Challenges and pitfalls in the diagnosis of hyperprolactinemia

Prolactin's paradox: Friend, foe, or both in immune regulation?

Over 100 diseases have been recognized as autoimmune in nature, collectively affecting ∼20 % of the population in industrialized countries. These conditions are more prevalent among women of childbearing age, reflecting the potential association between alterations in the immune-neuroendocrine network, on the one hand, and autoimmune conditions, on the other. Prolactin (PRL), a polypeptide hormone that is primarily (but not only) secreted by the lactotrophic cells of the pituitary gland, is a critical element of the immune-neuroendocrine network. Although this hormone has several nonimmune functions, its role in regulating immune responses and affecting autoimmune inflammation is particularly enigmatic and controversial. Indeed, PRL interacts with various immune cells to bolster the body defenses, but also potentially to exacerbate autoimmune conditions. Understanding how and when PRL acts as a 'friend or foe' is crucial for unraveling its role as a potential therapeutic target in the management of autoimmune diseases (AIDs). This review therefore provides a critical overview of PRL's role in the immune system, and of the influence of this pleiotropic hormone in the development of autoimmunity.

Usefulness of prolactin levels in predicting the etiology of hyperprolactinemia in a cohort of 770 patients

Objective

Determining the etiology of hyperprolactinemia is fundamental for selecting the most appropriate treatment strategy. The aim of this study was to evaluate the usefulness and accuracy of prolactin levels in predicting the etiology of nonphysiological hyperprolactinemia.

Subjects and methods

In this retrospective study, we reviewed medical records of patients with nonphysiological hyperprolactinemia seen at two neuroendocrine reference centers located in Recife, Brazil, from January 2000 to December 2019.

Results

The study included 770 patients aged 12-73 years (65% female). The three most frequent etiologies of hyperprolactinemia were prolactinomas (n = 263; 34.2%), drug-induced hyperprolactinemia (n = 160; 20.8%), and macroprolactinemia (n = 120; 15.6%). The highest mean prolactin levels were observed in cases of prolactinomas and idiopathic hyperprolactinemia. Most patients with hyperprolactinemia due to other etiologies had prolactin levels < 100 ng/mL, but these levels were also found in 16.5% of patients with microproplactinomas and in 20% of those with idiopathic hyperprolactinemia. Likewise, prolactin levels largely overlapped among patients with microprolactinomas, macroprolactinemia, and drug-induced hyperprolactinemia. Notably, prolactin levels > 250 ng/mL enabled a clear distinction between the etiologies of macroprolactinoma and nonfunctioning pituitary adenoma. Moreover, prolactin levels > 500 ng/mL were highly suggestive of macroprolactinomas, although they were also found in very few patients (<2%) with microprolactinomas or drug-induced hyperprolactinemia.

Conclusion

Despite considerable overlap in prolactin levels among the different etiologies of hyperprolactinemia, values > 250 ng/mL allowed a clear distinction between macroprolactinomas and nonfunctioning pituitary adenomas. Furthermore, prolactin levels > 500 ng/mL were almost exclusively found in patients with prolactinomas.

Pharmacological hyperprolactinemia: a retrospective analysis of 501 hyperprolactinemia cases in primary care setting

PURPOSE

To describe a series of cases with pharmacological hyperprolactinemia in primary care setting and the prolactin levels, clinical implications of different causes of pharmacological hyperprolactinemia.

METHODS

A retrospective study of all patients with detected hyperprolactinemia in hormonal studies was performed between 2019 and 2020 in 20 Spanish primary care centers. Hyperprolactinemia is defined as a serum prolactin >19.4ng/ml in men and >26.5ng/ml in women. Four pharmacological causes of hyperprolactinemia were established: (i) oral contraceptives (OCPs) and other hormonal treatments; (ii) antipsychotics and antidepressants; (iii) other drugs (calcium antagonists, antiemetics, H2 antihistamines, opioids, and anabolic agents); and (iv) hyperprolactinemia due to several drugs.

RESULTS

From a sample of 501 patients with elevated serum prolactin, 39.4% (n=162) had pharmacological hyperprolactinemia. The most common cause of pharmacological hyperprolactinemia in women was OCPs (n=61) while in men antipsychotics/antidepressants (n=21). In the cases of hyperprolactinemia due to antipsychotics/antidepressants, the prolactin levels were significantly higher in patients taking classical antipsychotics than in those taking second-generation antipsychotics (80.0±43.17 vs. 50.7±28.66 ng/dL, P=0.035). The antidepressant/antipsychotic group showed hyperprolactinemia-related symptoms more frequently than the group of other treatments (58.9% vs. 32%, P=0.001). The concomitant use of several drugs caused hyperprolactinemia-related symptoms more frequently than one drug alone (73% vs. 44%, P=0.031).

CONCLUSION

In this series of cases, drugs represented the 39.4% of the causes of hyperprolactinemia. The most common drugs were OCPs in women and antipsychotics/antidepressants in men. Antidepressants/antipsychotics were drugs that caused the greatest elevation of the prolactin levels and showed hyperprolactinemia-related symptoms more frequently.

Clival ectopic pituitary prolactinoma was successfully managed by transsphenoidal surgery: A rare case report

Key Clinical Message

Ectopic pituitary adenoma is a rare neoplasm located in the clivus and could mimic other clival tumors. Diagnosis and treatment could be challenging. It should be considered in the differential diagnosis of clival tumors.

Abstract

Ectopic pituitary adenomas (EPAs) are isolated adenomas that can be located in variable locations outside the sella turcica and have a normal-appearing pituitary gland. These tumors are rare and are thought to often arise from embryological remnants along the route of Rathke's pouch migration. EPAs are associated with a wide range of clinical manifestations depending on hormonal activity and involvement of adjacent structures, which can represent a challenge in making the diagnosis and deciding on the most appropriate management. In this case study, we report a 47-year-old male who presented with visual disturbances, a headache, and generalized weakness. Magnetic resonance imaging showed a 2 cm mass located in the clivus invading the sphenoid sinus with an intact pituitary gland. The patient underwent endoscopic transsphenoidal surgery to eradicate the mass while maintaining the integrity of the pituitary gland, which was successful and uneventful. Pathological studies were consistent with prolactinoma, with no cytological malignant features. Post-surgery, symptoms notably improved, and serum prolactin levels significantly dropped, The patient's condition was satisfactory on follow-up with no long-term complications reported. This paper contributes to the existing literature by sharing the clinical management of a challenging and uncommon case.

Macroprolactinemia: a mini-review and update on clinical practice

Hyperprolactinemia is common among infertile patients, with up to 15%-20% of women with oligomenorrhea having hyperprolactinemia. Suppression of the hypothalamic-pituitary-gonadal axis via inhibition of pulsatile gonadotropin releasing hormone because of hyperprolactinemia is a common endocrine etiology of infertility. There are 3 forms of human prolactin (PRL): monomeric PRL, dimeric PRL, and macro-PRL. Also known as big-big PRL, macro-PRL has a molecular weight >150 kDa and normally comprises 5%-10% of circulating PRL. When the predominant form of circulating PRL is macro-PRL, macroprolactinemia is diagnosed. Among patients with hyperprolactinemia, 10%-46% have macroprolactinemia. Patients with macroprolactinemia are at risk of unnecessary pituitary imaging and treatment with dopamine agonists if not correctly diagnosed. Given the high prevalence of macroprolactinemia among patients with elevated PRL levels and the different management of patients with macroprolactinemia vs true monomeric hyperprolactinemia, all patients with persistently elevated PRL levels should be screened for macro-PRL.

