar prominences with diffuse, thick, nodular subependymal enhancement of the lateral and third ventricles. Based on imaging, the differential diagnosis consisted primarily of malignancy, such as lymphoma, with inflammatory and infectious etiologies not excluded. Cerebrospinal fluid (CSF) samples were non-specific, and neuroendoscopic tissue biopsy histologically confirmed the diagnosis of pure germinoma. The patient was treated with radiation, and follow-up MRIs at one, three, six, and 12 months demonstrated progressive resolution of tumor burden with marked clinical improvement.

Germinomas are rare germ cell tumors that are more frequently diagnosed in Asian countries. They uncommonly seed into the lateral ventricles, and only two other cases have been described with diffuse subependymal involvement. Unlike other malignant germ cell tumors, germinomas have marker negative CSF samples that are important in the normal diagnostic workup of diffuse subependymal lesions. Histopathologic correlation is required for definitive diagnosis in the United States and can be achieved with endoscopic tissue sampling. Germinomas are highly radio- and chemotherapy sensitive and have a fair prognosis with modern therapeutic techniques. Germinoma should be considered with simultaneous midline and diffuse ventricular lesions.

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

BACKGROUND

It is difficult to diagnosis early stage germ cell tumors originating in the basal ganglia, but early recognition is important for better outcome.

OBJECTIVE

To evaluate serial MR images of basal ganglia germ cell tumors, with emphasis on the features of early stage tumors.

MATERIALS AND METHODS

We retrospectively reviewed serial MR images of 15 tumors in 14 children and young adults. We categorized MR images of the tumors as follows: type I, ill-defined patchy lesions (<3 cm) without cyst; type II, small mass lesions (<3 cm) with cyst; and type III, large lesions (≥3 cm) with cyst. We also assessed temporal changes of the MR images.

RESULTS

On the initial images, 8 of 11 (73%) type I tumors progressed to types II or III, and 3 of 4 (75%) type II tumors progressed to type III. The remaining 4 tumors did not change in type. All type II tumors (5/5, 100%) that changed from type I had a few tiny cysts. Intratumoral hemorrhage was observed even in the type I tumor. Ipsilateral hemiatrophy was observed in most of the tumors (13/15, 87%) on initial MR images. As tumors grew, cystic changes, intratumoral hemorrhage, and ipsilateral hemiatrophy became more apparent.

CONCLUSION

Early stage basal ganglia germ cell tumors appear as ill-defined small patchy hyperintense lesions without cysts on T2-weighted images, are frequently associated with ipsilateral hemiatrophy, and sometimes show microhemorrhage. Tumors develop tiny cysts at a relatively early stage.

Accelerated Unilateral Radiographic Huntingtonian Changes Following Neoadjuvant Chemotherapy for a Nongerminomatous Germ Cell Tumor Leading to Identification of Occult Disease in the Dorsal Striatum

Basal ganglia nongerminomatous germ cell tumors comprise 10% to 15% of germ cell tumor and have substantial morbidity at the time of local failure. In this submitted image we present a case where neoadjuvant chemotherapy unmasked a unilateral caudate head loss consistent with Huntingtonian changes. Careful review of the patient's imaging identified disease within the dorsal striatum that was not previously identified at the time of diagnosis. Review of the diffusion tensor fractional anisotropy imaging identified progressive white matter likely secondary to the occult disease within the dorsal striatum. Although this patient was asymptomatic and had no signs of a movement disorder, similar findings have been noted to be a prelude to such findings several months later. The occult disease was incorporated into the patient's radiotherapy planning target volume as oversight of these changes would have led to a marginal miss and potential early disease relapse.

Basal ganglia germinomas in children. Four clinical cases and a literature review

Basal ganglia germinomas are a specific group of intracranial germinomas. Their early diagnosis is complicated due to their atypical localization and diversity of neuroimaging and clinical signs.

