Immunohistochemical and Electron Microscopic Study of Meningeal Granular Cell Tumors in Rats

Morphological and Ultrastructural Study of the Histogenesis of Meningeal Granular Cell Tumors in Rats

“…Although the tumor cells of MMs and GCTs exhibited ultrastructural features that corresponded to human meningiomas (1, 13) and rat GCTs (6,9), respectively, the findings of a few dense bodies in MMs and a slight interdigitating appearance in GCTs emphasize the importance in accomplishing the present purpose. Friede and Yasargil (3) reported that a human suprasellar meningioma contained multifocal nests of granular cells in which there was ultrastructurally an interdependent relationship between meningioma cells and granular cells (3).…”

“…That granular cell tumors (GCTs) in the rat brain are derived from meningeal arachnoid cells has been suggested (6,7,9,10). The arachnoid cell origin has been supported by the following evidence: anatomical location of GCTs close to the leptomeninx, presence of mixed forms (MIXs) of GCTs and meningothelial meningiomas (MMs), and morphological similarities in ultrastructure between GCTs and arachnoid cells (6,9,10).…”

“…The arachnoid cell origin has been supported by the following evidence: anatomical location of GCTs close to the leptomeninx, presence of mixed forms (MIXs) of GCTs and meningothelial meningiomas (MMs), and morphological similarities in ultrastructure between GCTs and arachnoid cells (6,9,10). At the ultrastructural level, however, morphological similarities have not been investigated adequately in these tumors.…”

“…At the ultrastructural level, however, morphological similarities have not been investigated adequately in these tumors. Indeed, it is known that GCTs are composed of 2 types of tumor cells: granular cells with cytoplasmic dense bodies and filamentous cells with intermediate filaments con-nected with intercellular junctions (9). In rat meningiomas (4) (10).…”

“…Friede and Yasargil (3) reported that a human suprasellar meningioma contained multifocal nests of granular cells in which there was ultrastructurally an interdependent relationship between meningioma cells and granular cells (3). The (6,9,10). Thus, both tumors should be classified as granular cell meningiomas (6).…”