CT and MRI features of intracranial germ cell tumors

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.

Primary central nervous system germ cell tumors in children and young adults: A review of controversies in diagnostic and treatment approach

Primary central nervous system (CNS) germ cell tumors (GCT) are a rare heterogenous group of cancers, arising most commonly in the second decade of life. Through several clinical trials conducted around the world by various groups, the treatment approach for CNS GCT has advanced substantially with generally improved overall outcomes. In recent years, the goal of clinical trials has been focused on reduction of the radiotherapy burden and minimization of long-term toxicity. This review summarizes the current diagnostic and treatment regimens for CNS GCT, examines the controversies associated with these approaches, gaps in contemporary knowledge, and underscores the challenges we face. We also explore future directions in the management of CNS GCT with the ultimate overall aim of preserving curative outcomes, identifying novel biomarkers, and mitigating neurocognitive, endocrine, and psychological toxicity through prospective clinical studies.

Pineal region teratoma with metastases in uncommon locations: a case report

Background

We report a rare case in medical literature of a patient with pineal gland teratoma and uncommon metastases. Usually, metastases of this kind of tumor are located in several organs such as lung and breast, but here we found metastases to the spinal cord and vertebrae.

Case presentation

A 35-year-old Asian white man presented with diplopia and acute neural symptoms in the lower limbs such as numbness, tingling, and paralysis. His medical history was notable for pineal teratoma, treated 1 year previously with surgery, radiotherapy, and chemotherapy. Physical examination of the lower limbs showed absent reflexes and sensation with muscle power scale score of 1 in both limbs. Magnetic resonance imaging of brain and spine revealed many lesions in various locations, most compatible with neural, spinal, and vertebral metastases. Unfortunately, the patient died suddenly before any intervention was carried out.

Conclusion

It is extremely rare for pineal region teratoma to metastasize to the spinal cord and vertebrae, thus more vigilant observation and examination should be provided to patients with pineal teratoma to detect any new lesions and prevent them from becoming dangerous.

"Bones in the Medulla Oblongata?"-A Case Report of Intracranial Teratoma and Review of the Literature

Teratoma in the medulla oblongata is extremely infrequent and has been rarely reported. Severe and sustained brain stem compression resulting from these granitic tumors may cause potentially fatal impairment. Here, we reported a novel case of teratoma that occurred in the medulla oblongata. This 15 year-old boy suffered from a progressive gait disturbance and weakness of limbs for nearly 13 years. Magnetic Resonance Imaging (MRI) revealed an unusual mixed mass in the medulla oblongata and C1-2 spine, which was confirmed as mature teratoma by histopathological examination. Then, surgical resection was performed, followed by postoperative continuous rehabilitation. After a period of rehabilitation, this patient is currently able to mobilize with sticks. No signs of local recurrence occurred. Conclusively, surgical removal is still the preferred treatment for teratoma.

Craniopharyngioma

Craniopharyngiomas are rare malformational tumours of low histological malignancy arising along the craniopharyngeal duct. The two histological subtypes, adamantinomatous craniopharyngioma (ACP) and papillary craniopharyngioma (PCP), differ in genesis and age distribution. ACPs are diagnosed with a bimodal peak of incidence (5-15 years and 45-60 years), whereas PCPs are restricted to adults mainly in the fifth and sixth decades of life. ACPs are driven by somatic mutations in CTNNB1 (encoding β-catenin) that affect β-catenin stability and are predominantly cystic in appearance. PCPs frequently harbour somatic BRAFV600E mutations and are typically solid tumours. Clinical manifestations due to increased intracranial pressure, visual impairment and endocrine deficiencies should prompt imaging investigations, preferentially MRI. Treatment comprises neurosurgery and radiotherapy; intracystic chemotherapy is used in monocystic ACP. Although long-term survival is high, quality of life and neuropsychological function are frequently impaired due to the close anatomical proximity to the optic chiasm, hypothalamus and pituitary gland. Indeed, hypothalamic involvement and treatment-related hypothalamic lesions frequently result in hypothalamic obesity, physical fatigue and psychosocial deficits. Given the rarity of these tumours, efforts to optimize infrastructure and international collaboration should be research priorities.

Suprasellar Germinomas: 2 Case Reports and Literature Review

BACKGROUND

Germinomas are rare malignant central nervous system tumors, a type of germ cell tumor, according to the 2016 World Health Organization Classification of Brain Tumors. Most of these tumors develop along the midline, most often from the pineal gland, followed by tumors arising in the suprasellar cisterns. Suprasellar germinomas commonly manifest with diabetes insipidus, visual impairment, and hypothalamic-pituitary failure. We present a literature review from the PubMed database and report 2 cases of suprasellar germinomas.

CASE DESCRIPTION

Both pediatric patients presented with progressive visual loss; one did not show endocrinologic impairment, and the other presented with hypothyroidism, diabetes insipidus, and generalized edema. Magnetic resonance imaging showed expansive suprasellar masses in both cases, confirmed as germinomas at histopathologic examination. The patients were treated with the same surgical approach, although their outcomes were different because of endocrinologic and post surgical complications.

