A pheochromocytoma originates from which gland's medullary tissue?

• A. Adrenal medulla
• B. Anterior pituitary
• C. Thyroid gland
• D. Pancreas

Answer: (A)

Pheochromocytoma originates from chromaffin cells in the adrenal medulla, the inner part of the adrenal gland that stores and releases catecholamines like epinephrine and norepinephrine. A tumor here leads to excess catecholamine production, which drives sudden spikes in blood pressure and symptoms such as headaches, sweating, and rapid heart rate. The other options don’t contain medullary tissue involved in catecholamine secretion—anterior pituitary gland hormones come from the pituitary's anterior lobe, the thyroid’s tissue doesn’t produce catecholamines, and the pancreas’ islets regulate insulin and glucagon. Thus, the adrenal medulla is the source of pheochromocytoma.