Guidelines of the Pituitary Society for the diagnosis and management of prolactinomas

A review of hyperprolactinaemia and severe mental illness: Are there implications for clinical biochemistry?

Hyperprolactinaemia is a common adverse event reported in association with treatments used in schizophrenia and bipolar disorder. Recent data are suggestive that hyperprolactinaemia may have a range of significant short-and long-term clinical consequences. The objective of this review is to examine the causes, frequency and clinical consequences of hyperprolactinaemia in the severely mentally ill (SMI) with a focus on patients taking antipsychotic medications. A Medline search was carried out to identify relevant publications. Reference lists from previous review articles were also examined to search for additional data. Hyperprolactinaemia may be one of the most common adverse events associated with some antipsychotic medications. Precise rates with individual drugs had however until recently been poorly categorized. The relationship between hyperprolactinaemia and adverse outcomes in the SMI population appears similar to that in the general population. Adverse outcomes (such as sexual dysfunction) can occur acutely and in the longer term (bone fractures and possibly breast cancer), but the precise link between degree and length of hyperprolactinaemia and adverse outcome remains to be established. In conclusion, hyperprolactinaemia is a common treatment-emergent adverse event of some antipsychotic medications and may have clinical consequences. Physicians must balance the benefits and risks of treatment when determining appropriate therapy for individual patients.

[Use of a new protocol for prolactin extraction and reduction of false hyperprolactinemia]

INTRODUCTION

Numerous authors have reported that prolactin measurement is influenced by several factors and consequently the values obtained may not faithfully reflect the physiological reality of the individual studied. Unless a series of measures is adopted, especially in the pre-analytic stage, values may be falsely elevated. The objective of the present study was to evaluate the extent to which optimization or non-optimization of the extraction procedure translates into higher results and how reports expressed in terms of monomeric (biologically active) prolactin could be crucial to adopt a diagnosis and therapeutic approach.

MATERIAL AND METHODS

We performed two extractions in each woman (following the protocol universally used for this kind of analysis): one through direct puncture and another 60 min later without a new puncture (a catheter was inserted in the site of the first puncture and kept permeable by salinization). The monomeric fraction was then studied, if required.

RESULTS

A statistically significant difference was observed between the 2 extractions. The monomeric fraction was three times lower in the second extraction than in the first.

DISCUSSION

The results of this study justify systematic use of extraction techniques that avoid the stress of venous puncture, as well as the use of the term biologically active prolactin [monomeric (little) prolactin fraction] in reports.

Individualized high-dose cabergoline therapy for hyperprolactinemic infertility in women with micro- and macroprolactinomas

CONTEXT

Cabergoline is effective for hyperprolactinemic hypogonadism. However, the rate of cabergoline-induced pregnancy in women with prolactinoma remains unknown. Also unknown is whether cabergoline can control tumor growth and thereby achieve successful pregnancy in patients with macroprolactinomas.

METHODS

Eighty-five women with macroprolactinomas (n = 29) or microprolactinomas (n = 56) received prospective, high-dose cabergoline therapy for infertility based on individual prolactin suppression and/or tumor shrinkage. The patients included 31 bromocriptine-resistant, 32 bromocriptine-intolerant, and 22 previously untreated women. Conception was withheld until three regular cycles returned in women with microadenoma and until tumors shrank below 1.0 cm in height in women with macroadenoma. Cabergoline was withdrawn at the fourth gestational week.

RESULTS

Cabergoline normalized hyperprolactinemia and recovered the ovulatory cycle in all patients. All adenomas contracted, and 11 macroadenomas and 29 microadenomas disappeared. Eighty patients (94%) conceived 95 pregnancies, two of which were cabergoline-free second pregnancies. The dose of cabergoline at the first pregnancy was 0.25-9 mg/wk overall and 2-9 mg/wk in the resistant patients. Of the 93 pregnancies achieved on cabergoline, 86 resulted in 83 single live births, one stillbirth, and two abortions; the remaining seven were ongoing. All babies were born healthy, without any malformations. No mothers experienced impaired vision or headache suggestive of abnormal tumor reexpansion throughout pregnancy.

