A 5-year-boy has developed features that suggest puberty over the past 6 months. On physical examination, the boy has secondary sex characteristics, including pubic hair and enlargement of the penis. Which of the following morphologic features is most likely to be seen in his adrenal glands?

**Core Concept**
Precocious puberty in boys is often caused by an excess of androgens, which can be due to various factors including adrenal tumors or congenital adrenal hyperplasia. The adrenal glands play a crucial role in the production of androgens, and abnormalities in these glands can lead to precocious puberty.

**Why the Correct Answer is Right**
In this scenario, the most likely cause of precocious puberty is congenital adrenal hyperplasia (CAH), specifically the 21-hydroxylase deficiency type. This enzyme deficiency leads to an overproduction of androgens due to an accumulation of precursors. As a result, the adrenal glands undergo hyperplasia to compensate for the enzyme deficiency, leading to an increase in adrenal size and weight.

**Why Each Wrong Option is Incorrect**
**Option A:** **Adrenal adenoma** - While an adrenal adenoma can cause an excess of androgens, it is less likely to be the cause of precocious puberty in a 5-year-old boy compared to congenital adrenal hyperplasia.

**Option B:** **Pituitary gland tumor** - A pituitary gland tumor can cause precocious puberty due to an overproduction of gonadotropins, but it is not directly related to adrenal gland abnormalities.

**Option C:** **Hypothalamic hamartoma** - A hypothalamic hamartoma can cause precocious puberty due to an abnormal release of gonadotropin-releasing hormone (GnRH), but it is not directly related to adrenal gland abnormalities.

**Clinical Pearl / High-Yield Fact**
In cases of precocious puberty, it is essential to investigate the underlying cause, as some causes may require specific treatment to prevent long-term consequences such as short stature and infertility.

**Correct Answer:** C. Hyperplasia of the adrenal gland.

✓ Correct Answer: B. Cortical hyperplasia