CONCLUSIONS

Suprasellar germinomas are highly curable lesions when diagnosed early. The treatment remains controversial and should be individualized, but the association of chemotherapy and radiotherapy allows reduce adverse effects and shows great results.

A Case of Nongerminomatous Germ Cell Tumor of the Pineal Region: Risks and Advantages of Biopsy by Endoscopic Approach

A 21-year-old male was admitted to our department with headache and drowsiness. CT scan and MRI revealed acute obstructive hydrocephalus caused by a pineal region mass. The serum and CSF levels of beta-human chorionic gonadotropin (beta-hCG) were 215 IU/L and 447 IU/L, respectively, while levels of alpha-fetoprotein (AFP) were normal. A germ cell tumor (GCT) was suspected, and the patient underwent endoscopic third ventriculostomy (ETV) with biopsy. After four days from surgery, the tumor bled with mass expansion and ETV stoma occlusion; thus, a ventriculoperitoneal shunt was positioned. After ten months, the tumor metastasized to the thorax and abdomen with progression of intracerebral tumor mass. Despite the aggressive nature of this tumor, ETV remains a valid approach for a pineal region mass, but in case of GCT, the risk of bleeding should be taken into account, during and after the surgical procedure.

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.

Pineal germ cell tumors: Two cases with review of histopathologies and biomarkers

Pineal germ cell tumors (GCTs) are primarily seen in pediatric and Asian populations. These tumors are divided into germinomatous and non-germinomatous GCTs (NGGCTs). GCTs are thought to arise by misplacement of totipotent stem cells en route to gonads during embryogenesis. Intracranial GCTs display an affinity to develop along the pineal-suprasellar axis and have variable manifestations dependent upon the location of the tumor. Management and outcomes are driven by histopathologies. In this study, we highlight two cases of pineal GCTs and present a review of the literature with an emphasis on histopathologies and biomarkers.

Microsurgical resection of pineal region tumors

The extensive variety of possible histologic subtypes makes it imperative to establish a tissue diagnosis in patients with pineal region tumors. Management decisions regarding adjuvant therapy, prognosis, and follow-up strategies vary with the histologic diagnosis. Specialized surgical and stereotactic techniques have evolved to provide the neurosurgeon with an array of safe and effective options for obtaining a tissue diagnosis. Advanced microsurgical techniques combined with improved preoperative management and postoperative critical care methods have made aggressive surgical resection a mainstay of management. Aggressive surgical resection has resulted in excellent long-term prognoses for nearly all patients with benign tumors and a large percentage of patients with malignant tumors. However, pineal region surgery remains fraught with potential pitfalls, and these favorable results are dependent on an advanced level of surgical expertise.

Immature teratoma of the tectum mesencephali with histopathological detection of rudimentary eye anlage in a 3-year-old boy: Report of a rare case

Intracranial teratoma is a rare neoplasm derived from omnipotent germinal cells that can contain mesoderm, endoderm and/or ectoderm layer tissue. Histologically teratomas are characterized by abnormal structures like teeth or bone that can be further subdivided into mature and immature according to the presence of incompletely differentiated tissue. Characteristic intracranial teratomas are space-occupying lesions in the pineal region and often present with hydrocephalic symptoms due to aqueduct stenosis. A 3-year-old boy presented with a peracute hemiparesis, fatigue and speech deficit. MRI diagnostics showed a cystic, partially solid, inhomogeneous contrast-enhancing formation at the top of the tectum mesencephali with consecutive aqueduct compression. The patient underwent a sub-occipital craniotomy via a supracerebellar approach and complete resection was achieved. The histopathological examination mainly showed mature tissue of ectodermal, mesodermal and endodermal origin. However, small areas of undifferentiated neuroectodermal tissue within an optic vesicle formation were detected, leading to the diagnosis of an immature teratoma. In due course, the patient was discharged in good health without neurological deficits. To our knowledge, optic vesicle-containing intracranial germ cell tumors are extremely rare. Here we report a unique case with immature neuroectodermal tissue within an optic vesicle formation in an otherwise mature teratoma.

Ectopic intracranial germinoma

Intracranial ectopic germinomas are often associated with synchronous midline disease. Germinomas involving the corpus callosum are exceedingly rare. The reported imaging appearance is not as varied as one might expect and a review of the literature reveals a few common imaging features amongst most ectopic lesions, including cyst formation. We report a 24-year-old man with panhypopituitarism. Neuroimaging revealed three enhancing lesions involving the pituitary infundibulum, the pineal region, and a parenchymal lesion involving the genu of the corpus callosum. The described ectopic mass, a parenchymal lesion, was associated with small peripheral cysts. Stereotactic biopsy and histopathological evaluation revealed this mass to be a germinoma. Following chemotherapy and radiation therapy, there was near-total resolution of the intracranial disease. Preoperative imaging plays an important role, not only in delineating the extent of disease, but also in assisting in generating an appropriate differential diagnosis. Germinomas in the corpus callosum are exceedingly rare but should be considered in the differential of any young patient with a characteristic cystic and solid intra-axial mass.

