The Lipoma of Tuber Cinereum

Two cases of lipoma of the tuber cinereum, unexpectedly discovered in the course of autopsy examination, are reported. Each case was thoroughly investigated by serial sectioning of both the diencephalic floor and the tumor. Some peculiar findings observed and a complete survey of the literature revealed that such a growth may be considered an incomplete benign mesenchymoma, i.e., a mixed tumor of mesenchymal derivates, according to Stout (14). The error in development, consisting in the inclusion of embryonal germs of primitive meninx into the nervous system, may occur early during the third month of intrauterine life, at the time of the formation of the primitive septa.

Prenatal diagnosis of pericallosal curvilinear lipoma: specific imaging pattern and diagnostic pitfalls

We report the first series of cases of pericallosal curvilinear lipoma (CL) diagnosed prenatally and highlight the limitations in identifying a specific prenatal imaging pattern using ultrasound and magnetic resonance imaging (MRI). In all five of our cases, on ultrasound, the main feature leading to referral was a short corpus callosum. This subtle callosal dysgenesis was associated with a band of hyperechogenicity surrounding the corpus callosum, mimicking the pericallosal sulcus, which increased in size during the third trimester in three of the four cases in which sonographic follow-up was performed. On T2-weighted MRI, this band showed typical hypointensity in all cases; in contrast, on T1-weighted imaging, in only one case was there hyperintensity, suggestive of fat, as seen typically in the postnatal period. For appropriate prenatal counseling regarding outcome, it is important to identify or rule out CL when mild corpus callosal dysgenesis is observed. One should be aware of subtle diagnostic findings, such as a thin band of echogenicity surrounding the corpus callosum that is seen as a band of hypointensity on T2-weighted fetal MRI, and which may increase in size during gestation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Fetal optic nerve sheath measurement as a non-invasive tool for assessment of increased intracranial pressure

OBJECTIVES

To describe the sonographic technique for assessment of the fetal optic nerve sheath and to report on three fetuses with intracranial lesions and enlarged optic nerve sheath diameter (ONSD) compared with normal controls matched for gestational age (GA).

METHODS

In this cross-sectional study ONSD was measured sonographically in three fetuses (aged 23, 24 and 35 gestational weeks) with intracranial findings associated with increased intracranial pressure (ICP; dural thrombosis and intracranial tumors) as well as 42 healthy controls matched for GA ± 1 week (aged 22-25 and 34-36 weeks). For fetal eye assessment, transabdominal and transvaginal routes and high-resolution transducers were used for optimal visualization depending on fetal position. Measurements were made using an axial view at the level of the orbits, with the fetal face positioned towards the transducer. The ONSD was measured 1.5 or 2 mm behind the papilla (depending on GA) in all fetuses. Mean ± 2 SD ONSD of controls were calculated for each GA and compared with data from the three fetuses with intracranial pathology.

RESULTS

In the 42 normal fetuses, ONSD increased from 1.2 mm at 23 weeks to 2.6 mm at 36 weeks. The measurements at 36 weeks correlated well with those observed in newborns. ONSD measurements of the three cases were above mean + 2 SD of values obtained from healthy controls at the same GA and also exceeded values of fetuses that were 1 week older.

CONCLUSIONS

Fetal ONSD measurement is feasible using a technique similar to that used in adults and children. ONSD enlargement was observed in all three fetuses with intracranial lesions and may be an early tool with which to diagnose increased ICP.

Mosaic analysis with double markers reveals tumor cell of origin in glioma

Cancer cell of origin is difficult to identify by analyzing cells within terminal stage tumors, whose identity could be concealed by the acquired plasticity. Thus, an ideal approach to identify the cell of origin is to analyze proliferative abnormalities in distinct lineages prior to malignancy. Here, we use mosaic analysis with double markers (MADM) in mice to model gliomagenesis by initiating concurrent p53/Nf1 mutations sporadically in neural stem cells (NSCs). Surprisingly, MADM-based lineage tracing revealed significant aberrant growth prior to malignancy only in oligodendrocyte precursor cells (OPCs), but not in any other NSC-derived lineages or NSCs themselves. Upon tumor formation, phenotypic and transcriptome analyses of tumor cells revealed salient OPC features. Finally, introducing the same p53/Nf1 mutations directly into OPCs consistently led to gliomagenesis. Our findings suggest OPCs as the cell of origin in this model, even when initial mutations occur in NSCs, and highlight the importance of analyzing premalignant stages to identify the cancer cell of origin.

Review: the role of neural crest cells in the endocrine system

The neural crest is a pluripotent population of cells that arises at the junction of the neural tube and the dorsal ectoderm. These highly migratory cells form diverse derivatives including neurons and glia of the sensory, sympathetic, and enteric nervous systems, melanocytes, and the bones, cartilage, and connective tissues of the face. The neural crest has long been associated with the endocrine system, although not always correctly. According to current understanding, neural crest cells give rise to the chromaffin cells of the adrenal medulla, chief cells of the extra-adrenal paraganglia, and thyroid C cells. The endocrine tumors that correspond to these cell types are pheochromocytomas, extra-adrenal paragangliomas, and medullary thyroid carcinomas. Although controversies concerning embryological origin appear to have mostly been resolved, questions persist concerning the pathobiology of each tumor type and its basis in neural crest embryology. Here we present a brief history of the work on neural crest development, both in general and in application to the endocrine system. In particular, we present findings related to the plasticity and pluripotency of neural crest cells as well as a discussion of several different neural crest tumors in the endocrine system.

