A 16-year-old girl is brought to the physician because of a 1-month history of visual disturbances. She has been walking into doors and unable to see people unless they stand directly in front of her. Her menses have been irregular and have disappeared over the past few months. Physical shows visual deficits in both eyes in temporal areas. Nasal visual fields are within normal limits. Cranial MPh shows a mass inferior to the hypothalamus. Which of the following hormones do the cells found n the mass most likely produce?

**Core Concept**
The patient's symptoms are suggestive of a pituitary adenoma, specifically a prolactinoma, which is a type of functioning pituitary tumor. Prolactinomas are the most common type of functioning pituitary tumor and are often associated with hyperprolactinemia.

**Why the Correct Answer is Right**
The mass found inferior to the hypothalamus is most likely a pituitary adenoma, specifically a prolactinoma. This is because the patient's symptoms, such as visual disturbances and irregular menses, are consistent with hyperprolactinemia. The pituitary gland is located inferior to the hypothalamus, and prolactinomas arise from the lactotroph cells of the anterior pituitary gland. Elevated levels of prolactin can cause an inhibition of gonadotropin-releasing hormone (GnRH) secretion, leading to decreased estrogen levels and irregular menses.

**Why Each Wrong Option is Incorrect**
**Option A:** Growth hormone (GH) is produced by somatotroph cells, which are not typically associated with visual disturbances or irregular menses.

**Option B:** Adrenocorticotropic hormone (ACTH) is produced by corticotroph cells, which are not typically associated with visual disturbances or irregular menses.

**Option C:** Thyroid-stimulating hormone (TSH) is produced by thyrotroph cells, which are not typically associated with visual disturbances or irregular menses.

**Clinical Pearl / High-Yield Fact**
Prolactinomas are the most common type of functioning pituitary tumor and are often associated with visual disturbances due to their location and growth pattern. A high index of suspicion for prolactinoma should be maintained in patients with visual disturbances and galactorrhea (spontaneous milk production).

**Correct Answer:** C. Prolactin.

✓ Correct Answer: D. Thyroid stimulating hormone