Pheochromocytoma
Most common tumor of adrenal medulla in adults. Derived from chromaffin cells (arise from neural crest cells). Maybe associated with germline mutations (eg, NF-1, VHL, RET[MEN 2A, 2B]) Rule of 10's: 10% malignant 10% bilateral 10% extra adrenal (eg, bladder) 10% calcify Symptoms occurs in spells, relapse and remit. Increased BP, headache, perspiration. Palpitations (tachycardia) and pallor are specific symptoms because most tumors secret epinephrine which also causes episodic hypertension. Findings include increased catecholamines and its metabolites (eg, metanephrines) in urine and plasma. Irreversible alpha-antagonists (eg, phenoxybenzamine) followed by beta-blockers is given prior to tumor resection. Alpha-blockade must be achieved before giving beta-blockers to avoid a hypertensive crisis. Memorize it as A before B.
