Spongioblastomas, astrocytomas and Rosenthal fibers. Ultrastructural, tissue culture and enzyme histochemical investigations

Immunoelectron microscopy of Rosenthal fibers

Seventeen intracerebral gliomas containing Rosenthal fibers (RF) were studied by an immunoperoxidase method for localization of ubiquitin (UB), glial fibrillary acidic protein (GFAP), desmin and vimentin (VIM). The majority of RF showed an immunohistochemically negative core surrounded by a ring of overlapping reactions for UB, GFAP and VIM. Many RF were entirely negative for UB and intermediate filaments (IF). Immunoelectron microscopic localization of UB and GFAP was performed on seven selected tumors. UB was found in all RF and on IF in the proximity of RF. GFAP reaction was localized on astrocytic IF, including those trapped within RF, and within the granular component of some RF. In contrast to the light microscopic studies, neither GFAP- nor UB-negative RF were found on immunoelectron microscopy. VIM reaction on IF and a few RF was demonstrated in one tumor processed at low temperature into Lowicryl; it was much weaker than that for GFAP. Many cells with RF contained lysosome-like inclusions with material displaying electron density similar to adjacent RF; few of these inclusions were reactive for UB. It is concluded that RF formation is associated with ubiquitination of astrocytic IF. GFAP- and VIM-immunoreactive IF and products of their disintegration contribute to RF material. It is also suggested that the lysosomal system of astrocytes partially degrades RF.

Alpha B-crystallin is expressed in non-lenticular tissues and accumulates in Alexander's disease brain

Rosenthal fibers (RFs) are abnormal inclusions within astrocytes, characteristic of Alexander's disease. We have previously isolated a 22 kd protein component of RFs from Alexander's disease brain. By Western blotting, we detected its equivalent in several rat organs, with the highest level in heart, and in a human astrocytoma cell line (U-373MG). A cDNA library established from U-373MG was screened with an anti-RF protein antibody. A partial cDNA clone encoding the lens protein alpha B-crystallin was isolated. The anti-RF protein antibodies react with lens alpha B-crystallin. Furthermore, the distribution of alpha B-crystallin mRNA in rat organs is consistent with the Western blots. Therefore, alpha B-crystallin is not lens-specific and it can accumulate in large amounts in astrocytes in pathological conditions.

Glial filaments in the subcutaneous tumors of mouse glioma clones differently expressing glial fibrillary acidic protein. An immunohistochemical and ultrastructural study

Glial filaments contain vimentin and glial fibrillary acidic protein (GFAP). The question of how glial filaments change morphologically according to the expression of vimentin and/or GFAP has remained unclear. In this study, immunohistochemical and ultrastructural examinations were performed on the subcutaneously transplanted tumors of two clones (F6B3 and G10A10) derived from a mouse glioma. F6B3 tumor expressed GFAP and vimentin in large quantities. G10A10 tumor expressed plenty of vimentin but only a little of GFAP. Ultrastructurally, F6B3 tumor contained abundant cytoprocesses in most of which numerous intermediate filaments (IFs) were arranged in a parallel array. On the other hand, only a small number of the processes were seen in G10A10 tumor, which showed a few IFs arranged either randomly or sparsely in the processes. Both tumors commonly had the IFs accompanied by visible sidearms, but there was a difference in that the smooth and firm IFs were confined to part of F6B3 tumor. Thus, the comparison made between the two models presented differences in the content, arrangement and morphology of IFs, as well as in the manner of GFAP expression, suggesting correlation between these differences.

Distinctive growth patterns between cerebral and cerebellar astrocytomas--a tissue culture study

Astrocytomas have been alternatively considered as a single entity with topographical variabilities or as two different tumours--cerebral astrocytomas and mid line-cerebellar, astrocytomas. Twenty-two astrocytomas, 13 of the cerebral hemispheres, six cerebellar, two brain stem and one of spinal cord, have been studied by short-term tissue cultures. Two distinctive growth patterns have been found. Cerebral astrocytomas grew in the first week as radially arranged bipolar cells and subsequently by multipolar astrocytes in a reticular pattern. On the other hand, astrocytomas of the cerebellum, brain stem and spinal cord showed radial growth of long bipolar cells which persisted during the first 2-3 weeks. Only in the fourth week did a reticular pattern develop, but most of the cells remained bipolar. After the fourth week, a small number of multipolar astrocytes appeared and in two cases Rosenthal fibres were found. It is thus suggested that astrocytomas may be subdivided into two entities, those of the cerebral hemispheres and others in the cerebellum, optic nerve, brain stem and spinal cord which can be grouped as midline astrocytomas.

