Meningothelial meningioma with "amianthoid" fibers. Case report with ultrastructural study

The case of a meningothelial meningioma with 'amianthoid' fibers in a 48-year-old woman is presented. By light microscopy the tumor showed the typical features of meningothelial meningioma and rounded, deeply eosinophilic, and fibrillary areas, especially around and/or in the vicinity of blood vessels. These fibers are also called 'amianthoid' fibers. Ultrastructurally, these foci were made up of disorderly arranged and interwaving mature collagen fibrils with a variable width between 40 and 190 nm. No evidence of intracellular collagen synthesis by the tumor cells was found. The presence of 'amianthoid' fibers does not seem to carry any prognostic significance.

Transforming growth factor-beta and transforming growth factor beta-receptor expression in human meningioma cells

The transforming growth factor-beta (TGF beta) family in mammals includes three closely related peptides that influence proliferation and numerous physiologic processes in most mesenchymal cells. In this study, Northern blots, immunohistochemistry, TGF beta radioreceptor assays, TGF beta receptor affinity labeling and [3H] thymidine incorporation were used to evaluate whether primary cell cultures of human meningiomas synthesize the three TGF beta isoforms, bear TGF beta receptors, and respond to TGF beta. Transcripts for TGF beta 1 and 2 were detected in the three cases analyzed. Transforming growth factor-beta 1 immunoreactivity was detected in three of six cases, and TGF beta 2 and 3 immunoreactivity were detected in each case analyzed. Media conditioned by cells cultured from six meningiomas also contained latent TGF beta-like activity. Transforming growth factor-beta receptor cross-linking studies identified TGF beta binding sites corresponding to the type 1, type 2, and type 3 receptors on meningioma cells. Treatment with active TGF beta 1 produced a statistically significant reduction in [3H] thymidine incorporation after stimulation with 10% fetal calf serum and epidermal growth factor in all six cases studied.

[Secretory meningioma]

Pseudopsammomatous inclusions were found in two cases of secretory meningioma. Their description includes ultrastructural and immunohistochemical features.

[The ultrastructural and immunohistochemical observations of anaplastic meningioma]

Eighteen cases of anaplastic meningioma were studied by LM, EM and immunohistochemistry for vimentin, EMA, keratin, GFAP and S-100. Microscopically, there were four histologic types, i.e. fibrosarcoma-like, angiosarcoma-like, polymorphic giant cell sarcoma-like and angiopapillary structure. By EM, four kinds of cells: undifferentiated cell, intermediate transitional cell, spindle-shaped cell, and giant cell, were found and variant transitions from undifferentiated or poorly, differentiated to meningioma cells were observed. Their ultrastructures and immunohistochemical features are similar to those of malignant mesothelioma. Since these two kinds of neoplasm showed both mesenchymal and epithelial cells in the features, the authors consider that their histogenesis may also be similar.

Meningioma of the mandible

This is the first case report to the authors' knowledge of a primary extracranial meningioma located in the mandible. Ultrastructurally, the tumor cells had intricate cellular membranes and desmosome-like attachment structures. Using immunohistochemical analysis, the tumor expressed both epithelial membrane antigen and vimentin. Although the origin of extracranial meningiomas has been attributed to proliferation of ectopic embryonal nests of arachnoidal cells, the proliferation of perineural cells of peripheral nerves also is possible as a result of the structural and functional similarities of perineural cell and arachnoid cells. The authors suggest that extracranial meningiomas may be more common than published reports indicate because of certain histologic similarities between these tumors, neurilemomas, and solitary neurofibromas.

Pulmonary meningioma. Report of a case with electron microscopic and immunohistochemical findings

A pulmonary meningioma was removed from a 55-year-old woman. She had no evidence of a cranial meningioma after a 3-year follow-up period. Results of immunohistochemical and electron microscopic studies of the tumor were similar to those for cranial meningiomas. The literature on this subject was reviewed and a possible origin for these tumors in the lung is discussed.

Immunohistochemical localization of cell adhesion molecule epithelial cadherin in human arachnoid villi and meningiomas

Cadherins are a family of intercellular glycoproteins responsible for calcium-dependent cell adhesion and are currently divided into four types: epithelial (E), neuronal (N), placental (P), and vascular (V). Since cadherins are known to be indispensable for not only morphogenesis in the embryo but also maintenance of tumor cell nest, we examined the expression of E-cadherin in 31 meningiomas (11 syncytial, 12 transitional, 8 fibroblastic) and 3 arachnoid villi by immunoblot and immunohistochemical analyses. In the immunoblot analysis, E-cadherin was detected at the main band of Mr 124,000 in all of the arachnoid villi, as well as syncytial and transitional types of meningiomas, but not in the fibroblastic type. The immunohistochemical examination showed that E-cadherin was expressed at the cell borders of syncytial and transitional types, but the expression was absent in the fibroblastic type. Immunoelectron microscopy showed that E-cadherin was localized at the intermediate junctions in arachnoid villi, while it was detected diffusely at the cell surface in meningiomas. It is suggested from these data that the expression of E-cadherin might be closely related to the differentiation and organogenesis of meningioma cells.

