Which condition is commonly associated with elevated prolactin levels?

Elevated prolactin levels are most commonly associated with prolactinomas, which are benign tumors of the pituitary gland. These tumors specifically secrete excess prolactin, a hormone responsible for lactation and various reproductive functions. When a prolactinoma is present, it results in hyperprolactinemia, which can lead to various symptoms such as galactorrhea (the inappropriate secretion of breast milk), menstrual irregularities, and infertility in women, as well as erectile dysfunction and decreased libido in men.

The other conditions listed do not primarily affect prolactin levels. Insulinoma is related to insulin secretion and is characterized by episodes of hypoglycemia. Gastrinoma involves excessive secretion of gastrin, leading to conditions like Zollinger-Ellison syndrome. Pheochromocytoma is characterized by the secretion of catecholamines, which can lead to symptoms such as hypertension and palpitations. Therefore, the association of elevated prolactin levels is distinctly linked to prolactinomas.