The astrocytic nature of glioblastoma demonstrated by tissue culture

Forty-eight cerebral astrocytomas and glioblastomas were studied by tissue culture for two purposes: (a) the establishment of a definite growth pattern of cerebral astrocytomas and (b) the comparison of this growth pattern and that of glioblastomas. According to the grade of malignancy the series was divided into four groups: low-, middle-, and high-grade astrocytomas and undifferentiated glioblastomas. All the astrocytomas showed the same growth pattern with two successive phases. First, bipolar cells in radial arrangement emigrated from the explant, whereas in the last weeks, multipolar astrocytic-like cells in reticular arrangement predominated. The more malignant the cases, the more prolonged the bipolar phase, with retardation of the development of multipolar cells. Glioblastomas showed the same behavior with maximal persistence of the bipolar phase. On this basis, we believe that (a) cerebral astrocytomas have a characteristic behavior in vitro and (b) the glioblastoma is an astrocytic tumor showing maximal dedifferentiation.

Granulofilamentous inclusions in a meningioma

We have studied the histology, immunocytochemistry, and ultrastructure of a syncytial meningioma which contained the unusual feature of large eosinophilic intracytoplasmic inclusions. Electron microscopic examination revealed that these bodies were granular, osmiophilic masses, closely associated with cytoplasmic filaments of intermediate size. Desmosomal junctions with a somewhat abnormal morphology were also observed, and the possible relationship between the inclusions and the dense components of desmosomes is discussed. This tumor is also compared to other tumors of the central nervous system with hyaline and granulofilamentous inclusions.

Optic nerve gliomas. II. Cytological characteristics. Observations on cell and tissue cultures

Cytological characteristics of optic nerve gliomas were studied parallel with histological structures in cell and tissue cultures. Histologically the tumours consisted of four different cell types: spindle-shaped elongated cells, round cells, stellate forms, and multinucleated cells. Dynamic properties of cultured optic glioma cells showed that stable cellular elements of the parent tissue arise from two fundamental populations, viz from elongated (piloid), and from round cells. Cells of both populations displayed a series of changes in the course of their cultures. A certain part of the slender elongated cells enlarged and became plump piloid cells of various shapes, or big stellate astrocytes. Giant multinucleated variants of these forms also emerged by fusion of the mononucleate forms. The round cells gradually turned into immature Astrocytes, and by a subsequent cell fusion they gave birth to big stellate cells. With the ageing of the cultures a polymorphous cellular picture developed which was mainly due to the active migratory and intracellular movement of the elongated and round cellular elements. Mitoses played a negligible role in this process. Several characteristics suggest that the round shapes are immature glia cells, and represent the least differentiated elements among all the cell components. The stellate and giant multinucleated forms might be considered as end-products of glia cell differentiation and they could originate both from the elongated and the round cells.

Subependymal giant-cell astrocytoma. Case report with ultrastructural study

A 13-year-old boy presented with an obstructive left lateral intraventricular mass. Pathological examination revealed a subependymal giant-cell astrocytoma. Further clinical investigation confirmed the diagnosis of tuberous sclerosis. Ultrastructural examination confirmed previously reported features of this tumor. Tumor cells containing large dense granulated bodies and dense-core vesicles, not previously described in this tumor, were identified.

Long-term prognosis in children with benign cerebellar astrocytoma

In 44 children with benign cerebellar astrocytoma, operated on between 1935 and 1959, two histological types could be distinguished, namely, a so-called juvenile type (31 children) and a diffuse type (13 children). All the children were followed to April, 1976, and the histological review was performed without knowledge of the survival in the single patient. For children with the juvenile type of cerebellar astrocytoma the 25-year cumulative survival rate was 94%, as against 38% for children with the diffuse type. It has thus been demonstrated that the morphological difference between the two types corresponds to a marked difference in survival rate.

The dilemma of childhood optic gliomas

A retrospective series reviewing 28 cases of optic glioma in childhood is reported from the Columbus Children's Hospital. The literature is reviewed from a clinical and pathological standpoint; in the pathological literature there is support for consideration of these lesions as a neoplastic entity, but none for designation of these gliomas as "hamartomas." An approach to the management of optic gliomas is presented. Treatment should be tailored to the individual patient; no clear therapeutic protocol appears to be supported by available data.

Mesectodermal leiomyoma of the ciliary body: a tumor of presumed neural crest origin

Two benign tumors of the ciliary body diagnosed as neurogenic tumors by light microscopy were shown by electron microscopy to be composed of smooth muscle cells with unusual morphologic features. The light-microscopic appearance of a background fibrillary matrix imparting a "neural" appearance was the result of the interweaving of myriad cell processes filled with thin cytoplasmic filaments possessing fusiform densities. The perikaryon of the tumor cells was relatively free of filaments and displayed mitochondria and stacks of rough-surfaced endoplasmic reticulum suggestive of Nissl substance. The basis for these remarkable "hybrid" tumor cells--combining myogenic and neurogenic characteristics--is believed to reside in the neural crest origin of the smooth muscle of the ciliary body (mesectoderm). The histogenetic implications of mesectodermal tissue and the tumors that it spawns are discussed.

