Epithelial properties of pleomorphic xanthoastrocytomas determined in ultrastructural and immunohistochemical studies

The evolution of pleomorphic xanthoastrocytoma: from genesis to molecular alterations and mimics

Pleomorphic xanthoastrocytomas (PXAs) are rare tumors accounting for less than 1% of astrocytomas. They commonly occur in young patients and have relatively favorable prognosis. However, they are well known to have heterogenous morphology and biological behavior with the potential to recur and disseminate throughout the central nervous system, especially their anaplastic counterparts. Recent advances in the molecular characterization have discovered BRAFp.V600E mutations in conjunction with CDKN2A/B deletions and TERTp mutations to be the most frequent alterations in PXAs. These tumors can present a diagnostic challenge as they share overlapping histopathological, genomic as well as methylation profile with various other tumor types, particularly epithelioid glioblastomas (eGBs). This review provides the spectrum of evolution of PXAs from their genesis to recent molecular insights and attempts to review pathogenesis and relationship to other tumors that they mimic especially eGB. It is postulated based on evidence from literature that PXA and eGB are possibly related and not distinct entities, being two ends of a continuous spectrum of malignant progression (grade 2-grade 4) with anaplastic PXA (grade 3) lying in between. Future WHO classifications will have to possibly redefine these tumors using more confirmatory data from larger studies.

Pleomorphic xanthoastrocytoma: a brief review

Pleomorphic xanthoastrocytoma (PXA) is a rare primary CNS tumor. Recent advances in the molecular characterization are helping to define subtypes of tumor. The discovery of BRAF mutations within a substantial percentage of PXA fosters a clearer understanding of the pathophysiology of these tumors with clear prognostic and therapeutic implications. These findings are expected to provide insight into the spectrum of clinical behavior observed in PXA, ranging from cure with surgery to diffuse dissemination throughout the neuraxis. This review details the clinical presentation including radiographic appearance of PXA. Pathology, including molecular pathology is discussed. Therapeutic management including surgical resection, radiotherapy and systemic therapies are reviewed.

Demography, Pattern of Care, and Survival in Patients with Xanthoastrocytoma: A Systematic Review and Individual Patient Data Analysis of 325 Cases

Objectives Xanthoastrocytoma (XA) is a low-grade glial tumor seen in young adults and there is lack of robust data on treatment of this rare tumor. In this systematic review and individual patient's data analysis, we aimed to look into the demography, pattern of care, survival outcomes, and prognostic factors in patients with both Grade II and III XA.

Methods A comprehensive search was conducted with the Medical Subject Heading terms: “Xanthoastrocytoma; Pleomorphic Xanthoastrocytoma; Anaplastic Xanthoastrocytoma; Xanthoastrocytoma AND treatment; and Anaplastic Xanthoastrocytoma AND survival” to find all possible publications.

Results A total of 325 individual patients from a total of 138 publications pertaining to XA were retrieved. Median age of the entire cohort was 19 years. About 56.1% of the patients underwent a gross total resection (GTR) and 31.4% underwent a subtotal resection. Nearly, 76.6% of the patients had a Grade II tumor and adjuvant radiation was delivered in 27.4% of the patients. Estimated 2- and 5-year progression-free survival (PFS) were 68.5 and 51.2%, respectively. Age, grade, and extent of surgery were significant factors affecting PFS. Estimated 2- and 5-year overall survival (OS) was 88.8 and 78%, respectively. The median OS for Grade II and Grade III tumors were 209 and 49 months, respectively. Age and extent of surgery were significant factors affecting OS.

Conclusion XA is a disease of young adults with favorable prognosis. Younger patients (<20 years), patients who undergo a GTR, and patients with a lower grade tumor have a better treatment outcome.

Primary anaplastic pleomorphic xanthoastrocytoma in adults. Case report and review of literature

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A case report and literature review of anaplastic pleomorphic xanthoastrocytoma in adults.

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The tumor shows an aggressive clinical course compared with its benign variant.

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APXA shows histological characteristics comparable with grade III astrocytomas.

