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

Prolactinomas: Preconception and During Pregnancy

Prolactinomas are a common cause of infertility in women. Medical treatment with dopamine agonists (DAs) has an excellent efficacy at restoring fertility and a reassuring safety profile in early pregnancy. Surgical treatment before conception is required in some cases of large macroadenomas and incomplete treatment response. In women with microprolactinomas, the pregnancy course is usually uneventful. In women with macroprolactinomas that are near/abut the optic chiasm, symptomatic tumor enlargement can occur during pregnancy and require a multidisciplinary team approach. This review provides an update regarding outcomes and management of prolactinomas before conception, during pregnancy, and postpartum.

Aromatase inhibitors as a therapeutic strategy for male prolactinoma resistant to dopamine agonists: a retrospective cohort study and literature review

PURPOSE

To assess the effect of letrozole, an aromatase inhibitor (AI), in patients with resistant prolactinoma that presented an increase in serum prolactin (PRL) levels during testosterone replacement therapy (TRT).

METHODS

A retrospective cohort study in a single tertiary care center. From March 2012 to July 2023, 53 male patients over 18 years with prolactinoma were followed in our Neuroendocrine Unit. Of those, 90.6% presented macroadenomas, 41% of them were resistant to cabergoline and 25% presented persistent hypogonadism to whom TRT was indicated. Among them, five presented a significant increase in PRL levels and AI was initiated. All five patients had resistant prolactinomas. One of them was excluded due to tumor aggressiveness and concomitant use of temozolomide during AI therapy.

RESULTS

Four patients were included in the analysis, with a mean age of 28.5 (± 7.5) years, median prolactin of 1060 (600 to 6700) ng/mL and median of the largest tumor diameter of 3.6 (1.5 to 5) cm at the time of prolactinoma diagnosis. On TRT, all presented an increase in serum PRL levels (231 to 396%), with a subsequent decrease (61 to 93%) after adding AI. During AI treatment for a median time of 60.5 (21 to 120) months, tumor shrinkage was observed in two cases (-8 and -3 mm in the maximum diameter) and tumor stability in the other two. No major side effects occurred and AI was well tolerated.

CONCLUSION

AI might be an option for men with resistant prolactinoma who have an increase in PRL levels on TRT. Nevertheless, prospective randomized clinical trials are needed to ensure efficacy and security for this approach.

Gender Differences in Patients with Prolactinoma: Single-center Ukrainian Experience

INTRODUCTION

Prolactinomas are the most common type of pituitary gland tumors that secrete overly prolactin. They account for approximately 60% of all hormone-secreting hypophysis tumors.

AIM

This study aims to analyze gender differences in patients with prolactinomas who were operated on transsphenoidal surgery and conduct a single-center retrospective analysis of patient data.

MATERIAL AND METHODS

This study evaluated the medical records of 109 patients (61 females and 48 males) from 2009 to 2019 at Feofaniya Clinical Hospital of the State Administration of Affairs in Kyiv, Ukraine. The primary criterion for including patients was a Serum Prolactin (PRL) level of over 100 ng/ml and the presence of a pituitary adenoma (PA) as observed on MRI. Additionally, the histological examination needed to confirm the presence of Prolactin-Secreting Pituitary Adenomas (PSPAs) without plurihormonal activity through both microscopy and immunohistochemical (IHC) staining.

RESULTS

Significant differences in preoperative PRL levels were not observed. However, males had significantly larger tumor sizes and prevalence of macroadenomas. In male patients, the preoperative PLR levels showed a weak negative correlation with age (r=-0.304, p < 0.036) and a positive correlation with tumor size (r=0.555, p < 0.001) and cavernous sinus invasion (r=0.339, p < 0.018). In females, preoperative PRL was significantly associated only with tumor size and Knosp grade.

CONCLUSION

Prolactin-Secreting Pituitary Adenomas (PSPAs) are more common in women than men and are characterized by larger and more invasive tumors with high PRL levels at diagnosis. The PRL level and tumor size before surgery can predict early biochemical remission in both males and females with an accuracy of 58.3% and 68.8%, respectively.

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.

The role of endoscopic endonasal surgery in the management of prolactinomas based on their invasiveness into the cavernous sinus

PURPOSE

To review our institutional experience with the surgical management of prolactinomas through the endoscopic endonasal approach with specific focus on cavernous sinus invasion.

METHODS

Clinical and radiographic data were collected retrospectively from the electronic medical record of 78 consecutive patients with prolactinomas undergoing endoscopic endonasal resection from 2002 to 2019. Immediate and late post-operative remission were defined as prolactin < 20 ng/mL within 14 days and 1-year of surgery without adjuvant therapy, respectively. Cavernous sinus invasion was quantified by Knosp score.

RESULTS

A total of 78 patients with prolactinoma, 59% being male, underwent surgical resection with a mean age of 37 ± 13 years. Indications for surgery were medication resistance in 38 patients (48.7%), medication intolerance in 11 (14.1%), and patient preference in 29 (37.2%). Patients with Knosp 0-2 achieved higher immediate remission rates (83.8%) compared to patients with Knosp 3 (58.8%) and Knosp 4 (41.7%) patients (p = 0.003). Long-term remission rates were 48.7% and increased to 71.8% when combined with adjuvant treatments. Knosp 4 prolactinomas had significantly higher tumor volumes, higher preoperative prolactin levels, higher recurrence rates, higher rates of adjuvant therapy utilization, and were more likely to have failed dopamine agonist therapy compared to other tumor grades (p < 0.05). We encountered 18 complications in our series, and no cerebrospinal fluid leaks.

CONCLUSION

The endoscopic endonasal approach is a safe and effective modality that can be employed in properly selected patients with invasive prolactinomas. It is associated with improved control and remission rates despite cavernous sinus invasion, though at a lower rate than without invasion.

Are dopamine agonists still the first-choice treatment for prolactinoma in the era of endoscopy? A systematic review and meta-analysis

Background

For prolactinoma patients, dopamine agonists (DAs) are indicated as the first-line treatment and surgery is an adjunctive choice. However, with the development of surgical technique and equipment, the effect of surgery has improved. The aim of this study was to assess the efficacy and safety of surgery versus DAs in patients with different types of prolactinomas.

Methods

A systematic search of literature using Web of Science, PubMed, Cochrane Library, and Clinical Trial databases was conducted until July 12, 2019. Prolactinoma patients treated with DAs (bromocriptine or cabergoline) or surgery (microscopic or endoscopic surgery) were included. Outcomes included the biochemical cure rate, recurrence rate, prolactin level, improvement rates of symptoms, and incidence rates of complications. A random-effects model was used to pool the extracted data. Qualitative comparisons were conducted instead of quantitative comparison.

