Prolactinoma is best described as which of the following?

• A. Benign tumor in the pituitary causing the gland to produce too much prolactin, leading to infertility in women and erectile dysfunction in men.
• B. Malignant tumor in the pituitary causing excessive cortisol production.
• C. Adrenal tumor causing excess adrenaline production.
• D. Hypothalamic lesion causing decreased secretion of prolactin.

Answer: (A)

Prolactinoma is a benign pituitary adenoma that secretes prolactin. The excess prolactin in the bloodstream suppresses GnRH release from the hypothalamus, which lowers LH and FSH. In women this disrupts ovulation, leading to infertility (and often menstruation problems or galactorrhea); in men, reduced gonadal function can cause erectile dysfunction and decreased libido. The tumor itself is usually noncancerous, though it can grow large enough to cause headaches or vision changes. Treatments focus on lowering prolactin levels with dopamine agonists (like cabergoline or bromocriptine) and sometimes surgery if needed.

The other descriptions don’t fit prolactinoma: a malignant pituitary tumor causing cortisol production would point to a corticotroph issue (ACTH and Cushing’s-related), not prolactin; an adrenal tumor producing catecholamines describes pheochromocytoma; and a hypothalamic lesion would more likely disrupt dopamine’s inhibition of prolactin (often increasing prolactin, not decreasing it).