Fat-Cell Metaplasia in the Adrenal Cortex: Incidence, Structure, and Correlation to Basic Diseases in a Postmortem Series.

In a postmortem series of adrenals from 497 patients 25 cases (5%) showed foci of fat-cell metaplasia or bone-marrow metaplasia in the zona fasciculata or the zona reticularis. There was only one focus in 45% of adrenals with metaplasia, but in 36.4%. more than six foci were present. The sizes varied between 0.036 and 0.64 mm. The foci were composed of mature, mostly univacuolar, fat cells and various amounts of myeloid cells The incidence of fat-cell metaplasia or of bone marrow metaplasia correlated with arterial hypertension and severe coronary heart disease. In 76% of cases, nodular hyperplasia was demonstrable, but the metaplasia were more often found adjacent to, rather than within, the nodules. They appear to be related to metaplasia in adrenocortical tumors and to myelolipomas. The common pathogenesis is thought to be based on focal necroses in combination with local endocrine stimulation.