Epidermal growth factor receptor in human brain tumors

The expression of epidermal growth factor receptor (EGF-R) was examined in 27 primary human brain tumors (7 glioblastomas, 10 astrocytomas, 5 oligodendrogliomas, 1 schwannoma, 1 ganglioneuroma, 1 medulloblastoma, 1 ependymoma, 1 histiocytic lymphoma), in 6 brain metastases from lung carcinomas and in 20 meningiomas. Peritumoral tissues histologically normal excised surgically along with a large tumor were used as control. All plasma membranes from brain tissues tested showed specific EGF binding. The EGF receptor is expressed at low levels in the control human brain and at very high levels in 60% of the total intracranial tumors studied. When the various histological types of tumors were analyzed, the higher percentage of positive tumors was found with the meningiomas (85%) and the glioblastomas (71%), while the lower percentage of positivity was found with the oligodendrogliomas (40%) and the astrocytomas (30%). A good correlation between binding and total amount of EGF-R protein detected by Western Blot was also observed.

Intracranial meningioma with pulmonary metastases: diagnosis by percutaneous fine-needle aspiration biopsy and electron microscopy

The authors report a patient with a history of recurrent intracranial meningiomas in whom two lung nodules developed. A percutaneous fine-needle aspiration biopsy of one nodule demonstrated spindle-form cells; the tumour was specifically diagnosed as metastatic meningioma on the basis of electron microscopic findings.

[Malignant meningioma with lung metastases in a Boxer]

The rare case of a meningioma with pulmonary metastases in a dog is described. Clinically, the ten-year-old boxer bitch showed generalized seizures, strabismus and deficient proprioception. The post-mortem examination revealed a basically localized meningeal tumor, having the light- and electron-microscopic appearance of a malignant meningotheliomatous meningioma. Immunohistochemically, the tumor cells did not show any positive reaction with antibodies to GFAP, S-100 protein, NSE, vimentin, cytokeratin, desmin, and von Willebrand factor (factor VIII related antigen). Immunohistochemical examination of seven other canine meningiomas showed an identical pattern. The results and the relevant literature are discussed.

Pulmonary meningioma. Immunohistochemical and ultrastructural features

Two cases of solitary primary pulmonary tumors showing the immunohistochemical and ultrastructural features of meningothelial meningiomas are presented. The benign clinical and radiologic course, the negative computed tomography scan of the brain (case 1), and negative neuropathologic investigation (case 2) support the diagnosis of a primary pulmonary meningioma rather than a metastazing malignant intracranial meningioma. Negative neuroendocrine markers (neuron-specific enolase, chromogranin, bombesin) and the lack of neurosecretory granules by electron microscopy confirm the diagnosis of this rare pulmonary tumor.

Glycogen-rich meningioma. Case report and short review

A case of meningioma with cytoplasm rich in glycogen granules is described as an atypical type of meningotheliomatous meningioma.

Interaction between human brain tumour biopsies and fetal rat brain tissue in vitro

The invasiveness of human intracranial tumours was studied in an organ culture system. Biopsies from six glioblastomas, four astrocytomas, two mixed gliomas, one ependymoma, four meningiomas and two carcinoma metastases were cut into fragments of 0.5 mm diameter, and placed in agar overlay tissue culture. The tumour specimens formed spheroids which were co-cultured with cell aggregates or fragments from fetal rat brain for up to 10 days in vitro. The invasiveness of the glioblastoma spheroids was characterised by a gradual destruction of normal brain tissue by tumour cells, followed by replacement of normal tissue by these cells. Co-cultures from two glioblastomas showed lesions in the normal brain tissue in areas removed from the tumour cells. Tumour spheroids from four glioblastomas totally destroyed the normal brain tissue without any change in the original tumour spheroid configuration. The low-grade gliomas were less invasive than the glioblastomas. The meningiomas and the metastases were non-invasive. This organ culture assay appeared to reflect the in situ invasive behaviour of the brain tumours examined. It is suggested that it may be used for evaluating the aggressiveness of individual brain tumours with the specific aim of correlating clinical data with the biological character of the tumour.

