Desmoplastic cerebral astrocytomas of infancy: a histopathologic, immunohistochemical, ultrastructural, and molecular genetic study

Desmoplastic infantile astrocytoma and ganglioglioma: a series of 12 patients treated at a single institution

BACKGROUND

Desmoplastic infantile astrocytomas and gangliogliomas (DIA/DIG) usually present with a large size, large cystic component, large dural implant, encasement of big vessels, clinical presentation within 18 months of life, high incidence of seizures and overall good prognosis, even if tumour surgery can be very challenging at first procedure.

METHODS

We retrospectively reviewed clinical and radiological data of patients diagnosed with desmoplastic infantile tumours who were surgically treated between 2008 and 2019.

RESULTS

The series included 12 patients. The median age at surgery was 91 days. The average tumour volume was 212 cm³. Cystic components were predominant ranging from 0 to 295 cm³. Active hydrocephalus was pre-operatively evident in 5 cases. Eight patients (66.6%) received total or subtotal removal, three of them (25%) underwent partial removal, and one patient (8.3%) received a biopsy. One patient died within 24 h after surgery due to severe hypotension, as a consequence of significant intraoperative blood loss. Overall, seven (58.3%) patients were reoperated on the tumour after the first procedure: 4 patients were operated twice; 3 patients were operated 3 times. Two patients presented remote localizations and underwent chemotherapy. At last follow-up, 7 patients were tumour-free, 2 are alive with stable disease, and 2 are alive with progressive disease (leptomeningeal seeding).

CONCLUSION

Desmoplastic infantile tumours are rare giant neonatal tumours. Total removal is the goal of treatment, but prognosis remains good even if total removal is not achieved. In case of tumour progression or epilepsy from residual tumour, reoperation is the first option, with chemotherapy reserved to unresectable or disseminated cases with mixed results, while, to date, radiotherapy still plays no role.

Desmoplastic Infantile Ganglioglioma/Astrocytoma (DIG/DIA) Are Distinct Entities with Frequent BRAFV600 Mutations

Desmoplastic infantile ganglioglioma (DIG) and desmoplastic infantile astrocytoma (DIA) are extremely rare tumors that typically arise in infancy; however, these entities have not been well characterized in terms of genetic alterations or clinical outcomes. Here, through a multi-institutional collaboration, the largest cohort of DIG/DIA to date is examined using advanced laboratory and data processing techniques. Targeted DNA exome sequencing and DNA methylation profiling were performed on tumor specimens obtained from different patients (n = 8) diagnosed histologically as DIG/DIGA. Two of these cases clustered with other tumor entities, and were excluded from analysis. The remaining 16 cases were confirmed to be DIG/DIA by histology and by DNA methylation profiling. Somatic BRAF gene mutations were discovered in 7 instances (43.8%); 4 were BRAFV600E mutations, and 3 were BRAFV600D mutations. Three instances of malignant transformation were found, and sequencing of the recurrence demonstrated a new TP53 mutation in one case, new ATRX deletion in one case, and in the third case, the original tumor harbored an EML4-ALK fusion, also present at recurrence. DIG/DIA are distinct pathologic entities that frequently harbor BRAFV600 mutations. Complete surgical resection is the ideal treatment, and overall prognosis is excellent. While, the small sample size and incomplete surgical records limit a definitive conclusion about the risk of tumor recurrence, the risk appears quite low. In rare cases with wild-type BRAF, malignant progression can be observed, frequently with the acquisition of other genetic alterations.Implications: DIG/DIA are a distinct molecular entity, with a subset frequently harboring either BRAF V600E or BRAF V600D mutations. Mol Cancer Res; 16(10); 1491-8. ©2018 AACR.

A Rare Tumor in Childhood Desmoplastic Infantile Astrocytoma: Two Case Reports

Desmoplastic infantile astrocytomas (DIAs), are rare supratentorial tumors, usually observed in the first 24 months of life. Despite their aggressive appearance, they tend to follow a favorable clinical course. Total or near total resection of tumor is usually the treatment option. Desmoplastic Infantile Ganglioglioma (DIG) and DIA are WHO grade I tumors that have similar clinical and morphological findings. The only criterion in differential diagnosis is the neural component of DIG. These tumors both have dense fibroblastic stroma and positive staining with glial fibrillar acidic protein (GFAP) and CD34.

A rare case of desmoplastic infantile astrocytoma presenting with right side partial seizures presented in a 1-year-old child.

A rare case of desmoplastic infantile astrocytoma presenting with focal onset generalized seizures presented in a 1-year-old child.

Despite their radiological and histological properties, these tumors have a benign course. After 3-year follow-up for the first case and 1-year follow-up for the second case, there was no recurrence.

