In men with hyperprolactinemia, which of the following physical findings may occur?

• A. Decreased libido and erectile dysfunction
• B. Weight gain
• C. Gynecomastia
• D. Acne

Answer: (C)

When prolactin is high in men, it suppresses GnRH from the hypothalamus, which lowers LH and FSH. That leads to reduced testosterone production by the testes. The drop in testosterone decreases sexual drive and can cause erectile difficulties, but it also alters the balance between estrogen and testosterone. With less testosterone, estrogen’s effects on breast tissue become more prominent, allowing breast tissue to proliferate and producing gynecomastia. Prolactin can also have a direct stimulatory effect on breast tissue, reinforcing this change. Weight gain and acne are less specific to hyperprolactinemia and are not typical hallmark findings, whereas gynecomastia directly reflects the hormonal shifts caused by elevated prolactin.