## **Core Concept**
Prolactinoma is a type of pituitary adenoma that secretes excessive amounts of prolactin, leading to various clinical manifestations. The most common symptoms include galactorrhea, amenorrhea, and infertility in women, and impotence and gynecomastia in men.

## **Why the Correct Answer is Right**
The correct answer, **B. Amenorrhea**, is a common symptom in women with prolactinoma, aside from galactorrhea. Elevated prolactin levels can disrupt the normal secretion of gonadotropin-releasing hormone (GnRH), leading to decreased secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This hormonal imbalance can cause amenorrhea, which is the absence of menstruation.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While headaches can occur due to the mass effect of the tumor, they are not as specifically related to the hormonal effects of prolactinoma as amenorrhea.
- **Option C:** Visual disturbances can occur if the tumor extends beyond the sella turcica and compresses the optic chiasm, but this is not as common as amenorrhea in the context of prolactinoma symptoms.
- **Option D:** Bitemporal hemianopia is a specific type of visual field defect that can occur with large pituitary tumors, but like visual disturbances, it is not as commonly associated with prolactinoma as amenorrhea.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that prolactinoma is a common cause of secondary amenorrhea, and measuring prolactin levels is an essential part of the evaluation for amenorrhea. The diagnosis of prolactinoma can often be made based on clinical presentation (e.g., galactorrhea, amenorrhea) and confirmed by imaging studies and laboratory tests showing elevated prolactin levels.

## **Correct Answer:** . Amenorrhea