Approach to the Patient With Prolactinoma

Prolactinomas are the most common pituitary tumor histotype, with microprolactinomas being prevalent in women and macroprolactinomas in men. Hyperprolactinemia is among the most common causes of hypogonadotropic hypogonadism in both sexes, prompting medical advice for hypogonadism (infertility, oligo-amenorrhea, impotence, osteoporosis/osteopenia) in both sexes, and for signs and symptoms of mass effects (hypopituitarism, visual loss, optic chiasm compression, cranial nerve deficits, headaches) predominantly in men. Diagnostic workup involves a single prolactin measurement and pituitary imaging, but some laboratory artifacts (ie, the "hook effect" and macroprolactin) can complicate or delay the diagnosis. The treatment of choice for prolactinomas is represented by dopamine agonists, mainly cabergoline, which are able to induce disease control, restore fertility in both sexes, and definitively cure one-third of patients, thus permitting treatment discontinuation. Pregnancy and menopause may promote spontaneous prolactin decline and anticipate cabergoline discontinuation in women. Surgery and/or radiotherapy are indicated in case of resistance to cabergoline not overcome by the increase in drug dose up to the maximally tolerated or the patient's personal choice of surgery. The evidence of resistance to cabergoline in invasive and proliferative tumors may indicate biological aggressiveness, thus requiring alternative therapeutic approaches mainly based on temozolomide use as monotherapy or combined with radiotherapy. In uncontrolled patients, new medical approaches (alternative hormonal treatments, cytotoxic drugs, peptide receptor radionuclide therapy, mTOR/Akt inhibitors, tyrosine kinase inhibitors, or immunotherapy) may be offered but the experience collected to date is still very scant. This article reviews different facets of prolactinomas and discusses approaches to the condition in more common clinical situations.

Pool vs single sample determination of serum prolactin to explore venipuncture associated stress induced variation

Stress is identified as a cause of transient hyperprolactinemia, whereas venipuncture is considered a source of stress for patient. The aim of this study was to investigate the association of venipuncture-induced stress with elevation of serum prolactin. This was a cross-sectional observational study conducted on a group of 150 outdoor patients visiting a tertiary care hospital. Serial sampling was performed by drawing venous blood at different time intervals (0, 30 and 60 min) by single venipuncture to measure serum prolactin to diagnose stress-induced hyperprolactinemia. The study was conducted in two phases, namely, Phase 1 and Phase 2, at different times. The Phase 1 results were divided into two groups: Group 1 (0 min) and Group 5 (pool prepared from samples collected at 0 + 30 + 60 min). Likewise, the results of Phase 2 were segregated into five groups; Group 1 (0 min), Group 2 (30 min), Group 3 (60 min), Group 4 (average of three groups), and Group 5 (pool from samples collected at 0 + 30 + 60 min). In both Phase 1 and Phase 2 of the study, there was a statistically significant (p = 0.0003 in Phase 1 and p = 0.02 in Phase 2) decrease in the mean prolactin (17.99 ± 24.76 ng/mL in Phase 1 and 19.61 ± 23.42 ng/mL in Phase 2) in the pooled samples (Group 5) in comparison to the mean prolactin (19.67 ± 27.69 ng/mL in Phase 1 and 21.06 ± 25.06 ng/mL in Phase 2) of the serum collected at 0 h (Group 1). There was no significant difference in the mean prolactin measured from the pooled samples and average prolactin calculated after individual testing from each sample collected at 0 h, 30 min and 60 min. Venipuncture-triggered fear and apprehension may result in transient hyperprolactinemia. In comparison to performing multiple testing on the samples collected at different time intervals and determining the mean, measurement of the analyte from the pooled serum is the better alternative as it can conserve both time and resources.

Causes of hyperprolactinaemia in the primary care setting: How to optimise hyperprolactinaemia management

BACKGROUND AND PURPOSE

To analyse the causes of hyperprolactinaemia in patients with symptoms compatible with hyperprolactinaemia evaluated in a primary care setting.

PATIENTS AND METHODS

A retrospective study of all patients tested for serum prolactin levels between 2019 and 2020 in 20 primary care centres at the Hospital Ramón y Cajal in Madrid. Hyperprolactinaemia is defined as a serum prolactin>19.4ng/ml in men and >26.5ng/ml in women. Aetiology is grouped into physiological (pregnancy, lactation, inadequate venipuncture, macroprolactinaemia), pharmacological, pathological (hypothalamic and/or pituitary diseases, chronic renal failure, primary hypothyroidism), and idiopathic.

RESULTS

In 1630 patients tested for serum prolactin, 30.7% (n=501) had hyperprolactinaemia. Of these 501 patients, 89.6% were females. 149 patients were referred to the Endocrinology Department and 164 to the Gynaecology Department. Aetiological diagnosis of hyperprolactinaemia was achieved in 411 out of 501 cases. The most frequent cause of hyperprolactinaemia was pharmacological, in 39.1%. The second more frequent cause was idiopathic (29%) and less common were inadequate venipuncture extraction (13.4%), tumour (8.5%) and macroprolactinaemia (3.9%). Patients with tumoural hyperprolactinaemia presented higher serum prolactin levels (87.0±80.19 vs 49.7±39.62ng/ml, P=0.010). In addition, symptoms, such as galactorrhoea (33.3% vs 16.5%, P=0.018), and headache (25.7% vs 13.3%, P=0.045), were more frequent than in patients of the other aetiological groups.

CONCLUSION

Hyperprolactinaemia is common among patients evaluated in a primary care setting with symptoms of hyperprolactinaemia, but more than 50% of cases are due to pharmacological treatments or improper sample extraction. It is necessary to establish referral protocols to specialised medicine to optimise healthcare resources and avoid unnecessary studies.

A Meta-Analysis of Observational Studies on Prolactin Levels in Women with Polycystic Ovary Syndrome

Women with polycystic ovary syndrome (PCOS) are reported to have different levels of prolactin (PRL) compared to women without PCOS. This study aimed to evaluate the PRL levels in women with PCOS, compared to the control group, before and after adjustment for potential confounders. Using a logical combination of keywords, a comprehensive search was carried out in PubMed and Web of Science, from inception to 30 August 2022. Weighted mean differences (WMDs) with corresponding 95% CIs in PRL levels were employed with a random-effects model. I2 was applied to evaluate heterogeneity among studies. A meta-regression analysis and subgroup analysis were conducted to explore heterogeneity sources. Publication bias was assessed by the Egger test. Thirty-two studies, measuring PRL levels in 8551 PCOS patients according to the Rotterdam criteria and 13,737 controls, were included in the meta-analysis. Pooled effect size suggested that the overall weighted mean difference (WMD) of PRL level was significantly higher in women with PCOS, compared to controls (WMD = 1.01, 95% CI: 0.04-1.98, p = 0.040). The result of meta-regression adjusted for age, BMI, and the continent of origin, revealed no confounding effect on results. Sub-group analysis of PRL levels according to the continent of origin showed significantly higher PRL levels among Eurasian PCOS patients compared to the control; this difference was not statistically significant in the subgroups of women from Asia, Europe, and South America. In conclusion, PRL levels in patients who were diagnosed according to the Rotterdam criteria were significantly higher than non-PCOS participants. Slightly higher levels of PRL could be presented as a diagnostic feature of PCOS.

