Abstract
Background: Granular cell astrocytoma (GCA) is a rare variant of astrocytoma, characterized by an aggressive prognosis compared to conventional astrocytomas of the same World Health Organization grade. Intraoperative smears provide useful clues in diagnosing neuropathology, especially in rarely encountered central nervous system tumors. Case: The patient was a 53-year-old man who presented with a huge mass at the left temporal lobe with peritumoral edema on MRI. The crush smears revealed singly-scattered, large eosinophilic cells with eccentrically located nuclei as well as plump, finely-granular cytoplasm with distinct borders. Mild cellular atypia and absence of mitotic activity were noted. These cells were admixed with small mature lymphoid cells. Histology showed scattered large granular cells which were positive for glial fibrillary acidic protein. Conclusion: The most helpful imprint cytologic findings of GCA were as follows: (1) large cells containing eosinophilic granular cytoplasm rather than the foamy or bubbly cytoplasm associated with macrophages or renal cell carcinomas; (2) distinct granular cell borders in contrast to the ruffled membrane of macrophages, and (3) markedly large-sized granular cells, ranging from 60 to 100 µm in diameter.