Background

Pleomorphic xanthoastrocytoma (PXA) classified as a low Grade (WHO II) astrocytic neoplasm. It is known for its relatively favorable prognosis. It most commonly occurs in young adults. Malignant progression in PXA has been frequently reported since its first description in 1979; however, the presentation of a primary anaplastic PXA tumor with an aggressive clinical course in adults is rare especially in the later age group.

Case description

We present a case of primary anaplastic PXA in a 53 year old male that manifested with an early recurrence pattern at 9 weeks. Treatment performed was surgical excision and external beam radiotherapy. The aforementioned tumor followed an aggressive clinical course. Tumor cells exhibited the characteristic expression of GFAP (Glial fibrillary acidic protein), higher proliferative index (8–10%) on Ki-67 staining along with the presence of increased mitoses ( >5/10hpf). A review of previously reported primary anaplastic pleomorphic xanthoastrocytoma cases in adults with histological features was also done.

Conclusion

Our review of all reported cases of APXA in adults concludes that the clinical behavior of this tumor varies considerably from its benign variant. Early disease recurrence in anaplastic pleomorphic xanthoastrocytomas is associated with fatal outcomes. As per our review of literature it is seen that anaplastic variant of PXA shows histological characteristics as well as clinical course comparable with Grade III astrocytomas.

We recommend further evaluation of PXA with anaplastic features regarding their genetic characteristics to understand the origin as well as behavior of this tumor.

Angiomatous pleomorphic xanthoastrocytoma: a case report and literature review

BACKGROUND

Pleomorphic xanthoastrocytoma is rare, accounting for <1 % of all central nervous system (CNS) neoplasms. Angiomatous pleomorphic xanthoastrocytoma is an extremely rare variant of pleomorphic xanthoastrocytoma, with only six cases reported thus far.

CASE PRESENTATION

A 24-year-old Chinese female patient who presented with seizure and loss of consciousness for 15 min underwent computed tomography and magnetic resonance imaging, which revealed a mass in the left parietal lobe. Histologically, the tumor was characterized by pleomorphic tumor cells and prominent vascularity. The angiomatous region varied, ranging from a sinusoidal pattern to a venous malformation. Focal fibrinoid necrosis, hyalinization, and a moderate infiltration by lymphocytes and plasma cells were visible in the vessel wall. The tumor cells were in close proximity with adjacent small vessels. Capillaries adjacent to or extending between tumor cells were focally observed. Most tumor cells were positive for glial fibrillary acidic protein and oligodendrocyte lineage transcription factor 2. The Ki-67 index was low. Based on the patient's history, clinical data, and pathological findings, she was diagnosed with angiomatous pleomorphic xanthoastrocytoma (WHO grade II).

CONCLUSIONS

This case serves as a reminder to pathologists of the need to be aware of this rare variant of pleomorphic xanthoastrocytoma to avoid a misdiagnosis of this indolent CNS tumor and therefore inappropriate treatment.

Epithelioid Glioblastomas and Anaplastic Epithelioid Pleomorphic Xanthoastrocytomas--Same Entity or First Cousins?

Epithelioid glioblastoma (eGBM) and pleomorphic xanthoastrocytoma (PXA) with anaplastically transformed foci (ePXA) show overlapping features. Eleven eGBMs and 5 ePXAs were reviewed and studied immunohistochemically. Fluorescence in situ hybridization for EGFR amplification, PTEN deletion and ODZ3 deletion was also performed, with Ilumina 450 methylome analysis obtained in five cases. The average age for eGBM was 30.9 (range 2-79) years, including five pediatric cases and a M : F ratio of 4.5. The ePXA patients had a M : F ratio of 4 and averaged 21.2 (range 10-38) years in age, including two pediatric cases. Six eGBMs and two ePXAs recurred (median recurrence interval of 12 and 3.3 months, respectively). All tumors were composed of solid sheets of loosely cohesive, "melanoma-like" cells with only limited infiltration. ePXAs showed lower grade foci with classic features of PXA. Both tumor types showed focal expression of epithelial and glial markers, retained INI1 and BRG1 expression, occasional CD34 positivity, and lack of mutant IDH1 (R132H) immunoreactivity. BRAF V600E mutation was present in four eGBMs and four ePXAs. ODZ3 deletion was detected in seven eGBMs and two ePXAs. EGFR amplification was absent. Methylome analysis showed that one ePXA and one eGBM clustered with PXAs, one eGBM clustered with low-grade gliomas, and two eGBMs clustered with pediatric-type glioblastomas. Common histologic, immunohistochemical, molecular and clinical features found in eGBM and ePXA suggest that they are closely related or the same entity. If the latter is true, the nomenclature and WHO grading remains to be resolved.

