Archival, formaldehyde-fixed, and paraffin-embedded material comprising 27 adrenocortical carcinomas (ACC, meeting Weiss' histologic criteria), 28 pheochromocytomas (PCC), and adjacent nontumorous tissue (13 glands) were analyzed by immunogold-silver staining for the expression of polysialic acid (poly Sia), cytokeratins (CK), synaptophysin (SYN), chromogranin A (CrgA), somatostatin (SOM), calcitonin (CT), and the "adrenocortical marker" D11.