A Middle Cranial Fossa Dermoid Cyst Treated by an Endonasal Endoscopic Approach

Dermoid cysts are rare, benign, congenital ectodermal inclusion cysts in the skull base, comprising skin supplements surrounded by squamous epithelium. In the period of embryological development, the cysts originate from ectodermal cells left behind in the cranial region by the closure of the neural tube and are primarily located at the midline, especially in the subarachnoid spaces. These lesions are usually asymptomatic and diagnosed incidentally. When the cysts reach large sizes, they can be symptomatic due to infection, rupture, or mass effect around neurovascular tissue. The cysts typically demonstrate accurate radiological diagnostic features. In this case report, we present a rare dermoid cyst in the middle cranial fossa, treated by an endonasal endoscopic approach. The endonasal endoscopic management of appropriate middle cranial fossa is discussed as a recent advance in the extended applications of endoscopic sinus surgery.

Germinoma Mimicking Tumefactive Demyelinating Disease in Pediatric Patients

Cases of intracranial germinoma with granulomatous reaction are rare, so a pathological diagnosis of this disease is difficult. In this report, we describe the case of a 13-year-old boy with a bilateral thalamic germinoma which initially mimicked tumefactive demyelinating disease with inflammation, based on the clinical symptoms, imaging results and histology of a biopsy specimen obtained endoscopically. Upon examination of the cerebrospinal fluid, oligoclonal bands were detected. Although his symptoms and radiological findings improved following steroid pulse treatment, they worsened dramatically almost 1 year after the first surgery and even after an additional steroid pulse treatment. Prompted by the clinical course, a second biopsy was performed, and a pathological examination of the specimen showed a two-cell pattern. The diagnosis was changed to intracranial germinoma. After chemotherapeutic treatment with etoposide and cisplatin, the patient's symptoms and radiological findings dramatically improved. We conclude that it is very challenging to distinguish germinomas with a granulomatous reaction due to other inflammatory diseases, especially when only small specimens can be obtained. Stereotactic or endoscopic biopsies should be performed using samples from several different points even if the lesions are associated with eloquent brain regions.

Neuroimaging diagnosis of pineal region tumors-quest for pathognomonic finding of germinoma

INTRODUCTION

Our study aimed to elucidate the imaging features for the differentiation of pineal germinoma and other pineal region tumors.

METHODS

Image data sets of computed tomographic (CT) scan and magnetic resonance imaging (MRI) data of 93 pineal region tumors including 33 germinomas, 30 nongerminomatous germ cell tumors (NGGCTs), 20 pineal parenchymal tumors (PPTs), and 10 miscellaneous tumors of pineal region were reviewed. Imaging features on CT and MRI were qualitatively assessed by three readers. To know the reasons for morphological differences between germinomas and NGGCTs, histological investigation was done.

RESULTS

Localized calcification was seen in more than 70 % of germ cells tumors (GCTs: germinomas and NGGCTs) while it was scattered in more than half of PPTs. Cystic components in tumors were most frequent in NGGCTs (62 %). Multiplicity of lesion was restricted to GCTs: 39.4 % in germinoma and 10.0 % in NGGCTs. Thick peritumoral edema was more frequent in germinoma than in NGGCT: 40.6 vs. 14.8 % (p=0.0433, Fisher's test). Bithalamic extension of tumor was seen in 78.8 % of germinomas. It was significantly rare in other groups of tumors (p<0.0001, Fisher's test). The relative collagen amount per unit area was significantly lower in germinoma than in NGGCTs.

CONCLUSION

By paying attention to characteristic features as bithalamic extension, thick peritumoral edema, calcification pattern, multiplicity, and their combination, the preoperative differential diagnosis of pineal germinoma will become more accurate.

Early response to chemotherapy as an indicator for the management of germinoma-like tumors of the pineal and/or suprasellar regions

Recent advances in diagnostic imaging and experience with germinomas may allow for the differentiation of central nervous system germinomas from other tumors based on clinical information, without histological verification. We retrospectively analyzed clinically diagnosed germinoma-like tumors of the pineal and/or suprasellar regions. This was done to evaluate the efficacy of our strategy of defining germinoma-compatible tumors based on good responses to initial chemotherapy. The responses to chemotherapy and survival of 34 consecutive patients with germinoma-like tumors who underwent initial treatment from July 2001 to October 2010 were analyzed. The minimum apparent diffusion coefficient (minADC) value and proton magnetic resonance spectroscopy (MRS) were evaluated in recent patients. Twelve patients with histologically verified germinomas and 18 with germinoma-compatible tumors showed early logarithmic decreases in tumor volume in response to initial chemotherapy, typical low minADC values and typical MRS characteristics, including increased choline/creatine ratios, decreased N-acetylasparate/creatine ratios, and large lipid peaks. These patients had good progression-free survival. The other four patients, with histologically verified non-germinomas, showed no response to chemotherapy, and one patient with a pineoblastoma showed a similar minADC value and MRS characteristics to those of patients with germinomas. The response to initial chemotherapy can be used to distinguish germinoma-compatible tumors from non-germinoma in patients with germinoma-like tumors of the pineal and/or suprasellar regions. The evaluation of minADC and proton MRS are useful for distinguishing germinomas from other tumors. However, a subset of non-germinomas may show similar characteristics to germinomas. The benefit of bypassing unnecessary surgical intervention can be achieved, at least in Asian populations with a high incidence of germinomas.