Sonographic detection of fetal cerebellar cavernous hemangioma with in-utero hemorrhage leading to cerebellar hemihypoplasia

We report the prenatal diagnosis of cerebellar cavernous angioma. Ultrasound examination at 21 weeks' gestation showed a hyperechogenic lesion measuring 12 mm in diameter, occupying most of the right cerebellar hemisphere. At 24 weeks' gestation, significant hypoplasia of the right hemisphere was diagnosed, and the pregnancy was terminated. Pathological evaluation of the lesion revealed extensive hemorrhaging and a rich network of dilated vessels and small capillaries. The right cerebellar lobe was hypoplastic and covered with blood clots. Cerebral cavernous malformation should be considered in the differential diagnosis of hyperechogenic lesions in the fetal cerebellum.

Giant intracranial teratoma and lack of cortical development in a fetus. Case report

Antenatal diagnosis of an intracranial neoplasm is extremely rare. The authors describe a case in which a 21-week-old fetus was found, by using fetal ultrasonography, to have a large intracranial mass. Fetal magnetic resonance (MR) images, obtained at 21 and 25 weeks' gestation, supported the diagnosis of a teratoma. As the tumor increased in size, near-complete brain atrophy ensued. Premature labor was induced, and a nonviable fetus died within minutes of delivery. Postmortem analysis confirmed a teratoma occupying a major portion of the intracranial space. In cases in which abnormal brain development is suspected in a fetus, the use of fetal MR imaging can give a clearer picture of the pathological entity, which may allow for a more accurate diagnosis. The usefulness of fetal MR imaging in monitoring brain development and tumor growth during treatment planning is discussed.

Human and Rat Glioma Growth, Invasion, and Vascularization in a Novel Chick Embryo Brain Tumor Model

The mechanisms that control the insidiously invasive nature of malignant gliomas are poorly understood, and their study would be facilitated by an in vivo model that is easy to manipulate and inexpensive. The developing chick embryo brain was assessed as a new xenograft model for the production, growth, and study of human and rat glioma cell lines. Three established glioma lines (U-87 MG, C6, and 9L) were injected into chick embryo brain ventricles on embryonic day (E) 5 and brains were examined after several days to two weeks after injection. All glioma lines survived, produced vascularized intraventricular tumors, and invaded the brain in a manner similar to that in rodents. Rat C6 glioma cells spread along vasculature and also invaded the neural tissue. Human U-87 glioma cells migrated along vasculature and exhibited slight invasion of neural tissue. Rat 9L gliosarcoma cells were highly motile, but migrated only along the vasculature. A derivative of 9L cells that stably expressed the cell surface adhesion molecule NgCAM/L1 was produced and also injected into chick embryo brain ventricles to see if this protein could facilitate tumor cell migration away from the vasculature into areas such as axonal tracts. 9L/NgCAM cells, however, did not migrate away from the vasculature and, thus, this protein alone cannot be responsible for diffuse invasiveness of some gliomas. 9L/NgCAM cell motility was assessed in vitro using sophisticated time-lapse microscopy and quantitative analysis, and was significantly altered compared to parental 9L cells. These studies demonstrate that the chick embryo brain is a successful and novel xenograft model for mammalian gliomas and demonstrate the potential usefulness of this new model for studying glioma tumor cell growth, vascularization, and invasiveness.

Prenatal diagnosis of a fetal intracranial tumor

INTRODUCTION

The commonest fetal intracranial tumor is the teratoma. The prognosis is poor with death usually occurring shortly after birth. Modern high resolution ultrasound scanners facilitate examination of the cranial contents, allowing earlier diagnosis.

CASE REPORT

A fetus with a congenital intracranial teratoma presenting with a disproportionately enlarged head at 36 weeks' gestation is presented. The infant died of respiratory failure within 24 h of birth. On postmortem examination the histologic report revealed an immature teratoma. This article describes the prenatal sonographic diagnosis of a rare case of intracranial immature teratoma in a fetus at 36 weeks' gestation.

Class III beta-tubulin isotype: a key cytoskeletal protein at the crossroads of developmental neurobiology and tumor neuropathology

The expression of the cytoskeletal protein class III beta-tubulin isotype is reviewed in the context of human central nervous system development and neoplasia. Compared to systemic organs and tissues, class III beta-tubulin is abundant in the brain, where it is prominently expressed during fetal and postnatal development. As exemplified in cerebellar neurogenesis, the distribution of class III beta-tubulin is neuron associated, exhibiting different temporospatial gradients in the neuronal progeny of the external granule layer versus the neuroepithelial germinal matrix of the velum medullare. However, transient expression of this protein is also present in the telencephalic subventricular zones comprising putative neuronal and/or glial precursor cells. This temporospatially restricted, potentially non-neuronal expression of class III beta-tubulin may have implications in the accurate identification of presumptive neurons derived from transplanted embryonic stem cells. In the adult central nervous system, the distribution of class III beta-tubulin is almost exclusively neuron specific. Altered patterns of expression are noted in brain tumors. In "embryonal"-type neuronal/neuroblastic tumors of the central nervous system, such as the medulloblastomas, class III beta-tubulin expression is associated with neuronal differentiation and decreased cell proliferation. In contrast, the expression of class III beta-tubulin in gliomas is associated with an ascending grade of histologic malignancy and with correspondingly high proliferative indices. Thus, class III beta-tubulin expression in neuronal or neuroblastic tumors is differentiation dependent, whereas in glial tumors, it is aberrant and/or represents "dedifferentiation" associated with the acquisition of glial progenitor-like phenotype(s). From a diagnostic perspective, the detection of class III beta-tubulin immunostaining in neoplastic cells should not be construed as categorical evidence of divergent neuronal differentiation in tumors, which are otherwise phenotypically glial. Because class III beta-tubulin is present in neoplastic but not in normal differentiated glial cells, the elucidation of molecular mechanisms responsible for the altered expression of this isotype may provide critical insights into the dynamics of the microtubule cytoskeleton in the growth and progression of gliomas.

