Light micrograph of an adrenal cortical adenoma. An adrenal cortical adenoma is a benign tumour composed of the same cell types as the normal adrenal cortex. The adenoma occupies the bottom half of this image, whereas the normal adrenal cortex is at the top half of the picture. The adenoma and normal adrenal cells are very similar and separated by only a thin line of fibrous tissue. Haematoxylin and eosin stained tissue section. Magnification: 40x when printed at 10 centimetres.