Mature posterior fossa teratoma mimicking dermoid cyst

We describe a very rare case of mature posterior fossa teratoma in an adult who presented with clinico-radiological findings consistent with a dermoid cyst. A computed tomography scan showed a hypodense mass in the cistern magna with calcification and a sinus tract in the occipital bone. Magnetic resonance imaging revealed a hypo- to hyperintense mass without contrast enhancement. The intraoperative picture showed a dermal sinus and a cyst containing lipid, keratin and hair. Histopathological examination showed a tumor with components of all the three germ layers; thereby, a diagnosis of mature teratoma was made. The histopathological differentiation between teratoma and dermoid cyst is very valuable for ruling out the presence of immature/malignant or germinomatous components that would require further adjuvant therapies. Thus, we here present a rare case of posterior fossa teratoma mimicking dermoid cyst and emphasize the importance of histopathological differentiation between these entities.

Contrast-enhanced MR imaging in neuroimaging

MR imaging without and with gadolinium-based contrast agents (GBCAs) is an important imaging tool for defining normal anatomy and characteristics of lesions. GBCAs have been used in contrast-enhanced MR imaging in defining and characterizing lesions of the central nervous system for more than 20 years. The combination of unenhanced and GBCA-enhanced MR imaging is the clinical gold standard for the noninvasive detection and delineation of most intracranial and spinal lesions. MR imaging has a high predictive value that rules out neoplasm and most inflammatory and demyelinating processes of the central nervous system.

Effective radiotherapy cured cauda equina syndrome caused by remitted intracranial germinoma depositing

Cauda equina syndrome (CES) in children is very rare and can permanently disable. A remitted intracranial germinoma depositing on the spinal cord, leading to CES, has never been reported. We discuss the case of a 10-year-old girl who presented with sudden ataxia, low back pain, sensory deficits of the left lower extremity, and difficulty urinating and defecating 7 months after totally remitted intracranial germinoma postintracranial surgery and cranial irradiation. Magnetic resonance imaging (MRI) of the brain and spine showed multiple intradural extramedullary homogeneous masses from the cervical to lumbar levels, compressing the conus medullaris and cauda equina. After emergent craniospinal irradiation, the patient's neurologic symptoms dramatically subsided. A remitted intracranial germinoma depositing on her spinal cord could be the cause of CES. Early identification and a proper craniospinal irradiation may halt the progression of symptoms.

Morphologic features of human chorionic gonadotropin- or alpha-fetoprotein-producing germ cell tumors of the central nervous system: histological heterogeneity and surgical meaning

Our study of germ cell tumors (GCT) of the central nervous system (CNS) investigated the relationship between tumor histology and patient serum titers of human chorionic gonadotropin (HGC) and alpha-fetoprotein (AFP). Thirty-five patients were enrolled. Their serum titers of HCG (mlU/ml) and/or AFP (ng/ml) before initial treatment were available, as were tumor specimens obtained before the administration of adjuvant therapy. They were divided into three groups, depending on whether HCG alone (group H), AFP alone (group A), or both HCG and AFP (group HA) were detected. Each group was subdivided into three groups: patients in group I had H, A, and/or HA titers below 9.9; patients in group II/III had titers from 10.0 to 999; and those in group IV had titers of 1000 or more. Serial sections of tissue specimens were repeatedly stained, mainly with hematoxylin and eosin (H-E) stain, HCG immunostain, and AFP immunostain. There were seven patients in the H-I group and five in H-II/III. Of these 12 patients, 11 had germinomas (G) and one had an embryonal carcinoma (EC). Five patients were included in group A: one was classified as A-II/III and had a germinoma, and the remaining four patients were in A-IV and had yolk sac tumors (YST) or mixed GCT consisting mainly of YST or EC (MXGCT-YST, EC). The HA group consisted of 18 patients. Three were classified as HA-I and had germinomas; nine HA-II/III patients had T or MXGCT-T; and six HA-IV patients had choriocarcinoma (CC), YST, MXGCT-CC, or MXGCT-YST. Throughout the study, the situations for the elevated serum titers could be elucidated in only four cases (three in group A-IV and one in group HA-IV). These results led to the conclusion that serologic evaluation is superior to morphologic evaluation in diagnosing marker-producing GCTs. From a diagnostic perspective, the role of surgery is to verify the HCG- and AFP-immunonegative tissue in patients with G, T, and EC.

Imaging tumors of the pediatric central nervous system

Primary tumors of the central nervous system (CNS) are the second most common neoplasms in children and the leading cause of death in this patient population. The primary objective of this article is to describe the most common pediatric brain tumors and to offer an overview of their respective imaging features, primarily on magnetic resonance imaging. Precise anatomic characterization is essential for developing an appropriate differential diagnosis. Once equipped with this critical information, physicians should be better able to make firm diagnoses, leading to improved disease management and patient outcomes in the setting of CNS tumors of childhood.