Proteases in brain tumour progression

Local invasion of tumour cells is characteristic of brain tumour progression. It is associated with increased motility and a potential to hydrolyse macromolecular components of the extracellular matrix. The peptidases that have been most investigated, and are induced during this process, are reviewed: the plasminogen activators (PAs), matrix metalloproteinases (MMPs) and lysosomal cysteine peptidases called cathepsins (Cats). Increased levels of urokinase-type PA (uPA) are observed mainly at the invasive margins of a tumour, whereas the data on the expression of tissue-type PA (tPA) are still controversial. It has been shown that the endogenous inhibitor of PAs, PAI-1, is localised in both tumour and tumour-associated endothelial cells. Among MMPs, the expression of the gelatinases, MMP2 and MMP9, strongly correlates with glioma progression. Membrane bound MT-MMPs, in particular MT1- and MT2-MMP, seem to play a major role in activating MMP-2. Several members of the ADAMTS family have also been detected in brain tumours, the most relevant being ADAMTS4, due to its cleavage of CNS specific proteins. Lysosomal cathepsin B is highly expressed in malignant glial cells and in endothelial cells of vascularised glioblastomas and is a predictor of a shorter survival. In addition to invasion, cathepsin L may play a role in decreased susceptibility of anaplastic glioma cells to apoptosis. Finally, cathepsin B was proposed as a marker for malignancy in the more aggressive type of meningiomas. Each of these peptidases may act alone, or in concert with the others, to support malignant behaviour of brain tumour cells; the development of new inhibitors of invasion, therefore, should contribute to the control of local spread of a tumour.

Fetal brain tumors

INTRODUCTION

Fetal intracranial tumors are rare and their evolution is usually poor. With routine use of antenatal ultrasound imaging, a larger number of such tumors have been diagnosed.

METHODS

During the period from January 1992 to January 2002, 18 cases diagnosed as intracranial tumors in the fetal stage were treated in the Neurosurgery and Obstetrics Departments of the Federal University of São Paulo and in the Fetal Medicine Service of the Maternity Hospital Santa Joana.

RESULTS

The tumors most frequently found were those of the choroid plexus and teratomas. Out of those 18 cases, 11 patients presented with fetal hydrocephalus, and 5 of them, who were less than 34 weeks old (gestational age), underwent repeated cephalocenteses while awaiting better conditions for delivery. Two fetuses died while in utero before any intervention had taken place and 16 underwent craniotomy after birth. Twelve of those patients are still alive, 9 of whom are considered normal. The 3 others are slightly or moderately retarded.

Maternal prenatal exposure to nitrosatable drugs and childhood brain tumours

BACKGROUND

A compelling hypothesis was proposed that childhood brain tumours are associated with maternal exposure to N-nitroso compounds during the prenatal period. Many common drugs, such as antihistamines, aspirin, and antibiotics, are nitrosatable and depending upon the product, potentially carcinogenic. We hypothesized that maternal ingestion of certain subgroups of nitrosatable drug products during pregnancy increases the risk of brain tumour development in offspring.

METHODS

Data were collected as part of a population-based case-control study of childhood brain tumours and mothers' self-reported exposure to therapeutic drugs and dietary nitrites. Cases were enrolled from three US West Coast SEER tumour registries: Seattle-Puget sound, Los Angeles County, and the San Francisco-Oakland Bay Area. Tumours were grouped into three major histological tumour subtypes: astroglial, primitive neural ectodermal tumours, and all remaining glial tumours ('other glial'). Therapeutic drugs reported by mothers were translated into active chemical compounds and classified as secondary amines, tertiary amines, amides, or none of the three. Risk estimates were computed according to classes of nitrosatability, potential carcinogenicity, teratogenicity, and predicted end product.

RESULTS

We found no significant association between maternal use of nitrosatable drugs, either overall or within any of the nitrosatable drug classifications, and subsequent development of brain tumours in children. Nitrite consumption from cured meats was not an effect modifier. However, exposure to nitrosoephedrine during pregnancy was associated with significantly increased risk of 'other glial' tumours (OR = 3.1; 95% CI: 1.1-9.2).

CONCLUSIONS

These findings do not support an association between maternal use of nitrosatable drugs during pregnancy and brain tumour risk in offspring. While exposure to the nitrosation end product nitrosoephedrine was associated with increased risk for other glial tumours, the finding was not specific to any one type of tumour.

Encephalofacial angiomatosis sparing the occipital lobe and without facial nevus: on the spectrum of Sturge-Weber syndrome variants?

