Polycythemia vera (PV) is an acquired myeloproliferative disorder characterized by an elevated absolute red blood cell mass caused by uncontrolled red blood cell production, frequently associated with uncontrolled white blood cell and platelet production.

Pheochromocytomas (also known as chromaffin tumors) produce, store, and secrete catecholamines. Pheochromocytomas usually originate from the adrenal medulla but may also develop from chromaffin cells in or about sympathetic ganglia. A common symptom of pheochromocytoma is hypertension owing to release of catecholamines.