Nucleolar organizer regions in meningiomas. Correlation with histopathologic malignancy grading, DNA cytometry and clinical outcome

Eighty-one meningiomas (63 grade I, 9 grade II and 9 grade III) and 2 meningeal sarcomas (grade IV) were investigated by a simple one-step silver staining for nucleolar organizer region (NOR)-associated proteins (AgNOR technique) and by DNA cytometry. The number of NORs per cell and the NOR area per cell were correlated with the histopathologic grading, as were the 5c exceeding rate and the 2c deviation index (2cDI) obtained by DNA cytometry. The differences in NOR parameters were only significant (at P less than .001) between grades I and II; P was less than .05 for the 2cDI between grades I and II. No significant differences between grades II and III were found. Among recurrent tumors, the AgNOR technique revealed the proliferative potential in 8 of 11 tumors studied, whereas DNA cytometry failed to recognize malignant features in 8 of 10 tumors investigated.

Expression of PDGF beta-receptors in human meningioma cells

Meningioma is a generally benign tumor derived from arachnoid tissue. We have investigated the presence of functionally active PDGF-receptors on human meningioma cells in culture. Tumor samples were obtained from 3 surgically removed benign meningiomas and normal arachnoid tissue from an autopsy case. Binding studies were performed by using 125I-labelled recombinant PDGF-AA and PDGF-BB. Only 125I-PDGF-BB showed specific binding to all tumor-cell cultures after incubation of cells for 2 hr at 4 degrees C. Effects of PDGF-AA and PDGF-BB on DNA synthesis were measured as 3H-thymidine incorporation during 48 hr of labelling cells maintained in Eagle's minimum essential medium 0.5% fetal calf serum. PDGF-BB but not PDGF-AA stimulated DNA synthesis in all 3 tumor-cell cultures. Total cellular RNA was analyzed by Northern blotting and hybridization with a 32P-labelled human PDGF beta-receptor probe, and PDGF beta-receptor mRNA was found in both tumor and arachnoid cell cultures. Furthermore, PDGF beta-receptor mRNA was shown to be present in 2 meningioma biopsies and immunohistochemical staining revealed that PDGF beta-receptors are present in meningioma and arachnoid tissues in vivo. It appears that a possible way of maintaining human meningioma cell growth in vivo is through activation of PDGF beta-receptors.

Immunohistochemical expression of glutathione S-transferase placental type (GST-pi), a detoxifying enzyme, in normal arachnoid villi and meningiomas

Human normal dura mater containing arachnoid villi were examined for their expression of glutathione S-transferase placental type (GST-pi), a detoxifying enzyme, using an immunohistochemical method. All of the arachnoid villi and arachnoid cells in five normal cases were found to have expression of GST-pi, although no positive reaction for the enzyme was present in other tissues of the dura mater. The results show a possible role for arachnoid tissues in protecting human brain from hazardous xenobiotics in the cerebrospinal fluid. Twenty-six meningiomas were also examined for expression of the enzyme. Tissues of meningotheliomatous meningiomas were always positive for expression of the enzyme. Transitional meningiomas also showed the expression in their meningotheliomatous components. No staining reaction of GST-pi was recognized in fibroblastic meningiomas except for two cases with a tendency to meningotheliomatous differentiation. The findings suggest a functional similarity between the arachnoid tissues and meningotheliomatous components of meningiomas.

Peritumoral brain edema in intracranial meningiomas

We analyzed 38 patients with 39 meningiomas verified pathologically. The study included 27 females and 11 males. The ages of the patients on admission ranged from 11 to 77 years (averaged 47.6 years). The incidence of brain edema associated with meningiomas was 69%. The extent of peritumoral edema on the CT scans positively related to the duration of preoperative symptoms, the location and size of tumors, and breaching of the cortex by meningiomas. The meningotheliomatous meningiomas were frequently associated with significant brain edema. The ultrastructural features showed some relationship between increased secretory activity and the extent of peritumoral edema.

Comparison of a human granular cell tumour (myoblastoma) with granular cell tumours (meningiomas) of the rat meninges--an immunohistological and ultrastructural study

A single human granular cell tumour (myoblastoma) was compared with seven rat granular cell tumours (meningiomas) of the meninges. The comparison was made histologically, ultrastructurally and using immunocytochemical markers. A selection of antibodies to histiocytic, muscle, neural, neural crest and mesenchymal antigens was used. Histogenesis of both the human and rat tumours from neural crest-derived cells was evident and it is suggested that the term 'meningioma' for these rat tumours is a misnomer.