Aggressive behavior and anaplasia in pleomorphic xanthoastrocytoma: a plea for a revision of the current WHO classification

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic neoplasm that commonly affects children and young adults, and presents with seizures. PXA is typically supratentorial with a predilection to the temporal lobe, and often involves the cortex and the meninges. PXAs have a favorable prognosis with a 10-year survival probability of >70%, and are WHO grade II neoplasms. Recent observations and studies demonstrate that PXAs are clinically, histologically and genetically distinct. Some PXAs recur and exhibit aggressive clinical behavior. In such cases, certain histological and clinical factors could account for the aggressive behavior. However, the histological features that predict adverse outcome are poorly defined. In the current WHO classification of CNS tumors, there is no option for a high-grade PXA, even if the tumor had numerous recurrences and poor outcome. In this review, we focus on aggressive clinical behavior and anaplasia in PXA, and discuss how our current experience suggests modifications in the current WHO classification. We also review recent discoveries on the molecular characteristics of PXA that could help us better understand their biological behavior.

Composite pleomorphic xanthoastrocytoma-epithelioid glioneuronal tumor with BRAF V600E mutation - report of three cases

We report three examples of a composite pleomorphic xanthoastrocytoma-epithelioid glioneuronal tumor (PXAEGT) occurring in an adolescent male and two young women. All were superficial and two were located in proximity to the optic nerves. Previously reported composite PXA-gangliogliomas (PXA-GG), have been considered "collision tumors" since little intermingling of the two elements has been present. In contrast, we hypothesized that the two elements of the PXA-EGT might instead derive from a common origin. To test this, we sampled the separate regions of these biphasic tumors and assessed each component for the BRAF V600E mutation, a genetic feature seen in two-thirds of pure PXAs. The BRAF mutation was found in both tumor areas in all cases, suggesting a common origin for the components, rather than a collision tumor. These biphasic PXA-EGT cases represent a new histomorphological combination of neuroepithelial neoplastic elements. These cases further expand the range of glial neoplasia in which epithelioid morphology is encountered, and add to the growing list of biphasic tumors harboring the BRAF V600E mutation.

Prognostic factors and therapeutic outcomes in 22 patients with pleomorphic xanthoastrocytoma

OBJECTIVE

Pleomorphic xanthoastrocytoma (PXA) is a rare primary low-grade astrocytic tumor classified as WHO II. It is generally benign, but disease progression and malignant transformation have been reported. Prognostic factors for PXA and optimal therapies are not well known.

METHODS

The study period was January 2000 to March 2012. Data on MR findings, histology, surgical extents and adjuvant therapies were reviewed in twenty-two patients diagnosed with PXA.

RESULTS

The frequent symptoms of PXA included seizures, headaches and neurologic deficits. Tumors were most common in the temporal lobe followed by frontal, parietal and occipital lobes. One patient who died from immediate post-operative complications was excluded from the statistical analysis. Of the remaining 21 patients, 3 (14%) died and 7 (33%) showed disease progression. Atypical tumor location (p<0.001), peritumoral edema (p=0.022) and large tumor size (p=0.048) were correlated with disease progression, however, Ki-67 index and necrosis were not statistically significant. Disease progression occurred in three (21%) of 14 patients who underwent GTR, compared with 4 (57%) of 7 patients who did not undergo GTR, however, it was not statistically significant. Ten patients received adjuvant radiotherapy and the tumors were controlled in 5 of these patients.