Histologic classification of gliomas

Gliomas form a heterogeneous group of tumors of the central nervous system (CNS) and are traditionally classified based on histologic type and malignancy grade. Most gliomas, the diffuse gliomas, show extensive infiltration in the CNS parenchyma. Diffuse gliomas can be further typed as astrocytic, oligodendroglial, or rare mixed oligodendroglial-astrocytic of World Health Organization (WHO) grade II (low grade), III (anaplastic), or IV (glioblastoma). Other gliomas generally have a more circumscribed growth pattern, with pilocytic astrocytomas (WHO grade I) and ependymal tumors (WHO grade I, II, or III) as the most frequent representatives. This chapter provides an overview of the histology of all glial neoplasms listed in the WHO 2016 classification, including the less frequent "nondiffuse" gliomas and mixed neuronal-glial tumors. For multiple decades the histologic diagnosis of these tumors formed a useful basis for assessment of prognosis and therapeutic management. However, it is now fully clear that information on the molecular underpinnings often allows for a more robust classification of (glial) neoplasms. Indeed, in the WHO 2016 classification, histologic and molecular findings are integrated in the definition of several gliomas. As such, this chapter and Chapter 6 are highly interrelated and neither should be considered in isolation.

Desmoplastic astrocytoma: new insights into its clinical profile, diagnosis, and treatment

BACKGROUND

Desmoplastic astrocytoma (DA) is a rare intracranial tumor which usually affects pediatric patients. The aim of this study is to describe the clinical features and management of DA based on a joint analysis of the cases reported in the scientific literature.

MATERIAL AND METHODS

A thorough review was carried out, gathering those pathologically proven DAs reported since the first description of this entity. Two new own cases were included in order to illustrate this review. Epidemiological, clinical, radiological, therapeutic, and follow-up data were analyzed with the software SPSS version 20.

RESULTS

A total of 52 DAs were recorded. Most cases occurred in the first 2 years of life, although older patients were also reported. Patients mainly presented symptoms and signs of elevated intracranial pressure. According to their radiological features, we were able to classify DAs in four main groups, with distinct differential diagnosis and prognosis. After treatment, 14.2 % of patients presented persistent neurological impairment and the mortality rate was close to 10 %.

CONCLUSION

DAs can be diagnosed at any age from birth to adolescence. These neoplasms can show up a wider range of radiological morphologies than previously thought. Surgery represents the treatment of choice for DAs, although chemotherapy can also be useful in the setting of recurrence or progression of the disease. Those DAs lacking classic radiological features, especially type 4 tumors, were linked with a poorer clinical outcome.

Gliofibroma: Report of Four Cases and Review of the Literature

Gliofibroma is a relatively rare variant of a mixed glial-fibrous tumor more frequent in children than in adults. It has been reported to appear all along the neuraxis, with predilection for the midline. Its evolution is usually benign, although few examples have shown either multiple sites of involvement or leptomeningeal dissemination. Some authors regard it as part of the desmoplastic astrocytoma spectrum. We report here four examples of this rare condition which exemplify its histological patterns and biological behavior, and provide a review of the literature. Even though this tumor is commonly regarded as heterogeneous and with variable course, our literature review points to a set of clinical and pathological traits that are constant, such as age, location and gross and histological characteristics, as well as a predictable evolution. Currently, this tumor is not included in the WHO Classification of CNS tumors.

Perinatal (fetal and neonatal) astrocytoma: a review

INTRODUCTION

The purpose of this review is to document the various types of astrocytoma that occur in the fetus and neonate, their locations, initial findings, pathology, and outcome. Data are presented that show which patients are likely to survive or benefit from treatment compared with those who are unlikely to respond.

MATERIALS AND METHODS

One hundred one fetal and neonatal tumors were collected from the literature for study.

RESULTS

Macrocephaly and an intracranial mass were the most common initial findings. Overall, hydrocephalus and intracranial hemorrhage were next. Glioblastoma (GBM) was the most common neoplasm followed in order by subependymal giant cell astrocytoma (SEGA), low-grade astrocytoma, anaplastic astrocytoma, and desmoplastic infantile astrocytoma (DIA). Tumors were detected most often toward the end of the third trimester of pregnancy.

CONCLUSION

A number of patients were considered inoperable since their tumor occupied much of the intracranial cavity involving large areas of the brain. High-grade astrocytomas were more common than low-grade ones in this review. Fetuses and neonates with astrocytoma have a mixed prognosis ranging from as low as 20 % (GBM) to a high of 90 %. The overall survival was 47/101 or 46 %.

Radiological features of infantile glioblastoma and desmoplastic infantile tumors: British Columbia's Children's Hospital experience

