ABSTRACT Hyperprolactinemia is a frequent cause of menstrual irregularity, galactorrhea, hypogonadism, and infertility. The most common etiologies of hyperprolactinemia can be classified as physiological, pharmacological, and pathological. Among pathological conditions, it is essential to distinguish prolactinomas from other tumors and pituitary lesions presenting with hyperprolactinemia due to pituitary stalk disconnection. Proper investigation considering clinical data, laboratory tests, and, if necessary, imaging evaluation, is important to identify the correct cause of hyperprolactinemia and manage the patient properly. This position statement by […]

ABSTRACT Prolactinomas are the most common pituitary adenomas (approximately 40% of cases), and they represent an important cause of hypogonadism and infertility in both sexes. The magnitude of prolactin (PRL) elevation can be useful in determining the etiology of hyperprolactinemia. Indeed, PRL levels > 250 ng/mL are highly suggestive of the presence of a prolactinoma. In contrast, most patients with stalk dysfunction, drug-induced hyperprolactinemia or systemic diseases present with PRL levels < 100 ng/mL. However, exceptions to these rules are […]

Macroprolactinemia is characterized by the predominance in the serum of macroprolactin, a prolactin (PRL) with high molecular mass and low biological activity that does not need treatment. The prevalence of macroprolactinemia was evaluated in 115 consecutive patients with hyperprolactinemia. Among them, 19 (16.5%) had solely macroprolactinemia, 4 (3.5%) polycystic ovary syndrome, 7 (6.1%) acromegaly, 8 (6.9%) idiopathic hyperprolactinemia, 10 (8.6%) primary hypothyroidism, 14 (12.2%) clinically non-functioning pituitary adenomas, 20 (17.4%) drug-induced hyperprolactinemia and 33 (28.7%) prolactinomas. The diagnosis of macroprolactinemia […]

In the diagnostic approach of hyperprolactinemia three pitfalls or potential confounding problems deserve special attention: pituitary incidentalomas, the hook effect and macroprolactinemia. In as much as 10% of the population aged 20 to 40 years, incidental tumors of the pituitary gland are demonstrated by magnetic resonance imaging. The hook effect is characterized by the finding of falsely low levels of serum prolactin (PRL) when two-site immuno-assays are used in diagnosis in patients with very high prolactin levels. This confusion can […]

Serum prolactin measurement is a routine test in several conditions in every day clinical practice, and the finding of hyperprolactinemia can induce complex and expensive imaging studies. Circulating prolactin is a heterogeneous hormone and, from a molecular weight point of view, there are three main forms: the 23kDa monomer, the 45kDa dimer (big prolactin) and the higher than 150kDa macroprolactin, or big-big prolactin. In normal conditions, or in patients with symptomatic hyperprolactinemia, the monomeric form is the predominant. Macroprolactin is […]