Results

DAs were better than surgery in terms of the biochemical cure rate (0.78 versus 0.66), but surgery had a much lower recurrence rate (0.19 versus 0.57). Full advantages were not demonstrated in improvement rates of symptoms and incidence rates of complications with both treatment options. In microprolactinoma patients, the biochemical cure rate of endoscopic surgery was equal to the average cure rate of DAs (0.86 versus 0.86) and it surpassed the biochemical cure rate of bromocriptine (0.86 versus 0.76). In macroprolactinoma patients, endoscopic surgery was slightly higher than bromocriptine (0.66 versus 0.64) in terms of the biochemical cure rate.

Conclusion

For patients with clear indications or contraindications for surgery, choosing surgery or DAs accordingly is unequivocal. However, for patients with clinical equipoise, such as surgery, especially endoscopic surgery, in microprolactinoma and macroprolactinoma patients, we suggest that neurosurgeons and endocrinologists conduct high-quality clinical trials to address the clinical equipoise quantitatively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41016-022-00277-1.

To what extent does polycystic ovary syndrome influence the cut-off value of prolactin? Findings of a community-based study

PURPOSE

Polycystic ovary syndrome (PCOS) and hyperprolactinemia are the most frequent endocrine disorders in women which share several common features. There are inconsistent results regarding the existence of a possible pathophysiological interplay between these endocrinopathies and the elevation of prolactin (PRL) in PCOS. The purpose of this study was to explore the upper reference limit of PRL in PCOS women.

PATIENTS AND METHODS

This study is a cross-sectional analysis using data collected from two population-based PCOS prevalence studies. After considering the exclusion criteria, 216 women with PCOS diagnosed based on the Rotterdam criteria and 702 eumenorrheic non-hirsute controls, were enrolled. The age distribution of PRL and the effect of PCOS on the percentiles of serum PRL were compared between the PCOS group and controls. The possible contributing factors for the elevation of PRL were evaluated.

RESULTS

In the subgroup of women with PCOS, aged ≤35 years, the age-adjusted model of quantile regression revealed a significant elevation of PRL from the 60th percentile onwards, leading to an increase of nearly 10 ​ng/ml (p ​= ​0.023, 95% CI 1.3-17.62) of the 95th percentile of PRL. Hyperprolactinemic PCOS women had higher levels of luteinizing hormone (LH).

CONCLUSIONS

In PCOS women, aged ≤35 years, the upper reference limit of serum PRL was approximately 1.5-fold higher than in controls. The pathway underlying PRL elevation in PCOS might be attributed to a decline in central dopaminergic tone associated with PCOS which leads to an increase in levels of both - PRL and LH.

Occurrence of macroprolactinemia in schizophrenia patients treated with risperidone or amisulpride

OBJECTIVE

To investigate macroprolactinemia caused by antipsychotics and its clinical significance.

METHODS

A total of 133 patients with schizophrenia were selected, all of whom were treated with either risperidone or amisulpride alone. The levels of total prolactin (T-PRL) and macroprolactin (MPRL) were measured before treatment as well as the second, fourth, and sixth weeks of treatment.

RESULTS

After 2 weeks of treatment, 75.09% (100/133) of the patients met the diagnostic criteria for hyperprolactinemia, the incidence of macroprolactinemia was 43% (43/100), and MPRL levels were positively correlated T-PRL levels.

CONCLUSION

Risperidone and amisulpride caused hyperprolactinemia and macroprolactinemia; thus, detection of MPRL in the clinical setting should be performed as this phenomenon appears early in treatment (the second week) and continues, that can avoid unnecessary examination and treatment for asymptomatic patients with macroprolactinemia.

Optimal testosterone level to improve symptoms of hypogonadism without causing dopa-testotoxicosis in male macroprolactinoma

BACKGROUND

Male prolactinoma treatment by dopamine agonists (DA) restores sexual function. However, excessive DA dose can lead to impulse control disorder.

OBJECTIVES

The aim of this retrospective study was to determine the level of testosterone that eliminates symptoms and provides fertility in male macroprolactinoma, without causing these adverse effects.

MATERIALS AND METHODS

Twenty-seven male patients with macroprolactinoma were included. There were 16 macro (≥1-2.8 cm), 7 large macro (≥2.9-3.9 cm) and 4 giant (≥4 cm) adenomas. Prolactin (PRL) and testosterone (T) levels were evaluated. A timeline was created to analyze improvement in symptoms of hypogonadism and infertility. Testosterone levels were compared with age-matched controls.

RESULTS

Mean PRL, basal tumor diameter and shrinkage were 2,846±3,415 ng/mL, 27.2±10.2 mm and 63.4%, respectively. Basal T levels were 1.6±1.0 ng/mL for patients and 4.4±1.5 ng/mL for controls (p<0.001). Mean T level in the asymptomatic period was significantly lower than in controls (3.2±0.4 ng/mL vs. 4.4±1.5 ng/mL, respectively; p=0.002), while mean PRL was 27.2 ng/ml. Fertility was achieved in 6 of the patients seeking fertility, and there was no difference in T level between these patients and controls (3.7±0.8 ng/mL and 4.4±1.5 ng/mL, respectively; p=0.14); when fertility was achieved, mean PRL was 26.9±23 ng/mL.

CONCLUSION

Patients should be carefully questioned regarding complaints at each consultation, and DA dose should not be increased unnecessarily, to avoid possible serious adverse effects.

Cure and Hormonal Control After Prolactinoma Resection: Case Series and Systematic Review

Context

Surgical management of prolactinomas is an important treatment for patients intolerant of dopamine agonist therapy. However, predictors of postoperative outcomes remain unclear.

Object

While transsphenoidal surgical resection (TSSR) is important second-line therapy in prolactinoma patients, predictors of surgical cure and biochemical remission following TSSR remain sparse.

Methods

A retrospective review of prolactinoma patients undergoing TSSR at the USC Pituitary Center from 1995 to 2020 was conducted. Participants were categorized as surgical cure (normalization of serum prolactin without medical treatment), surgical noncure, biochemical control (prolactin normalization with or without adjuvant therapy), and nonbiochemical control. A systematic review of the outcomes of surgically managed prolactinomas was performed.

