Flow cytometric DNA analysis for the determination of malignant potential in adrenal and extra-adrenal pheochromocytomas or paragangliomas.

DNA ploidy studies were performed by flow cytometry on extracted nuclei from 53 adrenal, 13 carotid body, 14 retroperitoneal, two intrathoracic, two urinary bladder, and one cauda equina pheochromocytomas (paragangliomas). A specific technique was used for preparation of paraffin-embedded tissue into single associated nuclei, and another specific method was used for propidium iodide staining. Twenty normal adrenal glands were also analyzed as controls. Six tumors in the adrenal medulla yielded uninterpretable histograms (coefficient of variation >7%) because of excessive cell debris or other technical failure