Question

All are true about pheochromocytoma except?

• A. 90% are malignant
• B. 95% occur in the abdomen
• C. They secrete catecholamines
• D. They arise from sympathetic ganglions

Hint:

Recall the rule of 10s and which percentage gets reversed here.

Answer 1

The Correct Option is A

Step 1: Pheochromocytoma is a catecholamine-secreting tumour of chromaffin cells, classically described by the “rule of 10s”.
Step 2: By the rule of 10s, about 10% are malignant, 10% are bilateral, 10% are extra-adrenal, 10% occur in children and 10% are familial. So roughly 90% are benign, NOT malignant.
Step 3: Evaluating the statements: about 95% are located within the abdomen (true), they secrete catecholamines such as adrenaline and noradrenaline producing paroxysmal hypertension (true), and they arise from chromaffin cells of the sympathetic nervous system including the adrenal medulla and sympathetic ganglia (true).
Step 4: The statement “90% are malignant” is false because the figure is reversed; only about 10% are malignant.
Conclusion: The incorrect (except) statement is option 1.