Results

The 40 female and 16 male participants had an average age of 35.6 years. Prior treatment included transsphenoidal resection (6, 11%) and dopamine agonist treatment (47, 84%). The 40 macroadenomas and 15 microadenomas exhibited suprasellar extension (24, 43%) and parasellar invasion (20, 36%). Fifteen (27%) were purely intrasellar. Gross total resection was achieved in 25 patients (45%) and subtotal in 26 (46%). Surgical cure was achieved in 25 patients (46%) and biochemical control in 35 (64%). Surgical cure was more likely in smaller, noninvasive tumors, those that were fully resected, and patients with lower preoperative (< 1000 ng/mL) and immediately postoperative (< 7.6 ng/mL) prolactin levels. Ten of 26 patients (38%) undergoing adjuvant therapy achieved biochemical control, which was less likely in men and those with higher preoperative prolactin or invasive tumors.

Conclusion

Surgical resection of prolactinomas is a safe procedure that, when offered judiciously, can achieve symptom and/or biochemical control in a majority of patients. A variety of predictors may be useful in advising patients on likelihood of postoperative remission.

Pituitary Adenomas: From Diagnosis to Therapeutics

Pituitary adenomas are tumors that arise in the anterior pituitary gland. They are the third most common cause of central nervous system (CNS) tumors among adults. Most adenomas are benign and exert their effect via excess hormone secretion or mass effect. Clinical presentation of pituitary adenoma varies based on their size and hormone secreted. Here, we review some of the most common types of pituitary adenomas, their clinical presentation, and current diagnostic and therapeutic strategies.

Spontaneous Cerebrospinal Fluid Rhinorrhea from a Prolactin-Secreting Pituitary Macroadenoma

Cerebrospinal fluid (CSF) rhinorrhea is a rare complication of macroprolactinomas that, in the vast majority of cases, is subsequent to either medical or surgical intervention. Here, we present the successful management of a rare case of spontaneous, noniatrogenic CSF rhinorrhea in a patient with an untreated macroprolactinoma. A 27-year-old man with no significant medical history presented with six months of persistent CSF rhinorrhea, which was confirmed by testing for beta-2-transferrin. He had had decreased libido since adolescence and impaired growth of secondary sexual characteristics. Workup revealed an elevated prolactin level, and imaging demonstrated erosion of the anterior sellar floor and soft tissue within the sphenoid sinus, concerning for tumor. The patient underwent surgical repair of the CSF leak via a transnasal transsphenoidal approach, with resection and biopsy of tumor material within the sinus. No tumor was noted within the sella itself. The patient tolerated the procedure well and had subsequent normalization of his prolactin level with no further CSF egress. Spontaneous noniatrogenic CSF rhinorrhea, although rare, should be considered in the differential diagnosis of invasive pituitary macroadenomas, especially prolactinomas. The mechanism of CSF leak from a prolactinoma is not completely understood, but the CSF leak should be urgently repaired through a transnasal transsphenoidal approach. Concurrently, tumor resection should be performed and a postoperative lumbar puncture or lumbar drain should be considered to reinforce the skull base reconstruction.

Outcomes of Transsphenoidal Microsurgery for Prolactinomas - A Contemporary Series of 162 Cases

INTRODUCTION

Renewed interest in transsphenoidal surgery (TSS) as a therapeutic option for prolactinomas has emerged. This study is aimed at defining the current role of pituitary surgery in the management of prolactinomas.

MATERIALS AND METHODS

In this retrospective, consecutive single-center study, 162 patients who underwent primary microscopic TSS for prolactinomas between 2006 and 2019 were analyzed regarding surgical indication, previous dopamine-agonist (DA) treatment, early remission rates (3 months postoperatively), surgical complications and pituitary function.

RESULTS

Seventy-four microprolactinomas and 88 macroprolactinomas were operated by TSS. 62.3% of the patients had received prior DA treatment. For microprolactinomas, the predominant indication for surgery was patient's wish (41.9%), while indications for macroprolactinomas varied. For enclosed microprolactinomas, the initial remission rate was 92.1%, while for macroprolactinomas, the rate was 70.4%. No significant difference of remission rates was found between DA-pretreated (65.3%) and non-pretreated (72.1%) patients (p=0.373).None of the patients suffered a significant complication. Re-operation for a postoperative cerebrospinal fluid leak was required in one patient (0.6%). Permanent postoperative deterioration of pituitary function was only observed in one of 158 patients with surgery for a prolactinoma (0.6%). Improvement of pituitary function was observed in 8 of 25 patients (32%) with preoperative deficits.

CONCLUSION

Transsphenoidal microsurgery is safe and efficient for treatment of prolactinomas. It is particularly suitable for enclosed prolactinomas. The patient should be well informed of the pros and cons of the treatment options, which include DA medication and TSS, and the patient's preference should be taken into account during decision-making.

Neurobiology of puberty and its disorders

Puberty, which in humans is considered to include both gonadarche and adrenarche, is the period of becoming capable of reproducing sexually and is recognized by maturation of the gonads and development of secondary sex characteristics. Gonadarche referring to growth and maturation of the gonads is fundamental to puberty since it encompasses increased gonadal steroid secretion and initiation of gametogenesis resulting from enhanced pituitary gonadotropin secretion, triggered in turn by robust pulsatile GnRH release from the hypothalamus. This chapter reviews the development of GnRH pulsatility from before birth until the onset of puberty. In humans, GnRH pulse generation is restrained during childhood and juvenile development. This prepubertal hiatus in hypothalamic activity is considered to result from a neurobiological brake imposed upon the GnRH pulse generator resident in the infundibular nucleus. Reactivation of the GnRH pulse generator initiates pubertal development. Current understanding of the genetics and physiology of the brake will be discussed, as will hypotheses proposed to account for timing the resurgence in pulsatile GnRH and initiation of puberty. The chapter ends with a discussion of disorders associated with precocious or delayed puberty with a focus on those with etiologies attributed to aberrant GnRH neuron anatomy or function. A pediatric approach to patients with pubertal disorders is provided and contemporary treatments for both precocious and delayed puberty outlined.

High biochemical recurrence rate after withdrawal of cabergoline in prolactinomas: is it necessary to restart treatment?

PURPOSE

Treatment with dopamine agonists (DA) is highly effective in patients with prolactinomas. In selected patients, discontinuation of DA after several years of successful treatment is possible, however, hyperprolactinemia recurs in 60-80% of them. It is unclear what is the clinical significance of these recurrences and hence, whether or not reinitiation of therapy is necessary.

OBJECTIVES

To evaluate the recurrence rate in prolactinoma patients after DA withdrawal and the necessity to restart treatment.

