Cellular DNA Content of Pituitary Tumours: Its Relationship to Morphology and Hormonal Type of Tumour

The DNA content of 24 human pituitary tu- mours was analysed with flow-cytofluorometry, and com- pared with the morphologic characteristics of the tumours. Fifteen tumours had a diploid and 9 had an aneuploid DNA pattern. Minimal and moderate degrees of mitosis and nuclear polymorphism can possibly occur more fre- quently in aneuploid pituitary tumours than in diploid pituitary tumours (mitoses: 56% versus 27 %; nuclear polymorphism: 78 % versus 53 %). Otherwise no correla- tion between the degree of ploidy and the histopathologic or ultrastructural features could be registered. Thus, pitui- tary tumours of the same morphology can be subdivided according to their ploidy pattern.