We report two cases of leptomeningeal angiomatosis in atypical frontoparietotemporal locations without an associated facial port-wine stain. Evidence of a leptomeningeal angioma was found in each when they were evaluated for headaches and seizures. The diagnosis of a leptomeningeal angioma was suggested by calcifications noted on computed tomographic scan of the head and confirmed with contrast-enhanced magnetic resonance images of the brain. We hypothesize that given the lack of occipital involvement with the angioma, and therefore the noncontiguous nature of this lesion with the developing upper facial ectoderm, the failure to develop a facial angioma would be expected. We found that the useof an anticonvulsant along with a migraine prophylactic medication appeared to have the greatest efficacy in these two cases, whereas anticonvulsants alone were less helpful. This diagnosis should be considered in any child presenting with seizures or complicated migraines and intracranial calcifications.

No chromosomal imbalances detected by comparative genomic hybridisation in a case of fetal immature teratoma

CASE REPORT

We present the first application of comparative genomic hybridisation (CGH) in fetal brain tumours in the case of a fetal immature teratoma. The tumour was discovered in a female fetus at 22 weeks gestation after presentation with significant craniomegaly of such degree that the head size measured by sonography was found to correspond to a gestational age of 37 weeks, and the pregnancy was terminated.

RESULTS

Neuropathological examination showed an immature teratoma measuring 1.7 x 1.6 x 0.5 cm and containing tissue from all three germinal layers. CGH was successfully performed and, in contrast to earlier results in both cerebral and extracerebral teratomas also investigated with the same technique, it revealed no chromosomal imbalances.

CONCLUSION

This indicates that mono- or trisomies did not have a role in the pathogenesis in this particular case and that a fetal immature teratoma may contain aberrations smaller than the detection threshold of CGH. However, it remains to be seen in larger cohorts whether fetal teratomas follow a different pathogenetic pathway and may be triggered by different molecular events than teratomas occurring in later life.

[Lipomatous hamartomas of the brain--malformations of the subarachnoid space]

Lipomatous hamartomas are rare disorders affecting the central nervous system. In our report, two observations of this disorder are presented. Both are interhemispheric in location and are associated with a complete agenesis of the corpus callosum, while having different histological structures. In our first patient, the intracranial formation caused refractory seizures, was partially surgically removed, and a biopsy was performed. Light microscopic examination disclosed the presence of a highly vascularized mature adipose tissue with numerous calcifications. The second case was an incidental finding at autopsy. Microscopically, we found adipose tissue together with numerous foci of hemopoiesis and structures of lamelar bone. In both cases, the indistinct demarcation of the collagenous capsule from the surrounding brain tissue and the continuity of the hamartoma with the leptomeninges were striking. In recent findings about the development of meninges and brain commissures, the origin of this disorder is explained as a defective resorption of the embryonic meninx primitiva. This disorder then causes other developmental aberrations of the brain, which are often found in association. The varying microscopic pattern of these disorders can also be satisfactorily explained by their origin in the primitive meninx, which is formed from both mesenchyme and neuroectoderm.

Isolated large third-trimester intracranial cyst on fetal ultrasound: fact or fiction?

OBJECTIVE

To distinguish the fact from artifact of an isolated, large, intracranial cyst on prenatal sonography (PSG).

BACKGROUND

The use of PSG is rapidly increasing with most obstetric ultrasounds occurring in general community settings like small hospitals and clinics with personnel who have variable training, experience, and interest levels. In contrast, most PSG articles and books are produced in large subspecialty centers with concentrated referral bases plus both highly-trained and experienced personnel.

DESIGN/METHODS

We report a series of 2 normal newborn patients who had a large prenatal unilateral intracranial cyst diagnosed by PSG in the 10 years between July of 1989 and 1999 at a rural community hospital. The newborns had imaging studies at birth and their neurodevelopmental progress was followed for several years. Textbook, bibliography and computerized Medline (1966-present) searches including prenatal ultrasound, observer variation, diagnostic errors, reproducibility of results, sensitivity and specificity, accuracy, central nervous system, false-positive, prenatal diagnosis, and brain were examined starting in August 1996 for reports.

RESULTS

There were 4079 obstetric ultrasounds performed in 3.5 years, January 1996 through July 1999 at this rural community facility. This rate extrapolates to a total of 11 654 obstetric ultrasounds over the 10-year study period in which the 2 cases of intracranial cyst artifact occurred. Thus, the incidence of 2 intracranial cyst artifacts was estimated as 2/11 654 PSG, a .0002% false-positive rate.

CONCLUSIONS

This is the first report of the occurrence of PSG artifacts in a community facility. Artifact is a real problem and needs to be specified in differential diagnoses. There are ways to decrease sonographic artifact-or at least to recognize it-so our estimates at a community hospital for its occurrence are presented with the relevant technical and ethical issues. None of these issues have been previously reported in the pediatric literature. Our false-positive rate for large intracranial cyst compares favorably with other reports. Our estimate may inflate our denominator by reporting scans rather than the number of fetuses scanned, and our numerator may miss cases that moved from the community. Confusion differentiating PSG artifact from reality often occurs when interpreting static or frozen real-time images. The signs that sonogram images may be artifacts include defects that: extend outside the fetal body; change shape, size and echogenecity with different scan planes; are not seen on all examinations; and are isolated in an otherwise normal fetus. Failure to offer quality PSG in clinical settings where it is available restricts access of pregnant women to the diagnosis of fetal anomalies, and therefore restricts access to the options of pregnancy termination, fetal therapy like fetal surgery, and delivery options of timing, setting, and mode. We suggest a multidisciplinary approach to prenatal abnormalities like isolated third trimester unilateral intracranial cyst in both primary and tertiary care settings aids interpretation followed by expectant conservative management without elaborate, risky, or terminal interventions.

