Cytologic features of ependymomas in smear preparations.

Since the cytologic features of brain smear preparations have not been described adequately in the literature, 13 histologically proven ependymomas with diagnostic smear preparations were reviewed. The series also included cases of myxopapillary ependymoma and papillary ependymoma. The typical cytologic appearance consisted of dichotomous patterns of small, epithelium-like cells merging with bipolar, fibrillated cells with pseudo-rosette formations. It is believed that careful scrutiny of intraoperative preparations allows one to make a distinction between pilocytic astrocytoma, fibrillary astrocytoma and metastatic carcinoma.