METHODS

Patients with >2 years of treatment with cabergoline (CBG) who achieved normoprolactinemia and a > 50% reduction in tumor size were included. DA dose was down titrated until withdrawal. Basal tumor size, as well as PRL and gonadal steroid levels were recorded at diagnosis, at withdrawal of DA and every 3-6 months for 1-3 years.

RESULTS

Fifty patients were included (38 women, 34 macroprolactinomas). After withdrawal, 34 (68%) presented recurrence of hyperprolactinemia. PRL levels <5 ng/mL at the time of withdrawal predicted remission (sensitivity 76%, specificity of 63%). CBG was restarted in eight patients (23%) because of the presence of hypogonadism. CBG was withheld in the remaining 26, based on the following arguments: (1) premenopausal women without biochemical hypogonadism, (54%); (2) asymptomatic men under 65 without biochemical hypogonadism (19%); (3) asymptomatic postmenopausal women (19%); (4) asymptomatic men over 65 (8%). After a median follow-up of 30 months, no increase in PRL levels or tumor growth was documented.

CONCLUSIONS

Biochemical recurrence in prolactinomas is very frequent, however, in only a few of these patients reinitiation of DA is necessary.

Prolactinomas and nonfunctioning adenomas: preoperative diagnosis of tumor type using serum prolactin and tumor size

OBJECTIVE

Prolactinoma and nonfunctioning adenoma (NFA) are the most common sellar pathologies, and both can present with hyperprolactinemia. There are no definitive studies analyzing the relationship between the sizes of prolactinomas and NFAs and the serum prolactin level. Current guidelines for serum prolactin level cutoffs to distinguish between pathologies are suboptimal because they fail to consider the adenoma volume. In this study, the authors attempted to describe the relationship between serum prolactin level and prolactinoma volume. They also examined the predictive value that can be gained by considering tumor volume in differentiating prolactinoma from NFA and provide cutoff values based on a large sample of patients.

METHODS

A retrospective analysis of consecutive patients with prolactinomas (n = 76) and NFAs (n = 217) was performed. Patients were divided into groups based on adenoma volume, and the two pathologies were compared.

RESULTS

A strong correlation was found between prolactinoma volume and serum prolactin level (r = 0.831, p < 0.001). However, there was no significant correlation between NFA volume and serum prolactin level (r = -0.020, p = 0.773). Receiver operating characteristic curve analysis of three different adenoma volume groups was performed and resulted in different serum prolactin level cutoffs for each group. For group 1 (≤ 0.5 cm3), the most accurate cutoff was 43.65 μg/L (area under the curve [AUC] = 0.951); for group 2 (> 0.5 to 4 cm3), 60.05 μg/L (AUC = 0.949); and for group 3 (> 4 cm3), 248.15 μg/L (AUC = 1.0).

CONCLUSIONS

Prolactinoma volume has a significant impact on serum prolactin level, whereas NFA volume does not. This finding indicates that the amount of prolactin-producing tissue is a more important factor regarding serum prolactin level than absolute adenoma volume. Hence, volume should be a determining factor to distinguish between prolactinoma and NFA prior to surgery. Current serum prolactin threshold level guidelines are suboptimal and cannot be generalized across all adenoma volumes.

Antiprolactinoma Effect of Hordenine by Inhibiting MAPK Signaling Pathway Activation in Rats

Prolactinomas are harmful to human health, and the clinical first-line treatment drug is bromocriptine. However, 20% prolactinomas patients did not respond to bromocriptine. Hordenine is an alkaloid separated from Fructus Hordei Germinatus, which showed significant antihyperprolactinemia activity in rats. The aim of this study was to explore the effect and mechanism of hordenine on prolactinomas in rats. The study used estradiol to induce prolactinomas, which caused the activation of the pituitary mitogen-activated protein kinase (MAPK) pathway in rats significantly. The treatment of hordenine restored estradiol, induced the overgrowth of pituitary gland, and reduced the prolactin (PRL) accumulation in the serum and pituitary gland of rats by blocking the MAPK (p38, ERK1/2, and JNK) activation and production of inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). The antiprolactinoma effect of hordenine was mediated by inhibiting the MAPK signaling pathway activation in rats.

AN UNEXPECTED COMBINATION OF PROLACTINOMA AND SEPTO-OPTIC DYSPLASIA

Objective

To describe the unusual finding of pituitary adenoma in a patient with septo-optic dysplasia (SOD).

Methods

We describe the clinical presentation, biochemical and radiological evaluation, treatment, and outcomes of a patient with macroprolactinoma and previously undiagnosed SOD.

Results

A 41-year-old woman with optic nerve hypoplasia and growth hormone deficiency presented with new-onset galactorrhea, polyuria, and polydipsia. Physical exam was notable for bilateral galactorrhea. Laboratory workup showed a prolactin level of 176 μg/L (reference range is 6 to 20 μg/L), serum cortisol of 7.7 μg/dL (reference range is 5.0 to 20.0 μg/dL), and adrenocorticotropic hormone of 54 pg/mL (reference range is 0 to 46 pg/mL). Thyroid function and pituitary-gonadal axis testing were normal. Low-dose cosyntropin test showed a borderline cortisol response and persistently low adrenal androgens, suggestive of partial secondary adrenal insufficiency. A water deprivation test showed evidence of diabetes insipidus (DI). Magnetic resonance imaging of the sella showed a 1.0 × 1.0 × 1.5-cm mass compatible with pituitary adenoma, absence of septum pellucidum, and atrophy of the optic nerves.The patient was diagnosed with SOD with partial hypopituitarism and a concomitant macroprolactinoma of more recent onset resulting in DI. The patient was treated with cabergoline with good clinical and biochemical response including resolution of DI symptoms. Subsequent magnetic resonance imaging of the sella showed near resolution of the prolactinoma.

Conclusion

We conclude that a diagnosis of SOD should not exclude the possibility of a pituitary adenoma in the appropriate clinical context, and that the pattern of hormonal deficits in such a combination may be uncharacteristic of the deficits expected with pituitary adenoma alone.