Epidermal growth factor receptor expression in 72 meningiomas

The expression of epidermal growth factor receptor (EGF-R) was studied immunohistochemically in 72 meningiomas using two monoclonal antibodies with specificities to protein and carbohydrate components, respectively, of the external domain of the EGF-R. One third of the tumors had cytoplasmic and membrane positivity with the protein-specific antibody but in none were there positive tumor cells with the carbohydrate-specific antibody which recognizes the blood group A antigen. There was no difference in EGF-R expression between typical and aggressive meningiomas. No evidence was found to support previous reports of specific EGF-R immunoreactivity in the vascular endothelial cells of meningiomas. The authors believe this discrepancy to be due to detection of normal blood group A antigen attached to endothelial cells in patients of blood group A or AB. This occurs because many monoclonal anti-EGF-R antibodies are specific for A antigen which is found on the EGF-R of A431 cells but has not been reported on EGF-R elsewhere.

Myxoid meningioma

A mucosubstance-rich myxoid meningioma that recurred twice is reported. This rare form of meningioma is a potential source of confusion with other myxoid neoplasms such as metastatic adenocarcinoma or chordoma. In addition to the usual stigmata of meningial cell differentiation, ultrastructural examination revealed spaces delineated by a network of cellular processes and enclosing loose granular and fibrillar material. This neoplasm is probably linked to the so-called microcystic meningioma but has an overt production of acid mucosubstance.

An ultrastructural and immunohistochemical study of extracellular matrix in meningiomas

Extracellular matrix of meningiomas was studied by light and electron microscopy with the aid of immunohistochemical techniques. Special attention was paid to the distribution of type I, III, IV, V collagens and laminin with a comparison between meningothelial and fibroblastic types. Connective tissue fibers and basement membrane were not found among the tumor cells in the meningothelial type, but were found in the fibroblastic type. The immunolocalizations were consistently demonstrated extracellularly, but were not within the cytoplasm. Type I, III and V collagens were usually demonstrated in the fibrous septum in the meningothelial type, while they were localized among the tumor cells in the fibroblastic type. Furthermore, type IV collagen and laminin were demonstrated within the vascular walls or around the syncytium in the meningothelial type, while they were localized among the tumor cells in the fibroblastic type. In both types the expression of type IV collagen and laminin was closely related to the distribution of basement membrane. Although meningothelial and fibroblastic meningiomas showed quite different distribution of extracellular matrices, the profile of collagen types expressed by these two basic types was essentially the same. The cellular derivation of meningiomas was discussed with particular attention to the structure of human arachnoid villi and meninges.

Histological, ultrastructural and chromatographical discrimination of phospholipids in meningiomas

Phospholipids in meningiomas were studied by light and electron microscopy, and by high-performance liquid chromatography. They were microscopically demonstrated in six of the ten cases by Sudan III staining after the fixation with potassium dichromate. However, the conventional ultrastructural fixation with glutaraldehyde and osmium tetroxide failed to confirm phospholipids, as most of them were dissolved during dehydration. In contrast, the specimens pretreated with tannic acid before osmication ultrastructurally retained phospholipids which were represented by multilamellar bodies or ribbon-like rings. Both were found in 23 of the 30 cases within the cytoplasm, among the plasma membranes and in the extracellular matrices. The outermost lamella or ribbon showed a direct continuity from the neighbouring plasma membranes of the cytoplasm or the mitochondria. The multilamellar bodies showed an overall distribution, while the ribbon-like rings were predominantly distributed around the psammoma bodies. Precipitation of hydroxyapatite crystals within the ribbon-like rings resulted in matrix minerals of psammoma bodies. Chromatographical analyses of meningiomas disclosed phospholipids including phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, sphingomyelin and phosphatidyl inositol in that order. Psammomatous meningiomas contained a higher percentage of phosphatidyl serine than non-psammomatous tumors. Ultrastructural study of synthetic phospholipids adequately treated with tannic acid showed that the multilamellar bodies were similar to phosphatidyl choline, while the ribbon-like rings were similar to phosphatidyl serine. The role of phospholipids in meningiomas is discussed.

Meningioma of the paranasal sinuses. A report of two cases

Two patients presented with primary meningiomas arising in the paranasal sinuses. Despite nonspecific symptoms, both patients had extensive local clinical disease. One patient had a lateral rhinotomy with total removal of tumor; he has remained well for 3 years. The second patient, who was not a surgical candidate because of her cerebrovascular disease, was identified retrospectively. Her tumor was not originally studied using current day morphologic methods. She was irradiated following a diagnosis of malignant tumor. The histologic features of nasal meningioma are similar to those of conventional intracranial lesions, including nuclear pseudoinclusions. Although the unusual location may suggest carcinoma, melanoma, or olfactory neuroblastoma, adjunctive use of electron microscopy and immunohistochemistry can be combined to arrive at the correct diagnosis.