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

Demographics

• 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

Diagnosis