Background: Mixed pituitary adenoma-gangliocytomas are rare tumors with a broad morphologic spectrum. Smear cytology is a useful tool for recognizing these tumors in an intraoperative setting.
Cases: The patients were 45 and 30 years old, and both presented with headache. Intraoperative smears in both cases showed a tumor composed of adenomatous and neuronal elements, in varying proportions. The first case had sheets of monotonous neuroendocrine-type cells with occasional interspersed ganglion cells. The second case, however, had a prominent fibrillary background and was predominantly neurocytic, with a mixture of large ganglion-like cells, intermediate cells, and only rare adenomatous cells.
Conclusion: The diagnostic features of mixed pituitary adenoma-gangliocytomas can be recognized on intraoperative smear preparations. Smear preparations are often more useful than frozen sections because freezing artifacts may mask one of the two components of the tumor. The proportion of adenomatous and neuronal elements can vary widely from case to case. Careful search for a neuronal component should be made, especially if there is a clinical history of a pituitary adenoma showing incomplete response to hormonal therapy.