Semiquantitative histopathology and 3D magnetic resonance microscopy as collaborative platforms for tissue identification and comparison within teratomas derived from pedigreed primate embryonic stem cells

Teratoma formation in xenografts is a sufficiently stringent pluripotency assay for stem cells. However, little is known about the composition and spatial relationships of tissues within teratomas that may provide clues about development and platforms for studying organ development. Additionally, teratoma formation and analysis lack standards for reporting as assays of pluripotency. Three of 27 total teratomas derived from pedigreed primate embryonic stem cells underwent quantitative three-dimensional high-resolution magnetic resonance microscopy (MRM). Teratomas were subsequently serially sectioned and tissue types identified, semiquantitated, and correlated with MRM images. All teratomas demonstrated tissue derivatives from the three germ layers and approximately 23 different tissue types were identified. Certain tissue groups attempted to form organs more frequently (e.g., trachea/bronchi, small intestine). MRM discriminated some tissues readily (e.g., bone, adipose, cartilage) while other tissue types with like MR intensities could not be distinguished. Semiquantitative histopathological analysis of teratomas demonstrates the ability to delineate multiple tissues as derived from ectoderm, mesoderm, or endoderm and to use this information for comparison to other teratomas. MRM provides rapid quantitative imaging of intact teratomas that complements histology and identifies sites of interest for additional biological studies.

Modified grading system for clinical outcome of intracranial non-germinomatous malignant germ cell tumors

This study investigated the clinical outcome of intracranial non-germinomatous malignant germ cell tumors (NGMGCTs). All histologically proven cases of NGMGCTs treated in Shanghai Huashan Hospital, Fudan University were reviewed. A total of 39 cases were analyzed. There were 15 mixed germ cell tumors, 15 immature teratomas, 7 embryonal carcinomas and 2 yolk sac tumors. Patients were treated surgically first, followed by radiotherapy and/or chemotherapy. Some patients also received gamma knife surgery. The common 5-year survival rate was 36.8%. According to Matsutani's grading system, the 5-year actuarial survival rate for patients in the intermediate and poor prognosis groups were 45.8 and 14.3%, respectively. Individual analysis of each type of tumor showed that the median survival time of embryonal carcinoma was 27 months, which is very close to that of the intermediate group (28 months). We therefore classified embryonal carcinoma into the intermediate group where the 5-year actuarial survival rate for patients in the new intermediate prognosis group was 42.6%. Further analysis of immature teratoma cases found that the 5-year survival rate of patients with immature teratoma who received gamma knife surgery is 100%. This rate exhibited a significant difference (P=0.0049) compared to that of patients who did not undergo gamma knife surgery. In conclusion, we consider surgery as the first choice of treatment although for different histologis, the type of the tumor should be treated separately.

Central nervous system germ cell tumors: classification, clinical features, and treatment with a historical overview

Central nervous system germ cell tumors are neoplasms that affect children and young adults. They are subclassified into germinoma and nongerminomatous germ cell tumors. The latter include teratoma (mature teratoma, immature teratoma, teratoma with malignant transformation), choriocarcinoma, embryonal carcinoma, yolk sac tumors, and mixtures of these entities. Germinoma with syncytiotrophoblastic giant cells is a variant of germinoma. Germinomas respond well to radiation therapy, but late sequelae due to irradiation have been reported. The results of radiation treatment alone for nongerminomatous germ cell tumor are not satisfactory. Combination radiochemotherapy has been applied, and this yields a good outcome with less toxicity for germinomas and better survival of nongerminomatous germ cell tumors. This article also discusses other issues, including the controversy regarding spinal irradiation and the treatment of recurrent disease.

Pathological features of intracranial germinomas with reference to fibrous tissue and granulomatous change

Intracranial germinomas are accompanied occasionally by a significant granulomatous change and abundant fibrous tissue, and this has made their pathological diagnosis difficult. However, the incidence of the granulomatous reaction and the presence of fibrous tissue together with their clinical characteristics in intracranial germinomas have not been fully investigated. Twenty-four germinomas, none of which had received preoperative treatment, were clinicopathologically examined. The location of the tumor was the pineal region (5 cases), the suprasellar region (13 cases), multiple lesions (2 cases), the basal ganglia region (1 case), and other regions (3 cases). Histologically, the germinomas could be divided into two types: (1) type A (18 cases) consisted mainly of large neoplastic cells and small lymphocytes, showing a two-cell pattern; (2) type B (6 cases) consisted predominantly of fibroinflammatory tissues containing occasional neoplastic cells (5/6 cases) and, rarely, neoplastic cells (1/6 cases). Perioperatively, two-cell-pattern germinomas (type A) were characterized as soft tumors and fibroinflammatory germinomas (type B) as hard tumors. Thus, the fibroinflammatory type B accounted for 25% of the intracranial germinomas. Although there were no topographical and clinical differences between the two types, we conclude that immunohistological studies to detect neoplastic germ cells are warranted in cases of small stereotactic biopsies of hard type B tumors.