OBJECT Two of the more common infantile brain tumors, glioblastoma multiforme (GBM) and desmoplastic infantile tumors (DITs), can be difficult to distinguish on MRI. Both tumors occur in the supratentorial compartment and both have solid and cystic components. Differentiating between the 2 on MRI studies could assist the surgeon in discussions with family and child management. The authors report on their institutional experience with both tumors, focusing on radio-graphic features, especially the diffusion studies, which might be useful in distinguishing between infantile GBM and DIT. METHODS A retrospective review was undertaken of all infantile brain tumors treated at British Columbia's Children's Hospital between 1982 and 2012, and cases of GBM and DIT were recorded. Only cases that had imaging were included in the study. A literature review was completed to identify reported cases of infantile GBM and DIT. Only reports that described or included radiological studies (particularly MRI) of the tumors were included. Certain radiographic features of the tumors were reviewed, including location, size, consistency, pattern of enhancement, and features on MR diffusion studies. RESULTS Of 70 cases of infantile brain tumors, 2 GBM cases and 3 DIT cases (all 3 of which were desmoplastic infantile gangliogliomas [DIGs]) met the inclusion criteria. The radiological studies obtained in all 5 cases were reviewed by a neuroradiologist. All 5 patients had supratentorial tumors with cystic-solid consistency. Diffusion MRI studies showed restricted diffusion in the 2 GBM cases, but no evidence of restricted diffusion in the DIG tumors. The GBM tumors were heterogeneously enhancing, and the DIG tumors showed avid and homogeneous enhancement. The literature review revealed 29 cases of infantile GBM and 32 cases of DIG/DIT that met the inclusion criteria. The tumors were large in both groups. The tumors were cystic-solid in consistency in 10 of 30 (33%) of GBM cases and 28 of 32 (87.5%) of DIT cases. The contrast enhancement was heterogeneous in 9 of 30 (30%) GBM cases, and it was homogeneous and avid in 27 of 32 (84%) of DIT cases. Diffusion studies were recorded in 2 published infantile GBM cases, and in both of them diffusion was restricted. The authors only found 1 report that discussed DIG tumor features on MR diffusion studies, but the interpretation was difficult and unclear. CONCLUSIONS Magnetic resonance imaging, especially diffusion-weighted imaging, may be a useful aid in distinguishing between infantile GBM and DIT tumors, with infantile GBM demonstrating restricted diffusion.

BRAF V600E expression and distribution in desmoplastic infantile astrocytoma/ganglioglioma

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Genome-wide DNA copy number analysis of desmoplastic infantile astrocytomas and desmoplastic infantile gangliogliomas

Little is known about the molecular features of desmoplastic infantile ganglioglioma (DIG) and desmoplastic infantile astrocytoma (DIA). We performed a genome-wide DNA copy number analysis in combination with a multiplex ligation-dependent probe amplification-based analysis of copy number changes of candidate genes in 4 DIAs and 10 DIGs. Molecular inversion probe (MIP) assay showed that large chromosomal alterations were rare among DIG and DIA. Focal recurrent genomic losses were observed in chromosome regions such as 5q13.3, 21q22.11, and 10q21.3 in both DIA and DIG. Principal component analysis did not show any significant differences between the molecular profiles of DIG and DIA, and a hierarchical cluster analysis did not clearly separate the 2 tumor groups according to their molecular profiles. In 6 cases, gain of genomic material at 7q31 (corresponding to MET gene) was found in multiplex ligation-dependent probe amplification (MLPA) analysis. Furthermore, two cases showed gain at 4q12, and a single case showed BRAF mutation. In agreement with previous analyses, this study demonstrates the absence of consistent recurrent chromosomal alterations in DIA and DIG and overall rarity of the BRAF mutation in these tumors. Notably, these results suggest that DIA and DIG represent a histologic spectrum of the same tumor rather than 2 separate entities.

Combined fontanelle puncture and surgical operation in treatment of desmoplastic infantile astrocytoma: case report and a review of the literature

Desmoplastic infantile astrocytoma is a rare low-grade malignant brain tumor found in infants. Its pathological diagnosis can be made on the basis of its histological characteristics and immunohistochemical staining. A case of desmoplastic infantile astrocytoma, including its clinical manifestations, pathological characteristics, differential diagnosis, treatment, and prognosis, is reported. Presurgical percutaneous decompression and subsequent resection resulted in a satisfactory therapeutic outcome.

Multifocal desmoplastic noninfantile astrocytoma

This is a report of a case of multifocal desmoplastic astrocytoma in an 11-year-old child in which we describe the MRI findings and discuss the possible mechanism of its development. The MRI appearances in our case support the view that the tumor is primarily of leptomeningeal or superficial cortical origin, with cystic formation secondary to entrapment of cerebrospinal fluid. The question of whether or not the lesions are metastases or metachronous lesions is also discussed. Desmoplastic astrocytoma at a noninfantile age is extremely rare: only four cases have been reported in the literature so far. Even more unusual is the presence of this lesion in multiple locations at the initial presentation.

Desmoplastic infantile astrocytoma and characteristics of the accompanying cyst. Case report

A desmoplastic infantile astrocytoma (DIA) is an extremely rare tumor that comprises a solid astrocytic tumor accompanied by a large cyst and involves the superficial cerebral cortex and leptomeninges in infants. The solid part of this type of tumor has been well described in various reports and books, but characteristics of the cystic portion have remained unclear. Because adequate resection is required to ensure a favorable prognosis, information about the cyst is very important for diagnostic purposes and surgical planning. The authors report on the clinical and histological features of the cyst in a case of a DIA. A 12-month-old boy presented with vomiting. Contrast-enhanced magnetic resonance imaging revealed a strongly enhancing single-lobed large cyst located in the deep white matter, under the solid part of the tumor attached to the dura mater of the left frontal lobe. Both the solid and cystic portions of the tumor were surgically removed. The border between the cyst wall and surrounding white matter was unclear. Histologically, the cyst wall was composed of gliosis representing a rough accumulation of reactive astrocytes, lymphocytes, and small capillary vessels in edematous parenchyma, but no tumor cells. The present case and previous reports suggest that the cyst does not contain tumor cells, even if strongly depicted on contrast-enhanced neuroimaging, and that a thickly enhancing cyst wall indicates gliosis with accumulation of numerous small vessels.