MATERIAL AND METHODS

We describe 4 cases of basal ganglia germinoma in boys of 13, 14, 15, and 16 years of age. The medical history data, clinical features, neuroimaging and histological characteristics of basal ganglia germonomas, and preliminary results of the treatment are presented.

CONCLUSION

Basal ganglia germinomas are usually verified at the late stage of the disease when patients are detected with extended lesions of the basal ganglia and severe neurological and neuroendocrine deficits. This situation is due to clinical and imaging signs that are untypical of common germinomas.

Differential dosimetric benefit of proton beam therapy over intensity modulated radiotherapy for a variety of targets in patients with intracranial germ cell tumors

Background

We performed dosimetric comparisons between proton beam therapy and intensity modulated radiotherapy (IMRT) of intracranial germ cell tumors (ICGCTs) arising in various locations of the brain.

Materials

IMRT, passively scattered proton therapy (PSPT), and spot scanning proton therapy (SSPT) plans were performed for four different target volumes: the whole ventricle (WV), pineal gland (PG), suprasellar (SS), and basal ganglia (BG). Five consecutive clinical cases were selected from the patients treated between 2011 and 2014 for each target volume. Total 20 cases from the 17 patients were included in the analyses with three overlap cases which were used in plan comparison both for the whole ventricle and boost targets. The conformity index, homogeneity index, gradient index, plan quality index (PQI), and doses applied to the normal substructures of the brain were calculated for each treatment plan.

Results

The PQI was significantly superior for PSPT and SSPT than IMRT for ICGCTs in all locations (median; WV: 2.89 and 2.37 vs 4.06, PG: 3.38 and 2.70 vs 4.39, SS: 3.92 and 2.49 vs 4.46, BG: 3.01 and 2.49 vs 4.45). PSPT and SSPT significantly reduced the mean dose, and the 10 and 15 Gy dose volumes applied to the normal brain compared with IMRT (p ≤ 0.05). PSPT and SSPT saved significantly greater volumes of the temporal lobes and hippocampi (p < 0.05) in the SS and PG targets than IMRT. For tumors arising in the BG, PSPT and SSPT also saved greater volumes of the contralateral temporal lobes.

Conclusions

PSPT and SSPT provide superior target volume coverage and saved more normal tissue compared with IMRT for ICGCTs in various locations. Future studies should assess whether the extent of normal tissue saved has clinical benefits in children with ICGCTs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0441-5) contains supplementary material, which is available to authorized users.

Germinoma in the bilateral basal ganglia presented with cognitive deterioration

PURPOSE

Here, we report a case of pediatric germinoma located in the bilateral basal ganglia, which presented with severe cognitive deteriorations.

CASE REPORT

A 15-year-old boy presented with decreased school performance and mild cognitive disturbances. Magnetic resonance images (MRI) of the brain revealed T2 hyperintensity in the bilateral basal ganglia. The patient was initially observed by a local hospital and had screening for metabolic diseases or inflammatory diseases. Lesions with similar characteristics were also found in the pituitary stalk and infundibulum, and these lesions were enhanced with gadolinium (Gad). MR spectroscopy suggested that these should be neoplastic lesions other than metabolic or inflammatory diseases. Biopsy was performed with ventriculoscope, which proved all lesions of infundibulum, pineal, and basal ganglia were pathologically germinoma. The lesions responded well to the chemotherapy and radiation, and his cognitive function improved significantly.

CONCLUSION

A case of germinoma in the bilateral basal ganglia which significantly affect cognitive functions is reported. Differential diagnoses of cognitive symptoms are various, but germinoma could be considered as a possible pathology for it. Early MRI and tumor marker exams are recommended, unless organic brain diseases are completely denied. MR spectroscopy and biopsy with ventriculoscope are useful for diagnosis.