Prolactinomas: Prognostic Factors of Early Remission After Transsphenoidal Surgery

Background and Objective: Most patients with prolactinomas receive pharmacological treatment only, resulting in limited research on the predictors of successful prolactinoma surgery. In this study, we analyzed whether early postoperative serum prolactin concentrations and selected tumor characteristics could predict early, hormonal remission after removal of prolactinomas. Methods: We prospectively enrolled 48 consecutive patients with prolactinomas who underwent transsphenoidal resection performed by the same surgeon. Early remission, defined as a lack of hyperprolactinemia symptoms and normalization of serum prolactin concentration, was ascertained in all patients at 3 months. We evaluated the invasiveness of prolactinomas on the Knosp grading scale and measured serum prolactin concentrations on the first postoperative day. Routine immunohistochemical analysis, evaluation for plurihormonality, and assessment of the Ki-67 proliferation index (<3 or ≥3% of positive nuclei) were performed in all tumor samples. Results: Of 48 patients, 38 (79%) achieved early biochemical remission at 3 months. Patients in early remission at 3 months had lower serum prolactin concentrations on the first postoperative day than patients with recurrent or persistent hyperprolactinemia (p < 0.001). Using univariate logistic regression, larger maximum tumor diameter (p = 0.014), higher Knosp grade (p < 0.001), and plurihormonality predicted remission at 3 months (p = 0.021). However, using multivariate stepwise logistic regression, only the Knosp grade remained significant (p < 0.001). Conclusions: Radiological assessment of prolactinoma invasiveness (Knosp grades) and early postoperative serum prolactin concentrations are important predictors of early remission following transsphenoidal prolactinoma resection.

Prevalence of Thyroid Disease in Patients Surgically Treated for Pituitary Disease

Thyroid disease mainly has a thyroid origin but can occasionally have a pituitary origin. Clinicians face several challenges when these conditions occur together. We aimed to determine the prevalence of thyroid disorders in patients undergoing trans-sphenoidal adenomectomy (TSA) for pituitary disease. We reviewed the medical records of patients undergoing TSA for pituitary disease between 2008 and 2017 at Severance Hospital. Thyroid disorders were categorized using blood test results and medical histories at the time of preoperative evaluation. Among 2202 patients, 44 (2%), 218 (9.9%), and 74 (3.4%) had hyperthyroidism, hypothyroidism, and post-thyroidectomy status before TSA, respectively. Among the 44 patients with hyperthyroidism, 30 (68.2%) had central hyperthyroidism. Among the 218 patients with hypothyroidism, 165 (75.7%) had central hypothyroidism. Central hypothyroidism was more common in patients with adrenocorticotropic hormone-secreting pituitary adenomas (aOR (adjusted odds ratio) 1.85), Rathke’s cleft cysts (aOR 2.34), and craniopharyngiomas (aOR 2.58) (all p < 0.05) than in those with nonfunctioning pituitary adenomas. Contrastingly, thyroid cancer had an increased prevalence in patients with growth hormone- (aOR 3.17), prolactin- (aOR 3.66), and thyroid-stimulating hormone-secreting (aOR 6.28) pituitary adenomas (all p < 0.05). Pituitary disease sometimes accompanies thyroid disorders; their characteristics vary according to the type of pituitary disease.

[Interdisciplinary Management of Sellar Masses]

Interdisciplinary Management of Sellar Masses Abstract. Sellar masses may present with an impairment of pituitary function (hypopituitarism), hormone hypersecretion (prolactinoma, acromegaly, glucocorticoid excess) or neurological symptoms (visual impairment, headache). An increasing number of them is discovered as an incidentaloma. Among the various entities, benign pituitary adenomas and cystic lesions are most frequently encountered. The work-up includes a laboratory evaluation for hormone hyper- or hyposecretion and an MRI of the pituitary gland. If the optic chiasm is compromised, a visual field examination is mandatory. Except for prolactinomas, symptomatic sellar masses are usually resected via an endoscopic transsphenoidal approach. If a total resection is not feasible because of the invasion of surrounding structures, debulking to relieve pressure from the optic chiasm is the primary goal and radiotherapy may be considered. Residual hormone excess can be treated medically. In the early postoperative period special attention to the development and treatment of disordered body water homeostasis and hypopituitarism is crucial. Interdisciplinary work-up and decision making are of utmost importance and will offer the best management.

The epidemiology, diagnosis and treatment of Prolactinomas: The old and the new

Prevalence and incidence of prolactinomas are approximately 50 per 100,000 and 3-5 new cases/100,000/year. The pathophysiological mechanism of hyperprolactinemia-induced gonadotropic failure involves kisspeptin neurons. Prolactinomas in males are larger, more invasive and less sensitive to dopamine agonists (DAs). Macroprolactin, responsible for pseudohyperprolactinemia is a frequent pitfall of prolactin assay. DAs still represent the primary therapy for most prolactinomas, but neurosurgery has regained interest, due to progress in surgical techniques and a high success rate in microprolactinoma, as well as to some underestimated side effects of long-term DA treatment, such as impulse control disorders or impaired quality of life. Recent data show that the suspected effects of DAs on cardiac valves in patients with prolactinomas are reassuring. Finally, temozolomide has emerged as a valuable treatment for rare cases of aggressive and malignant prolactinomas that do not respond to all other conventional treatments.

Association of High Prolactin Level on Postoperative Day 1 and Tumor Invasion with Female Gonadal Dysfunction After Trans-Sphenoidal Surgery of Pituitary Adenomas

Background

The aim of this study was to evaluate the risk factors of gonadal dysfunction among Chinese women of reproductive age with pituitary adenomas (PAs) after trans-sphenoidal surgery.

Material/Methods

We retrospectively evaluated 317 women (16–44 years old) who underwent gonadal function and hormone testing before and after trans-sphenoidal surgery for PAs during 2003–2012. Gonadal function was assessed on the basis of menstrual status.

Results

Three women were excluded because of pre-existing gynecological diseases. Before trans-sphenoidal surgery, 34 (10.7%) women were eugonadal and 283 (89.3%) women had gonadal dysfunction. After trans-sphenoidal surgery, 130/189 (68.7%) women with follow-up menstruation data were eugonadal, and 59/189 (31.2%) women exhibited gonadal dysfunction. In addition, 67.4% women of reproductive age with PAs and gonadal dysfunction were restored by trans-sphenoidal surgery (P<0.01). Postoperative gonadal dysfunction was independently associated with high prolactin level at day 1 after trans-sphenoidal surgery (odds ratio (OR)=1.024; 95% confidence interval (CI)=1.005–1.043; P=0.012) and tumor invasion (OR=5.752; 95%CI=1.618–20.447; P<0.01). Based on the receiver operating characteristic (ROC) curve, prediction of gonadal dysfunction in women of reproductive age after trans-sphenoidal surgery for PAs using prolactin >46.82 μg/L on postoperative day 1 had sensitivity of 88%, specificity of 95%, positive predictive value of 98%, and negative predictive value of 76%, and an area under the ROC curve of 0.701.

