Fifty adrenalectomy specimens containing normal (n = 3), hyperplastic (n = 4), or neoplastic (n = 43) medullary tissue were subjected to quantitative measurements of DNA content. Of the 43 pheochromocytomas, 16 were neoplasms inherited in the setting of multiple endocrine neoplasia type 2A. Five of 27 sporadic pheochromocytomas followed a malignant clinical course. Follow-up data were available in 25 patients. In normal medulla and adrenomedullary hyperplasia either diploid or euploid DNA distributions were found. In contrast, 87% (33 of 38) of the benign and all five malignant pheochromocytomas exhibited nondiploid or aneuploid DNA histograms. No differences in DNA content existed between sporadic and hereditary tumors. In contrast to earlier reports, in this study DNA cytophotometry was not suitable to discriminate benign from malignant adrenomedullary tumors. In addition, DNA measurements appeared not to be a useful tool to assess the prognosis of an individual malignant pheochromocytoma.