CONCLUSION

The prognosis for PXA is good; in our patients overall survival was 84%, and event-free survival was 59% at 3 years. Atypical tumor location, peritumoral edema and large tumor size are significantly correlated with disease progression. GTR may provide prolonged disease control, and adjuvant radiotherapy may be beneficial, but further study is needed.

Pleomorphic xanthoastrocytoma with malignant transformation and multiple recurrences in an Iranian girl

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic tumour of the brain. Some PXAs are accompanied by anaplastic features and are difficult to manage because of frequent recurrences that lead to early death. Well-documented cases of malignant transformation in PXA and of anaplastic PXA are rare in the literature. The authors report a case of PXA with malignant transformation in the right temporo occipital lobe in a 13-year-old Iranian girl.

Malignant potential of pleomorphic xanthoastrocytoma

Pleomorphic xanthoastrocytoma (PXA) is a low-grade astrocytic tumour that occasionally progresses to a higher grade. We have extensively reviewed the literature on the potential for malignant transformation of PXA. An illustrative case of a PXA transforming to glioblastoma multiforme is presented.

MEDROXYPROGESTERONE ACETATE INDUCES C6 GLIOMA CHEMOSENSITIZATION VIA ANTIDEPRESSANT-LIKE LYSOSOMAL PHOSPHOLIPIDOSIS/MYELINOSISIN VITRO

The authors have previously shown that medroxyprogesterone acetate (MPA) inhibits growth and increases drug sensitivity in C6 glioma with myeloid bodies. Myeloid bodies can occur in cells either due to robust toxicity with mitochondrial membrane disruption or due to milder events such as seen in lysosomal-phospholipidosis. Exact patterns of myelinosis accompanying to MPA chemo-sensitization is important, because uncoupling of nuclear versus mitochondrial toxicity of anti-neoplastics by MPA would lead to safer employment of glioma chemotherapy with reduced neurotoxicity. By monitoring and comparing cell kinetics with fine structural features of cell death, the authors estimated subcellular effects accompanying growth-inhibitory drug actions in C6 glioma. The analysis revealed that MPA induced mainly lysosomal phospholipidosis, while inhibiting clonogenicity alone and augmenting procarbazine efficacy. It induced apoptosis in combination with cisplatin. It reduced mitochondrial-damage-based early cytotoxicity of methotrexate, yet it did not hinder its anti-clonogenic efficacy. Progesterone analogues - similar to antidepressants - inhibit cholesterol esterification, and this efficacy relates with their P-glycoprotein inhibition. Reducing esterification and plasma-membrane localization of cholesterol may lead MPA induction of lysosomal phospholipidosis, growth indolency, and drug sensitization in glioma.

Classification and grading of low-grade astrocytic tumors in children

This article reviews current perspectives in the classification and grading of astrocytomas in children and calls attention to several histologically distinct groups of low-grade tumors that characteristically arise during childhood. Recognition of these tumors and the range of histological features that they may exhibit is essential for making rational assessments regarding their expected behavior and, more importantly, for guiding therapeutic intervention. For example, pleomorphic xanthoastrocytoma, which may exhibit "anaplastic" features, generally carries a relatively favorable prognosis and should not be classified with other high-grade gliomas, such as anaplastic astrocytoma and glioblastoma multiforme. Similarly, the finding of anaplastic features, such as vascular proliferation or necrosis, in pilocytic astrocytomas does not automatically portend the unfavorable prognosis that such features would imply for "diffuse" astrocytomas. Increased appreciation of the morphological diversity of astrocytomas in children should help to improve the management of children with low-grade astrocytic tumors by avoiding potentially dangerous overtreatment of otherwise indolent lesions.

Cerebellar pleomorphic xanthoastrocytoma: case report and literature review

BACKGROUND

PXA generally has histologic features characteristic of benign biological behavior, although malignant forms have been reported. This neoplasm has also been observed in atypical locations.

METHODS

The authors report a case of cerebellar PXA with rapid malignant transformation in a 58-year-old woman and review the rare presentations and atypical features of this tumor.

