NEUROENDOCRINE DIFFERENTIATION OF ADRENOCORTICAL TUMORS

Background. The syndrome of multiple endocrine neoplasia type 1 freque ntly involves the adrenal cortex. The relationship between the diffuse neuroendocrine system and the adrenal cortex is not clear however, pa rticularly as the adrenal cortex is not considered to be an intrinsic part of the diffuse neuroendocrine system. Methods. The possible relat ionship between the adrenal cortex and the diffuse neuroendocrine syst em was investigated in a study of the immunohistochemical characterist ics of ten normal adrenal glands, four adrenal adenomas, and 18 adreno cortical carcinomas using the indirect peroxidase method of staining i ntermediate filaments and neuroendocrine proteins. Results. With synap tophysin, NSE, and vimentin there was focal staining in only few zona glomerulosa cells in the normal adrenal cortex, whereas adrenocortical carcinomas and adenomas were extensively positive for these proteins. Keratin immunoreactivity, present in 100% of the normal cortices, was demonstrable in only half of the carcinomas and absent in all adenoma s. Conclusions. Adrenocortical tumors may originate from neuroendocrin e foci. The findings illuminate the pathogenesis of adrenocortical car cinoma, and may carry significant implications about the choice of tre atment of patients with this malignancy and other related tumors.