by Jason Wasserman MD PhD FRCPC
March 2, 2022
An adrenocortical adenoma is a non-cancerous tumour that starts from the cells normally found cortex (outer layer) of the adrenal gland. Many adrenocortical adenomas are called incidental because they do not produce any symptoms and are found when imaging of the abdomen or pelvis is performed for other reasons.
A functioning adrenocortical adenoma is a tumour that makes one of the hormones normally made by the adrenal cortex such as cortisol, aldosterone, and dehydroepiandrosterone (DHEA). The symptoms caused by a functioning tumour depend on the type of hormone produced. Cortisol producing tumors can lead to high blood sugar levels, swelling of the face and abdomen, and muscle weakness. Aldosterone producing tumours cause high blood pressure and low levels of potassium in the blood. DHEA producing tumours can result in virilization which is the development of adult male physical characteristics (deepening voice, excess body hair) in female and prepubertal males.
A non-functioning adrenocortical adenoma is a tumour that is not producing any hormones. As a result, most non-functioning tumours do not cause any symptoms although large non-functioning tumours may cause pain if they push on nearby organs or tissues.
The diagnosis of adrenocortical adenoma is usually made after the entire tumour and adrenal gland have been removed in a procedure called a resection and sent to a pathologist for examination under a microscope. In some situations, the diagnosis can be made after a small sample of the tumour is removed in a procedure called a biopsy.
When examined under the microscope, most adrenocortical adenomas are made up of cells that resemble the cells normally found in the adrenal cortex. These cells are large and the cytoplasm (body) of the cell is full of lipid (fat) rich material. For this reason, the cells look white or clear when examined under the microscope. Some tumours also include smaller cells that contain less lipid and look eosinophilic (pink) when examined under the microscope. The tumour cells are usually arranged in small groups that are often described as cords, nests, or islands. Mitotic figures (tumour cells that are dividing to create new tumour cells) are very rarely seen and the tumour cells are usually surrounded by a thin layer of tissue called a tumour capsule.