Desmoplastic infantile ganglioglioma with a malignant course

Desmoplastic infantile gangliogliomas (DIGs) are rare supratentorial tumors that arise in infancy. Despite the large size of these lesions, the prognosis is generally considered favorable after gross-total resection (GTR); however, in incidental cases tumor progression has been described. The authors report on a child harboring a DIG with a high-grade primitive cell population and glial differentiation. The progressive clinical course was determined by this cell component in spite of GTR and adjuvant chemotherapy. The significance of the presence of a high-grade primitive tumor component in the context of DIG is discussed.

Desmoplastic infantile ganglioglioma with calcification

Desmoplastic infantile gangliogliomas (DIGs) are rare intracranial, cystic tumors, usually detected within the first 2 years of life. Histologically, these tumors are characterized by intense desmoplasia and a divergent astrocytic and neuronal differentiation. Less than 60 well-documented cases of this extremely rare tumor are reported in the literature. We present the case of a 10-month-old male child presenting with a large, cystic, intracranial lesion and having the characteristic histological features of a DIG. In addition, the lesion also showed focal areas of calcification within the tumor, not usually considered a feature of this entity. The present case extends the reported spectrum of this rare entity and describes the unusual occurrence of calcification within the lesion.

Cerebellar gliofibroma with numerous psammoma bodies

A case of psammoma body rich gliofibroma is reported. Computed tomography (CT) showed a high-density mass without contrast enhancement in the right cerebellar hemisphere. Magnetic resonance images (MRI) demonstrated a mass with a mixture of high- and iso-intensity regions without meningeal attachment on both T1- and T2-weighted images. Pathological examinations revealed a biphasic pattern consisting of tumor cells in sparce cellularity and dense fibrous connective tissue. Numerous psammoma bodies of uniform size were found in the stroma. The tumor cells expressed glial fibrillary acidic protein and S-100, but not p53, vimentin and EMA. This is the first report describing a case of psammomatous gliofibroma.

Intracranial gliofibroma mimicking a meningioma: a case report and review of literature

Gliofibromas are rare glio-mesenchymal tumors composed of astrocytic and benign mesenchymal components, which commonly occur in the first two decades of life. They are not listed as a distinct entity in the current WHO classification of CNS tumors. Their biological behaviour is unknown, and histogenesis is debatable. We describe a case of histopathologically proven gliofibroma in the region of the left quadrigeminal plate in a 15-year-old child that mimicked a tentorial meningioma both at imaging and surgery. Post-operatively, the residual tumor regrew to a size similar to the initial mass (4 cm x 3.6 cm x 3.5 cm), within one and a half years after the first surgery. The histopathology of the tumor was similar on both occasions. Although a poor prognosis has been characteristically noted in gliofibromas with high-grade glial component, but the present case had recurrence despite being of low-grade, thus highlighting the uncertain behaviour of this rare tumor.

A Report of a Desmoplastic Ganglioglioma in a 12-year-old Girl with Review of the Literature

Desmoplastic infantile ganglioglioma is a supratentorial tumor that typically occurs in infants below the age of 24 months. Rare tumors with the same radiological and histological characteristics have been described in older subjects. We report a case of desmoplastic ganglioglioma in a 12-year-old girl with a 13 years follow-up. The patient presented with an inaugural generalized seizure. CT scan demonstrated a large superficial parieto-occipital mass, attached to the dura with solid and cystic components. Surgical resection was macroscopically complete. No adjuvant treatment was given. Thirteen years after surgery, the patient is symptom free. Histological examination revealed a pleomorphic tumor involving the meningeal space and the cortex. Meningeal portion was made of neoplastic astrocytes enmeshed in a dense network of connective tissue. The cortical component showed abnormal neurons, tumoral astrocytes and small foci of poorly differentiated cells with rare mitoses. Our observation and the seven others found in the literature indicate that desmoplastic gangliogliomas can occur in children and even in young adults. Despite some worrisome radiological and histological features, these tumors should not be misdiagnosed as malignant glioma. Like infantile cases, non-infantile desmoplastic gangliogliomas seem to have a favorable prognosis without additional therapy, if a total surgical resection can be performed.

Carboplatinum and vincristine chemotherapy for central nervous system gliofibroma: case report and review of the literature

Gliofibromas are bimorphic tumors of the central nervous system. Although they are composed of astrocytic and fibroblastic elements, their histogenesis is not clear. An attempt has been made to classify the tumors as low- or high-grade based on morphology and proliferative labeling index, but the clinical behavior and the optimal therapeutic strategies remain unknown. Although they are considered benign, the authors' review shows a 23% mortality rate. The authors report the successful use of carboplatinum and vincristine as treatment of this disease.