Management of primary intracranial germ cell tumors

Primary intracranial germ cell tumors are rare and usually localized in the pineal and the suprasellar regions. They are divided into the following histologic types: germinoma, teratoma (mature, immature, malignant), choriocarcinoma, embryonal carcinoma, endodermal sinus tumor (yolk sac tumor), and mixed tumors. Clinically, they are manifested with ocular signs or signs of obstructive hydrocephalus. Localized germinomas are treated with radiation therapy and exhibit a relatively good prognosis. Chemotherapy is reserved for disseminated germinomas. Mature teratomas are treated with surgery. The rest of germ cell tumors are managed with various combinations of surgery, chemotherapy, and radiotherapy depending on the tumor type. If the tumors secrete beta-human chorionic gonadotrophin (hCG) or alpha-fetoprotein (FP), these tumor markers can be used to accurately monitor response to treatment. Prognosis is best for germinomas and mature teratomas and worst for choriocarcinomas and embryonal carcinomas.

Inherent diagnostic and treatment challenges in germinoma of the basal ganglia: a case report and review of the literature

Among intracranial germinomas, basal ganglia germinomas represent a specific clinical and anatomical entity. Based on an unusual case of a basal ganglia germinoma in a 13-year-old Caucasian male, we highlight the diagnostic challenges and discuss treatment considerations in this disease.

CNS germinoma with elevated serum human chorionic gonadotropin level: clinical characteristics and treatment outcome

PURPOSE

The prognostic significance of human chorionic gonadotropin (HCG) level in central nervous system germinoma remains controversial. The purpose of this study was to compare clinical characteristics and prognosis of germinoma patients with normal and high HCG titers in the serum.

METHODS AND MATERIALS

We undertook a multi-institutional retrospective analysis of 103 patients with central nervous system germinoma whose serum HCG and/or beta-HCG level had been measured before treatment between 1984 and 2002. All patients had been treated with radiation therapy either alone (n = 66) or in combination with chemotherapy (n = 37) with a median dose of 47.8 Gy.

RESULTS

HCG and/or beta-HCG level in the serum was high in 39% of all patients. The proportion of HCG-producing tumors was higher in the lesions at the basal ganglia than in the lesions at the other sites. No correlation was found between tumor size and HCG level, but there seemed to be a weak correlation between size and beta-HCG. The 5- and 10-year survival rates were 96% and 94%, respectively, in both patient groups with normal and high HCG (p = 0.99). The 5- and 10-year relapse-free survival rates were 87% and 82%, respectively, in patients with normal HCG level and were both 87% in patients with high HCG (p = 0.74). Also, no other patient-, tumor-, or treatment-related factors seemed to influence the prognosis of the patients.

CONCLUSION

Serum HCG level does not seem to influence patient prognosis when treated with sufficient doses of radiation. Relationship between tumor size and site and HCG level should be investigated further.

Pineal Germinoma With Granulomatous Reaction-Case Report-

A 20-year-old man presented with diplopia. Neurological examination revealed mild skew deviation and upbeat nystagmus. Computed tomography showed a clover-shaped isodense mass in the pineal region with homogeneous enhancement. The lesion was isointense on both T(1)- and T(2)-weighted magnetic resonance (MR) imaging with homogeneous enhancement by gadolinium-diethylenetriaminepenta-acetic acid. Cerebral angiography showed no tumor staining. Serum and cerebrospinal fluid were negative for beta-human chorionic gonadotropin, alpha-fetoprotein, and placental alkaline phosphatase. Open biopsy was performed using a right occipital transtentorial approach. Histological examination revealed a tumor consisting of clusters of germinoma cells, but with prominent infiltration of lymphocytes, plasma cells, and macrophages, and proliferation of small vessels. The histological diagnosis was germinoma with granulomatous reaction. MR imaging showed complete disappearance of the tumor after chemoradiotherapy. Neurosurgeons should be aware of this rare tumor to avoid misdiagnosis as granulomatous inflammation.

Radiological Features of Germinoma Arising From Atypical Locations-Three Case Reports-

Three cases of intracranial germinoma arising from atypical locations occurred in 13-, 22-, and 28-year-old males. The location of the tumor was the corpus callosum (2 cases) and the temporal lobe. Computed tomography and magnetic resonance imaging showed all three tumors had a largest dimension, including the internal cyst, of over 6 cm, and the cysts were larger than 2.5 cm. Radiotherapy and chemotherapy caused all tumors to disappear. Large tumor and large cyst are features of germinoma arising from atypical locations.

Suprasellar germ cell tumor with subarachnoid seeding

A case of suprasellar germinoma with subarachnoid seeding is presented. Patient had a history of depression unresponsive to drug therapy and recently developed diabetes insipidus. MR imaging revealed a huge suprasellar mass, heterogenous in signal intensity due to cystic components. MR spectroscopy of the mass showed prominent lipid peak suggesting high malignant potential.

Clinical management of primary central nervous system germ cell tumors

Despite excellent long-term results for patients with germinoma treated with radiation therapy, the potential for late effects makes the treatment controversial. On the other hand, most patients with non-germinomatous tumors treated by conventional treatment with surgery and radiation therapy fail to survive longer than 3 years. After combination chemotherapy with cisplatin was confirmed to be effective in gonadal germ cell tumors, germ cell tumors of the brain became candidates for chemotherapy. The author reviews several prospective phase II studies that are being investigated to assess the effect of combination chemotherapy and radiation therapy for germ cell tumors. The aim of these studies is to reduce the volume and dose of radiation therapy for germinoma and prolong the survival of patients of non-germinomatous tumors. For germinoma, a trial with chemotherapy alone failed, with a high rate of recurrence, but Japanese and European trials with reduced-dose chemotherapy and a smaller volume of radiation therapy have resulted in high event-free survival (EFS) rates. Ongoing phase II studies with combined chemotherapy and radiation therapy for non-germinomatous tumors will result in a 5-year survival rate of greater than 50%, which is better than that achieved by radiation therapy alone.

