According to the rule of 10s, what percentage of pheochromocytomas are bilateral?

According to the rule of 10s, what percentage of pheochromocytomas are bilateral?

• A. 5%
• B. 10%
• C. 15%
• D. 20%

Answer: (B)

The rule of 10s is a traditional way to capture several classic features of pheochromocytoma in a single memory aid. One key part of that mnemonic is that about one in ten pheochromocytomas involve both adrenal glands, so bilateral disease occurs in roughly 10% of cases. This reflects the general pattern that most pheochromocytomas are unilateral, with bilateral cases more commonly seen in familial syndromes such as MEN2, VHL, or NF1. So, when asked about the percentage that are bilateral under the rule of 10s, the figure is about 10%. The other percentages aren’t part of this classic rule, though modern data can vary in particular populations or when considering hereditary risk.

The rule of 10s is a traditional way to capture several classic features of pheochromocytoma in a single memory aid. One key part of that mnemonic is that about one in ten pheochromocytomas involve both adrenal glands, so bilateral disease occurs in roughly 10% of cases. This reflects the general pattern that most pheochromocytomas are unilateral, with bilateral cases more commonly seen in familial syndromes such as MEN2, VHL, or NF1.

So, when asked about the percentage that are bilateral under the rule of 10s, the figure is about 10%. The other percentages aren’t part of this classic rule, though modern data can vary in particular populations or when considering hereditary risk.