Conclusions

Gonadal dysfunction is very common in Chinese women of reproductive age with PAs and can be effectively restored by trans-sphenoidal surgery. Prolactin >46.82 μg/L at 1 day after trans-sphenoidal surgery and tumor invasion can predict postoperative gonadal dysfunction in these patients.

Medically induced CSF rhinorrhea following treatment of macroprolactinoma: case series and literature review

PURPOSE

Although several reports have addressed cerebrospinal fluid (CSF) rhinorrhea following dopamine agonist (DA) therapy of macroprolactinomas, further study is warranted for this relatively uncommon entity. Toward this aim, our retrospective series and review of literature further clarifies recommendations in treatment of this rare problem.

METHODS

We retrospectively reviewed all macroprolactinoma cases in our hospital for a 15-year period. Our systematic search of PubMed identified original articles and reviews of all macroprolactinoma cases with an associated medication-induced CSF leak.

RESULTS

Five patients with drug-induced CSF leak were identified; four of these patients received cabergoline therapy an average of 6 weeks before the onset of rhinorrhea and then underwent surgical repair of the CSF leak. Of 35 published studies included, we identified 60 patients with medication-induced CSF leak. Medical therapy included bromocriptine in 34 patients, cabergoline in 21 patients, and use of both DAs in two patients. Three cases did include complete diagnostic and treatment data. Median time from initiation of the DA treatment to occurrence of rhinorrhea was 6 weeks. For CSF rhinorrhea, 49 patients underwent surgical repair (38 by the transnasal approach) and seven patients were treated nonoperatively.

CONCLUSION

Baseline skull base erosion in macroprolactinomas in combination with subsequent tumor shrinkage induced by DA therapy may result in spontaneous CSF rhinorrhea. Therefore, such patients should be advised about and monitored for this potential setback. Once CSF leak is diagnosed, prompt treatment must be carried out to avoid infectious complications. Transnasal surgery appears the most effective therapeutic approach.

[Modern Management of Pituitary Adenomas - Current State of Diagnosis, Treatment and Follow-Up]

Modern Management of Pituitary Adenomas - Current State of Diagnosis, Treatment and Follow-Up Abstract. Pituitary adenomas (PA) are benign neoplasms originating from parenchymal cells of the anterior pituitary. Tumor mass effect can cause headaches, visual deficits by compression of the optic chiasm, and partial or complete hypopituitarism. Hormone secreting PA can cause several forms of specific syndromes such as Cushing's disease or acromegaly depending on the type of hormone. Endoscopic transsphenoidal resection is the preferred treatment option for most symptomatic or growing PA. Nowadays techniques like high definition intraoperative MRI can assist the surgeon in his goal of maximal safe resection. An exception are prolactinomas which can usually be treated medically with dopamine agonists. Therapy of PA is complex and should be managed in a high-volume center with an interdisciplinary team approach including neurosurgeons and endocrinologists.

Resolution of dopamine agonist-resistant hyperprolactinemia by hysterectomy: a case report

Prolactin-producing uterine leiomyomas are very rare. Although hyperprolactinemia rapidly improves after removal of such leiomyomas, no preoperative diagnostic test has been established for prolactin-producing uterine leiomyomas. A 45-year-old Japanese woman, gravida 3 para 3, was referred to our hospital for further examination of hyperprolactinemia resistant to a dopamine agonist. A pituitary prolactinoma was undetectable by brain magnetic resonance imaging. A bromocriptine loading test revealed an increased serum prolactin concentration after loading. Examination for the detection of an ectopic prolactinoma revealed a 9.0 cm diameter uterine leiomyoma that had measured 6.6 cm in diameter about six months before the first visit to our hospital. The hyperprolactinemia rapidly improved after hysterectomy. A prolactin-producing uterine leiomyoma should be considered as a possible cause of hyperprolactinemia resistant to dopamine agonists. Responsiveness to dopamine agonists; deterioration of hyperprolactinemia may be diagnostic for prolactin-producing uterine leiomyomas, although further research is required.

Medical versus surgical treatment of prolactinomas: an analysis of treatment outcomes

INTRODUCTION

Prolactinomas are unique tumors that may go into both hormonal and radiographic remission with dopamine agonist therapy or transsphenoidal surgery. Regardless of modality, the goals of therapy remain the same: (1) biochemical remission, including reduction of prolactin and normalization of sex hormones; (2) radiographic tumor control, with a range including prevention of tumor growth, tumor regression, or complete tumor resolution; (3) resolution of preoperative symptoms, including those that are hormonal or neurologic; and (4) prevention of new hypopituitarism or new neurologic symptoms.

AREAS COVERED

In the following review, we performed a search of the literature using keywords 'prolactinoma,' 'dopamine agonist,' 'surgery,' 'cost-effectiveness,' 'recurrence,' and 'complication' to compare the relative merits of medical versus surgical therapy for prolactinoma, including special circumstances such as cystic tumors, pregnant patients, and the cost-effectiveness of different strategies.

EXPERT COMMENTARY

Medical therapy can offer a cure, but surgery provides an important adjunct to patients with resistance or intolerance to dopamine agonists, and offers excellent outcomes including when combined with continued postoperative medical therapy. Further head to head comparisons will benefit patients and practitioners weighing the relative risks and benefits of medical and surgical intervention, including the issue of their relative cost-effectiveness.

Serum prolactin revisited: parametric reference intervals and cross platform evaluation of polyethylene glycol precipitation-based methods for discrimination between hyperprolactinemia and macroprolactinemia

BACKGROUND

Hyperprolactinemia diagnosis and treatment is often compromised by the presence of biologically inactive and clinically irrelevant higher-molecular-weight complexes of prolactin, macroprolactin. The objective of this study was to evaluate the performance of two macroprolactin screening regimes across commonly used automated immunoassay platforms.

METHODS

Parametric total and monomeric gender-specific reference intervals were determined for six immunoassay methods using female (n=96) and male sera (n=127) from healthy donors. The reference intervals were validated using 27 hyperprolactinemic and macroprolactinemic sera, whose presence of monomeric and macroforms of prolactin were determined using gel filtration chromatography (GFC).

RESULTS

Normative data for six prolactin assays included the range of values (2.5th-97.5th percentiles). Validation sera (hyperprolactinemic and macroprolactinemic; n=27) showed higher discordant classification [mean=2.8; 95% confidence interval (CI) 1.2-4.4] for the monomer reference interval method compared to the post-polyethylene glycol (PEG) recovery cutoff method (mean=1.8; 95% CI 0.8-2.8). The two monomer/macroprolactin discrimination methods did not differ significantly (p=0.089). Among macroprolactinemic sera evaluated by both discrimination methods, the Cobas and Architect/Kryptor prolactin assays showed the lowest and the highest number of misclassifications, respectively.