Mutations in the beta-propeller domain of the Drosophila brain tumor (brat) protein induce neoplasm in the larval brain

Inactivation of both alleles of the fruit fly D. melanogaster brain tumor (brat) gene results in the production of a tumor-like neoplasm in the larval brain, and lethality in the larval third instar and pupal stages. We cloned the brat gene from a transposon-tagged allele and identified its gene product. brat encodes for an 1037 amino acid protein with an N-terminal B-boxl zinc finger followed by a B-box2 zinc finger, a coiled-coil domain, and a C-terminal beta-propeller domain with six blades. All these motifs are known to mediate protein-protein interactions. Sequence analysis of four brat alleles revealed that all of them are mutated at the beta-propeller domain. The clustering of mutations in this domain strongly suggests that it has a crucial role in the normal function of Brat, and defines a novel protein motif involved in tumor suppression activity. The brat gene is expressed in the embryonic central and peripheral nervous systems including the embryonic brain. In third instar larva brat expression was detected in the larval central nervous system including the brain and the ventral ganglion, in two glands - the ring gland and the salivary gland, and in parts of the foregut - the gastric caecae and the proventriculus. A second brat-like gene was found in D. melanogaster, and homologs were identified in the nematode, mouse, rat, and human. Accumulated data suggests that Brat may regulate proliferation and differentiation by secretion/transport-mediated processes.

Paediatric brain tumours: an embryological perspective

Primitive neuroectodermal tumours are amongst the most common paediatric tumours of the central nervous system. These tumours are composed of undifferentiated cells and a variable component of more differentiated cell types. Most analysis of these tumours has focused on molecules normally found in the differentiated cells or those found in all primitive neuronal precursors. In this article we describe recent advances in understanding of the molecular processes involved in normal neurogenesis. We discuss the relevance of these data to the biology of neuronal tumours and describe strategies we and others have adopted to investigate the usefulness of molecules found in undifferentiated neuronal tissues in understanding the events which underlie oncogenesis in this tumour type.

Clinical, radiological and histological presentations of dysembryoplastic neuroepithelial tumors (DNT). Report of two cases

Dysembryoplastic neuroepithelial tumor (DNT) is a recently described rare brain neoplasm with characteristic clinical and morphological features and favorable prognosis. We report here two cases of DNT. The first concerned a 12 years old girl who presented complex seizures preceded by acoustic aura (melodies). Computed tomography revealed a hypodense tumor measuring 2 x 2.5 cm in diameter, located paracortically in the left temporal lobe. The second tumor was removed from a 21-year-old man with partial complex seizures. Nine years earlier patient underwent neurosurgery with partial removal of the tumor The tumor's histopathologic diagnosis is unfortunately lacking. Computed and magnetic resonance imaging showed a mass occupying the cortex and paracortical areas of the anterior pole of the temporal lobe. Histologically, both tumors consisted of small, S-100 protein immunopositive oligodendrocyte-like cells (OLCs) arranged between synaptophysin- and, to a lesser degree, NFP-immunopositive axons (glioneuronal element). In the second case, an area of pilocytic astrocytoma-like appearance was also found, these cells were immunopositive for GFAP. The present study provides clinical, radiological and histological data, which may be helpful in differential diagnosis of this newly recognised brain tumor.

Prenatal diagnosis of a highly undifferentiated brain tumour--a case report and review of the literature

Intracranial tumours, often presenting with progressive hydrocephalus, are rare congenital diseases accounting for 0.5-1.5 per cent of all cases of brain tumours diagnosed during childhood. The differential diagnosis includes vascular malformations, infarctions, and haemorrhages. Sonographic signs suggestive of glioblastoma, teratoma, and astrocytoma do not establish the histological diagnosis, however. We report a case of an undifferentiated fetal glioma detected at 29 weeks' gestation. The diagnosis of an undifferentiated brain tumour was suspected by sonography because of the lack of normal brain structures in conjunction with a diffuse echogenic central lesion and an external hydrocephalus. Because of the very poor prognosis, we induced labour by intravaginal and intravenous administration of prostaglandin E2 and achieved the vaginal delivery of a stillborn child whose head circumference corresponded to 38 weeks of pregnancy. Histological and immunochemical features of this undifferentiated congenital glioma (glioblastoma) are presented.

