Immunocytochemical and ultrastructural studies of eosinophilic granular bodies in astrocytic tumors.

Eosinophilic granular bodies (EGBs) are studied immunocytochemically and ultrastructurally in a case of low-grade and a case of high-grade astrocytoma. EGBs are recognized as brightly eosinophilic round bodies of variable size in hematoxylin and eosin-stained sections. Immunocytochemically some EGBs are positive for antibodies raised against alpha B-crystallin, ubiquitin and glial fibrillary acidic protein with the staining patterns for each being different from one another. Ultrastructurally EGBs consist of membrane-bound round body of various diameter ranging from 50 nm to 20 microns. Small EGBs contain electron-dense homogeneous material with occasional myelin figures, while electron-dense homogeneous material or loose granular profiles. Our studies demonstrate (1) ultrastructural variety of EGB; (2) and alpha B-crystallin epitope in EGB; and (3) the presence of EGB in high-grade as well as low-grade astrocytoma.