CONCLUSIONS

Current automated immunoassays for prolactin testing require macroprolactin screening methods based on PEG precipitation in order to discriminate truly from falsely elevated serum prolactin. While the recovery cutoff and monomeric reference interval macroprolactin screening methods demonstrate similar discriminative ability, the latter method also provides the clinician with an easy interpretable monomeric prolactin concentration along with a monomeric reference interval.

An updated view of hypothalamic-vascular-pituitary unit function and plasticity

The discoveries of novel functional adaptations of the hypothalamus and anterior pituitary gland for physiological regulation have transformed our understanding of their interaction. The activity of a small proportion of hypothalamic neurons can control complex hormonal signalling, which is disconnected from a simple stimulus and the subsequent hormone secretion relationship and is dependent on physiological status. The interrelationship of the terminals of hypothalamic neurons and pituitary cells with the vasculature has an important role in determining the pattern of neurohormone exposure. Cells in the pituitary gland form networks with distinct organizational motifs that are related to the duration and pattern of output, and modifications of these networks occur in different physiological states, can persist after cessation of demand and result in enhanced function. Consequently, the hypothalamus and pituitary can no longer be considered as having a simple stratified relationship: with the vasculature they form a tripartite system, which must function in concert for appropriate hypothalamic regulation of physiological processes, such as reproduction. An improved understanding of the mechanisms underlying these regulatory features has implications for current and future therapies that correct defects in hypothalamic-pituitary axes. In addition, recapitulating proper network organization will be an important challenge for regenerative stem cell treatment.

A combined opiate agonist and antagonist treatment reduces prolactin secreting pituitary tumor growth

Prolactin secreting pituitary adenomas (prolactinomas) is the most common pituitary tumors in humans. Animal studies have identified aggressive prolactinoma development in fetal alcohol exposed rats. We have recently identified a combination treatment of a μ opioid receptor antagonist naltrexone and a δ opioid receptor agonist D-Ala2-,N-Me-Phe4,Gly-ol Enkephalin (DPDPE) increases innate immune function. In this study, we tested whether naltrexone and DPDPE combination therapy is useful to control pituitary tumor growth. Fetal alcohol exposed and control Fischer 344 female rats at 60 days of age were ovariectomized and received an estrogen implant to induce prolactinomas. Six weeks after the estrogen implant, these animals received treatments of naltrexone and DPDPE or saline. The growth of the pituitary tumor prior to and after opioidergic agent treatments was visualized using magnetic resonance imaging (MRI). At the end of the treatment, pituitary weights, plasma prolactin and splenic levels of cytotoxic factors were determined. Both imaging data and weight data indicated that the volume and the weight of the pituitary were increased more after estrogen treatment in animals exposed to fetal alcohol than control. Naltrexone and DPDPE treatment reduced the weight and volume of the pituitary gland and plasma levels of prolactin in both fetal alcohol exposed and control-fed animals. The treatment of opioidergic agents also increased the levels of cytotoxic factors in the spleen. These data provide a novel possibility in treating pituitary tumors using a combination therapy of naltrexone and DPDPE.

Surgical treatment for male prolactinoma: A retrospective study of 184 cases

A total of 184 cases of surgically treated male prolactinoma were analyzed retrospectively to summarize the outcome of this surgical intervention. We analyzed the general characteristics, clinical manifestations, hormone levels, imaging features, preoperative treatments, surgical outcomes, pathology results, and follow-up records for all included patients. The most common clinical manifestations included sexual dysfunction (47.4%), headache (55.9%), and visual disturbance (46.7%). Serum prolactin levels ranged from 150 to 204,952 ng/mL. Tumor size varied from 6 to 70 mm. Pituitary adenomas grew in a parasellar pattern with visual deficits occurring 40.7% of the time. After surgical therapy, 88.6% of patients achieved symptom relief, and 98.4% experienced an immediate postoperative decline in prolactin level. Fifty-seven patients (31.0%) achieved initial remission, and 26 patients (45.6%) experienced recurrence. Hence, our results suggest that in male prolactinoma characterized by a large pituitary diameter and high serum prolactin level, tumor size predicts the degree of gross resection. The prognostic predictors included preoperative tumor growth pattern and Ki-67 index.Citation: Yi-jun S, Mei-ting C, Wei L, Bing X, Yong Y, Ming F, Ren-zhi W. (2016) Surgical treatment for male prolactinoma: a retrospective study of 184 cases.

Cancer in Transgender People: Evidence and Methodological Considerations

Transgender people comprise a diverse group of individuals whose gender identity or expression differs from that originally assigned to them at birth. Some, but not all, transgender people elect to undergo medical gender affirmation, which may include therapy with cross-sex hormones and/or surgical change of the genitalia and other sex characteristics. As cross-sex hormones administered for the purposes of gender affirmation may be delivered at high doses and over a period of decades, the carcinogenicity of hormonal therapy in transgender people is an area of considerable concern. In addition, concerns about cancer risk in transgender patients have been linked to sexually transmitted infections, increased exposure to well-known risk factors such as smoking and alcohol use, and the lack of adequate access to screening. Several publications have identified cancer as an important priority in transgender health research and called for large-scale studies. The goals of this article are to summarize the evidence on factors that may differentially affect cancer risk in transgender people, assess the relevant cancer surveillance and epidemiologic data available to date, and offer an overview of possible methodological considerations for future studies investigating cancer incidence and mortality in this population.

Recurrence of hyperprolactinemia following dopamine agonist withdrawal and possible predictive factors of recurrence in prolactinomas

BACKGROUND

The optimal duration of cabergoline (CAB) treatment of prolactinomas that minimizes recurrences is not well established. 2011 Endocrine Society Guidelines suggested that withdrawal may be safely undertaken after 2 years in patients achieving normoprolactinemia and tumor reduction.

MATERIALS

We analyzed 74 patients (mean age = 46.9 ± 14.4, M/F = 19/55, macro/micro = 18/56) bearing a prolactinoma divided in 3 groups: group A (23) treated for 3 years, group B (23) for a period between 3 and 5 years, and group C (28) for a period >5 years. CAB therapy was interrupted according to Endocrine Society Guidelines. Prolactin (PRL) levels were measured 3, 6, 12 and 24 months after withdrawal. Recurrence was defined with PRL levels ≥30 ng/ml.