Sociodemographic and clinical characteristics related with hyperprolactinaemia in psychiatric clinical population

BACKGROUND

Hyperprolactinaemia (HyperPRL) induced by psychotropic drugs is a high-prevalence consequence which has repercussions in psychical and mental health in the psychiatric population, so this research had the objective to expand which sociodemographic and clinical features are associated with prolactin (PRL) elevation in patients treated with antidepressant and/or antipsychotic drugs.

METHODS

An observational, cross-sectional, comparative and retrolective study was conducted on 300 patients who received clinical attention in a third level of psychiatric care unit in Mexico during 2017. These patients have been reported to show PRL levels greater than 25 ng/mL among women and greater than 20 ng/mL among men. In the same way, sociodemographic and clinical variables were collected, as well as psychiatric diagnosis and type of psychopharmacological treatment used by the patients.

RESULTS

HyperPRL was more frequent in women (80.7%) than men (19.3%). The mean levels of PRL were 68.94 ± 62.28 ng/mL with higher levels in women (71.9 ± 67.3, p=.02). Regarding the treatment, 78.3%, 71.3% and 49.7% consumed antipsychotics, antidepressants, and both drugs, respectively. The relationship between hyperPRL (>100 n/mL) and typical antipsychotics was dose-dependent (33.23 ± 13.24 mg, p=.01). In the multivariate regression models according to the type of treatment, as well as the demographic and clinical features, hyperPRL was associated independently with the use of antipsychotic treatment, pituitary adenoma and hypertension (R²=0.05).

CONCLUSIONS

HyperPRL is a complex clinical syndrome frequent in the psychiatric population with detrimental long-term consequences, as well as its relationship with the use of psychotropic drugs as in the case of antipsychotics. Effective actions should be implemented in the prevention, approach and treatment of this condition paying special attention to the accompanying medical comorbidities.

Prevalence of Macroprolactinemia in People Detected to Have Hyperprolactinemia

Background Macroprolactinemia is an analytic laboma encountered as a part of prolactin assay. No data are available on the burden of macroprolactinemia in Indians. This study aimed to determine the prevalence and predictors of macroprolactinemia among people with hyperprolactinemia.

Methods Consecutive patients detected to have serum prolactin > 18 ng/mL as per the upper reference limit were further screened for macroprolactin by post-polyethylene-glycol (PEG)-precipitation test. Macroprolactinemia was defined as post-PEG recovery of prolactin < 40%.

Results The four most common underlying etiologies for the testing of hyperprolactinemia were polycystic ovary syndrome ( n = 402; 32.71%), pituitary adenomas ( n = 318; 25.87%), drug-induced hyperprolactinemia ( n = 224; 18.23%), and infertility ( n = 126; 10.25%). A total of 1,229 patients (male:female = 191:1038) having mean age 30.46 ± 10.14 years had hyperprolactinemia, of which 168 (13.7%) were diagnosed to have macroprolactinemia. Macroprolactinemia was significantly higher in females than males (15.03 vs. 6.28%; p < 0.001). Age quartile-based analysis revealed no difference in occurrence of macroprolactinemia. Only 34 patients (2.76%) with macroprolactinemia (< 40% recovery of prolactin post-PEG precipitation) had raised prolactin levels after recovery. These patients primarily had underlying pituitary pathology.

Conclusion Macroprolactinemia is not uncommon in people being tested for hyperprolactinemia. We should not hesitate to screen for macroprolactinemia in patients who have incidentally been detected to have hyperprolactinemia.

Metabolic effects of prolactin and the role of dopamine agonists: A review

Prolactin is a polypeptide hormone that is well known for its role in reproductive physiology. Recent studies highlight its role in neurohormonal appetite regulation and metabolism. Elevated prolactin levels are widely associated with worsening metabolic disease, but it appears that low prolactin levels could also be metabolically unfavorable. This review discusses the pathophysiology of prolactin related metabolic changes, and the less commonly recognized effects of prolactin on adipose tissue, pancreas, liver, and small bowel. Furthermore, the effect of dopamine agonists on the metabolic profiles of patients with hyperprolactinemia are discussed as well.

A link between migraine and prolactin: the way forward

Migraine is an incapacitating neurological disorder that predominantly affects women. Sex and other hormones (e.g., oxytocin, and prolactin) may play a role in sexual dimorphic features of migraine. Initially, prolactin was recognized for its modulatory action in milk production and secretion; later, its roles in the regulation of the endocrine, immune and nervous systems were discovered. Higher prolactin levels in individuals with migraine were found in earlier studies, with a female sex-dominant trend. Studies that are more recent have identified that the expression of prolactin receptor in response to neuronal excitability and stress depends on sex with a dominant role in females. These findings have opened up potentials for explanation of sex-related pathophysiology of migraine, but have left some unanswered questions. This focused review examines the past and present of the link between prolactin and migraine, and presents open questions and directions for future experimental and clinical efforts.

Sex hormones (e.g., estrogen and progesterone) have been investigated to explain the sex-related manifestation of migraine, which is predominant in females. Prolactin is known for promoting lactation, but accumulating evidence supports that it can promote pain in females. An increasing number of studies have shown that the expression of a prolactin receptor in female nociceptors and their responses to external stimuli such as stress are different, which can help explain the female sex-dominant feature of migraine. In this focused review, the current knowledge is presented and the directions where prolactin research in migraine may evolve are proposed. The ultimate goal is to shape an overview toward considering sex-based treatments for migraine with highlighting the role of prolactin.

Vitamin D status determines the impact of metformin on circulating prolactin levels in premenopausal women

WHAT IS KNOWN AND OBJECTIVE

Metformin was found to normalize secretory function of overactive pituitary cells. Its effect on circulating thyrotropin levels was more pronounced in women receiving exogenous vitamin D. The aim of the current study was to investigate whether vitamin D status determines the impact of metformin on prolactin levels in premenopausal women with hyperprolactinaemia.

METHODS

The study population consisted of three groups of women with prediabetes and elevated prolactin levels: vitamin D-naïve women with vitamin D insufficiency (group 1; n = 19), women receiving vitamin D preparations because of vitamin D deficiency (group 2 n = 20), as well as vitamin D-naïve women with normal vitamin D status (group 3 n = 23). All participants were then treated with metformin (2.55-3 g daily). Circulating levels of glucose, insulin, prolactin, thyrotropin, free thyroid hormones, gonadotropins, estradiol, calcium and 25-hydroxyvitamin were determined at baseline and six months later.

RESULTS AND DISCUSSION

At baseline, prolactin levels were higher in group 1 than in the remaining groups of patients. Although metformin decreased glucose levels and improved insulin sensitivity in all treatment groups, this effect was more pronounced in groups 2 and 3. Only in subjects with 25-hydroxyvitamin D levels within the reference range, metformin reduced prolactin levels. The impact on prolactin levels correlated with 25-hydroxyvitamin D levels and with the improvement in insulin sensitivity. The drug produced a neutral effect on circulating levels of thyrotropin, free thyroid hormones, gonadotropins, estradiol, calcium and 25-hydroxyvitamin D.

