Ultrastructural types of cell in adrenal cortical adenoma with primary aldosteronism

By means of electron microscopy, three types of cell were identified in the adrenal cortical adenomas obtained by surgery from three patients with primary aldosteronism. They were zona glomerulosa-type cells, compact cells and clear cells. The former two types of cell were quite similar to those found in the zona glomerulosa and the zona reticularis respectively. The clear cell with large lipid vacuoles possessed mitochondria similar to those found in the outer zona fasciculata. The ultrastructure of the vacuoles was rather complex and their relationship to those in the zona fasciculata cell was not clear. Glycogen particles in the beta-form, which were present in the zona glomerulosa and reticularis cell but not in the zona fasciculata cell, were observed within the cytoplasm of this tumour cell. The clear cells of the tumours were therefore considered to possess features of both the zona glomerulosa and the zona fasciculata cell.