RESULTS

Groups did not differ in pretreatment PRL levels (123.2 ± 112.1, 120.9 ± 123.8, 176.6 ± 154.0), pituitary deficit (4, 17, 17 %), mean CAB weekly dose (0.7 ± 0.4, 0.6 ± 0.3, 0.7 ± 0.4) and PRL levels before withdrawal (17.1 ± 19.6, 11.4 ± 8.8, 13.8 ± 13.5). Recurrence occurred within 12 months in 34 patients (45.9 %), without significant differences among groups. Neuroradiological evaluation showed a significantly higher presence of macroadenoma in group C (13, 17 and 39 %, respectively). Recurrence rate of hyperprolactinemia did not depend on sex, tumor size or CAB dose but it was significantly correlated with PRL levels at diagnosis and before withdrawal (p = 0.03). Finally, patients with pituitary deficit at diagnosis showed a significantly higher recurrence rate (p = 0.03).

CONCLUSIONS

The study provides additional evidence that prolonging therapy for more than 3 years does not reduce recurrence rate. In particular, recurrence risk was similar in micro- and macroadenomas, and higher in patients with pituitary deficits at diagnosis.

Sellar Lesions/Pathology

The sellar region is a tiny anatomic compartment in which many lesions and developmental diseases can be found. If pituitary adenomas represent most of the sellar mass, it is important to recognize other pathologic conditions before any surgical procedure, because the optimal treatment may differ considerably from one lesion to another. A careful clinical evaluation followed by neuroimaging studies and an endocrinologic and ophtalmologic workup will lead, in most cases, to a diagnosis with near certainty. This article provides an overview of sellar diseases with emphasis on their most useful characteristics for clinical practice.

Targeting the dopamine D3 receptor: an overview of drug design strategies

INTRODUCTION

Dopamine is a neurotransmitter widely distributed in both the periphery and the central nervous system (CNS). Its physiological effects are mediated by five closely related G protein-coupled receptors (GPCRs) that are divided into two major subclasses: the D1-like (D1, D5) and the D2-like (D2, D3, D4) receptors. D3 receptors (D3Rs) have the highest density in the limbic areas of the brain, which are associated with cognitive and emotional functions. These receptors are therefore attractive targets for therapeutic management.

AREAS COVERED

This review summarizes the functional and pharmacological characteristics of D3Rs, including the design and clinical relevance of full agonists, partial agonists and antagonists, as well as the capacity of these receptors to form active homodimers, heterodimers or higher order receptor complexes as pharmacological targets in several neurological and neurodegenerative disorders.

EXPERT OPINION

The high sequence homology between D3R and the D2-type challenges the development of D3R-selective compounds. The design of new D3R-preferential ligands with improved physicochemical properties should provide a better pharmacokinetic/bioavailability profile and lesser toxicity than is found with existing D3R ligands. It is also essential to optimize D3R affinity and, especially, D3R vs. D2-type binding and functional selectivity ratios. Developing allosteric and bitopic ligands should help to improve the D3R selectivity of these drugs. As most evidence points to the ability of GPCRs to form homomers and heteromers, the most promising therapeutic strategy in the future is likely to involve the application of heteromer-selective drugs. These selective ligands would display different affinities for a given receptor depending on the receptor partners within the heteromer. Therefore, designing novel compounds that specifically target and modulate D1R-D3R heteromers would be an interesting approach for the treatment of levodopa (L-DOPA)-induced dyskinesias.

The pituitary TGFβ1 system as a novel target for the treatment of resistant prolactinomas

Prolactinomas are the most frequently observed pituitary adenomas and most of them respond well to conventional treatment with dopamine agonists (DAs). However, a subset of prolactinomas fails to respond to such therapies and is considered as DA-resistant prolactinomas (DARPs). New therapeutic approaches are necessary for these tumors. Transforming growth factor β1 (TGFβ1) is a known inhibitor of lactotroph cell proliferation and prolactin secretion, and it partly mediates dopamine inhibitory action. TGFβ1 is secreted to the extracellular matrix as an inactive latent complex, and its bioavailability is tightly regulated by different components of the TGFβ1 system including latent binding proteins, local activators (thrombospondin-1, matrix metalloproteases, integrins, among others), and TGFβ receptors. Pituitary TGFβ1 activity and the expression of different components of the TGFβ1 system are regulated by dopamine and estradiol. Prolactinomas (animal models and humans) present reduced TGFβ1 activity as well as reduced expression of several components of the TGFβ1 system. Therefore, restoration of TGFβ1 inhibitory activity represents a novel therapeutic approach to bypass dopamine action in DARPs. The aim of this review is to summarize the large literature supporting TGFβ1 important role as a local modulator of pituitary lactotroph function and to provide recent evidence of the restoration of TGFβ1 activity as an effective treatment in experimental prolactinomas.

[Misleading diagnosis of hyperprolactinemia in women]

Prolactin is a major hormone, involved in gonadotroph axis regulation. Hyperprolactinemia induces gonadotropin deficiency and therefore hypogonadotropic hypogonadism. It should be suspected in front of menstrual cycle abnormalities, infertility and/or galactorrhea. If drugs and/or PRL adenoma represent the vast majority of causes of hyperprolactinemia, other etiologies and misleading diagnosis of hyperprolactinemia should be searched for. After eliminating a pregnancy, in women of childbearing age, the first step is to interpret the result of hyperprolactinemia, according to the assay technique used. Indeed, the major active form of prolactin is the 23kDA non-glycosylated prolactin. However, some assays interfere with macroprolactinemia, an inactive form of prolactin, including glycosylated prolactin bound to an IgG immunoglobulin. Its presence in the serum is misleading as it may induce increased levels of prolactin, usually below 100 ng/mL. The diagnosis of macroprolactinemia has major issues as pituitary MRI does not need to be performed. Furthermore, neither treatment nor follow-up of patients with macroprolactinemia are necessary. It should be suspected in the presence of normal menstrual cycles. Drugs inducing hyperprolactinemia usually raise prolactin levels below 100 ng/mL. If prolactin level is higher than 250 ng/mL, the main diagnosis is pituitary macro-adenoma. If prolactin ranges between 100 and 250 ng/mL, it is usually related to a micro-adenoma or a necrotic macro-adenoma. A mixed PRL/GH should always be suspected. If prolactin level is below 150 ng/mL, in the presence of a large hypothalamic-pituitary tumor, the major diagnosis is hyperprolactinemia due to pituitary disconnection. Ectopic secretions of prolactin remain very rare. A new etiology of hyperprolactinemia is loss of function mutation of prolactin receptor.