**Core Concept**
Fibroadenomas are benign breast tumors that arise from the epithelial and stromal components of the breast. They are the most common type of benign breast tumor and are often found in young women.

**Why the Correct Answer is Right**
Fibroadenomas are characterized by a mixture of glandular and connective tissue. They are typically well-circumscribed, mobile, and painless masses. The exact pathogenesis of fibroadenomas is not fully understood, but they are thought to result from an abnormal growth of the breast ductal epithelium and the surrounding stroma. Fibroadenomas typically express estrogen receptors and may grow in response to hormonal influences.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because fibroadenomas are not typically aggressive or malignant. While they can grow and change over time, they are generally not a cause for concern.
**Option B:** This option is incorrect because fibroadenomas are not typically associated with genetic mutations or hereditary disorders. They are not a risk factor for breast cancer.
**Option C:** This option is incorrect because fibroadenomas are not typically found in older women. They are most commonly found in young women, often in their 20s and 30s.

**Clinical Pearl / High-Yield Fact**
Fibroadenomas are often described as "breast mice" due to their firm, rubbery texture and well-circumscribed borders.

**Correct Answer:** C.