Understanding the Treatment Strategies of Intracranial Germ Cell Tumors: Focusing on Radiotherapy

Intracranial germ cell tumors (ICGCT) occur in 2-11% of children with brain tumors between 0-19 years of age. For treatment of germinoma, relatively low radiation doses with or without chemotherapy show excellent 10 year survival rate of 80-100%. Past studies showed that neoadjuvant chemotherapy combined with focal radiotherapy resulted in unacceptably high rates of periventricular tumor recurrence. The use of generous radiation volume which covers the whole ventricular space with later boost treatment to primary site is considered as standard treatment of intracranial germinomas. For non-germinomatous germ cell tumors (NGGCT), 10-year overall survival rate is still much inferior than that of intracranial germinoma despite intensive chemotherapy and high-dose radiotherapy. Craniospinal radiotherapy combined with cisplatin-based chemotherapy provides the best treatment outcome for NGGCT; 60-70% of overall survival rate. There is a debate on the surgical role whether surgery can contribute to improved treatment outcome of NGGCT when added to combined chemoradiotherapy. Because higher dose of radiotherapy is required for treatment of NGGCT than for germinoma, it is tested whether whole ventricular irradiation can replace craniospinal irradiation in intermediate risk group of NGGCT to minimize radiation-related late toxicity in the recent studies. To minimize the treatment-related neural deficit and late sequelae while maintaining long-term survival rate of ICGCT patients, optimized administration of chemotherapy and radiotherapy should be selected. Use of technically upgraded radiotherapy modalities such as intensity-modulated radiotherapy or proton beam therapy is expected to bring an improved neurocognitive outcome with longitudinal assessment of the patients.

Basal ganglia germinoma: MRI classification correlates well with neurological and cognitive outcome

Basal ganglia germinomas (BGG) are often associated with delayed diagnosis because of their nonspecific clinical presentation and subtle abnormalities on initial neuroimaging. Despite excellent survival, the prognostic indicators still remained unclear. From our case series, we demonstrated that the MRI classification scheme devised by Phi and colleagues is useful in predicting neurological and cognitive outcomes for patients with unilateral BGG. Subtle lesions with faint or no contrast enhancement are associated with early cerebral atrophy with progressive neurological deficits and poor cognitive outcomes. BGG along with bilateral involvement, regardless of the types of lesion, are also associated with poor neurological and cognitive outcomes.

Current concepts and future strategies in the management of intracranial germinoma

Radiation therapy is the backbone in the management of intracranial germinoma. In localized disease chemotherapy followed by whole brain irradiation is the present standard providing cure rates in excess of 90%. Craniospinal irradiation alone in metastatic disease provides equally excellent outcome. Chemotherapy is able to convert macroscopic to microscopic disease permitting a dose reduction to the tumor site and possibly the ventricular system and is investigated in prospective trials. Chemotherapy alone cannot replace radiotherapy as sole treatment. Whole-ventricular radiotherapy followed by a boost to tumor site without chemotherapy might be feasible. New treatment technologies such as intensity-modulated radiotherapy or proton therapy permit a dose reduction to non-target brain. Data on functional outcome are conflicting and based on small heterogeneous series only mandating prospective investigations.

Latency of intracranial germ cell tumors and diagnosis delay

BACKGROUND

Intracranial germ cell tumors (GCTs) frequently take an insidious clinical course before diagnosis. To date, clinical latency has been discussed in the context of germinoma in the suprasellar area and basal ganglia.

OBJECTIVE

In this study, we classified the clinical latency of intracranial GCTs into three categories and described their characteristics in order to understand the full spectrum of the phenomenon.

METHODS

In a cohort of 181 patients with intracranial GCTs, 17 patients had a delayed diagnosis of more than 3 months (90 days) from the initial brain magnetic resonance imaging to the definitive GCT diagnosis. Clinical records and radiological data of the patients were reviewed.

