[Flow cytometric DNA analysis of normal adrenal tissues and adrenal tumors]

Flow cytometric DNA analysis (FCM) of adrenal tumors was studied to evaluate whether FCM will be a useful examination for differentiating between benign and malignant adrenal tumors. 10 specimens of surgically resected (for renal cell carcinoma confined within the middle or lower pole) normal adrenal glands and 20 specimens of surgically resected adrenal tumors were submitted for the study. Hyperplastic adrenal cortex as well as normal adrenal gland showed normal diploid pattern. On the other hand, some of the cortical adenomas showed tetraploid patterns, which has been known to be an index of malignancy in most of the flow cytometric intervention to other solid tumors. Conn adenomas were especially apt to show this tendency, in which as much as 86% showed tetraploid pattern. Proliferation Index (PI) (ratio of S + G2 +M cells for the whole population of analyzed cells) were as much as 9.45 +/- 6.97% in normal adrenal cells, whereas it was much higher in cortical adenomas (17.75 +/- 8.53%). As a matter of fact, PI of hyperplastic adrenal cortex was within the same range as that of the normal adrenal glands. In pheochromocytomas, aneuploid pattern, which has been believed to be a definite index of malignancy, was shown in 60% of the cases, tetraploid pattern in 20%, and normal diploid pattern in only 20%. As a matter of fact, a case of non functioning cortical adenocarcinoma and a case of malignant pheochromocytoma were judged to show typical aneuploid pattern. Thus, the application of the flow cytometric diagnosis for adrenal tumors was supposed to require some refinement in understanding the significance of aneuploidy or tetraploidy.