RESULTS

Among the "unusual" locations, the most frequent is the cerebellum with 15 cases having been described, 9 in adults, with an average age of 33 years. In contrast, supratentorial forms had a younger age profile (26 years). The time from onset of symptoms to diagnosis was approximately 5.3 months. PXA in the posterior fossa had a higher rate of solid enhancing tumor (9/14). Regarding histologic appearance, two thirds were composite lesions.

CONCLUSIONS

The clinicopathologic features of cerebellar PXA show some differences from PXA located in the cerebral hemispheres. Recognizing the potential for PXA to present with unusual manifestations, regardless of location, has an obvious impact on the accuracy of diagnosis.

Malignant progression in pleomorphic xanthoastrocytoma: Personal experience and review of the literature

Pleomorphic xanthoastrocytoma (PXA) is a rare primary low-grade astrocytic tumor, recently classified as a neuroglial tumor. It generally occurs in children and young adults and shows benign behaviour (WHO II), although an anaplastic variant and malignant potential have been described. Pleomorphic xanthoastrocytomas with malignant transformation have been reported in three out of eight patients operated on for this type of tumor in our department in the last 15 years. The three patients were two adult women and a child, the primary tumors were located in the cortex of the right temporal lobe, and treatment consisted of complete surgical resection. Histological examination revealed simple PXA in two patients and a PXA with anaplastic foci in the other. Mean recurrence time was 5.7 years, with the original xanthoastrocytoma evolving to glioblastoma in two cases and anaplastic astrocytoma in the third. All three patients underwent a second operation, followed by adjuvant therapies. Two died from tumor progression and one from brain edema after intracerebral haemorrhage. A review of the available PXA literature dating back to 1979 revealed 16 cases of primary anaplastic astrocytoma and 21 cases of PXA with malignant transformation. Our experience adds three more cases of malignant transformations, outlining once again the potential malignancy of pleomorphic xanthoastrocytomas and the fact that prognosis in these cases is the same as for primary anaplastic astrocytoma and glioblastoma. Analysis of glioneuronal markers, Ki67 and p53 in all pleomorphic xanthoastrocytomas did not prove to be a discriminating factor to identify a subgroup of xanthoastrocytomas prone to malignancy. Accordingly, these tumors demand close long-term clinical and radiological follow-up.

Pleomorphic xanthoastrocytoma of the spinal cord

✓ The authors present clinical, radiological, and pathological features in a patient with a pleomorphic xanthoastrocytoma (PXA) of the spinal cord. To their knowledge, this is only the second report of a spinal cord PXA. In addition they perform a review of the literature on these tumors.

Multicentric pleomorphic xanthoastrocytoma in a patient with neurofibromatosis Type 1

✓ The authors report an unusual case of multicentric pleomorphic xanthoastrocytoma (PXA) in a 36-year-old woman with neurofibromatosis Type 1 (NF1). Both lesions were diagnosed as PXA but demonstrated different neuroimaging features and very different outcomes. Although the occipital lesion was cured surgically, the cerebellar tumor recurred three times and underwent malignant transformation into an anaplastic oligodendroglioma.

The authors discuss the causes of PXA and suggest that it could originate from common bipotential precursor cells with two phenotypes.

Accumulation of MDM2 in pleomorphic xanthoastrocytomas

The molecular genetic basis and the tumorigenic mechanism of pleomorphic xanthoastrocytoma (PXA) still remain to be elucidated. The amplification of the mdm2 gene and accumulation of the MDM2 protein, which is considered to be one of the major cellular regulators of p53-mediated cell growth control, were studied in eight specimens of PXA obtained from five patients. All of the PXA samples showed at least focal immunopositivity for MDM2. However, none of the samples showed mdm2 gene amplification. These results suggest that accumulation of MDM2 without gene amplification may be one of the major molecular events occurring in the tumorigenesis of PXA.