WHAT IS NEW AND THE CONCLUSION

The results of the current study suggest that the impact of metformin on secretory function of overactive lactotropes depends on the vitamin D status of patients.

A case of hyperprolactinaemia in a patient with metastatic melanoma

Ectopic prolactin production from a malignancy is infrequently reported. We report here a 60-year-old gentleman who presented with hyperprolactinaemia (9100 mIU/L) causing expressible galactorrhoea, decreased libido and fatigue thought to be due to ectopic prolactin secretion from a metastatic melanoma. Upon initiation of pembrolizumab, the patient's symptoms resolved and he became normoprolactinaemic. This corresponded with a partial response on radiological imaging. Although the core biopsy of the metastatic melanoma did not exhibit immunostaining for prolactin, we believe that only a subset of the tumour cells possesses prolactin-secreting capacity. This case illustrates the need to consider ectopic prolactin production for a solid malignant tumour as a rare cause of hyperprolactinaemia in patients with a normal pituitary MRI, in the absence of other causes.

Optimization of a Screening Method for Macroprolactinemia

OBJECTIVE

To optimize a screening method for macroprolactinemia and improve the accuracy of free prolactin (freePRL) detection.

METHOD

Overall efficiency, calculated as the product of the immunoglobulin G (IgG) precipitation rate and the freePRL recovery rate were employed to determine the concentration of the precipitant polyethylene glycol (PEG). Then, an optimized screening method for macroprolactinemia was established. The concentrations of freePRL, obtained by gel filtration chromatography (GFC), from 66 cases were used as the gold standard, and the sensitivity, specificity, accuracy and precision of the optimized and traditional methods for detecting macroprolactinemia were compared.

RESULTS

(1) The IgG precipitation rate increased with increasing PEG6000 concentration, and the freePRL recovery rate decreased with increasing PEG6000 concentration; the overall efficiency first increased and then decreased. When the IgG concentrations in the mixture were 10 g/L, 25 g/L and 40 g/L, the concentrations of PEG6000 with the highest overall efficiency were 24%, 20% and 18%, respectively. (2) The effect of high and low IgG on the overall efficiency was 4.7% when using 20% PEG6000, which was lower than the effects when using 18% or 24% PEG6000 (9.2% and 13.2%). (3) In the optimized method established using 20% PEG6000, the macroprolactin (macroPRL) chromatographic peak disappeared, but the freePRL chromatographic peak was retained. The sensitivity of this macroprolactinemia screening method was 96.7%, and the specificity was 100%. (4) The freePRL concentrations obtained by the optimized method for samples from 30 macroprolactinemia cases and 36 true hyperprolactinemia cases were 15.8 (10.2-21.4) ng/mL and 60.2 (51.8-79.9) ng/mL; the concentrations were similar to those obtained using the GFC method (16.3 (11.9-27.2) ng/mL and 68.1 (49.5-92.9) ng/mL, respectively (p > 0.05)) and higher than those obtained using the traditional method (9.1 (6.1-17.6) ng/mL and 51.4 (43.7-71.9) ng/mL), respectively, p < 0.05)). (5) The relative deviation between the optimized and GFC methods was -7.0%, which was significantly lower than the relative deviation between the traditional and GFC methods (-21.4%, p < 0.01). (6) The in-batch coefficients of variation (CVs) for the dual-level quality control materials measured by the optimized method were 1.88% and 1.87%, and the within-laboratory CVs were 2.55% and 2.29%, which were slightly lower than the in-batch CVs (1.93% and 2.81%) and within-laboratory CVs (2.75% and 2.81%) measured by the traditional method.

CONCLUSION

The established optimized method for screening macroprolactinemia using 20% PEG6000 as a precipitant can completely precipitate macroPRL components and effectively retain freePRL components. Compared with traditional methods, the optimized method is simpler, more accurate and more stable for the quantitative detection of freePRL.

Ectopic hyperprolactinaemia due to a malignant uterine tumor resembling ovarian sex cord tumors (UTROCST)

PURPOSE

Moderate hyperprolactinaemia (2-5 times upper limit of normal) occurring in a patient with a normal pituitary MRI is generally considered to be due to a lesion below the level of detection of the MRI scanner assuming macroprolactin and stress have been excluded. Most patients with mild-to-moderate hyperprolactinaemia and a normal MRI respond to dopamine agonist therapy. We present the rare case of a patient who had prolactin elevation typical of a prolactin-secreting pituitary macroadenoma,with a normal cranial MRI, and in whom the prolactin rose further with dopamine agonist treatment. Subsequent investigations revealed ectopic hyperprolactinaemia to a uterine tumor resembling ovarian sex cord tumor (UTROSCT) which resolved following tumor resection. Although mostly considered to be benign, the UTROSCT recurred with recurrent hyperprolactinaemia and intraabdominal metastases.

METHODS

We have systematically and critically reviewed existing literature relating to ectopic hyperprolactinaemia in general and UTROCST specifically.

RESULTS

Fewer than 80 cases of UTROSCTs have been reported globally of which about 23% have shown malignant behaviour. There are fewer than 10 cases of paraneoplastic hyperprolactinaemia originating from uterine neoplasms including one other case of ectopic hyperprolactinaemia to a UTROSCT.

CONCLUSIONS

Our case demonstrates the importance of screening for extracranial hyperprolactinaemia in the context of: (1) substantially raised prolactin (10× ULN) and (2) normal cranial MRI assuming macroprolactin has been excluded. The majority of extracranial ectopic prolactin-secreting tumors occur in the reproductive organs.

Evaluation of autoantibodies and immunoglobulin G subclasses in women with suspected macroprolactinemia

BACKGROUND

Macroprolactin mostly composed of an immunoglobulin G (IgG) and a monomeric prolactin (PRL) represents the major circulating PRL form in the patients with macroprolactinemia that are usually asymptomatic and may not require treatment. In this study, we aimed to evaluate the prevalence of antithyroid and antinuclear antibodies, as well as the IgG subclass distributions in the patients suspected for macroprolactinemia.

METHODS

From January to July in 2018, totally 317 patients with elevated PRL were subjected to the polyethylene glycol (PEG) precipitation assay. The patients with recovery rates of ≤60% were subjected for IgG subclass determination and autoantibody testing including thyroid peroxidase antibody (aTPO), antithyroglobulin antibody (aTG), and antinuclear antibodies (ANA).

RESULTS

The higher the post-PEG PRL recovery rates, the less typical hyperprolactinemia symptoms and the higher prevalence of autoantibodies were observed. The IgG1 and IgG3 were the predominant subclasses in the PRL-IgG complexes according to the immunoprecipitation experiments.

CONCLUSION

The patients with post-PEG PRL recovery rates of <40% and 40%-60% were likely to represent two distinct populations of different clinical presentations. The prevalence of autoantibodies and IgG subclasses distribution suggested their pathogenic significance in the development of macroprolactinemia.

