It is a common disease cause of hyperprolactinemia and also the most common pituitary tumor.

bubble_chart Diagnosis

1. Medical history, symptoms, and signs:

Females present with milk regurgitation, amenorrhea (blood PRL >50ug/L, idiopathic hyperprolactinemia with normal menstruation), infertility and hyposexuality, delayed development in adolescents, and may also have hirsutism and acne, osteoporosis, obesity, and water retention. Males have fewer symptoms, mainly impotence and infertility, with a few cases of milk regurgitation, breast development, and sparse hair. Most seek medical attention due to compressive symptoms from pituitary adenomas.

2. Auxiliary examinations:

(1) PRL >100ug/L strongly suggests prolactinoma; >200ug/L is almost always prolactinoma; RL <100ug/L者多考慮高泌乳素血症．PRL抑制試驗　口服L-多巴500mg，於服藥前及服藥後1、2、3及6h測PRL。正常服藥後1～3h PRL 水平抑制到4ug/L以下或基礎值的50%以上， 以後逐漸回升，泌乳素瘤患者不被抑制。

(2) TRH stimulation test: Intravenous injection of 200μg TRH in the basal state, with PRL measured at 30min before injection and 15, 30, 60, 120, and 180min after injection. In normal and hyperprolactinemic patients, the peak mostly occurs at 30min post-injection, with a peak/baseline ratio >2. In prolactinoma patients, the peak is delayed, and the peak/baseline ratio <1.5。

(3) Metoclopramide stimulation test: PRL is measured before and at 1, 2, and 3h after taking metoclopramide. In normal and hyperprolactinemic patients, the peak occurs at 1–2h, with a peak/baseline ratio >3. In prolactinoma patients, the peak/baseline ratio <1.5。

(4) Other hormone tests: Gonadotropins are normal or low, with an enhanced response to GnRH stimulation test; female patients have low estradiol; males have reduced testosterone.

(5) Imaging studies: Most skull X-rays are normal. Pituitary CT scans or MRI may reveal microadenomas.

The treatment of prolactinoma depends on the tumor size, PRL elevation level, symptoms, and fertility requirements.

1. Drug Therapy:

The first choice is bromocriptine, starting with 1.25 mg at bedtime, increasing by 1.25–2.5 mg every 2–3 days, with a daily effective dose of 5–7.5 mg. After treatment, blood PRL levels decrease, and menstruation resumes after 2–3 months. Medication can be discontinued after about one year for observation, but the recurrence rate increases annually.

2. Surgical Treatment:

Applicable for: ① large adenomas with no significant effect after more than 3 months of bromocriptine therapy; ② patients desiring fertility. However, surgical treatment is often incomplete, and most patients still require bromocriptine postoperatively.

3. Radiation Therapy:

Prevents recurrence after discontinuation of medication to achieve long-term control.

4. Management of Prolactinoma During Pregnancy:

1. The risk of prolactinoma enlargement during pregnancy is very small.

2. Bromocriptine should be discontinued immediately upon conception.

3. The following situations warrant induced labor or resumption of bromocriptine: tumor size >10 mm; visual field checks every 4–6 weeks; if headache or visual field narrowing occurs, induced labor should be performed. If childbirth must be delayed, bromocriptine should be continued to shrink the tumor.

4. For pregnant women on bromocriptine, the medication should generally be discontinued 24 hours postpartum. Breastfeeding is not recommended.

5. Patients using bromocriptine during the puerperium should be aware of the effects of contraceptives. If contraception is needed, estrogen-based contraceptives should not be used.

It should be differentiated from other disease causes of hyperprolactinemia:

1. Physiological factors such as pregnancy, postpartum, nipple stimulation, newborns, the intermediate stage of menstruation [second stage] (due to increased estrogen), sleep, sexual intercourse, etc.;

2. Pathological factors: other pituitary tumors; hypothalamic diseases; empty sella syndrome; ectopic prolactinomas; primary hypothyroidism; renal failure; chest and breast diseases.

3. Drugs: such as estrogen-containing contraceptives; morphine and hypnotics; tricyclic antidepressants, reserpine, and chlorpromazine-like drugs; anti-dopamine drugs; phenothiazines, isoniazid, verapamil, cyproheptadine, cimetidine, etc.;

4. Idiopathic hyperprolactinemia.