Anaplastic pleomorphic xanthoastrocytomas. Review of the literature with reference to malignancy potential

Malignancy potential of pleomorphic xanthoastrocytomas (PXAs) has rather been an underestimated reality. We report the case of a 13-year-old boy who presented with signs of increased intracranial pressure. The child had been epileptic since the age of 2. Computed tomography and magnetic resonance scans revealed a huge left frontal mass. At surgery, a subtotal excision was accomplished. Histopathological diagnosis was anaplastic PXA (grade III; WHO, 2000). The tumor showed an increased mitotic index and minimal endothelial proliferation. The patient died 3.5 months later due to a fatal intracranial hemorrhage. A review of the entire PXA literature revealed 15 well-documented cases of PXA with subsequent malignant transformation and 11 cases of primary anaplastic PXA. The prognosis was grim for both subsets of patients. Anaplastic PXAs clearly represent the transition between the original PXA concept and lipidized giant-cell glioblastoma.

Molecular genetic analysis of anaplastic pleomorphic xanthoastrocytoma

A case of pleomorphic xanthoastrocytoma in a 10-year-old Malay boy is reported. The patient presented with headache and epilepsy. On computed tomography, a ring-enhancing low-density lesion was observed in the left fronto-temporal area. During surgery, a cystic tumour containing serous fluid was found and almost totally removed. Histologically, the tumour exhibited marked pleomorphism of oval and spindle-shaped cells intermixed with uni- and multinucleated giant cells, and xanthomatous cells with foamy cytoplasm. The tumour displayed pericellular reticulin and periodic acid-Schiff positive granules. Focally, six mitotic characters per 10 high-power fields were seen, and necrosis was confined only to the inner lining of the cyst. Mutational analysis showed that a frameshift mutation (a 4-bp deletion) in the p53 gene had occurred in codons 273 and 274 of exon 8. No mutation was detected in the p16 gene. No allelic loss and/or loss of heterozygosity were observed on chromosome 10 using microsatellite marker D105532. The patient was treated with postoperative radiotherapy because of histological anaplasia and the presence of residual tumour. The patient showed marked neurological recovery after a follow-up period of 2 years.

Genetic imbalances in pleomorphic xanthoastrocytoma detected by comparative genomic hybridization and literature review

Pleomorphic xanthoastrocytoma (PXA) is a rare, low-grade astrocytic tumor found in the central nervous system. Histologically, the tumor is characterized by markedly pleomorphic and lipidized cells. Although most of the patients have a favorable prognosis, a small number of cases undergoing recurrence or progression to anaplastic astrocytoma were reported. Very few genetic studies have been performed on PXA because of its rarity and the pathogenesis of this neoplasm is largely unknown. In order to provide an overview of genetic alterations in PXA, we performed comparative genomic hybridization to identify chromosomal imbalances (DNA gains and losses) in three cases of PXA. Genetic imbalance was detected on at least one chromosome for each case. One case, which revealed multiple genetic alterations, showed a poor prognosis. DNA gain on chromosome 7 and loss on 8p were demonstrated in two of three cases, suggesting that the candidate gene(s) located on these regions may play a role in the development of PXA. Further studies are needed to identify the residing candidate genes that are involved in the tumorigenesis of PXA. In addition, the histopathological features and previous genetic studies on PXA are reviewed.

Pleomorphic xanthoastrocytomas: immunohistochemistry, grading and clinico-pathologic correlations. An analysis of 34 cases from a single Institute

Pleomorphic xanthoastrocytomas (PXAs) are characterized as a well-delineated tumor entity with clear peculiarities in clinico-radiological picture, pathological appearance and biological behavior. Usually the PXAs are associated with relatively good prognosis. Nevertheless, up to 35% of patients die following one and more recurrence with or without tumor malignant transformation. Till now, there is no agreement on what histopathological features constitute to objective and reliable signs of PXAs malignancy and clinical outcome. Thirty-four PXAs were subdivided on three subsets: typical (Grade I) - tumors without mitoses per 20 high power fields, proliferating (Grade II) tumors with mitoses but without necroses, and malignant (Grade III) - tumors with elevated mitotic index and necrotic foci. Also, immunohistochemical investigation with various tumor-associated antigens was performed. All PXAs subtypes showed differences in clinical outcomes. There were no recurrences and death among the tumors Grade I. Five out of 14 (36%) Grade II PXAs have recurred and one of them died. All 5 patients with PXAs Grade III have rapidly recurred and four of them died. Immunohistochemical variables, such as Ki-S1, p27/Kip1, vascular endothelial growth factor expression, p53 immunoreactivity and apoptotic index also exhibited significant differences among the three PXAs grades. The progression-free survival was significantly reduced for PXAs grade and presence of mitoses, whereas overall survival was reduced for mitotic index >or= 3 and presence of necroses. No one from immunohistochemical variables reached significant value. In summary, the three-tiered PXAs subdivision proposed by us is carrying some element of rationality but, undoubtedly, requires further prospective studies.