Relationship between Prolactin, Chronic Kidney Disease, and Cardiovascular Risk

CKD has a high prevalence worldwide, mainly due to its main etiologies-diabetes and hypertension. It has high cardiovascular morbidity and mortality, with traditional risk factors such as atherosclerosis, hypertension, diabetes, smoking, and left ventricular hypertrophy being common. Nontraditional cardiovascular risk factors, such as anemia, hyperparathyroidism, chronic inflammation, and microalbuminuria, are also well studied. Prolactin is a hormone not only related to lactation but also being considered a uremic toxin by some authors. It accumulates with loss of renal function, and it is associated with cardiovascular outcomes in both normal renal function population and CKD population. The purpose of this narrative review is to raise the main common aspects of CKD, prolactinemia, and cardiovascular risk.

Hyperprolactinaemia

Hyperprolactinaemia is one of the most common problems in clinical endocrinology. It relates with various aetiologies (physiological, pharmacological, pathological), the clarification of which requires careful history taking and clinical assessment. Analytical issues (presence of macroprolactin or of the hook effect) need to be taken into account when interpreting the prolactin values. Medications and sellar/parasellar masses (prolactin secreting or acting through “stalk effect”) are the most common causes of pathological hyperprolactinaemia. Hypogonadism and galactorrhoea are well-recognized manifestations of prolactin excess, although its implications on bone health, metabolism and immune system are also expanding. Treatment mainly aims at restoration and maintenance of normal gonadal function/fertility, and prevention of osteoporosis; further specific management strategies depend on the underlying cause. In this review, we provide an update on the diagnostic and management approaches for the patient with hyperprolactinaemia and on the current data looking at the impact of high prolactin on metabolism, cardiovascular and immune systems.

Aetiologies of Hyperprolactinaemia: A retrospective analysis from a tertiary healthcare centre

Objectives

This study aimed to evaluate the aetiologies of hyperprolactinaemia in the United Arab Emirates (UAE).

Methods

This retrospective study used laboratory databases to identify all patients who underwent evaluation for prolactin at Tawam Hospital, Al Ain, UAE, between 2009 and 2015. Of those 2,280 patients, all patients with low or normal prolactin (n = 1,315) were excluded. Subsequently, charts of the remaining patients (n = 965) with hyperprolactinaemia were reviewed and those with incomplete work-ups or insufficient documentation of the hyperprolactinaemia’s aetiology were excluded (n = 458).

Results

A total of 507 patients were included in the study. The average age at prolactin evaluation was 36 ± 13.2 years and the majority (67.1%) of patients were female. The most common reasons for requesting prolactin were menstrual disorders (29.5%), infertility (18%), evaluation of sellar masses (14.3%), ruling out seizures (13.4 %) and monitoring while on psychiatric medications (8.7%). The most common causes of hyperprolactinaemia were prolactinoma (17%), transient hyperprolactinaemia (14.6%), drug-induced side effects (14.4%), polycystic ovarian syndrome (11.8%) and seizure disorder (7.7%). In females, common aetiologies were prolactinomas, transient and idiopathic hyperprolactinaemia, while sellar masses, seizures, chronic kidney disease and acute illnesses were common aetiologies of hyperprolactinaemia in males. The prolactin level varied between the different aetiologies and a level of >250 ng/mL was suggestive of macro-prolactinoma.

Conclusion

A significant proportion of patients with hyperprolactinaemia have transient hyperprolactinaemia. Before further investigations are carried out, prolactin level assessment should be repeated, especially in patients with mild hyperprolactinaemia.

Serum prolactin overestimation and risk of misdiagnosis

BACKGROUND

Falsely elevated prolactin measurements risk overdiagnosis, and unnecessary imaging and treatment.

DESIGN

We conducted a clinical audit of 18 patients who presented with hyperprolactinaemia, followed by a laboratory audit of 40 split samples across a range of serum prolactin (5-5051 mIU/L). In each case (total n = 58), serum prolactin was measured on both Roche and Siemens platforms.

RESULTS

Serum prolactin as measured by Roche was higher than the corresponding Siemens value in every case, despite similar reference ranges. The mean discrepancy in serum prolactin by Roche vs. Siemens was +81% in the clinical audit and +50% in the laboratory audit. This led to unnecessary interventions in 7/18 patients (39%) in the clinical audit.

CONCLUSIONS

Serum prolactin is overestimated on the Roche relative to the Siemens platform. Laboratories should review Roche reference intervals for serum prolactin, and clinicians should consider repeating serum prolactin on another platform if the serum prolactin is incongruent with the clinical scenario.

Cardiometabolic Risk Factors in Men with Elevated Macroprolactin Content: A Pilot Study

BACKGROUND

Macroprolactinemia is a condition associated with the presence of large amounts of high molecular weight complexes of prolactin. Despite high prevalence, clinical significance of macroprolactin remains poorly understood.

OBJECTIVE

The aim of this study was to assess cardiometabolic risk in men with isolated macroprolactinemia.

METHODS

The study population included 11 men with isolated macroprolactinemia, 14 subjects with monomeric hyperprolactinemia and 14 men with prolactin levels within the reference range. Glucose homeostasis markers, plasma lipids, as well as plasma levels of uric acid, high-sensitivity C-reactive protein (hsCRP), fibrinogen, homocysteine and 25-hydroxyvitamin D were determined in all included patients.

RESULTS

Compared to healthy counterparts, men with isolated macroprolactinemia had higher levels of 2-h postchallenge glucose, hsCRP and fibrinogen, lower levels of 25-hydroxyvitamin D and reduced insulin sensitivity. Patients with monomeric hyperprolactinemia were characterized by increased plasma levels of 2-h postchallenge glucose, triglycerides, uric acid, hsCRP, fibrinogen and homocysteine, reduced insulin sensitivity and decreased plasma concentrations of HDL cholesterol and 25-hydroxyvitamin D. Subjects with isolated macroprolactinemia differed from patients with monomeric hyperprolactinemia in postchallenge plasma glucose, insulin sensitivity, uric acid, hsCRP, fibrinogen, homocysteine and 25-hydroxyvitamin D. In men with monomeric hyperprolactinemia, uric acid, hsCRP, fibrinogen, homocysteine and 25-hydroxyvitamin D, while in men with elevated levels of macroprolactin, uric acid, hsCRP, fibrinogen and 25-hydroxyvitamin D correlated with a content of monomeric prolactin or macroprolactin, respectively, as well as with a degree of insulin sensitivity.

CONCLUSIONS

The obtained results suggest that macroprolactinemia may increase cardiometabolic risk but to a lesser extent than monomeric hyperprolactinemia.