Therapeutic strategies and management of desmoplastic infantile ganglioglioma: two case reports and literature overview

INTRODUCTION

Desmoplastic infantile gangliogliomas (DIG) are rare cerebral glioneural tumors usually occurring in early childhood. DIGs are generally benign although rare cases with poor outcome are known. Total resection, if possible, is the treatment of choice, without further adjuvant therapy. After incomplete resection, adjuvant chemo-and/or radiotherapy is generally applied, despite the potential negative side effects in such young patients.

CASE REPORTS

We describe two girls with DIG, one who twice underwent subtotal resection at 3 and 5 months, the other who underwent total resection at 2 years. Neither had adjuvant therapy and there was no tumor recurrence.

CONCLUSIONS

Our own experience and a review of the literature suggest that in most DIGs adjuvant therapy is not justified even after incomplete resection. After tumor recurrence a second surgical intervention should be considered instead of adjuvant therapy. An exception may be made for rare, deep-seated DIGs, which are more aggressive and have a poorer outcome.

I. Perinatal brain tumors: a review of 250 cases

Central nervous system tumors occur considerably less often in the fetus and neonate than in the older child. These tumors are not entirely the same as those found later in life. Their location, biologic behavior, response to therapy, and histologic types are different. Reports of 250 fetal and neonatal brain tumors were collected from the literature and studied for this review. The overall survival rate was 28%. The entire cranial cavity may be filled with tumor, and stillbirth is not uncommon. Macrocephaly was the most frequent presentation regardless of histology. Outcome is related to the size and location of the tumor, the histologic type, surgical resectability, and the condition of the infant at the time of diagnosis. Neonates with choroid plexus papillomas, gangliogliomas, and low-grade astrocytomas have the best prognosis, whereas those with teratomas and primitive neuroectodermal tumors have the worst prognosis.

Good clinical course in infants with desmoplastic cerebral neuroepithelial tumor treated by surgery alone

We investigated why surgery alone provides for a benign clinical course in patients with desmoplastic infantile ganglioglioma and astrocytoma (DIG/A). The clinical course of 4, less than six-month-old girls, surgically treated at our institutions, was evaluated retrospectively. All presented with the clinical symptom of increasing head circumference. CT and MRI scans revealed a solid tumor attached to the dura that was surrounded by large, multiple cysts, in fronto-temporo-parietal lobe. Gross total removal succeeded in all 4 cases because the solid components of the tumor were very firm in contrast to the soft adjacent brain tissue. Microscopically, the surgical specimens consisted almost entirely of dense fibrous connective tissue containing generally elongate cells with inconspicuous cytoplasm. Most of these cells were immunopositive for GFAP. There was no evidence of tumor cells in the cyst wall. In 3 cases, some small neurons were positive for neurofilament immunostain. A high proportion of undifferentiated small cells in a less demoplastic area far from the dura were immunopositive for MIB-1. All of the 4 patients have been free of recurrence for more than five years. In patients with DIG/A, there are 5 reasons for a good clinical course. [1] At surgery, the tumor margin is clearly discernible because of the difference between the solid tumor and the soft adjacent brain tissue. [2] The tumor is located in the superficial cerebral hemisphere. [3] Large, multiple cysts surround the tumor. [4] The growth point appears to be adjacent to the cysts. [5] The cyst walls are free of invading tumor cells.

Desmoplastic cerebral astrocytoma of infancy intermingling with atypical glial cells

Despite the rarity of desmoplastic cerebral astrocytoma of infancy (DCAI), it has distinct clinical and pathological features. The present case is a typical DCAI except for its detection and operational age and intermingling with pleomorphic glial cells. In this case, although a cystic lesion of the right temporal lobe was noticed when the patient was 6 months old, it was not regarded as a tumor and wasn't removed until he was 9 years old. It is quite unusual that a DCAI was able to exist in the cerebrum for 9 years. However, no metastasis occurred and distinct macroscopic and microscopic features of the tumor were not different from typical DCAI except for an intermingling with pleomorphic glial cells. Furthermore, even in the pleomorphic areas, the absence of necrosis and an MIB-1 index of 2.9% indicated non-aggressive growth. These features of the present case may provide additional information as to the character of DCAI, which generally has a favorable prognosis.

Unique desmoplastic cerebral tumor in a patient with complex partial seizures

Primary brain tumors with prominent desmoplasia include the gliofibroma, desmoplastic infantile ganglioglioma (DIG), pleomorphic xanthoastrocytoma (PXA), and desmoplastic cerebral astrocytoma. In the present report, we describe unusual pathological appearances in two successive resections of a left temporal tumor in a patient with complex partial seizures. Both tumors showed focal astroglial and very prominent neuronal differentiation. In the first resection at age 11 years, the tumor showed only focal desmoplastic areas and prominent neuronal differentiation with bizarre atypical giant cells. In the second resection at age 14 years, the morphology was dramatically different. Now the tumor showed marked desmoplasia with tumor cells coexpressing neuronal and glial markers. Electron microscopy showed prominent neuronal differentiation in both resections and presence of basal lamina around tumor cells. Our case represents a unique example of an extraordinary degree of neuronal differentiation in a desmoplastic cerebral tumor. While cellular pleomorphism in a desmoplastic tumor traditionally suggests the diagnosis of PXA, we wish to underscore that many cells exhibiting marked cytologic atypia may in fact be of neuronal rather than of glial origin as in our case.

