Does the pleomorphic xanthoastrocytoma exist? Problems in the application of immunological techniques to the classification of brain tumors

Primary undifferentiated sarcoma of the meninges: A case report and comprehensive review of the literature

BACKGROUND AND IMPORTANCE

Sarcomas make up 1% of all cases of adult cancer, with 5-10% of those classified as undifferentiated pleomorphic sarcomas (UPS/PUS) and 0.1-4.3% primary intracranial sarcomas. Intracranial undifferentiated sarcoma is characterized by an earlier age of onset and generally poorer prognosis compared to extracranial undifferentiated sarcomas. Current therapies involve surgical excision with wide margins and radiotherapy, with minimal data available regarding the efficacy of chemotherapy.

CASE DESCRIPTION

A 79-year-old man with a history of remote superficial bladder cancer presented with a large frontal scalp lesion. A biopsy was initially attempted by a dermatologist in the outpatient setting, but a follow-up CT scan revealed a skull-eroding, enhancing soft tissue lesion. Neurosurgical treatment revealed an undifferentiated sarcoma. The patient underwent adjuvant radiation therapy of 59.4 Gy fractionated over 45 days following surgery. Follow-up brain MRIs at 1-, 6-, 9-, 12-, 15-, 21-, and 27 months after surgery have not shown any indications of local recurrence or tumor metastasis. Despite the high propensity that undifferentiated sarcomas have for recurrence and metastasis and the patient's advanced age, this patient remains uniquely disease-free.

CONCLUSION

We provide a description of an unusual case and comprehensive literature review of UPS to clarify the hallmarks of the disease, identify the difficulties in diagnosis, and provide a summary of therapies employed in the literature with their corresponding patient outcomes.

Pleomorphic Xanthoastrocytoma with Anaplastic Features in the Tectal Region in a Young Adult Patient: A Case Report

BACKGROUND

Pleomorphic xanthoastrocytomas (PXAs) in the tectal region are exceedingly rare and have distinctive clinicopathological features.

CASE PRESENTATION

A 17-year-old man was admitted to our hospital owing to headache and diplopia. Magnetic resonance imaging showed a mass lesion in the tectal gland accompanied by obstructive hydrocephalus. A biopsy and third ventriculostomy were performed. Pathological examination revealed a PXA. Total excision of the lesion was achieved via an occipital transtentorial procedure performed 6 weeks after the biopsy. A pathological examination at that time showed a PXA with anaplastic features and a high mitotic index in surgical specimens. The patient's symptoms improved after the second operation, and radiation and temozolomide-based chemotherapy were administered. No recurrence was found at 24 months after the second operation.

CONCLUSIONS

Maximum resections are recommended in cases with anaplastic features such as a high mitotic index in biopsy specimens because of the likelihood of recurrence and the low overall survival rate. We administered radiotherapy and temozolomide-based chemotherapy because of the high mitotic activity detected in surgical specimens. The postoperative course in this case is currently deemed acceptable.

Pleomorphic xanthoastrocytoma with anaplastic features presenting without GFAP immunoreactivity: Implications for differential diagnosis

Pleomorphic xanthoastrocytoma (PXA) is an uncommon, usually low-grade, astrocytic tumor. Characteristic histological features include tumor cell pleomorphism and lipidization of tumor cells. Albeit prognosis in PXA is generally good, cases with histological signs of anaplasia have been observed. In these cases, the differential diagnosis needs to exclude other malignancies, for example, glioblastoma or malignant fibrous histiocytoma. Immunocytochemical detection of GFAP may support exclusion of non-glial neoplasms resembling PXA. However, GFAP expression in PXA may be faint or focal, although complete lack of GFAP has not been described. A 43-year-old woman was operated on for a left occipital parasagital tumor attached to the dura. Histopathology showed a pleomorphic tumor with moderate mitotic activity and necrosis, lack of GFAP immunoreactivity and ultrastructural detection of premelanosome-like structures. These features led to the tentative diagnosis of amelanotic melanoma, and the patient was irradiated. Three years later she had local tumor recurrence and underwent another operation. The recurrent tumor showed similar plain histology as the first specimen. In contrast, anti-GFAP immunoreactivity was now detectable in pleomorphic tumor cells. Anti-GFAP staining of the first biopsy was repeated using monoclonal and polyclonal antibodies in combination with prolonged tissue pretreatment. Focal GFAP staining of tumor cells was now achieved. We conclude that non-standard GFAP staining protocols may enhance sensitivity and thus lead to detection of a low level of GFAP expression in tumor specimens, in which PXA is considered in the differential diagnosis. This may avoid misleading diagnostic considerations that impact on postoperative patient management.