Characteristics of human optic gliomas in tissue culture

Nine human optic gliomas were examined in tissue culture. Typically, growth from the explants revealed well differentiated bipolar cells with abundant 9 to 10 nm fibers similar to those observed in the surgical specimens. Multinucleation was rare except for one culture, which had as many as 20 nuclei arranged in a palisading fashion along the periphery of some of the cells. Degenerative changes of the 9 to 10 nm fiber bundles with the production of amorphous electron-dense deposits were observed both in vivo and in vitro, and were thought to represent the formation of Rosenthal fibers. A distinctive feature of some of the optic gliomas was the ability of their long, thin cellular process to form fibrous tangles in tissue culture. The correlation of these fibrous tangles in culture with Rosenthal fibers in vivo is still uncertain.

Tumors of the optic nerve

This is a review of primary and secondary tumors of the optic nerve. The emphasis is an optic nerve gliomas and meningiomas. Optic nerve gliomas are slowly growing astrocytic neoplasms of the anterior visual pathways, the majority of which occur within the first two decades of life, with equal sex incidence in about 1 of 200,000 patients presenting with eye complaints. The incidence is greater in neurofibromatosis. The typical presentation is visual impairment in a verbal pre-school child with optic canal enlargement and optic atrophy. An intraorbital location of the tumor leads to axial, irreducible, non-pulsatile proptosis. An intracranial location may disturb hypothalamic and pituitary function and produce hydrocephalus. Ocular findings may also include limited motility on a mechanical-restrictive basis, a pupillary relative afferent defect, nystagmus, and variable, non-specific visual field defects. Roentgenographic studies may show concentric unilateral enlargement of the optic canal with preservation of a well corticated margin, a fossa under the anterior clinoid process in continuity with the optic canal ('J'-shaped sella), and findings of increased intracranial pressure. On pathologic examination the tumor is a smooth, fusiform, intradural enlargement of the optic nerve. Histologically there is proliferation of elongated (pilocytic) astrocytes in reticulated patterns with intervening microcystic spaces containing mucosubstance and surrounding reactive hyperplasia of the arachnoid. Mitoses are not found. The diagnosis is clinical X-ray studies and brain scan should be performed. The differential diagnosis is that of unilateral proptosis in a child and includes acute ethmoiditis, hyperthyrobidism, craniostenosis, other neoplasms, Hand-Schuller-Christian disease, and orbital hemorrhage due to trauma. Surgical resection is performed in cases with unilateral optic nerve involvement, the surgical approach being determined by tumor location. Bilateral or chiasmal cases are treated with radiotherapy when progression occurs. Malignant optic nerve gliomas and optic nerve hyperplasia are also discussed. Optic nerve meningiomas arise from the nerve sheath and are to be distinguished from orbital meningiomas arising from ectopic arachnoidal cells or those secondarily involving the orbit by extension from adjacent sites. Up to 80% of orbital meningiomas occur in females, in two age peaks, 25% in the first decade, and the rest in the 5th decade. Meningiomas present with visual loss and may produce proptosis, papilledema and/or optic atrophy, retinal striae, opticociliary shunts, limitation of extra-ocular movements, and lid edema, Signs of von Recklinghausen's disease should be sought. X-rays are the mainstay of diagnosis. Orbital meningiomas are composed of cells in sheets or in whorls with some spindle shaped cells. Calcifications are typical. Usually the dura is penetrated and the orbit invaded. Primary orbital meningiomas are locally infiltrating but do not metastasize. Complete local excision en bloc is recommended...

Rod-shaped filamentous inclusions and other ultrastructural features in a cerebellar astrocytoma

A biopsy specimen of a cerebellar astrocytoma from a 14-year-old girl was studied by light and electron microscopy. Histologically the tumor showed a mixture of loose and compact areas with numerous Rosenthal fibers. By electron microscopy most tumor cells contained, besides the usual organelles, large amounts of 70 to 100 A thick filaments. Classical Rosenthal fibers were also identified. In addition many cell bodies and processes were sprinkled with fragments of Rosenthal fiber material. Ordered filamentous arrays (so-called Hirano bodies) were seen in a number of tumor astrocytes. They are considered to be a nonspecific arrangement of filament units largely devoid of cytopathologic significance. Other ultrastructural features of some tumor cells were inchoate forms of the granulated bodies of conventional histology, paired cisternal elements of rough endoplasmic reticulum, and honeycomb-like profiles of transversely cut cylindrical units of smooth endoplasmic reticulum. Microtubular bodies were numerous in the endothelial cells of the tumor vessels.

Optic nerve glioma in an 18-month-old child

An optic nerve glioma in an 18-month-old child was examined by both light and electron microscopy. The tumor revealed the characteristic features of uniform benign and fibrillary astrocytoma. Rosenthal fibers and calcium depostis were found within numerous intracellular glial processes. The above features indicated a slow-growing tumor of long duration, confirming the generally supported assumption of the congenital nature of optic nerve glioma. One unsuspected feature was the presence of fenestrated blood vessels.