Molecular changes during the genesis of human gliomas

Neoplastic transformation in the normal human brain occurs as a result of the accumulation of a series of genetic alterations. These genetic alterations include the loss, gain or amplification of different chromosomes which lead to altered expression of proteins that play important roles in the regulation of cell proliferation. Several common genetic alterations at the chromosomal level (loss of 17p, 13q, 9p, 19, 10, 22q, 18q and amplification of 7 and 12q) have been observed. These alterations lead to changes in the expression of several genes; protein 53 (p53), retinoblastoma (RB), interferon (INF) alpha/beta, cyclic AMP dependent kinase number 2 (CDKN2), mutated in multiple advanced cancers 1 (MMAC1), deleted-in-colon carcinoma (DCC), epidermal growth factor receptor (EGFR), platelet derived growth factor (PDGF), platelet derived growth factor receptor (PDGFR), MDM2, GL1, CDK4 and SAS during the genesis and progression of human gliomas. Recent studies suggest that altered expression of several other genes [MET; MYC; transforming growth factor beta (TGF beta); CD44; vascular endothelial growth factor (VEGF); human neurological-related cell adhesion molecule (hNr-CAM); neuroglial cell adhesion molecule (NCAM L1); p21waf1/Cip1; TRKA; mismatch repair genes (MMR); C4-2; D2-2] and proteins [e.g., cathepsins, tenascin, matrix metalloproteases, tissue inhibitors of metalloproteases, nitric oxide synthase, integrins, interleukin-13 receptor (IL-13R), Connexin43, urokinase-type plasminogen activator receptors (uPARs), extracellular matrix proteins and heat shock proteins] are associated with the genesis of human gliomas. Taken together, these findings point to the accumulation of multiple genetic mutations coupled with extensive changes in gene expression in the etiology of human gliomas.

Congenital central nervous system tumors

Congenital central nervous system (CNS) tumors are a rare and diverse group of tumors with variable biological behavior depending on location and histology. This review summarizes the published literature and describes the definition, epidemiology, diagnosis and evaluation, and treatment of congenital central nervous system tumors.

Ultrastructural pathology of glial brain tumors revisited: a review

The ultrastructural pathology of primary brain tumors of glial origin is examined. These are divided into two major groups. The first category comprises astrocytoma with the variants: fibrillary, protoplasmic, gemistocytic, and anaplastic. These are biologically aggressive tumors of a relatively high proliferative potential and include a substantial proportion of cases that transform into the most malignant secondary glioblastoma. The second category, comprised of rather benign tumors of a limited proliferative capacity and a reasonable good prognosis, includes such clinico-pathological entities as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and subependymal giant cell astrocytoma of tuberous sclerosis. There is no ultrastructural feature, however, which makes it possible to discriminate between major subclasses of astrocytes; but secondary glioblastoma cells, while still retaining the stigmata of neoplastic astrocytes, are characterized by nuclei that seem to be more indented, cisterns of the endoplastic reticulum may be distended, and intranuclear pseudoinclusions are frequently observed. Primary glioblastoma, which probably originates de novo, is characterized by poorly differentiated cells with a paucity of subcellular organelles and no obvious features of astrocytic origin. Granular cell tumor also belongs to neoplasms of astrocytic lineage and the hallmark of this entity is a cell characterized by the presence of numerous membrane-bound, electron-dense autophagic vacuoles. Its malignant analogue is the granular cell glioblastoma. Two subtypes of granular cell glioblastoma have been distinguished. The first is characterized by the presence of numerous granular, electron-dense bodies which correspond to autophagic vacuoles. The second type is characterized by numerous electron-dense, amorphous masses within cellular processes. These electron-dense inclusions are virtually indistinguishable from minute Rosenthal fibers. The pilocytic astrocytoma is virtually indistinguishable at the ultrastructural level from fibrillary astrocytomas but cells tend to be more elongated. Besides Rosenthal fibers, two types of distinctive structures are relatively common in pilocytic astrocytomas: eosinophilic hyaline droplets and round granular bodies, which are composed of large aggregates of electron-dense secondary lysosomes or small electron-dense bodies, respectively. Pleomorphic xanthoastrocytoma is characterized by astrocytes surrounded by basal membranes. It belongs to a peculiar category of astrocytic "desmoplastic" brain tumors occurring in younger patients, the common denominator for which is the presence of basal lamina. The last category in this group is subependymal giant cell astrocytoma, a tumor of bivalent (glial and neuronal) differentiation, the cells of which are characterized by the presence of peculiar crystalloids. The hallmark of oligodendroglioma is the presence of concentric arrays of membranes (so-called membrane laminations, whorls, or scrolls). A fragment of the cytoplasm sequestrated within a particular whorl may contain mitochondria, lysosomes, or abundant glycogen granules. Ependymomas are characterized by a florid picture dominated by the presence of microlumina, cilia with basal bodies (blepharoplasts), microvilli, and long, interdigitating intercellular junctions of the zonulae adherentiae type. Ganglioglioma, the last category covered by this review, is a mixed glio-neuronal tumor. While glial cells are indistinguishable from their counterparts encountered elsewhere (mostly pilocytic astrocytes), the ganglion cells are characterized by abundant intracytoplasmic dense-core vesicles, absence of intermediate filaments, and numerous microtubules. Occasionally a close apposition of ganglion cells and Rosenthal fibers is seen. Dense-core vesicles are pleomorphic and ranged in a diameter from small synaptic vesicles to large lysosome-like neurosecretory granules.