Pitfalls in the Diagnostic Evaluation of Hyperprolactinemia

An appropriate diagnostic evaluation is essential for the most appropriate treatment to be performed. Currently, macroprolactinemia is the third most frequent cause of nonphysiological hyperprolactinemia after drugs and prolactinomas. Up to 40% of macroprolactinemic patients may present with hypogonadism symptoms, infertility, and/or galactorrhea. Thus, the screening for macroprolactin is indicated not only for asymptomatic subjects but also for those without an obvious cause for their prolactin (PRL) elevation. Before submitting patients to macroprolactin screening and pituitary magnetic resonance imaging, one should rule out pregnancy, drug-induced hyperprolactinemia, primary hypothyroidism, and renal failure. The magnitude of PRL elevation can be useful in determining the etiology of hyperprolactinemia. PRL values >250 ng/mL are highly suggestive of prolactinomas and virtually exclude nonfunctioning pituitary adenomas (NFPAs) and other sellar masses as the etiology of hyperprolactinemia. However, they can also be found in subjects with macroprolactinemia, drug-induced hyper-prolactinemia or chronic renal failure. By contrast, most patients with NFPAs, drug-induced hyperprolactinemia, macroprolactinemia, or systemic diseases present with PRL levels <100 ng/mL. However, exceptions to these rules are not rare. Indeed, up to 25% of patients harboring a microprolactinoma or a cystic macroprolactinoma may also have PRL <100 ng/mL. Falsely low PRL levels may result from the so-called "hook effect," which should be considered in all cases of large (≥3 cm) pituitary adenomas associated with normal or mildly elevated PRL levels (≤250 ng/mL). The hook effect may be unmasked by repeating PRL measurement after a 1:100 serum sample dilution.

Beneficial Effects of High Doses of Cabergoline in the Treatment of Giant Prolactinoma Resistant to Dopamine Agonists: A Case Report with a 21-Year Follow-Up

INTRODUCTION

Prolactinomas are pituitary tumors with a very low prevalence in childhood and adolescence compared to adulthood. This condition is preferentially treated with dopamine agonists. Resistance to these drugs is rare.

CASE REPORT

We describe the case of a boy diagnosed with macroadenoma at the age of 9 and followed up for 21 years. He did not fully respond to treatment with dopamine agonists. His initial prolactin level was 2,400 ng/mL (in males, normal values are <16.0 ng/mL) and never normalized. At the last assessment, his prolactin level was 21.5 ng/mL, recorded after 21 years of treatment with the dopamine agonist cabergoline at a dose as high as 4.5 mg per week. Although the prolactin level remained elevated throughout the follow-up period, the patient never presented a low testosterone level and had normal pubertal development. An MRI of the sella turcica showed that the tumor became progressively cystic and disappeared, but a normal pituitary gland was observed. The pituitary gland retained its normal functions despite a partially empty sella.

DISCUSSION

Long-term treatment with high doses of cabergoline may cause cystic degeneration of a prolactinoma considered to be resistant to this treatment, but we cannot rule out the possibility that this outcome represents the natural development of the tumor.

Controversial issues in the management of hyperprolactinemia and prolactinomas - An overview by the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism

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 not rare. On the other hand, among patients with macroprolactinomas (MACs), artificially low PRL levels may result from the so-called "hook effect". Patients harboring cystic MACs may also present with a mild PRL elevation. The screening for macroprolactin is mostly indicated for asymptomatic patients and those with apparent idiopathic hyperprolactinemia. Dopamine agonists (DAs) are the treatment of choice for prolactinomas, particularly cabergoline, which is more effective and better tolerated than bromocriptine. After 2 years of successful treatment, DA withdrawal should be considered in all cases of microprolactinomas and in selected cases of MACs. In this publication, the goal of the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism (SBEM) is to provide a review of the diagnosis and treatment of hyperprolactinemia and prolactinomas, emphasizing controversial issues regarding these topics. This review is based on data published in the literature and the authors' experience.

The value of prolactin in predicting prolactinοma in hyperprolactinaemic polycystic ovarian syndrome

BACKGROUND

To identify a serum prolactin (PRL) cut-off value indicative of a PRL-producing adenoma in women with polycystic ovarian syndrome (PCOS) and hyperprolactinaemia and characterize such patients.

MATERIALS AND METHODS

In the present retrospective case-control study, the medical records of 528 PCOS women were reviewed. Pituitary magnetic resonance imaging (MRI) was performed in PCOS patients with PRL levels ≥94.0 ng/mL and/or symptoms suspicious of a pituitary adenoma (PA). Prolactinoma diagnosis was made in the presence of an MRI-identifiable PA with biochemical and radiological response to dopamine agonists. Receiver operating characteristic (ROC) curve analysis was performed to determine a serum PRL threshold that could identify hyperprolactinaemic PCOS subjects with prolactinomas. Clinical, metabolic and endocrine parameters were also analysed.

RESULTS

Among 528 patients with PCOS, 60 (11.4%) had elevated PRL levels. Of 44 (73.3%) patients who had pituitary imaging, 19 had PAs, 18 normal MRI and 7 other abnormalities. Patients harbouring prolactinomas had significantly higher PRL levels compared to patients without adenomas (median PRL 95.4 vs 49.2 ng/mL, P < .0001). A PRL threshold of 85.2 ng/mL could distinguish patients with prolactinomas with 77% sensitivity and 100% specificity [Area Under the curve (AUC) (95%) 0.91(0.8-1.018), P = .0001]. PCOS women with prolactinomas were younger and had lower LH levels compared to women without prolactinomas.

CONCLUSIONS

In women with PCOS, PRL levels exceeding 85.2 ng/mL are highly suggestive of a prolactinoma warranting pituitary imaging. Pituitary MRI could also be considered in young PCOS patients with milder PRL elevation and low LH levels.

Impact of macroprolactin on galactorrhea and the rate of patients possibly affected by macroprolactin

The clinical influence of macroprolactin (MPRL) is not clearly understood and the rate of patients potentially affected by MPRL is unknown. We investigated the influence of MPRL on the onset of galactorrhea and estimated the rate of patients with a proportion of MPRL fraction that may possibly affect galactorrhea. Data of patients with obstetric or gynecological symptoms who had undergone PRL fractionation testing were retrospectively analyzed. To evaluate factors influencing galactorrhea, a multivariate logistic regression analysis was performed and the adjusted odds ratios of MPRL for galactorrhea were calculated. Cutoff values for the total PRL level and the proportion of MPRL fractions for galactorrhea were determined by ROC analysis using a multivariate logistic model. The prevalence of patients with a proportion of MPRL fraction greater than or equal to the cutoff value for galactorrhea was estimated. The median proportion of MPRL fraction was 30.1% and increased as PRL level increased. Total PRL and MPRL had a significant influence on the onset of galactorrhea and the adjusted odds ratio was 1.09 in total PRL and 0.94 in MPRL. The rate of patients with a proportion of MPRL fraction that may possibly affect galactorrhea was estimated to be 33.5% of the study population, and thus found to be twelve times or more the number of macroprolactinemia patients. Future prospects for hyperprolactinemia may require diagnostic criteria using free prolactin levels and so MPRL fraction measurement is important for the diagnosis and treatment of patients with obstetric and gynecological symptoms.

