Objective: To review the cytomorphologic picture of pituitary adenomas as revealed by intraoperative smear preparation and to note features useful in differential diagnosis from other sellar tumors.
Study design: A total of 46 pituitary adenomas in which intraoperative smears were available were reviewed. All tumors were subsequently examined by paraffin section and immunohistochemistry.
Results: The important cytologic appearances were epithelial cords and sheets with dyscohesive ends, acini and papillary formations. Cytoplasmic contents, depending on functional status, were variably clear, with vacuolation or eosinophilic bodies and occasional paranuclear bodies. Mild cellular pleomorphism and binucleate forms were common.
Conclusions: Pituitary adenomas possess distinct cytologic features that are important in intraoperative differential diagnoses from normal pituitary tissues, germinomas, meningiomas, craniopharyngiomas and oligodendrogliomas.