The use of tissue culture in differentiation between angioblastic meningioma and hemangiopericytoma

(11)C-acetate PET/CT in a case of recurrent hemangiopericytoma

Intracranial hemangiopericytoma (IHPC) is a rare tumor representing less than 1% of all CNS tumors and is often indistinguishable from meningioma on structural imaging alone. Unlike meningioma, IHPC is an aggressive tumor with the propensity for early locoregional recurrence and distant metastases. Hence, its management strategies differ greatly from that of meningioma. Some investigators have reported the potential role of multitracers (F-FDG, C-methionine, and O-H2O) PET imaging in distinguishing IHPC from meningioma. We described the findings of dual-tracer (C-acetate and F-FDG) PET/CT imaging in a histopathologically proven case of IHPC with extensive extracranial osseous metastases that showed significantly greater C-acetate avidity.

Management of intracranial meningeal hemangiopericytomas: outcome and experience

Hemangiopericytomas represent rare intracranial tumors that have a tendency to recur locally and have the unique characteristic of giving extracranial metastases. Our current communication reviews a series of patients diagnosed with hemangiopericytoma who were treated in our facility. Eleven patients with a mean age of 51.2 years underwent follow-up for a mean time of 7.1 years. Their neuroimaging preoperative evaluation included plain skull X-rays, head CT scans, brain MRI, angiograms, and (1)HMRS. Preoperative embolization of the tumor was employed in 6/11 patients. All patients underwent craniotomy for tumor resection and postoperative radiation treatment was employed on all but one. Grade I resection was accomplished in 6/11 (54.5%), grade III in 4/11 (36.4%), and grade IV in 1/11 (9.1%). Local recurrence was detected in 3/11 (27.3%) at a mean period of 5 (range 2-7.5) years. Extracranial metastatic disease was documented in 4/11 (36.4%) patients at a mean of 4.9 (range 2.5-7) years after the initial diagnosis. The GOS score was: 7/11 (63.6%) scored 5, while 4/11 (36.4%) died at a mean time of 5.5 (range 3-8) years after the initial diagnosis. Intracranial hemangiopericytomas management requires aggressive surgical resection, postoperative radiation treatment, and extensive follow-up to rule out local recurrences and delayed extracranial metastases.

Bone metastasis of intracranial meningeal hemangiopericytoma

The authors investigated the clinical and radiological features and the treatment strategy for bone metastasis from a rare tumor, intracranial meningeal hemangiopericytoma. The clinical presentations and characteristic imagings were retrospectively reviewed in 15 bony metastatic lesions of four patients with this tumor. All four cases were initially diagnosed as atypical meningioma, and all of the bone metastases developed more than 10 years after the initial intracranial surgery. The common symptom induced by the metastatic lesions was pain. On plain roentgen films and computed tomography (CT), the involved bones showed thinning and expansion. On bone scintigraphy, a "cold-in-hot" appearance was typically observed. The clinical and radiological findings were diagnosed as bone metastasis from intracranial meningeal hemangiopericytoma. The prognosis after bone metastasis was relatively short compared to the long duration before bone metastases, because of the coexistence of other, visceral, metastasis. Combined with effective radiation therapy, surgical intervention for bone metastasis of this tumor should be carefully considered.

Expression of epithelial and extracellular matrix protein markers in meningiomas

In an attempt to characterize the dual mesenchymal and epithelial differentiating potential of meningiomas, cryostat sections from 50 meningiomas of diverse histological subtypes were examined immunohistochemically with a panel of markers for epithelial and mesenchymal differentiation. The overall positivities were: keratins 50%, epithelial membrane antigen 94%, human milk fat globules 38%, carcinoembryonic antigen 4% (secretory meningiomas only), desmoplakins 64%, collagen I 82%, procollagen I 96%, collagen III 74%, collagen IV 60%, laminin 54%, fibronectin 98% and vimentin 98%. Such production of keratins was not found in many previous immunohistochemical analyses of meningiomas with paraffin sections. The extracellular matrix proteins were present in a pericellular distribution suggestive of their being produced by the tumour cells. The potential of dual epithelial and mesenchymal differentiation in meningiomas was further examined in seven cases established on short-term cultures. Morphologically, subcultured tumour cells resembled fibroblasts and in five cases revealed similar epithelial and mesenchymal immunohistochemical profiles as for direct tumour immunostaining. In two cases, cells from the primary cultures revealed a fine skeleton of intercellular matrix proteins stainable by immunohistochemical methods, providing further proof that meningioma cells possess the capability to elaborate extracellular matrix proteins, a major mesenchymal function akin to that of fibroblasts.