Cerebellar malignant fibrous histiocytoma: case report and literature review

OBJECTIVE AND IMPORTANCE

Malignant fibrous histiocytoma in the central nervous system is uncommon. Fewer than 70 cases have been documented and, to the best of our knowledge, this is the first case arising from the cerebellum.

CLINICAL PRESENTATION

A 44-year-old woman presented with headaches, vomiting, and dizziness. A neurological examination revealed right cerebellar syndrome. Brain computed tomographic scans revealed an isodense tumor in the right cerebellar hemisphere. The breast ultrasonographic, bone scintigraphic, and thoracoabdominal computed tomographic findings were normal.

INTERVENTION

The patient was surgically treated. The tumor recurred 1.5 months later, demonstrating hemorrhagic characteristics on brain computed tomographic scans. The patient underwent a second operation, followed by radiotherapy.

CONCLUSION

Malignant fibrous histiocytoma is still a controversial entity, and the lack of specific criteria means that it must be diagnosed via the process of elimination. With currently available therapy, our review can provide only a very poor prognosis. The median survival time was 27 months. In attempts to develop better therapeutic strategies, total excision and radiotherapy seem to represent the best treatment approach.

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.

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.

Pleomorphic xanthoastrocytoma: report of six cases with special consideration of diagnostic and therapeutic pitfalls

BACKGROUND

Pleomorphic xanthoastrocytoma (PXA) is a rare clinicopathologic entity that occurs typically in young patients. Improved neuroradiologic techniques, especially gadolinium-enhanced magnetic resonance imaging (MRI), reveal a characteristic tumor appearance.

METHODS

We present six cases of PXA operated on with unusual clinical course, elucidating different clinical implications.

RESULTS

Two patients showed subsequent progression into a malignant glioma, one case was a primary anaplastic PXA. The latter case had not previously been reported in the literature. Increased mitotic activity seems to indicate a worse clinical course; whereas focal infiltration of the brain does not necessarily lead to malignant transformation.

CONCLUSIONS

Surgical removal is the treatment of choice. A consequent follow-up is mandatory in order to detect a potentially malignant recurrence as early as possible and to select patients who need additional therapy.

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.

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.

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.

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.

Increased mitotic activity as a negative prognostic indicator in pleomorphic xanthoastrocytoma. Case report

Pleomorphic xanthoastrocytoma is a recently characterized neoplasm with a favorable prognosis despite aggressive histological features. The authors report a case of pleomorphic xanthoastrocytoma that recurred 4 years after complete gross resection. The original tumor exhibited histological features characteristic of this neoplasm, but up to 4 mitoses/10 high-power fields were present focally. The recurrent tumor contained small foci of classical pleomorphic xanthoastrocytoma, but consisted predominantly of glioblastoma multiforme. Transitional zones contained nests of glial fibrillary acidic protein (GFAP)-immunopositive cells surrounded by delicate collagenous and reticulin-rich septa. Electron microscopy of the transitional zone showed continuous basal lamina investing cells containing bundles of intermediate filaments. These were GFAP-positive by immunogold electron microscopy, confirming the astrocytic nature of pleomorphic xanthoastrocytoma. This example illustrates the capacity of this tumor to evolve into glioblastoma. The indolent clinical behavior of most pleomorphic xanthoastrocytomas is evident from a literature review, which confirms the prolonged survival of many patients after onset of symptoms. Completeness of excision, subjectively assessed at surgery, did not influence the risk of recurrence or survival up to 10 years after initial resection. Postoperative radiotherapy did not improve survival, but may reduce the probability of recurrence; more studies are needed to corroborate this finding. The data compiled herein support the designation of pleomorphic xanthoastrocytoma as a distinct astrocytic neoplasm with a favorable prognosis. An increased mitotic rate has not previously been correlated with a worse outcome, and should not be used to exclude this diagnosis. However, anaplastic transformation of pleomorphic xanthoastrocytoma confers a much worse prognosis, and this case suggests that increased mitotic activity may be a negative prognostic indicator since it may herald subsequent anaplastic transformation.