Desmoplastic supratentorial neuroepithelial tumours of childhood: imaging in 5 patients

Desmoplastic neuroepithelial tumours are rare supratentorial neoplasms of infancy with a favourable prognosis. We characterised their imaging findings by reviewing the clinical and radiological reports of five affected children. The tumours were massive, predominantly cystic and with preferential frontal and parietal lobe involvement. The cystic component was in the white matter, with no communication with the ventricle. The solid part was superficially, abutting a meningeal surface, and showed intense contrast enhancement. A heterogeneous predominantly solid mass was observed in one patient. Thinning and deformation of the skull adjacent to the tumour was shown in four cases. Peritumoral oedema was absent or moderate. No calcification or haemorrhage were present. Angiography showed a tumour blush from the internal or external carotid arteries in one case each. Follow-up (3 months-9 years, mean 4.5 years) showed no recurrence.

Central nervous system neoplasms: indications for electron microscopy

Diagnostic dilemmas of biopsy specimens in the central nervous system (CNS) tumors are often the result of multiple factors, including fixation artifact, biopsy size, lack of immunohistochemical techniques to distinguish cell types, and unawareness of rare entities. Correct diagnosis and confirmation of diagnosis of primary CNS neoplasms is imperative and may require electron microscopic examination. In some instances, use of electron microscopy may be the only approach for accurate recognition of an entity. Although diagnostic electron microscopy is expensive and cost cutting is encouraged in today's practice of medicine, cost must be weighed against the consequences of even 1 patient developing CNS treatment-related necrosis or a radiation-induced neoplasm secondary to misdiagnosis of a benign entity. This study reviews the ultrastructural differences of three groups of diagnostically difficult CNS lesions: clear cell neoplasms (ependymoma, oligodendroglioma, central neurocytoma), rare entities containing astrocytes invested by a basal lamina (pleomorphic xanthoastrocytoma, the desmoplastic neuroepithelial tumors of infancy), and benign entities characterized by transitional cell forms (subependymoma, subependymal giant cell astrocytoma).

Primary diffuse leptomeningeal gliomatosis with anaplastic features

A case of primary diffuse leptomeningeal gliomatosis with anaplastic features, diagnosed during life and confirmed at autopsy, is presented. The clinical, radiological and pathological features are compared with those of the very few cases reported in the literature. Early papilloedema and hydrocephalus were followed by spinal and cranial nerve palsies. The NMR images and the tissue biopsy turned out to be useful for reaching an in vivo diagnosis. While in the previously reported cases the glial proliferation was microscopically a slow growing astrocytoma, the present case was histologically malignant and had a high labelling index (LIs) for proliferation markers (PCNA and KI-67). The high growth rate and the wide diffusion of the tumour at presentation may account for the poor prognosis of diffuse leptomeningeal gliomatosis and the inefficacy of radiotherapy and chemotherapy. The presence of basal lamina arount tumour cells and the immunohistochemical distribution of the proliferation markers are consistent with the origin of primary leptomeningeal gliomatosis from ectopic glia.

Pleomorphic xanthoastrocytoma with a gangliomatous component: an immunohistochemical and ultrastructural study

We report a case of a 24-year-old woman with left temporal pleomorphic xanthoastrocytoma (PXA) with atypical neuronal cells. Many neoplastic cells, otherwise typical of PXA, expressed glial fibrillary acidic protein, while neuronal cells with marked atypia were immunopositive for synaptophysin and neurofilament protein. This report supports a notion that PXA, like other astrocytic tumors, may have its gangliogliomatous counterpart.

Desmoplastic low grade astrocytoma: a case report and review of literature

A 7-year-old girl presented with focal seizures without symptoms of raised intracranial tension. Routine histological, immunocytochemical and ultrastructural methods revealed a desmoplastic low grade cerebral astrocytoma. Follow up for 2 years after biopsy did not show recruitment of neurological symptoms or signs. Biphasic tumours containing glial and mesenchymal elements have been described in the literature under various diagnostic headings. As the histologically benign variants of mixed glial and mesenchymal tumours appear to have a good prognosis, identification of these as separate entities seems imperative. With a review of literature we propose a pathological classification of mixed glial and mesenchymal tumours.