Third ventricle immature teratoma: a case report

We present the case of a 1-year-old girl with persistent vomiting who was found to have a disproportionately large immature teratoma in the third ventricle. Magnetic resonance imaging demonstrated a heterogeneous intracranial mass in the third ventricle, with a compressed left cerebral hemisphere and hydrocephalus. Bifrontal craniotomy via a transchiasmatic approach achieved total resection of the tumor. No significant neurologic deficit was seen except for double vision and disturbances in eye movement. Third ventricle immature teratoma, although extremely rare, may present as a suprasellar mass lesion and hydrocephalus. The prognosis after gross total resection is favorable; however, radiotherapy is usually postponed until 36 to 48 months of age in order to avoid complications such as stunted growth, endocrine disturbances and neuropsychologic problems.

MRI and CT findings of neurohypophyseal germinoma

OBJECTIVE

Magnetic resonance (MR) imaging and computed tomography (CT) findings of neurohypophyseal germinoma have not previously been described in detail. The purpose of the present study was to establish the spectrum of MR imaging and CT findings in neurohypophyseal germinomas.

MATERIALS AND METHODS

MR and CT images of 13 consecutive patients (seven males, six females; mean age: 15 years; range: 6-31 years) with neurohypophyseal germinoma were retrospectively analyzed. The diagnosis had been made either histologically (n=8) or clinically according to established criteria (n=5). All patients had been examined using MR imaging and CT before treatment.

RESULTS

On MR imaging, infundibular thickening (up to 16 mm) was observed in all 13 cases. Hyperintensity of the posterior pituitary on T1-weighted image was absent in all 13 cases (100%) and 12 of the 13 displayed central diabetes insipidus. Ten germinomas (77%) were isointense to cerebral cortex on T1-weighted image, but variable intensities were exhibited on T2-weighted image. MR images revealed intratumoral cysts in six cases (46%), most of which demonstrated intra-third ventricular extension. Eleven of the 13 cases (85%) revealed hyperdense solid components on unenhanced CT. Calcification was absent in all cases (100%).

CONCLUSION

Infundibular thickening, absence of the posterior pituitary high signal on T1-weighted image, lack of calcification and hyperdensity on unenhanced CT are common imaging features of neurohypophyseal germinoma.

Suprasellar germ cell tumours: specific problems and the evolution of optimal management with a combined chemoradiotherapy regimen

OBJECTIVE

Suprasellar germ cell tumours are rare, and there are few series of patients outlining the problems in diagnosis and management, and providing clear guidelines for optimal therapy. We have therefore reviewed our own series of 11 such patients who were managed in a joint endocrinology/clinical oncology setting.

PATIENTS AND DESIGN

A retrospective case review assessment of all patients seen within a given time. Clinical, biochemical and radiological findings were reviewed, the types of therapy administered noted, and the responses to treatment analysed.

RESULTS

In the years 1977-2001, 11 patients with suprasellar (SS) germ cell tumours (GCT) were seen (germinomatous : nongerminomatous = 8 : 3). SSGCT had an approximately equal sex incidence (M : F, 6 : 5), in contrast to pineal tumours, the commonest site of origin of intracranial GCT and which occur predominantly in men. The median age at presentation was 20 years (range 6-49 years) with a median duration of symptoms before diagnosis of 17 months (range 1-35 months). Polyuria was the commonest presenting symptom (10 patients). Diabetes insipidus occurred in all patients, as did partial or complete anterior pituitary failure. Visual failure was present in 55% of cases. Anorexia, weight loss and disturbed thirst sensation were also common. Positron emission tomography scanning was occasionally useful in the evaluation of suprasellar tumours/pituitary stalk lesions deemed too risky to biopsy. A "central nervous system-friendly" chemoradiotherapy regimen comprising vincristine, etoposide and carboplatin and differential daily dose irradiation, usually administered using a partial transmission block technique, produced a 5-year survival of 100% with low morbidity. Treatment did not correct previously abnormal endocrine function although it did improve vision in three of six patients.

CONCLUSIONS

We therefore emphasize the use of techniques other than biopsy in the diagnosis of these patients, note the problems in the management of their fluid control, and highlight the favourable response to a combined chemotherapy-radiotherapy protocol.

Intracranial germinoma with syncytiotrophoblastic giant cells in the cerebellopontine angle--case report

A 23-year-old man presented with a 3-week history of left hearing disturbance and left facial nerve paresis. T1-weighted magnetic resonance (MR) imaging showed an iso-intense mass in the left cerebellopontine angle (CPA), with homogeneous enhancement with gadolinium-diethylenetriaminepenta-acetic acid. T2-weighted MR imaging showed the mass as heterogeneously iso- to hyperintense. Gross total removal of the tumor was achieved. Histological examination revealed that the tumor was a germinoma with syncytiotrophoblastic giant cells. Whole central nervous system irradiation with cisplatin-etoposide chemotherapy was performed postoperatively. He has been in good condition with no sign of recurrence for 7 years. Intracranial germ cell tumors in the CPA are very rare. Total surgical removal followed by irradiation and chemotherapy will provide a good outcome.

