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For further information, see CMDT Part 26-04: Hyperprolactinemia

Key Features

Essentials of Diagnosis

  • Women

    • Oligomenorrhea, amenorrhea

    • Galactorrhea

    • Infertility

  • Men

    • Hypogonadism

    • Decreased libido and erectile dysfunction

    • Infertility

  • Elevated serum prolactin (PRL) levels

  • CT or MRI may show pituitary adenoma

General Considerations

  • Table 26–1 lists causes of hyperprolactinemia

  • Hyperprolactinemia (without a pituitary adenoma) may be familial

  • Augmentation or reduction mammoplasty, and mastectomy, may stimulate PRL secretion

  • In acromegaly, there may be co-secretion of growth hormone and PRL

  • Microadenomas (< 1 cm in diameter)

    • More common in women

    • Typically do not grow even with pregnancy or oral contraceptives

  • Macroprolactinomas

    • Occur in 3.7% of the general population

    • Account for 10–25% of all cases of hyperprolactinemia

    • Pituitary MRI shows a nonpathological abnormality in 22% of such patients

    • Aggressive macroprolactinomas (> 1 cm)

      • More common in men

      • Can spread into the cavernous sinuses and suprasellar areas

      • May erode the floor of the sella to invade the paranasal sinuses, albeit rarely

Table 26–1.Causes of hyperprolactinemia.


  • Prolactin-secreting pituitary tumors (prolactinomas) more common in women

  • Usually sporadic but rarely familial as part of multiple endocrine neoplasia type 1 or 4 (MEN-1 or MEN-4)

Clinical Findings

Symptoms and Signs

  • Hypogonadotropic hypogonadism

    • Men

      • Erectile dysfunction

      • Diminished libido

      • Gynecomastia (sometimes)

    • Women

      • Amenorrhea, oligomenorrhea, or infertility

      • Estrogen deficiency can cause decreased vaginal lubrication, irritability, anxiety, and depression

      • Galactorrhea

      • During pregnancy, clinically significant enlargement of a microprolactinoma (diameter < 10 mm) occurs in < 3%; clinically significant enlargement of a macroprolactinoma (diameter ≥ 10 mm) occurs in about 30%

  • Pituitary prolactinomas

    • May co-secrete growth hormone and cause acromegaly

    • Large tumors may cause

      • Headaches

      • Visual symptoms

      • Pituitary insufficiency (hypogonadism)

Differential Diagnosis

  • Idiopathic galactorrhea

  • Other pituitary lesions and malignancies

  • Pregnancy (pregnant women have high serum PRL and physiological hyperplastic enlargement of the pituitary on MRI); increased pituitary size is a normal variant in young women

  • Primary hypothyroidism

  • See Table 26–1


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