Endocrine Disorders & Thyroid Physiology
Study Guide | Nursing Practice Questions &
Exam Prep
2026/2027
, Pheochromocytoma A rare catecholamine-secreting tumor of the adrenal medulla derived from
chromaffin cells.
Anatomic location of 85% of pheochromocytomas Adrenal medulla.
Malignancy rate in pheochromocytoma Most are benign; approximately 10% are malignant.
Paraganglioma A rare extra-adrenal form of pheochromocytoma arising from chromaffin cells.
Proportion of catecholamine-secreting tumors that are Approximately 15%.
paragangliomas
Malignancy risk for paragangliomas 10-20% chance of malignancy.
Anatomic sites for paragangliomas Cranial nerves, vagus nerve, or sympathetic ganglia in pelvis, mediastinum, or
neck.
Most common extra-adrenal paraganglioma location The neck.
Three primary catecholamines in pheochromocytoma Epinephrine, norepinephrine, and dopamine.
Receptors activated by epinephrine Alpha and beta receptors.
Receptors activated by norepinephrine Alpha-1 and alpha-2 receptors.
Vascular effect of catecholamine excess Marked vasoconstriction leading to hypertension and pallor.
Prevalence of pheochromocytoma in hypertensive patients Approximately 0.05-0.1%.
Proportion of asymptomatic pheochromocytomas Approximately 50%.
Proportion of incidentally discovered pheochromocytomas Approximately 10%.
Study Guide | Nursing Practice Questions &
Exam Prep
2026/2027
, Pheochromocytoma A rare catecholamine-secreting tumor of the adrenal medulla derived from
chromaffin cells.
Anatomic location of 85% of pheochromocytomas Adrenal medulla.
Malignancy rate in pheochromocytoma Most are benign; approximately 10% are malignant.
Paraganglioma A rare extra-adrenal form of pheochromocytoma arising from chromaffin cells.
Proportion of catecholamine-secreting tumors that are Approximately 15%.
paragangliomas
Malignancy risk for paragangliomas 10-20% chance of malignancy.
Anatomic sites for paragangliomas Cranial nerves, vagus nerve, or sympathetic ganglia in pelvis, mediastinum, or
neck.
Most common extra-adrenal paraganglioma location The neck.
Three primary catecholamines in pheochromocytoma Epinephrine, norepinephrine, and dopamine.
Receptors activated by epinephrine Alpha and beta receptors.
Receptors activated by norepinephrine Alpha-1 and alpha-2 receptors.
Vascular effect of catecholamine excess Marked vasoconstriction leading to hypertension and pallor.
Prevalence of pheochromocytoma in hypertensive patients Approximately 0.05-0.1%.
Proportion of asymptomatic pheochromocytomas Approximately 50%.
Proportion of incidentally discovered pheochromocytomas Approximately 10%.