Desmoplastic cerebral astrocytoma of infancy. A case report with immunohistochemical, ultrastructural and proliferation studies

We present a case of desmoplastic cerebral astrocytoma of infancy (DCAI) in a 7 1/2-month-old girl and include immunohistochemical, ultrastructural and proliferative activity studies. The dural-based cystic tumor showed a biphasic pattern consisting of glial fibrillary acidic protein (GFAP)-positive astrocytes embedded in a desmoplastic stroma. The astrocytic processes were lined with basal lamina at their surface contacting the collagen. Scattered islands of undifferentiated small cells were seen acquiring GFAP positivity at their peripheral zone facing the collagen. Studies with silver nucleolar organizer region and proliferating cell nuclear antigen disclosed a high proliferative activity. Flow cytometric study showed an elevated S phase and 15% hypertetraploid cell population. These findings contrast the favorable prognosis of the tumor at 26 months follow-up. Probably, extracellular-matrix-induced maturation of the undifferentiated cells with the formation of basal lamina may account for this unique disparity.

Desmoplastic infantile ganglioglioma and desmoplastic cerebral astrocytoma of infancy

The desmoplastic infantile ganglioglioma and desmoplastic cerebral astrocytoma of infancy are rare neoplasms arising in the cerebral hemispheres within the first two years of life which are defined by a combination of distinctive clinicopathologic features. The tumours are massive, partially cystic and invariably occur in a supratentorial location. Involvement of multiple lobes is common with a predilection for frontoparietal areas. In one series of 22 desmoplastic infantile gangliogliomas, all patients presented between 2 and 24 months of age (mean = 6 months; median = 4 months) with a male to female ratio of 1.4:1. In the nine reported cases of the desmoplastic cerebral astrocytoma of infancy, all patients presented between 1.5 and 14 months of age (mean = 6.8 months; median = 6 months) with a male to female ratio 0.8:1. The hallmark feature of both neoplasms is an abundant and often dense desmoplasia, imparting a characteristic firmness to the neoplasms. In the desmoplastic infantile gangliogliomas, astroglial and neuronal tumour cells in addition to variable numbers of more primitive, mitotic cells comprise the neoplastic neuroepithelial populations. In contrast, the neuroepithelial component of the desmoplastic infantile astrocytomas is restricted to neoplastic astrocytes. Despite the large size, cellular pleomorphism and cellular atypia, prognosis following successful surgical resection in both types of tumours is quite favorable. The longest followup data is available for the desmoplastic infantile gangliogliomas. With the median interval of 8.7 years (range 1 to 14.5 years) following surgery for 14 patients in this series, there were no deaths due to tumour or any evidence of tumour recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

The new WHO classification of brain tumours

The new edition of the World Health Organization (WHO) book on 'Histological Typing of Tumours of the Central Nervous System' reflects the progress in brain tumour classification which has been achieved since publication of the first edition in 1979. Several new tumour entities have been added, including the pleomorphic xanthoastrocytoma, central neurocytoma, the infantile desmoplastic astrocytoma/ganglioglioma, and the dysembryoplastic neuroepithelial tumour. The list of histological variants has also been expanded. In line with recent morphological and molecular data on glioma progression, the glioblastoma is now grouped together with astrocytic tumours. The classification of childhood tumours has been largely retained, the diagnosis primitive neuroectodermal tumour (PNET) only being recommended as a generic term for cerebellar medulloblastomas and neoplasms that are histologically indistinguishable from medulloblastoma but located in the CNS at sites other than the cerebellum. The WHO grading scheme was revised and adapted to new entities but its use, as before, remains optional.

Deletions on the long arm of chromosome 17 in pilocytic astrocytoma

Pilocytic astrocytomas are the most common astrocytic tumors of childhood and differ clinically and histopathologically from those astrocytomas that affect adults. Studies of adult astrocytic tumors have revealed allelic losses on chromosomes 10, 17p, 19q and alterations in the epidermal growth factor receptor (EGFR) gene. We have previously examined pilocytic astrocytomas for allelic losses on chromosomes 10 and 19q and for amplification of the EGFR gene, but did not detect genomic alterations at these loci. In the present study we assayed 20 pilocytic astrocytomas for loss of allelic heterozygosity of chromosome 17p, including one locus in the p53 tumor suppressor gene. In addition, because pilocytic astrocytomas frequently affect patients with neurofibromatosis type 1 (NF1) and the NF1 gene has been mapped to 17q11.2, we also examined multiple loci on the long arm of chromosome 17. Allelic loss was observed on chromosome 17 in four cases (three sporadic, one NF1); all lost portions of the long arm in chromosome 17, and one tumor lost the short arm as well. One tumor showed an interstitial deletion on the long arm that included the region of the NF1 gene. These data suggest the presence of a tumor suppressor gene on 17q that is associated with pilocytic astrocytomas. A potential candidate for this gene is the NF1 tumor suppressor gene.