Clinicopathological study of pleomorphic xanthoastrocytoma: correlation between histological features and prognosis

The correlation between histopathological characteristics and prognosis was studied in six cases of pleomorphic xanthoastrocytomas (PXA) found in five patients. With regard to the duration from onset to the resection of the tumor, and the postoperative course, three cases had a favorable prognosis, although one case fatally recurred and in another, serial CT showed rapid tumor growth for 3 years. The histological characteristics of the favorable group of PXA comprised remarkable degeneration, low mitotic activity and a low MIB-1 labeling index. In contrast, the characteristics of the latter two cases of PXA rarely showed degeneration, had atypical mitoses, increasing mitotic activity and a higher MIB-1 labeling index, which indicates that the findings of degeneration, atypical mitoses, mitotic activity and MIB-1 labeling index correlate with the biological behavior of PXA. However, with regard to histological appearance and clinical course, PXA are tumors with a wide range of biological behavior.

Late sequelae of treated pleomorphic xanthoastrocytoma: malignant brain stem astrocytoma occurring 15 years after radiation therapy

The pleomorphic xanthoastrocytoma (PXA) is a unique astrocytic neoplasm with an unexpectedly favorable prognosis despite striking pleomorphism of the cellular constituents. Although a majority of patients experience extended survival, these tumors may recur and some cases progress to high-grade astrocytoma. Recurrence inevitably involves the anatomic vicinity of the primary tumor. In this report, we describe a malignant brain stem astrocytoma that occurred 15 years after surgery and radiation treatment of a 16-year-old patient who had a temporal lobe PXA. To our knowledge, this is the first reported case of a malignant astrocytoma arising outside the primary anatomic site of a previously treated PXA and likely represents a radiation-induced secondary neoplasm.

Pleomorphic xanthoastrocytoma: clinical, imaging and pathological features of four cases

Four cases of pleomorphic xanthoastrocytoma (PXA) were collected from among 688 glioma patients who underwent operation at the Institute of Neurosurgery, University of Naples "Federico II" between January 1973 and December 1994. Three were females and one male, ranging in age from 10 months to 65 years. Three tumors were superficial in location, appearing as a meningo-cerebral mass in the temporo-parietal region. In one case, the tumor was situated deep within the brain (capsulo-thalamic region), without contact with leptomeninges. Three patients had experienced epileptic seizures, whereas one patient presented with an ictal episode. Tumor excision was grossly total in two cases, and subtotal in the remaining two. In three cases, histological examination demonstrated a "typical" PXA; conversely one tumor (subtotal excised) was an "atypical" PXA. The two patients with incomplete surgical resection were postoperatively treated with fractionated brain radiation therapy. Of the two patients who had grossly total removals, one showed tumor recurrence 6 years after surgery, and underwent operation (the recurrent neoplasm did not exhibit malignant transformation); the second patient was free of tumor at 14 months following craniotomy. Of the two patients who had undergone subtotal removals, one died because of massive regrowth of the lesion 22 months after surgery, whereas the second patient was asymptomatic at 1 year follow up.

Multicentric pleomorphic xanthoastrocytomas: case report

We report the case of a 22-year-old woman who developed multicentric pleomorphic xanthoastrocytomas (PXAs) in the cerebral hemisphere. She underwent a first operation for a PXA in the right parietal lobe at the age of 7 years and a second operation at the age of 15 years in the right frontal lobe, remote from the previous tumor site. At age 22 years, she was found to have a tumor, which was a newly formed PXA, in the left occipital lobe. There was no recurrent tumor in the right frontal lobe. Clinical and pathological aspects of multicentric PXAs are reviewed and discussed.

