Pheochromocytoma
A rare, catecholamine-secreting tumor derived from chromaffin cells of the adrenal medulla. It is a critical “can’t-miss” diagnosis for patients presenting with paroxysmal hypertension.
1. Clinical Triad (The “5 Ps”)
- Pressure (Paroxysmal hypertension)
- Pain (Headache)
- Perspiration (Diaphoresis)
- Palpitations (Tachycardia)
- Pallor
2. Diagnostic & Pathological Must-Knows
| Category | Details |
|---|---|
| Laboratory | Increased plasma free metanephrines and 24-hour urine metanephrines/catecholamines. |
| Rule of 10s | 10% malignant, 10% bilateral, 10% extra-adrenal (paraganglioma), 10% familial. |
| Genetics | Associated with MEN 2A/2B (RET), VHL, and NF1. |
3. Management Hint
If diagnosed, you must block alpha receptors first (e.g., phenoxybenzamine) before blocking beta receptors. Using a beta-blocker alone can lead to unopposed alpha-mediated vasoconstriction, resulting in a hypertensive crisis.
Pathology Board Hint: For test questions, remember: Pheochromocytoma = adrenal medulla, while Paraganglioma = extra-adrenal (e.g., organ of Zuckerkandl). Always screen patients with episodic hypertension and the classic triad. Remember the order of medication: Alpha before Beta.