Prolactinomas Resistant to Treatment With Dopamine Agonists: Long-Term Follow-Up of Six Cases

Introduction: Prolactinomas are preferentially treated with dopamine agonists. However, a few adenomas are resistant to this treatment. Objective: To evaluate the characteristics of patients with resistance to dopamine agonists in the long-term. Method: A retrospective study of six cases was made. Patients who did not achieve normalized prolactin blood concentrations and a reduction of more than 50% of the tumor volume with the minimum dose of 3.5 mg per week of cabergoline for 3 months or the maximum supported dose of bromocriptine for 6 months were considered resistant to dopamine agonists. Patients were followed up at the Clinic of Neurology and Endocrinology or the University Hospital of Brasilia. Results: Six patients were selected. Three patients were initially treated with bromocriptine prior to treatment with cabergoline. Four patients were men, and two were women. At the time of diagnosis, ages ranged from 9 to 62 years. Initial prolactin concentrations ranged from 430 to 14,992 ng/mL and in the last assessment ranged from 29.6 to 2,169 ng/mL. The tumor volume ranged from 0.77 to 24.0 mm³. Tumor regression occurred in all patients, ranging from 20 to 100%, but total disappearance of the adenoma with an empty sella occurred in one patient. The maximum weekly doses of cabergoline ranged from 3.0 to 4.5 mg. Follow-up time ranged from seven to 17 years. Normalization of prolactin concentrations occurred only in one woman after 17 years of treatment. Three patients also underwent surgery, but only one woman was cured of the disease. Conclusion: This study confirms that tumors resistant to dopamine agonists are more aggressive, since we did not have any microadenoma; treatment with high dose of cabergoline may reduce the size of the tumor without its disappearance, and that normalization of prolactin concentration rarely occurs. To our knowledge, this is the longest follow-up of a series of cases with resistance to dopamine agonists.

Acromegaly: clinical features at diagnosis

BACKGROUND

Acromegaly is a rare and underdiagnosed disorder caused, in more than 95% of cases, by a growth hormone (GH)-secreting pituitary adenoma. The GH hypersecretion leads to overproduction of insulin-like growth factor 1 (IGF-1) which results in a multisystem disease characterized by somatic overgrowth, multiple comorbidities, physical disfigurement, and increased mortality.

OBJECTIVE

This article aims to review the clinical features of acromegaly at diagnosis.

DISCUSSION/CONCLUSION

Acromegaly affects both males and females equally and the average age at diagnosis ranges from 40 to 50 years (up to 5% of cases < the age 20). Due to insidious onset and slow progression, acromegaly is often diagnosed five to more than ten years after its onset. The typical coarsening of facial features include furrowing of fronthead, pronounced brow protrusion, enlargement of the nose and the ears, thickening of the lips, skin wrinkles and nasolabial folds, as well as mandibular prognathism that leads to dental malocclusion and increased interdental spacing. Excessive growth of hands and feet (predominantly due to soft tissue swelling) is present in the vast majority of acromegalic patients. Gigantism accounts for up to 5% of cases and occurs when the excess of GH becomes manifest in the young, before the epiphyseal fusion. The disease also has rheumatologic, cardiovascular, respiratory, neoplastic, neurological, and metabolic manifestations which negatively impact its prognosis and patients quality of life. Less than 15% of acromegalic patients actively seek medical attention for change in appearance or enlargement of the extremities. The presentation of acromegaly is more often related to its systemic comorbidities or to local tumor effects.

Prevalence and predictors of hyperprolactinemia in subclinical hypothyroidism

BACKGROUND AND AIMS

Hyperprolactinemia has been reported in 0-57% of primary hypothyroidism. Data on hyperprolactinemia in subclinical hypothyroidism (ScH) is scant and inconsistent. This study aimed to determine the prevalence and predictors of hyperprolactinemia in ScH.

METHODS

Consecutive patients diagnosed to have normal thyroid function, ScH or overt primary hypothyroidism underwent serum prolactin, gonadotropins, testosterone and estradiol estimation. Patients with pregnancy, pituitary adenomas, secondary hypothyroidism, hyperthyroidism, comorbid states and drug-induced hyperprolactinemia were excluded.

RESULTS

From initially screened 4950 patients, hormonal data from 2848 individuals who fulfilled all criteria were analyzed. The occurrence of hyperprolactinemia (females:males) was highest in primary hypothyroidism (42.95%:39.53%) (n=192), followed by ScH (35.65%:31.61%) (n=770) and euthyroid individuals (2.32%:2.02%) (n=1886) (P<0.001). Hyperprolactinemia in ScH with TSH 5-7.5, 7.5-10 and >10mIU/L (females: males) was 25.56%:20.73%, 49.07%:50% and 61.43%:35.71% respectively (P<0.001). Significant positive correlation between TSH and prolactin was noted in ScH and primary hypothyroidism. In females, testosterone was lowest in patients with primary hypothyroidism. In males, serum estradiol was significantly higher, and testosterone significantly lower in men with ScH and primary hypothyroidism. Regression analysis revealed serum TSH followed by free T₄, to be best predictors of serum prolactin in both sexes.

CONCLUSION

Hyperprolactinemia is common in ScH, especially in those with TSH>7.5mIU/L. ROC analysis confirmed that TSH≥7.51mIU/L in females and ≥8.33mIU/L in males had a sensitivity of ≈50% with a very high specificity of >90% in detecting hyperprolactinemia. Prolactin screening may be warranted in ScH with TSH>7.5mIU/L, and may form an indication for treating ScH.

The risks of overlooking the diagnosis of secreting pituitary adenomas

Secreting pituitary adenomas that cause acromegaly and Cushing’s disease, as well as prolactinomas and thyrotroph adenomas, are uncommon, usually benign, slow-growing tumours. The rarity of these conditions means that their diagnosis is not familiar to most non-specialist physicians. Consequently, pituitary adenomas may be overlooked and remain untreated, and affected individuals may develop serious comorbidities that reduce their quality of life and life expectancy. Because many signs and symptoms of pituitary adenomas overlap with those of other, more common disorders, general practitioners and non-endocrinology specialists need to be aware of the “red flags” suggestive of these conditions. A long duration of active disease in patients with secreting pituitary adenomas is associated with an increased risk of comorbidities and reduced quality of life. Appropriate treatment can lead to disease remission, and, although some symptoms may persist in some patients, treatment usually reduces the incidence and severity of comorbidities and improves quality of life. Therefore, correct, early diagnosis and characterization of a pituitary adenoma is crucial for patients, to trigger timely, appropriate treatment and to optimize outcome. This article provides an overview of the epidemiology of hormonal syndromes associated with pituitary adenomas, discusses the difficulties of and considerations for their diagnosis, and reviews the comorbidities that may develop, but can be prevented, by accurate diagnosis and appropriate treatment. We hope this review will help general practitioners and non-endocrinology specialists to suspect secreting pituitary adenomas and refer patients to an endocrinologist for confirmation of the diagnosis and treatment.

Prolactinomas: evolution after menopause

OBJETIVE

The aim was to assess the evolution of tumor size and prolactin (PRL) levels in patients with micro and macroprolactinomas diagnosed and treated with dopamine agonists during fertile age, and the effects of suspension of drugs after menopause.

SUBJECTS AND METHODS

Retrospective study, 29 patients with prolactinomas, 22 microadenomas and 7 macroadenomas, diagnosed during their fertile age were studied in their menopause; treatment was stopped in this period. Age at menopause was 49 ± 3.6 years. The average time of treatment was 135 ± 79 months. The time of follow-up after treatment suspension was 4 to 192 months. Results: Pre-treatment PRL levels in micro and macroadenomas were 119 ± 57 ng/mL and 258 ± 225 ng/mL, respectively. During menopause after treatment suspension, and at the latest follow-up: in microadenomas PRL levels were 23 ± 13 ng/mL and 16 ± 5.7 ng/mL, respectively; in macroadenomas, PRL levels were 20 ± 6.6 ng/mL 5t5and 25 ± 18 ng/mL, respectively. In menopause after treatment suspension, the microadenomas had disappeared in 9/22 and had decreased in 13/22. In the group of patients whose tumor had decreased, in the latest follow-up, tumors disappeared in 7/13 and remained unchanged in 6/13. In macroadenomas, after treatment suspension 3/7 had disappeared, 3/7 decreased and 1/7 remained unchanged. In the latest control in the 3 patients whose tumor decreased, disappeared in 1/3, decreased in 1/3 and there was no change in the remaining.