Clinical, radiological, and therapeutic features of pleomorphic xanthoastrocytoma: report of three patients and review of the literature

Two out of three patients with pleomorphic xanthoastrocytoma were initially misdiagnosed and correctly interpreted only at tumour recurrence, with progression to malignancy in one. The third patient presented with a remarkably long history of epilepsy. Pleomorphic xanthoastrocytoma is a low grade astrocytoma that is still confused with other tumours. Because pleomorphic xanthoastrocytoma can become malignant even after many years of benign behaviour, a long term follow up is necessary.

Divergent differentiation in pleomorphic xanthoastrocytoma. Evidence for a neuronal element and possible relationship to ganglion cell tumors

We report the detection of cytoplasmic immunoreactivity for neuronal/neuroendocrine antigens in a subpopulation of tumor cells within seven pleomorphic xanthoastrocytomas (PXAs). The expression of glial and neuronal polypeptides was examined in routinely prepared surgical resections by immunohistochemistry using well-characterized antibodies that recognize glial fibrillary acidic protein (GFAP), synaptophysin (SYN), and neurofilament triplet polypeptides (NFPs) in microwave-enhanced single- and double-immunolabelling experiments. Each neoplasm contained cells that were immunoreactive for SYN and/or NFPs, GFAP, and occasionally for both GFAP and either NFP or SYN. We conclude that abortive neuronal/neuroendocrine differentiation may occur in PXAs, suggesting a relationship between PXA and other developmental neoplasms that reveal a more overt neuronal phenotype, such as ganglioglioma, dysembryoplastic neuroepithelial tumor, and desmoplastic ganglioglioma, and with tumors expressing ambiguous glial/neuronal lineage, such as the subependymal giant cell tumor of tuberous sclerosis. These findings suggest that aberrant expression and accumulation of neuronal intermediate filaments may account for the large, pleomorphic cell morphology observed in many of these tumors.

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).

Cytoplasmic inclusions of astrocytic elements of glial tumors: special reference to round granulated body and eosinophilic hyaline droplets

Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB appeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.

Cerebellar pleomorphic xanthoastrocytoma: case report

We report a case of pleomorphic xanthoastrocytoma occurring in the midline cerebellum of a 48-year-old woman. Radiological, histological, immunohistochemical, and flow cytometric findings are discussed. Pleomorphic xanthoastrocytoma typically occurs in the superficial cerebral hemispheres of young patients. To our knowledge, this is the first report of the occurrence of this neoplasm in the cerebellum. The English literature is reviewed with regard to the clinicopathological features of this uncommon form of astrocytoma.

Pleomorphic xanthoastrocytoma in the spinal cord. Case report

The authors present the clinical, radiological, and pathological features of a patient with a recurrent pleomorphic xanthoastrocytoma located in the spinal cord. This is the first report of a pleomorphic xanthoastrocytoma at this location; until now, only cerebral supratentorial pleomorphic xanthoastrocytomas have been described. The treatment of this case is discussed.

Pleomorphic xanthoastrocytoma--report of four cases, with MRI scan appearances and literature review

Pleomorphic xanthoastrocytoma (PXA) is a rare glial tumour typically occurring in young patients in the first three decades, having a superficial cortical location and with a relatively good prognosis for long-term survival. Four cases are reviewed. The magnetic resonance imaging (MRI) appearances, which in PXA have been reported only once before, are described in three cases. The fourth case was studied by computed tomography and angiography. One patient developed seizures at age 2 days and was aged 2 1/2 years at presentation. This is the youngest patient with PXA yet reported. Three of the four patients had seizures, but in one case the tumour was not the cause of the seizures. Review of the literature has revealed 47 reported cases. Mean age at presentation was 14.3 years. Epilepsy occurred in 78%. Seventeen patients were alive without recurrence at a mean of 7.9 years after diagnosis and 10 patients died at a mean of 7.4 years after diagnosis. Thirteen cases had recurrence at a mean of 6 years after surgery and in five instances the recurrence was in the form of a glioblastoma. Resections which were grossly total were less likely to develop recurrence than those which were subtotal. Complete gross resection of tumour offers the best therapeutic option in PXA.