Neuroendocrine differentiation of adrenocortical tumors.

BACKGROUND

The syndrome of multiple endocrine neoplasia type 1 frequently involves the adrenal cortex. The relationship between the diffuse neuroendocrine system and the adrenal cortex is not clear however, particularly as the adrenal cortex is not considered to be an intrinsic part of the diffuse neuroendocrine system.

METHODS

The possible relationship between the adrenal cortex and the diffuse neuroendocrine system was investigated in a study of the immunohistochemical characteristics of ten normal adrenal glands, four adrenal adenomas, and 18 adrenocortical carcinomas using the indirect peroxidase method of staining intermediate filaments and neuroendocrine proteins.

RESULTS

With synaptophysin, 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 adenomas.

CONCLUSIONS

Adrenocortical tumors may originate from neuroendocrine foci. The findings illuminate the pathogenesis of adrenocortical carcinoma, and may carry significant implications about the choice of treatment of patients with this malignancy and other related tumors.