**Core Concept**
Adrenal adenomas are benign tumors that arise from the adrenal cortex, leading to an overproduction of various steroid hormones. These tumors can cause Cushing's syndrome, Conn's syndrome, or other hormonal imbalances.

**Why the Correct Answer is Right**
Adrenal adenomas usually have a single hormone-producing cell type, such as cortisol-secreting adenomas causing Cushing's syndrome. They are typically well-circumscribed and non-invasive, with a small risk of malignant transformation. The growth of adrenal adenomas is driven by mutations in genes such as PRKAR1A or GNAS.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be true, as some adrenal adenomas can cause an overproduction of aldosterone, leading to Conn's syndrome. However, option A is not specified in the question, so we assume the correct answer is not this option.
**Option B:** This option is false, as adrenal adenomas are generally benign and non-invasive. Malignant adrenal tumors are typically more aggressive and have a worse prognosis.
**Option C:** This option might be true, as some adrenal adenomas can cause an overproduction of cortisol, leading to Cushing's syndrome. However, option C is not specified in the question, so we assume the correct answer is not this option.
**Option D:** This option is false, as adrenal adenomas are typically well-circumscribed and non-invasive, with a small risk of malignant transformation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that adrenal adenomas can cause a range of hormonal imbalances, including Cushing's syndrome, Conn's syndrome, and other endocrine disorders. A high index of suspicion and careful diagnostic workup are necessary to diagnose these conditions.

**Correct Answer: B.**