Pleomorphic xanthoastrocytoma: the birth of a diagnosis and a concept

This review deals with one of the newly adopted entities in the second edition of the histologic typing of CNS tumours by the World Health Organization: pleomorphic xanthoastrocytoma and reviews the clinical features, gross and microscopic characteristics as well as the common and some of the unusual variants of this tumor. The steps and events leading to the recognition of the basic character of this neoplasm and its designation as an independent entity are recollected and a few characteristic MRI scans and photomicrographs of pleomorphic xanthoastrocytomas are provided.

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.

Pleomorphic xanthoastrocytoma associated with von Recklinghausen neurofibromatosis

The authors present a case of pleomorphic xanthoastrocytoma that occurred in a 14-year-old boy with von Recklinghausen's neurofibromatosis. The circumscribed tumor with a cystic component was located in the medial right temporal lobe. The designation of pleomorphic xanthoastrocytoma has been suggested for this neoplasm on the basis of its unique histological features. These include positive glial fibrillary acidic protein staining.

Temporal lobe tumor demonstrating ganglioglioma and pleomorphic xanthoastrocytoma components. Case report

The case is reported of a 16-year-old boy with a left temporal lobe tumor composed of a ganglioglioma and a pleomorphic xanthoastrocytoma. Histologically, the tumor had two different components. One component involved the cortex of the left posterior temporal lobe and showed an aggregation of neuronal cells with an astroglial stroma. Ultrastructurally, numerous dense-cored vesicles, diagnosed as ganglioglioma, were found in the neuronal cells. The other component involved the adjacent cortex and white matter of the left anterior temporal lobe and the surrounding subarachnoid space. This was composed of pleomorphic cells with many multinucleated giant cells and occasional foamy cells. Most of the tumor cells were positive for glial fibrillary acidic protein. These features correspond well to earlier descriptions of pleomorphic xanthoastrocytoma. At 24 months following total tumor extirpation, the patient is alive and has had no evidence of tumor recurrence.

The pleomorphic xanthoastrocytoma and its differential diagnosis: a study of five cases

Five brain tumors with the histopathologic features of pleomorphic xanthoastrocytomas (PXAs) are presented. Computed tomography scans showed a remarkable homology. Two cases had atypical localizations for a PXA, while one 46-year-old patient did not conform to the normal age distribution of this tumor. Nevertheless, in these cases, the histopathology was always characteristic for PXA, a remarkable pleomorphism, in addition to simultaneous expression of glial fibrillary acidic protein and histiocytic markers in the various tumor cells. In one of the presented tumors, however, clusters of neoplastic neuronal cells were also found. In this particular case, differential diagnostic criteria to distinguish between a PXA and a desmoplastic infantile ganglioglioma are lacking.

Primary intracranial sarcomas: histopathological features of 19 cases

Nineteen primary intracranial sarcomas out of a total of about 25,000 brain tumour biopsies are reported. Subtypes included malignant fibrous histiocytoma (6 cases), leiomyosarcoma (3), rhabdomyosarcoma (2), angiosarcoma (2), and one case each of fibrosarcoma, low-grade fibromyxoid sarcoma, malignant ectomesenchymoma, mesenchymal chondrosarcoma, differentiated chondrosarcoma and Ewing's sarcoma. Histological and immunohistochemical features corresponded to those of extracranial sarcomas. Nests of pleomorphic astrocytes mimicking glioma were detected in the five storiform-pleomorphic malignant fibrous histiocytomas. Our results indicate that intracranial sarcomas can be classified like their extracranial counterparts. The low incidence compared with earlier series is related to changes in classification and progress in histogenetic clarification.