Interhemispheric lipoma with variable callosal dysgenesis: relationship between embryology, morphology, and symptomatology

Eight interhemispheric lipomas (five tubulonodular lipomas and three curvilinear lipomas) were examined by magnetic resonance imaging (MRI). The purpose was to further investigate the relationship between the morphology of the different subtypes and the clinical presentation. The imaging findings were reviewed in light of a recent theory on the development of the corpus callosum. Interhemispheric lipomas should be considered as one entity with a variable expression depending on the severity and/or the time of the insult. Curvilinear lipomas can be either small or extensive and are usually not symptomatic. Tubulonodular lipomas can be either predominantly anterior or posterior in location. The anterior subtype appears to be a more severe form of tubulonodular lipoma. The associated structural abnormalities are most likely responsible for the symptoms, rather than the lipoma itself. Magnetic resonance imaging allows a more precise timing of the insult, resulting in the development of a lipoma. The knowledge of the embryology between the 6th and the 20th week is important to explain these abnormalities. Until now it has been accepted that the corpus callosum develops in an orderly fashion. A recent theory has demonstrated that this is not necessarily true, and that fibers can cross the midline at any place irrespective of the normal development. This theory explains the sometimes amorphous appearance of the remnant of the corpus callosum if a lipoma is present.

So-called intracranial germ cell tumours: are they really of germ cell origin?

We have studied 139 cases of intracranial germ cell tumours up to the beginning of 1993, 63.3% of which showed monotypic histological patterns and 36.7% were shown to be mixed tumours. All these cases underwent surgery followed by radiation and/or chemotherapy. All cases of choriocarcinoma died within 2 years. Cases of yolk sac tumour (endodermal sinus tumour) and embryonal carcinoma also showed poor results. Mature teratoma had a 5-year survival rate (5 YSR) and 10-year survival rate (10 YSR) of 92.9% each. Immature teratoma and malignant teratoma showed a 5-YSR and 10-YSR of 75.0% each. Germinoma showed a 5-YSR of 94.7% and a 10-YSR of 91.2%. All these results may bring into question the validity of the germ cell theory, since germinoma, which should be the most undifferentiated according to the theory, was the most benign and choriocarcinoma and yolk sac tumour (endodermal sinus tumour) which should be the most differentiated, were the most malignant in the follow-up study. Therefore, germ cell tumours may not originate from one single type of cells (primordial germs cells), except for germinoma. The embryonic cells of various stages of embryogenesis may perhaps be misplaced in the bilaminar embryonic disc and become involved in the stream of lateral mesoderm at the time of the primitive streak formation and be carried to the future cranial area to be wrongly enfolded into the brain at the time of the neural tube formation. The following law may be propounded: Tumours composed of cells resembling the cells appearing in the earlier stages of embryogenesis (ontogenesis) are more malignant than those resembling the cells appearing in the later stages of embryogenesis (ontogenesis).

Tumor induction by ras and myc oncogenes in fetal and neonatal brain: modulating effects of developmental stage and retroviral dose

Introduction into fetal rat brain cells of a replication-defective retroviral vector harboring v-Ha-ras and v-gag-myc rapidly causes the induction of highly malignant undifferentiated neuroectodermal tumors following transplantation into the brains of syngeneic hosts [Wiestler, et al. (1992) Cancer Res. 52: 3760-3767]. In the present study, we have investigated the modulating effect of the developmental stage of neural target cells and of the dose of the retroviral vector used in the grafting experiments. Exposure of fetal cells from embryonic day (E)12 or E14 produced a 100% incidence of malignant neuroectodermal tumors which led to the death of recipient animals after a median latency period of 32 days. A 100-fold reduction of the virus dose from 2.062 x 10(6) to 2.062 x 10(4) focus-forming units/ml resulted in a lower tumor incidence of 25%. Of six neural grafts exposed to v-Ha-ras and v-myc at E16, only one showed evidence of tumorigenesis (low-grade astrocytoma and hemangioma). All other transplants were morphologically normal for observation periods of 26 weeks, indicating a marked loss of transforming activity of ras and myc in more advanced stages of brain development. In retrovirus-exposed donor cells which caused the development of neural tumors in recipient rats, malignant transformation was also evident during culture in vitro, usually after 9-12 days. Oncogene complementation was also studied in the newborn rat brain. After microinjection of the retroviral vector into the brain at postnatal day (P)0, P1 and P3, 5 out of 20 animals (25%) developed a total of seven brain tumors. Histopathologically, three of these neoplasms were malignant neuroectodermal tumors which, in contrast to those induced in fetal brain transplants showed evidence of focal glial and/or neuronal differentiation. In addition, we observed one oligodendroglioma, two hemangiomas and a malignant hemangioendothelioma. These data indicate that neural precursor cells and endothelia of the rat brain represent the major target cells for the complementary action of ras and myc and that the use of target cells from later developmental stages (E16 and postnatal) leads to the induction of both primitive and more differentiated neoplasms.

Prenatal ultrasound diagnosis of an intracranial teratoma influencing management: case report and review of the literature

Of seventeen cases of prenatally diagnosed intracranial teratomas, fourteen babies were delivered through a cesarean section. All children died before or shortly after delivery. In this report another case is presented of ultrasound diagnosis of an intracranial teratoma. The teratoma filled the whole fetal cranium, and eroded through the skull base into the left maxillary region. In full agreement with the wishes of the parents, conservative management resulted in the spontaneous vaginal delivery of a fetus that died during labor as a result of brain compression and acidosis during the second stage. In contrast with other cases in the literature, no encephalocentesis was performed. In order to minimize maternal morbidity, it is advised to induce or accept labor as soon as the diagnosis is clear and to pursue a vaginal delivery.

Twin fetuses with abnormalities that overlap with three midline malformation complexes

Twin fetuses aborted at an estimated gestational age of 145 days were concordant for oral, facial, skeletal, and central nervous system malformations. The twins were discordant for other anomalies including cardiac defects, polydactyly, and malrotated short bowel. The combination of malformations observed overlaps with that of the oral-facial-digital syndrome, hydrolethalus syndrome, and Pallister-Hall syndrome. The problem of phenotypic overlap between these syndromes is discussed.

