Fifty adrenalectomy specimens containing normal (n = 3), hyperplastic (n = 4) or neoplastic (n = 43) medullary tissue were subjected to quantitative cytophotometric measurements of DNA content. Differing evaluation schemes were applied for interpretation of DNA distribution patterns. Of the 43 phaeochromocytomas (PCC), 16 were inherited as part of the syndrome of multiple endocrine neoplasia type 2a (MEN 2a). Five of 27 sporadic PCCs followed a malignant course. Three benign and three malignant PCCs lacked endocrine activity. In normal medulla and in adrenomedullary hyperplasia, diploid or euploid DNA distributions were found. In contrast, 87% (33/38) of the benign and all 5 malignant PCCs exhibited non-diploid or aneuploid DNA histograms. No differences in DNA content existed between functioning and non-functioning PCCs or between sporadic and hereditary tumours. In this study, in contrast to earlier communications, DNA cytophotometry did not discriminate between benign and malignant adrenomedullary tumours. In addition, as opposed to the findings in a variety of other endocrine tumours, DNA measurements did not appear to be a useful tool to assess the prognosis of an individual malignant PCC.