Mesenchymal, non-meningothelial tumors of the central nervous system

The spectrum of non-meningothelial mesenchymal tumors that may arise within the central nervous system is presented, based on the current classification of soft tissue tumors. Among malignant types, hemangiopericytoma, rhabdomyosarcoma, mesenchymal chondrosarcoma, and malignant fibrous histiocytoma are the most frequent ones. Rare tumor entities are mentioned. As in soft tissue sarcomas, diagnosis is mainly based on light and electron microscopy, while immunohistochemistry can improve accuracy of diagnosis.

Tumors of the meninges: proposed modifications of the World Health Organization classification

The present WHO classification of meningiomas has served us well. In keeping with the adage, "if it ain't broke, don't fix it," alterations should be made with due caution. These proposed modifications of the WHO classification are prompted by advances in our understanding of the pathobiology of meningeal neoplasms, as well as a need for an orderly scheme based upon factors of clinical importance. The author is well aware, that given the vastly differing technologies available to those utilizing the "blue book," its application must have a basis in routine histology rather than in "high-tech" procedures. No classification is ideal, but the modifications suggested represent a compromise between the pathologist's need for a complete morphologic exposition and the clinician's desire for a concise classification of therapeutic and prognostic significance.

Immunohistochemistry in childhood brain tumors: what are the facts?

In the past, contradictory results have been reported concerning the specificity of neuronal or glial cell markers. However, we have investigated this aspect in a large group of more than 550 brain tumors (among them 60 medulloblastomas). These contradictions can easily be explained by considering two basic facts. First, every neoplastic cell population, especially in embryonic tumors, diffusely infiltrates the brain tissue: non-neoplastic cells, intermingled with tumor cells, can therefore give rise to immunohistochemical and histogenetic misinterpretations. Second, different cell markers can be expressed by one and the same cell (e.g., GFAP, NSE, vimentin), making nosological interpretation of the tumor difficult, impossible, or at best rather subjective. Clear-cut marker positivity is mostly found in the differentiated tumors for which the nosological classification is already clear by the usual histological methods. Only synaptophysin seems to be a reliable marker for neurogenic cells. In embryonic brain tumors (so-called PNET), no correlations between the presence of a given cell marker and the biological behavior of the tumor have so far been detected.

Intracerebral malignant fibrous histiocytoma at site of a previously excised low grade glioma

The case of a 42-year-old patient is reported who developed an intracerebral malignant fibrous histiocytoma at the site of an oligoastrocytic mixed glioma which had been excised 2 1/2 years previously. Reasons for the extreme rarity of intracranial malignant fibrous histiocytomas, the probability of a traumatic aetiology of this particular tumour, and the possible significance of intratumoural cells positive for glial fibrillary acidic protein (GFAP) are discussed.

Histopathological features of recurrent pleomorphic xanthoastrocytomas: further corroboration of the glial nature of this neoplasm. A study of 3 cases

Pleomorphic xanthoastrocytoma (PXA), a tumor most often presenting superficially over the cerebral hemisphere of young subjects, has certain morphological similarities to fibrous histiocytoma (or fibrous xanthoma) of the meninges and brain, namely the occurrence of lipid-laden neoplastic cells and, frequently, a dense reticulin fiber network. The detection of glial fibrillary acidic (GFA) protein in the tumor cells helped to establish its astrocytic derivation, but it has been advanced that, in spite of this agreed observation, the tumor should still be regarded as a fibrous xanthoma of meningeal origin. Although many patients have a long symptom-free postoperative survival, local recurrences at varying intervals after surgery have been noted in some instances. Weldon-Linne et al. first reported that such a recurrence had the morphology of a small-cell glioblastoma. We are reporting three further examples of locally recurrent neoplasms in patients whose original meningocerebral tumors had the typical features of PXA; the recurrences (developing 7 months, 7 years and 15 years, respectively, after surgery) were small-cell glioblastomas. The rich reticulin network present in the initial tumor was mostly lost in the recurrences. This anaplastic evolution further confirms the astrocytic nature of the PXA.