Differentiation markers in hemangiopericytoma

Normal pericytes were found to express factor XIIIa (F-XIII) and histocompatibility antigen HLA-DR. These markers were studied in 15 hemangiopericytomas (HPC) and 16 other tumors with an HPC-like pattern. A subpopulation of tumor cells expressing F-XIII and HLA-DR antigens was a constant feature of HPC and supported their pericytic origin. Meningeal HPC did not differ in phenotype from peripheral soft tissue HPC. Most tumors with an HPC-like pattern (including synovial sarcomas, malignant schwannomas, leiomyosarcomas, and liposarcomas) were negative for F-XIII and HLA-DR. Malignant fibrous histiocytomas, however, invariably contained a subpopulation expressing these antigens. Therefore, F-XIII can be considered as a marker of fibrohistiocytic differentiation in HPC. Individual tumor cells in HPC occasionally were positive for factor VIII-related antigen (F-VIII-R-Ag), suggesting that the spectrum of differentiation in HPC may include the endothelial cell line. The differentiation characteristics of HPC support the concept that pericytes are primitive cells that may act as precursors to other mesenchymal cells.

Malignant haemangiopericytoma of lung: a cell culture and ultrastructural study

Malignant haemangiopericytoma was grown in vitro to assess the histogenesis of the tumour. Disaggregated tumour cells maintained in serum-supplemented Waymouth's MB 752/1 medium showed monolayers of homogeneous spindle cells. Post-confluent cultures exhibited hillocks or plaques of multilayer growth within which considerable amount of basal lamina-like material and fibrillar matrix were present between cells. Delicate basal laminae were also expressed on cell surfaces facing matrix material. Other consistent features were attenuated cytoplasmic processes, desmosome-like junctions, abnormal mitochondria and a paucity of intracellular filaments. The three-dimensional organization of tumour cells with concomitant expression of differentiated phenotype in vitro has significant implications on the cell of origin and differentiation process of haemangiopericytoma.

Soft-tissue and meningeal hemangiopericytomas: an immunohistochemical and ultrastructural study

The debate on the nosologic position of hemangiopericytomas of the meninges has been based mainly on light microscopic and ultrastructural considerations; recent immunohistochemical studies have yielded controversial results. We have used a panel of antibodies to vimentin, desmin, actin, S100 protein, epithelial membrane antigen, cytokeratins, Leu-7, factor VIII-related antigen and type IV collagen to compare the immunophenotype of 10 soft-tissue and seven meningeal hemangiopericytomas. The immunophenotypic profile of these tumors is identical, and differs from that of meningiomas in that epithelial membrane antigen and cytokeratin are not present. The vascular pattern occurring in some meningiomas can simulate true hemangiopericytomas of the meninges. Immunohistochemical studies should allow their distinction in each instance. Meningeal and soft-tissue hemangiopericytomas display similar ultrastructural features.

Excision of a large pineal region hemangiopericytoma (angioblastic meningioma, hemangiopericytoma type)

A large hemangiopericytoma was located posterocentrally. The patient presented with headaches and papilledema. Surgical management consisted of total gross excision by a combined right occipital transtentorial and right occipitoparietal transfalcine approach under magnification in three stages over a 6-week period. Removal was aided by dilatation of the right temperooccipital horn ("trapped ventricle") and meningioma-like encapsulation allowed separation of the tumor from the brain and surrounding structures after internal debulking of the tumor. Subsequent peritoneal shunting of the trapped ventricular horn and 5000 rads of radiotherapy were given to the patient. She remains well with an inferior quadrantanopsia on the left side more than 1 year after treatment. Meningiomas of the pineal region, the relationship of meningioma to hemangiopericytoma and malignant mesenchymal tumors (sarcomas) are considered in reference to presumed cells of origin.

Ultrastructural and electrophysiological features of meningioma whorls in tissue culture

Cultured cells derived from a psammomatous meningioma were induced to from whorls in vitro by deprivation of nutrients. The ultrastructural features of desmosomes and junctional complexes were similar to sections from the surgical specimen; also prominent were 9-10 nm cytoplasmic filaments. Microelectrode recording of whorled cells showed a larger resting membrane potential than that of similar isolated meningioma cells in culture. Whorl formation seen in this tumor may be a result of relative nutritional deprivation and the need for metabolic cooperation among tumor cells.

Hemangiopericytoma of the spinal canal. Report of three cases

Hemangiopericytoma is a vascular neoplasm consisting of capillaries outlined by an intact basement membrane that separates the endothelial cells of the capillaries from the spindle-shaped tumor cells in the extravascular area. These neoplasms are found in soft tissues but have rarely been shown to involve the spinal canal. This is a report of three such cases. Surgical removal of the tumor from the spinal canal was technically difficult. A high risk of recurrence has been reported but in these three cases adjunctive radiotherapy appeared to be of benefit in controlling the progression of the disease. These cases, added to the six cases in the literature, confirm the existence of hemangiopericytoma involving the vertebral column with extension into the spinal canal. This entity should be included in the differential diagnosis of lesions of the spinal canal. The risk of intraoperative hemorrhage should be anticipated.

Orbital hemangiopericytoma: a report of a three-year-old child

A case of orbital hemangiopericytoma is described in a three-year-old child. Its clinical and microscopic differentiating features from other ocular and orbital tumors is discussed.

