Assessment of the pituitary hyperplasia/neoplasia interface

The determination of the type of proliferative process in the pituitary causing clinical symptoms is quite difficult using classical morphologic techniques, including immunocytochemistry and electron microscopy. The problem is unusually difficult when the material received from the surgeon consists of 1-2 mm fragments of tissue removed from the sella turcica. Morphologic criteria were extensively discussed by other investigators in this symposium. This manuscript discusses the application of flow cytometry using formalin-fixed, paraffin-embedded tissues, in the diagnosis of pituitary lesions.