CONCLUSIONS

Normal PRL levels and sustained reduction or disappearance of adenomas were achieved in most of patients, probably due to the decrease of estrogen levels. Dopamine agonists might be stopped after menopause in patients with prolactinomas.

Update on prolactinomas. Part 1: Clinical manifestations and diagnostic challenges

The authors provide an update on the clinical manifestations and diagnostic challenges of prolactinomas. Prolactinomas are the most common pituitary adenoma seen in clinical practice. Secondary causes of hyperprolactinemia should be ruled out by assessment of the clinical history, including current medications, physical examination, pregnancy test, routine biochemical analysis with a thyroid function test, and neuroimaging, before a confirmatory diagnosis of prolactinoma is made. Prolactinomas are associated with endocrine dysfunction, affecting gonadal function and causing neurological deficits due to mass effect. The progress in elucidating the pathogenesis of prolactinomas and advances in diagnostic methods, including more sensitive diagnostic hormone assays and neuroimaging, have enriched the current diagnostic approach and management. Making the correct diagnosis is crucial to implementing the appropriate therapy. Dopamine agonist therapy remains the first line of treatment for prolactinomas, as it is effective in normalizing serum prolactin levels and reducing tumor size. Surgery is typically indicated for patients who are resistant to medical therapy or intolerant of its adverse side effects, or for those experiencing progressive neurological deficits. Nevertheless, curative surgical resection as a primary mode of treatment for smaller prolactinomas has recently gained attention as an alternative to lifelong dopamine agonist treatment.

Gigantomastia and Macroprolactinemia Responding to Cabergoline Treatment: A Case Report and Minireview of the Literature

Background. Macroprolactinemia is defined as predominance of high molecular weight prolactin forms in the circulation. Although macroprolactin is considered as a biologically inactive molecule, some authorities suggest treatment in symptomatic cases. Gigantomastia is defined as excess breast tissue and most cases in the literature were treated by surgical intervention. Case. A 44-year-old woman was admitted to our clinic with gigantomastia and galactorrhea. The patient had a demand for surgical therapy. In laboratory examination, she had hyperprolactinemia and macroprolactinemia. Pituitary imaging revealed 6 mm microadenoma in right side of the hypophysis. Since she was symptomatic, cabergolin treatment was started. Macroprolactin became negative, breast circumference decreased significantly, and galactorrhea resolved after treatment. Conclusion. Gigantomastia might be the presenting symptom in patients with macroprolactinemia. In these patients medical treatment with cabergoline may be used initially as an alternative to surgical approach.

The effect of short-term metformin treatment on plasma prolactin levels in bromocriptine-treated patients with hyperprolactinaemia and impaired glucose tolerance: a pilot study

Metformin was found to affect plasma levels of some pituitary hormones. This study was aimed at investigating whether metformin treatment has an impact on plasma prolactin levels in bromocriptine-treated patients with hyperprolactinaemia and impaired glucose tolerance. The study included 27 patients with hyperprolactinaemia, who had been treated for at least 6 months with bromocriptine. Based on prolactin levels, bromocriptine-treated patients were divided into two groups: patients with elevated (group A, n = 12) and patients with normal (group B, n = 15) prolactin levels. The control group included 16 age-, sex- and weight-matched hyperprolactinaemia-free individuals with impaired glucose tolerance (group C).The lipid profile, fasting plasma glucose levels, the homeostatic model assessment of insulin resistance ratio (HOMA-IR), glycated haemoglobin, as well as plasma levels of prolactin, thyrotropin and insulin-like growth factor-1 (IGF-1) were assessed at baseline and after 4 months of metformin treatment (2.55-3 g daily). In all treatment groups, metformin reduced HOMA-IR, plasma triglycerides and 2-h postchallenge plasma glucose. In patients with hyperprolactinaemia, but not in the other groups of patients, metformin slightly reduced plasma levels of prolactin, and this effect correlated weakly with the metabolic effects of this drug. Our study shows that metformin decreases plasma prolactin levels only in patients with elevated levels of this hormone. The obtained results suggest that metformin treatment may bring some benefits to hyperprolactinaemic patients with coexisting glucose metabolism disturbances already receiving dopamine agonist therapy.

Second Attempt of Cabergoline Withdrawal in Patients with Prolactinomas after a Failed First Attempt: Is it Worthwhile?

Successful discontinuation of cabergoline (CAB) treatment has been reported in 31-75% of prolactinomas patients treated for at least 2 years. In contrast, it is not well established whether CAB therapy can be successfully withdrawn after a failed first attempt. This prospective open trial was designed to address this topic and to try to identify possible predictor factors. Among 180 patients with prolactinomas on CAB therapy, the authors selected those who fulfilled very strict criteria, particularly additional CAB therapy for at least 2 years, normalization of serum prolactin (PRL) levels following CAB restart, no tumor remnant >10 mm, no previous pituitary radiotherapy or surgery; and current CAB dose ≤1.0 mg/week. Recurrence was defined as an increase of PRL levels above the upper limit of normal. A total of 34 patients (70.6% female) treated with CAB for 24-30 months were recruited. Ten patients (29.4%) remained without evidence of recurrence after 24-26 months of follow-up. Twenty-four patients (70.6%) recurred within 15 months (75% within 12 months) after drug withdrawal and ~80% were restarted CAB. Median time to recurrence was 10.5 months (range, 3-15). Despite overlapping values, non-recurring patients had significantly lower mean PRL levels before withdrawal. Moreover, the recurrence rate was lower in subjects without visible tumor on pituitary magnetic resonance imaging (MRI) than in those with small remnant tumor (60 vs. 79%), though the difference was not statistically significant (P = 0.20). No other characteristic could be identified as a predictor of successful CAB discontinuation. In conclusion, a second attempt of CAB withdrawal after two additional years of therapy may be successful, particularly in patients with lower PRL levels and no visible tumor on pituitary MRI. Close monitoring of PRL level is mandatory, especially within the first year after withdrawal, where most recurrences are detected.

Challenges and controversies in the treatment of prolactinomas

Recent studies have reported a higher prevalence of pituitary tumors than previously thought. Among these tumors, prolactinomas occur in up to 66% of cases. Since the mid-1980s, the widespread use of dopamine agonists has facilitated the management of the majority of prolactinomas, allowing biological and tumoral control in most cases. The less frequent cases of resistant prolactinomas remain challenging despite a multimodal therapy approach. The understanding of genetic alterations in familial and aggressive pituitary tumors provides new perspectives in the management of some prolactinomas. Genetic screening should be considered, particularly in familial cases but also in young patients with macroprolactinomas, as some mutations can predict potential aggressiveness.