Which region of the brain is most likely the site of a mass in a patient with galactorrhea and bitemporal hemianopsia?

• A. Hypothalamus
• B. Midbrain
• C. Pituitary gland
• D. Pons

Answer: (C)

In this scenario, the presence of galactorrhea (the abnormal discharge of milk from the breasts) and bitemporal hemianopsia (loss of vision in the outer half of the visual field in both eyes) strongly suggests the involvement of the pituitary gland, specifically in relation to a pituitary adenoma.

The pituitary gland is located in the sella turcica at the base of the skull, just below the optic chiasm. A growth or mass in this gland can exert pressure on the optic chiasm, leading to the characteristic bitemporal hemianopsia as the optic nerve fibers carrying visual information from the outer fields of vision are compressed.

Additionally, galactorrhea can occur due to hyperprolactinemia, which is often caused by prolactin-secreting adenomas. Thus, a tumor in the pituitary gland could directly lead to both symptoms—pressing on the optic chiasm to cause visual field defects and secreting excess prolactin leading to galactorrhea.

The other regions of the brain mentioned either do not typically relate to these specific symptoms or are not commonly sites for masses that would induce them in this context. Therefore, the pituitary