RESULTS

The patients with a delayed diagnosis were categorized into three groups according to their tumor location: suprasellar (nine patients), basal ganglia (six patients), and pineal (two patients). Initial symptomatology corresponded with the tumor location: central diabetes insipidus for the suprasellar group, hemiparesis for the basal ganglia group, and precocious puberty for the pineal group. The overall survival of patients with germinoma and delayed diagnosis was significantly shorter than that of patients who were diagnosed within 3 months (P = 0.002).

CONCLUSIONS

Clinical latency and delayed diagnosis are not restricted to germinomas in the suprasellar area and basal ganglia; they are canonical features of intracranial GCTs including pineal non-germinomatous GCTs. Early detection and proactive diagnosis of these tumors are required because diagnosis delay may negatively influence patient survival.

The enigma of bifocal germ cell tumors in the suprasellar and pineal regions: synchronous lesions or metastasis?

OBJECT

Intracranial germ cell tumors (GCTs) frequently present with bifocal lesions in both the suprasellar and pineal areas. The pathogenesis of these bifocal GCTs has been the subject of controversy. Bifocal GCTs may be caused by synchronous tumors or by metastatic spread of tumor cells from one site to the other. The prognosis associated with bifocal GCTs has also been a cause of concern.

METHODS

The authors constructed a single-institution patient cohort comprising 181 patients with intracranial GCTs. The clinical characteristics of bifocal GCTs were compared with those of suprasellar and pineal GCTs.

RESULTS

Bifocal GCTs were observed in 23 patients (12.8%). Eighteen patients presented with bifocal GCTs that were diagnosed as germinomas, but 5 patients exhibited mixed GCTs. Analyses of age distributions and comparisons of tumor sizes were compatible with a model of a metastatic origin of bifocal GCTs. Eleven patients (47.8%) presenting with bifocal GCTs exhibited tumor seeding at presentation. Tumor seeding was significantly associated with bifocal lesions (p < 0.001). Patients with bifocal germinomas showed significantly shorter event-free survival and overall survival than did those presenting with germinomas from a single site of origin.

CONCLUSIONS

Bifocal GCTs are not restricted to germinomas, as had been previously reported, but do include mixed GCTs. The authors hypothesize that bifocal GCTs may result from the metastatic spread of suprasellar or pineal GCTs. The bifocal presentation of germinomas may be a poor prognostic sign and should alert clinicians to the possibility of a disseminated disease.

Disseminated germinoma in the brain and cervical spinal cord 10 years after radiographic resolution of pineal germinoma

Intracranial germinoma, a radiosensitive tumor, is seldom recurrent following initial treatment. When it does recur, it is usually soon after initial treatment and secondary to inadequate radiation field coverage of the tumor. Rarely, there have been case reports of late recurrence many years after initial therapy. Patients with recurrent germinoma in the spine have a less favorable prognosis in terms of treatment response compared to the initial lesion. Thus, careful consideration of the initial lesion, its treatment, and serial imaging of the neural axis with close follow-up is important. We report a patient with a rare delayed recurrence in the brain and cervical spinal cord despite close follow-up with clinical examination and serial imaging.

Navigation-guided endoscopic biopsy for pathological diagnosis for intraparenchymal pure germinoma near the ventricular trigone

BACKGROUND

The authors report a case of intraparenchymal germinoma pathologically diagnosed using navigation-guided endoscopic biopsy.

CASE DESCRIPTION

A 27-year-old man had mild left hemiparesis, transcortical motor aphasia, and amnesia. Magnetic resonance (MR) imaging revealed an intraparenchymal mass lesion near the left ventricular trigone. Navigation-guided endoscopic biopsy was performed, and histopathology revealed large neoplastic cells immunohistochemically positive for germinoma-specific antigens, which were diagnosed as pure germinoma. Chemotherapy with whole-brain radiotherapy was performed, and the neurological symptoms did not change during the treatment. Follow-up MR imaging 1 year after the surgery showed no evidence of recurrence or dissemination.

CONCLUSIONS

Navigation-guided endoscopic biopsy can be a useful technique in such intraparenchymal germinoma cases.