**Core Concept**
Mifepristone is a synthetic steroid with potent antiprogestational and antiglucocorticoid activities. It acts by competitively inhibiting the progesterone receptor, thereby preventing the maintenance of pregnancy and exerting antiglucocorticoid effects.

**Why the Correct Answer is Right**
Mifepristone is most useful in the medical management of **cervical intraepithelial neoplasia (CIN)**, specifically in the treatment of **cervical dysplasia**. It is also used in the management of **endometriosis** and **cushing's syndrome**. The antiprogestin properties of mifepristone induce endometrial atrophy, leading to a decrease in estrogen production, which in turn reduces the growth of endometrial tissue.

**Why Each Wrong Option is Incorrect**
**Option A:** Mifepristone is not primarily used to treat **hypertension**. Although it has some antiglucocorticoid effects, its use in hypertension is not a standard practice.
**Option B:** Mifepristone is not the first-line treatment for **breast cancer**. It may be used in the management of certain types of breast cancer, but its primary indication is not breast cancer.
**Option C:** Mifepristone is not used to treat **epilepsy**. Its primary mechanism of action is not related to the treatment of epilepsy.

**Clinical Pearl / High-Yield Fact**
Mifepristone is also known as RU-486, a name coined from the laboratory code it was originally given.

**Correct Answer: D. Cervical intraepithelial neoplasia (CIN)**