Central nervous system germinomas. A review

The germinoma represents a less malignant form of germ cell tumor. Depending on the individual's age, this neoplasm constitutes approximately 0.1% to 3.4% of all intracranial tumors. The embryologic origin remains a mystery; however, current theories implicate an aberration in primordial germ cell migration. Clinical presentation depends on tumor location and may involve endocrine, hypothalamic, visual, and cognitive dysfunction. In evaluating midline intracerebral masses, it is imperative that one be aware of the various radiologic appearances, endocrinologic changes, and chemical markers that help to distinguish germinomas from other neoplasms that appear in the pineal, suprasellar, and periventricular regions. Only through the careful evaluation of all available studies can the physician institute appropriate therapies such as biopsy, radiation, and chemotherapy. This article focuses on the epidemiology, embryology, clinical presentation, means of diagnosis, treatment, and outcome of this rare neoplasm.

Modifying factors in prenatal carcinogenesis (review)

A description of the experimental approaches devised to control the growth of tumors induced by transplacental exposure to carcinogens is given. Due to the massive cell proliferation and differentiation taking place during embryogenesis, fetal tissues are believed to be privileged targets of neoplastic changes. As a consequence, trace amounts of environmental carcinogens capable of accumulating into the conceptuses may determine the appearance of tumors in the offspring, a possibility documented in several animal species including humans. Endogenous and exogenous factors counteracting this process have potential application as regulators of developmental carcinogenesis. Their identification is regarded as a means to chemoprevent pediatric tumors and can be instrumental in the analysis of the aetiopathogenesis of neoplastic phenotypes.

Intracranial malignant teratoma diagnosed in a fetus--case report

The authors describe a case of intracranial malignant teratoma in a 28-week fetus, discovered on assessment of the mother's excessive abdominal enlargement. Alpha-fetoprotein levels in amniotic fluid and serum were high. Ultrasonography revealed a large, solid intracranial mass. The fetus was viable until completion of a cesarean delivery, at which time the heart stopped. At autopsy, the fetal brain was found to have been extensively replaced by a solid, cystic tumor, which proved to be a malignant teratoma comprising elements of all three germ cell layers. The authors' experience and review of the reported cases indicate that prenatal malignant intracranial teratoma can be safely and accurately diagnosed, and that immediate delivery or cranial decompression may be advisable when the diagnosis is established. The usefulness and limitations of ultrasonography are particularly emphasized.

Cerebral venous angiomas: MR findings

Seven patients with suspected cerebral venous angioma studied by either CT or angiography were imaged with magnetic resonance. Six of seven cases demonstrated a stellate appearance on contrast enhanced CT. In two patients this finding was verified by angiography. Flow void was identified on both T1- and T2-weighted pulse sequences. In one patient a field echo sequence demonstrated high intensity signal within the venous angioma. Magnetic resonance proved superior to CT in the identification of these lesions. A stellate configuration with an emanating transcortical vein and centrifugal drainage (transcortical venous flow) from the angioma into a sinus was present in all cases. Centripetal drainage via thalamostriate and internal cerebral veins was not seen. There was no evidence of mass effect, scar, or hemorrhage. Four of the angiomas were located in a frontal lobe and three in a cerebellar hemisphere. This distribution of the lesions is similar to that reported in the literature in which the frontal lobe is the most common location followed by the cerebellar hemisphere. An embryological explanation is cited and supported by a review of the literature.

Dysontogenetic brain tumours--proposal for an improved classification

The International World Health Organisation (WHO) classification of central nervous system tumours does not give an extensive classification of germ cell tumours and other malformative tumours and tumour-like lesions. In the same way, no consistent classification of dysontogenetic brain tumours can be found in the classical handbooks. For an eventual new edition of the WHO classification, it is proposed to reconsider and improve the classification of these tumours, based on their ontogenetic relations.

Ultrasonic diagnosis of intracranial teratoma in utero. A case report and literature review

Intracranial teratoma was detected ultrasonically in utero. The infant died before term. Neonatal mortality seems to be inevitable with this condition. It is important to distinguish this entity from hydrocephalus, which is recognized more frequently.

Two massive congenital intracranial immature teratomas with neck extension

In this report we detail two congenital intracranial immature teratomas, noteworthy for their massive intracranial growth and extension through the skull with compromise of neck structures. Cytogenetic studies were done in both cases on the fetuses and their tumors and are the first in the literature. Few previously reported congenital intracranial teratomas have been described with neck extension. In both cases, polyhydramnios was detected by prenatal ultrasonography and was possibly caused by the laryngoesophageal and/or brainstem distortion by neoplasm. Possible reasons for such excessive, unchecked growth of teratomas in the fetal period are discussed.

