グリオーマ腫瘍組織内の変性構造物 (Rosenthal線維, 円形顆粒小体, 硝子様封入体) に関する組織学的, 免疫組織化学的, 電顕的検討

抄録

The histology, immunohistochemistry and ultrastructure of three types of intracytoplasmic degenerative structures (Rosenthal fibers, rounded granular corpuscles and hyaline inclusions) were studied in 10 gliomas containing these structures.
The elongated hyaline bodies known as Rosenthal fibers were found in three pilocytic astrocytomas. Immunoperoxidase stain for GFAP were generally negative and the bodies were often encompassed peripherally by GFAP-positive rims of the cytoplasm. Electron microscopic examination revealed that these bodies were osmiophilic amorphous masses of irregular shape, closely associated with cytoplasmic filaments of intermediate size. In two other gliomas (pleomorphic astrocytoma and mixed oligo-astrocytoma) cells packed with tiny eosinophilic granules were found within the tumor tissue. By electron microscopy the granules were found to have a structure corresponding to that of Rosenthal fibers. It is considered that degradation of glial filaments may be in some way related to the formation of Rosenthal fibers.
Rounded granular corpuscles appeared as round or oval bodies with finely granulated internal structures. The corpuscles were observed in 3 pilocytic astrocytomas and 5 pleomorphic astrocytomas. Immunohistochemically, the corpuscles were generally positive for S-100 protein and their peripheral rims were immunoreactive for GFAP. By electron microscopy the bodies were found to be distended cytoplasms of neoplastic astrocytes packed with numerous membrane-bound dense bodies, vacuoles and membranous profiles. Intracytoplasmic filaments were found pushed towards the periphery of the cytoplasm. Intracytoplasmic hyaline inclusions were found in 5 pleomorphic astrocytomas. These were of a globular or oblong shape and their size varied greatly. By electron microscopy the inclusions appeared as rounded electrondense bodies of varying size within the cytoplasm of neoplastic cells, some of which were membrane-bound. Larger inclusions of oblong shape displayed a complicated internal structure. Because of the fine structural features both the granular corpuscles and hyaline inclusions were considered to be of lysosomal origin.