Pheochromocytoma follows the 'rule of 10s.' Which of the following correctly represents this mnemonic?
- A 10% bilateral, 10% extra-adrenal, 10% malignant, 10% familial, 10% occur in children ✓
- B 10% occur in adults, 10% are sporadic, 10% secrete epinephrine only
- C 10% bilateral, 10% extra-adrenal, 10% associated with hyperaldosteronism
- D 10% cause hypertension, 10% are calcified, 10% respond to alpha-blockade
Correct answer: A. 10% bilateral, 10% extra-adrenal, 10% malignant, 10% familial, 10% occur in children
Explanation
The classic 'rule of 10s' for pheochromocytoma: 10% bilateral, 10% extra-adrenal (paragangliomas), 10% malignant, 10% familial (associated with MEN2A/2B, VHL, NF1, SDH mutations), and 10% occur in children. In reality, modern data suggest higher rates — particularly for familial cases (~25%) and bilateral disease in MEN2 — but the rule of 10s remains a standard exam mnemonic.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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