**5.2 Evaluation**

Diagnosis of prolactinoma requires both: radiological evidence of adenoma and sustained hyperprolactinemia. Normal PRL levels in women are <25 μg/l and in men are <20 μg/l. Single random measurement of PRL at any time of the day is adequate for evaluation of hyperprolactinemia. The differential diagnosis of hyperprolactinemia is wide (**Table 3**), but PRL level is seldom >100 μg/l in these conditions. Pituitary stalk compression (Stalk Effect) can also cause hyperprolactinemia (e.g. PRL level up to 150 μg/l) [11, 12].

In PRL-secreting adenomas, PRL level usually correlates with tumor size as levels above 250 μg/l are commonly seen in macroadenomas [12]. In the setting of low PRL level in patients with clinical presentation strongly suggestive of a prolactinoma, "hook effect" should be suspected. Hook effect occurs due to the impairment of immunecomplex formation in the presence of high levels of PRL. To overcome this phenomenon, serial dilution of the sample with repetition of the immunoassay is needed.

After ruling-out other causes of hyperprolactinemia, diagnosis confirmation of prolactinoma is made by gadolinium-enhanced brain MRI.

## **5.3 Management**

Management of prolactinomas depends on several factors: tumor size, patient symptoms and preferences, and PRL level. All patients with macroadenoma require treatment, however, mildly symptomatic microadenoma patients (e.g. premenopausal woman with normal menstrual cycles and galactorrhea, or postmenopausal woman with tolerable galactorrhea) can be followed-up with serial PRL level measurement and brain MRI. Since only 5–10% of microadenomas will enlarge in size [13], management of microadenomas should not be based on size control alone. Prolactinomas respond very well to medical therapy, and dopamine agonists are the first line of management (e.g. bromocriptine or cabergoline) (**Table 4**).

Bromocriptine is a non-selective dopamine receptor agonist. It is the first line of management for microadenoma patients seeking fertility restoration and it is effective in 90% of patients and PRL level normalization can be achieved in 82% of patients [14]. If pregnancy has been achieved, bromocriptine can be stopped safely without a risk of abortion or congenital malformation. In child-bearing age women

