Immunopathology of adrenal and renal cortical tumors. Coordinated change in antigen expression is associated with neoplastic conversion in the adrenal cortex.

A series of adrenal cortical adenomas (ACA) and carcinomas (ACC), as well as normal adrenal cortex have been studied by a panel of 11 antibodies to characterize antigenic changes that may distinguish these morphologically similar entities. Normal adrenal cortex and ACA express low-molecular weight cytokeratin intermediate filaments. However, none of the six primary or seven metastatic ACCs were found to express detectable levels of cytokeratins. In contrast, vimentin was seen in all ACCs studied and was heterogeneously expressed by ACAs. However, its expression was usually confined to stromal elements of the normal adrenal cortex. We conclude that adrenal cortical cells undergo characteristic changes in intermediate filament expression during the process of neoplastic conversion and malignant transformation. Undetectable expression of cytokeratins and strong expression of vimentin is associated with malignant adrenal cortical lesions. In addition, we examined the antigenic phenotype of a series of primary renal cell carcinomas (RCC). Renal cell carcinomas express cytokeratins, while ACCs do not. The majority of primary RCCs express Lewis blood group isoantigens (most commonly Lewis X), while ACAs and ACCs do not. The panel of antibodies described here may help to distinguish morphologically similar lesions of like histogenesis (ACAs vs. ACCs) and lesions of different histogenesis (adrenal vs. renal) on the basis of their composite antigenic phenotypes.