The association of extracranial and intracranial vascular malformations in children

This review is an attempt to relate the types of angiomas and other cutaneous vascular lesions appearing in the face with abnormalities in the formation of cerebral vessels including arteries at their origin, veins and venous sinuses, and with other less constant alterations that affect other organs, particularly the heart and cerebellum. After angiographic study of a series of patients exhibiting diverse types of vascular nevi (capillary and cavernous hemangiomas, nevus flammeus, and lymphangiomas), a correlation was established for each type of dermal nevus with a corresponding group of intracranial vascular anomalies. An explanation of these malformations based on the embryological development of the principal cerebral vessels during the 7th and 8th weeks of gestation is offered. Involvement of the facial and scalp dermatome innervated by the first sensory trigeminal branch correlates most consistently with the presence of abnormal cerebral vessels. The capillary hemangioma occurs preferentially in girls and frequently is associated with developmental anomalies of major cerebral arteries characterised by the absence of some adult vessels and the persistence of others that should have disappeared during embryogenesis such as the fetal trigeminal artery. The complete angiographic exploration of the cerebral vessels from their origin in the aortic arch to the phase of intracranial venous evacuation may reveal unexpected important findings, and is recommended for children with major facial vascular nevi, even if they are neurologically asymptomatic.

Meckel's cave epidermoid with trigeminal neuralgia: CT findings

An epidermoid tumor of Meckel's cave was found in a middle-aged woman with trigeminal neuralgia. On CT the lesion had negative attenuation numbers of fat and extended from an expanded Meckel's cave through the porous trigeminus into the ambient and cerebellopontine angle cisterns. Surgical excision provided relief of the patient's trigeminal neuralgia.

Cerebral medulloepithelioma with bone, cartilage, and striated muscle. Light microscopic and immunohistochemical study

A two-and-a-half-year-old girl had a cerebral medulloepithelioma with histologic evidence of ependymal, astroglial, oligodendroglial, and neuroblastic differentiation, as well as islands of cartilage and bone, and a microscopic focus of striated rhabdomyoblasts. Immunohistochemical staining for glial fibrillary acidic protein and S-100 protein with the peroxidase-antiperoxidase technique revealed positive staining in the various differentiating neural elements of the tumor. Mesectodermal differentiation, or the production by neuroectoderm of tissues usually considered to be mesodermal, is being increasingly recognized in the fields of embryology and tissue culture. Although this is the likely explanation for the composition of this tumor, other possibilities are considered as well.

The developmental potential of a euploid male teratocarcinoma cell line after blastocyst injection

A karyotypically normal male embryonal carcinoma (EC) cell line, P19, produced large numbers of chimaeras in midgestation after groups of cells were injected into mouse blastocysts. A wide variety of apparently normal tissues were colonized by the EC cells but most chimaeras were also morphologically abnormal. Few live chimaeras were produced and all contained tumours of EC cell origin as well as EC contributions to normal tissues. This apparently incomplete regulation of the EC cells by the embryonic environment was not due to EC cell variation, since a clonal subline. P19S18, produced similar patterns of colonization. It was also not caused by the inability of the blastocyst to regulate large numbers of injected EC cells, since a single P19S18 cell could contribute to both normal and tumour tissue in the same mouse. Neither a high rate of colonization of the embryo nor a normal karyotype is, therefore, sufficient to ensure reversion of EC cells to normal embryonic behaviour.

Cytotoxic effects of ethylnitrosourea on central nervous system of rat embryos. Special references to carcinogenesis and teratogenesis

For the purpose of observing the cytotoxic effect of N-ethyl, N-nitrosourea (ENU), a potent carcinogen on the central nervous system (CNS) at the late period of organogenesis, the embryonal telencephalic wall was hourly examined under the light and electron microscopes. Pregnant rats on the 13th day and 15th day of gestation were given either a single intravenous injection of 40 or 80 mg/kg, of ENU. The cytotoxic effect on the embryo treated on the 15th day of gestation was severer than that treated on the 13th day of gestation. The common pathological changes in both treated groups are; (1) mitotic arrest 1 hour after administration in the most inner zone of the ventricular layer, (2) degeneration and necrosis accurred predominantly in the so-called DNA synthetic zone and resulting in cell loss of the ventricular layer, (3) elimination of degenerating products; and (4) tissue repair. The findings mentioned may indicate a cytotoxic effect inducing microencephalia, and furthermore, the teratogenic and carcinogenic mechanisms are discussed.

[Giant connatal glioma (author's transl)]

A clinico-neuropathological report is given on a four months old girl with head enlargement first recognized at the age of four weeks. A giant intracranial tumor was found at autopsy, which was histologically an isomorphous, largely pilocytic astrocytoma without morphological features suggesting rapid growth. This connatal astrocytoma seems unique in size, suggesting tumor formation already during very early embryonal development.

Cranial computed tomography of epidermoid and congenital fatty tumors of maldevelopmental origin

The computed tomographic and clinical findings in 17 patients with fatty intracranial tumors and in 10 patients with epidermoid tumors, all of maldevelopmental origin, are presented. Fat was found in lipomas (the most frequent), dermoids, and teratomas. Differentiation between these tumors is discussed on the basis of density, calcification, location, and symptomatology.

[Organ cultures of embryonal rat brain tissue (hippocampal area) in a study of the transplacental effect of nitrosoethylurea]

The transplacental action of nitrosoethylurea (NEU) was studied in organic cultures of the embryonic rat brain tissue (the hyppocampus region). The brain tissue proved to be highly sensitive to NEU. This was expressed in a greater survival of the experimental cultures in comparison with the control and in the appearance of epithelial proliferations of the vascular plexus resembling, in individual cases, adenomas. The amount of morphological changes observed in the experiment depended on the carcinogen dose.