MRI of pineal region tumors

The pineal region is a heterogeneous area that includes the pineal gland and several parapineal structures. Pineal region masses include germ cell tumors (GCTs), pineal parenchymal cell tumors, glioma, meningioma, metastases, and non-neoplastic masses such as pineal cysts, lipoma, epidermoid, vascular malformations. Although MRI has allowed an improvement in distinguishing true pineal masses from parapineal masses impinging into the region of the gland, it is still difficult to differentiate the pineal GCTs from pineal parenchymal tumors with only images, and the clinical informations such as age, sex, and the tumor markers are very important.

Delayed resolution of intracranial germinoma after radiotherapy: a preliminary study of the correlation between histology and magnetic resonance imaging

A central nervous system germinoma is curable in most cases by radiotherapy, and most of the tumor mass disappears promptly after 20-30 doses. However, some germinomas take a longer period to vanish completely from magnetic resonance imaging (MRI) or computed tomography (CT) scans. In such cases, the tumor may contain components such as teratoma. The aim of this study was to clarify the nature of the persistence of some germinomas. Five cases of histologically verified germinoma in which radiotherapy was performed to treat residual tumor were selected. The doses of focal radiotherapy and whole brain radiotherapy were 10-20 Gy and 20-34 Gy, respectively. In these cases, correlation was made between the degree of persistence of the tumor when assessed by MRI and the amount of interstitial content, as determined by histology. The histological evaluation, using hematoxylin-eosin stain, silver impregnation and Azan staining was carried out independently of clinical information. The tumor vanished soon after radiotherapy in three cases, but 3-15 months passed before the tumor completely vanished from the MRI scans in the other two cases. The histology of the cases in which the tumor disappeared rapidly was predominantly of large tumor cells and only small amounts of reticulin. However, in the persistent tumors, large amounts of reticulin and vascular components were present. Thus, it is proposed that tumors with a large parenchymal component disappear soon after radiotherapy, whereas tumors composed mainly of interstitial component persist. Long-standing enhancement seen on MRI or CT scans of patients with an intracranial germinoma is indicative of a large amount of interstitial component in the tumor.

Germ cell tumors of the central nervous system originating from non-pineal regions: CT and MR features

CT and MR findings were retrospectively reviewed in 12 patients with germ cell tumors originating from the non-pineal regions. Cystic or necrotic components were seen in 6 patients. Of 4 germinomas, 2 showed mixed density on the CT. The MR signal intensity of the tumor was non-specific. Of 8 germinomas, 4 were inhomogeneously enhanced on postcontrast CT and T1-weighted MR images. CT and MR features of germinomas originating from non-pineal regions frequently differ from those of germinomas originating from the pineal region. The mass of the tumor often appeared cystic and inhomogeneously enhanced following contrast infusion.

Spontaneous regression of a residual pineal tumor after resection of a cerebellar vermian germinoma

A case of multiple intracranial germ cell tumor in which a pineal tumor regressed spontaneously after resection of the cerebellar mass is reported. Immunohistochemical staining of the cerebellar mass showed that most of the infiltrating lymphocytes were positive for CD3 and CD8. The anti-Ki-67 monoclonal antibody MIB-1 staining of the resected tumor revealed a high MIB-1 positivity ratio (36.1%) among the large tumor cells, and TUNEL staining demonstrated that positivity in up to 6% of the tumor cells. Possible mechanisms responsible for this spontaneous regression including immunological responses and apoptosis induced by T lymphocytes are discussed.

Pathologically-proven intracranial germinoma treated with radiation therapy

BACKGROUND AND PURPOSE

A retrospective multi-institutional study was conducted to survey what percentage of intracranial germinomas were treated with pathological confirmation before radiotherapy and to investigate the influence of field selection on outcome.

MATERIALS AND METHODS

Thirty-seven percent of patients (41 of 110 patients) were pathologically confirmed before radiotherapy during the past 16 years at eight institutions in Northern Japanese prefectures. Pathological confirmation was obtained in 26, 37 and 53% of cases during 1978-1983, 1984-1989 and 1990-1994, respectively. All 110 patients were examined using computed tomography (CT) scans. Among the 41 patients with pathologically confirmed germinoma, radiation fields were craniospinal in 23 patients, whole-brain in 10 patients and local without ventricle inclusion in eight patients.

RESULTS

For the 41 patients with pathologically confirmed germinoma, the actuarial and cause-specific survival rates were 91/94% at 5 years and 87/90% at 10 years, respectively. The relapse-free survival rate at 10 years was 90. 76 and 22% for the craniospinal field, whole-brain field and local field without ventricle inclusion, respectively.

CONCLUSION

Pathological confirmation was obtained in only 37% of CT-scan era cases, although the confirmations were more commonly carried out later in the study period. Limited local irradiation alone without ventricle inclusion cannot be recommended for localized tumors even with the help of CT scanning.