Meningioma and intracranial hemangiopericytoma. A comparative electron microscopic study

Electron microscopic study of 2 intracranial hemangiopericytomas and 7 meningiomas revealed fundamental morphologic differences between the 2 neoplasms. The most significant finding in hemangiopericytoma was the presence of ultrastructure features suggesting leiomyoblastic differentiation. These included characteristic fusiform intracytoplasmic and submembranous dense bodies, abundant cytoplasmic filaments, elongated cells with blunt-ended nuclei and juxtanuclear polarization of organelles. This observation is considered highly significant as an indicator of the pericytic nature of this tumor. In addition, hemangiopericytoma cells sometimes were arranged in spirals around pools of basement membrane-like material, perhaps a manifestation of the biologic capability of the cells to synthetize such material. Meningioma cells displayed as their main feature an ability to produce surface membrane specializations including interdigitations, desmosomes, zonulae adhaerentes and gap functions. Sometimes the last 3 elements were linearly juxtaposed forming junctional complexes similar to those seen in certain epithelia. It is suggested that the characteristic whorls of meningioma are the result of cell interconnections arising from the specialized junctional attachments. Thus the distinctive morphology of the 2 neoplasms appears to derive from basic biologic properties of their elements.

The angioblastic meningioma: a reappraisal of the nosological problem. Light-, electron-microscopic, tissue, and organ culture observations

The validity of the concept of the angioblastic meningioma, now in dispute, was reexamined by reviewing 79 meningeal and angioblastic tumors of the central nervous system and by comparing the fine structural characteristics and in vitro evolution of 2 typical meningiomas and 1 intracranial hemangiopericytoma. While most tumors show the consistent features of either hemangiopericytoma or hemangioblastoma, there exist transitional forms between these tumors and typical meningioma. There is also a greater degree of morphological overlap at the electron microscopic level than has been recognized up till now. In view of these findings the concept of the angioblastic meningioma deserves to be retained as a generic term to include craniospinal hemangiopericytomas and transitional forms between hemangiopericytoma, hemangioblastoma and classic meningioma. It is postulated that all these tumors share a common origin from polyblastic mesenchymal cells originating in or derived from the meninges.

Intracranial hemangiopericytoma: ultrastructural evidence of its leiomyoblastic differentiation

Two intracranial hemangiopericytomas revealed subcellular features of the neoplastic elements comparable to those observed in normal and neoplastic smooth muscle. These included intracytoplasmic and submembranous fusiform dense bodies associated with bundles of filaments, tapered configuration of cells with grouping of cytoplasmic organelles at nuclear poles and deposition of intercellular basal lamina-like material. These observations are consistent with the pericytic origin but opposed to the ofttimes postulated meningothelial derivation of the neoplasm.

Malignant metastasizing angioblastic meningiomas

The authors report and discuss the unusual clinical and roentgenographical features of three cases of angioblastic meningioma with extracranial metastases. The primary lesions occurred in the cervical canal, the parasagittal region, and the posterior fossa. Metastases were to lungs, liver, pancreas, and kidneys.

Histological subtypes and prognostic problems in meningiomas

The incidence of the various histological subtypes of meningiomas was examined in 1238 patients with surgically treated meningiomas, about 80% arising within the cranial cavity. The histological classification used was that of Courville (1950) and Rubinstein (1972), but "angioblastic" meningiomas were segregated into 3 groups: highly vascularized meningiomas, hemangioblastomas, and hemangiopericytomas. Endotheliomatous and transitional forms constituted 85% of the total (71.5% of intracranial tumors), fibroblastic forms 6.6 and 7.5%, respectively, and highly vascularized (endotheliomatous or transitional) meningiomas 5.2% of the intracranial tumors, while true "angioblastic" meningiomas (hemangioblastomas and hemangiopericytomas) amounted to 2.8% of the total (3.1% of the intracranial tumors). 1.2% were "atypical" (so-called malignant) meningiomas; true meningeal sarcomas were excluded. The incidence of recurrence in patients surviving at least 5 years after apparently complete removal of the tumor was 13% for all sites, and 14.2% for intracranial tumors, but almost twice as high after partial removal. There were no significant differences in the recurrence rate and intervals between first and second operation according to the various histological subtypes of meningiomas, except for hemangiopericytomas which recurred with significantly higher frequency and, together with atypical meningiomas, at much shorter intervals than the others. The prognostic significance of some histological criteria in "non-angiomatous" meningiomas was examined in 211 patients surviving at least 5 years after apparently complete removal of the tumor. Among the recurrences, there was a significantly higher degree of cellularity and increased mitotic rate and, probably, of cortical invasion, while nuclear pleomorphism, increased vascularity, and focal necroses showed no definite differences. The presence of mitotic figures alone appeared to be of no prognostic value. While most recurrent meningiomas did not change their basic morphological type significantly, about 12.5% of the recurrences appeared to have a different rate of growth as suggested by increased cellularity and mitotic rates. In 2 cases an isomorphic (benign) meningioma became a true spindle cell sarcoma.