CONCLUSION

Cabergoline achieved a high pregnancy rate with uneventful outcomes in infertile women with prolactinoma, independent of tumor size and bromocriptine resistance or intolerance. Cabergoline monotherapy could substitute for the conventional combination therapy of pregestational surgery or irradiation plus bromocriptine in macroprolactinomas.

The Beckman DxI 800 prolactin assay demonstrates superior specificity for monomeric prolactin

BACKGROUND

Commercially available prolactin immunoassays detect macroprolactin to variable degrees. Best practice requires laboratories to assess the cross-reactivity of their prolactin assay with macroprolactin, and where appropriate, introduce a screen for the presence of macroprolactin. Our policy has been to reanalyse hyperprolactinaemic samples following polyethylene glycol (PEG) precipitation and to report the resultant value as the monomeric prolactin content of the sample. The goal of this study was to determine the need to continue PEG precipitation when prolactin measurements with the Wallac AutoDELFIA were replaced by the Beckman DxI 800.

METHODS

A total of 317 apparently hyperprolactinaemic samples were analysed for prolactin using the Beckman DxI 800 and results compared with those determined with the PEG screening technique on the Wallac AutoDELFIA. Any samples demonstrating a discordance of >25% were re-analysed using gel filtration chromatography (GFC) for a definitive result.

RESULTS

The results indicate the Beckman DxI overestimates the prolactin concentration in 1%-2% of hyperprolactinaemic samples. PEG precipitation prior to analysis with the Wallac AutoDELFIA resulted in a 1% false negative diagnosis of hyperprolactinaemia.

CONCLUSIONS

Prolactin results can be reported directly from the DxI. When results are discordant with the clinical presentation, prolactin should be measured using GFC.

Factors determining the remission of microprolactinomas after dopamine agonist withdrawal

BACKGROUND

Withdrawal of dopamine agonist (DA) therapy in the management of microprolactinoma is common practice, but it is unclear which patients are likely to attain long-term remission.

OBJECTIVE

To identify predictive factors for long-term remission.

DESIGN

Prospective cohort study.

PATIENTS

Forty subjects (39 female, aged 24-60 years) with microprolactinoma; all had been normoprolactinaemic on DA therapy for at least 2 years [mean duration of therapy 9 years (range 2-27)].

MEASUREMENTS

A pituitary magnetic resonance imaging (MRI) was performed on 36 (90%) subjects before DA withdrawal. Relapse was defined as prolactin greater than 480 mIU/l (22.8 microg/l) on two occasions.

RESULTS

Nine out of 40 (22.5%) subjects were normoprolactinaemic 12 months after DA withdrawal. Amongst the relapse group, 24 of 31 subjects (79.4%) had already relapsed at 3 months. Normalization of MRI prior to DA withdrawal (P = 0.0006) and longer duration of DA treatment (P = 0.032) were significant predictors of remission. Age, pre-treatment prolactin, nadir prolactin, previous failure of DA withdrawal, pregnancy, dose and type of DA were not significant predictors of remission. The nine patients who were in remission at 12 months were then followed up for 58.0 +/- 5.8 months; all remained in remission.

CONCLUSIONS

As many as 22.5% of subjects with microprolactinoma remained normoprolactinaemic 12 months after DA withdrawal and these subjects stayed in remission for up to 5 years. Significant predictive factors were normalization of MRI prior to discontinuation, and duration of DA treatment. Our findings support intermittent DA withdrawal after a period of normoprolactinaemia, particularly where MRI appearances have normalized.

Role of stereotactic radiosurgery in the management of pituitary adenomas

Trans-sphenoidal neurosurgery is the gold standard treatment for pituitary adenomas, but it can be contraindicated or ineffective. Stereotactic radiosurgery is a procedure aimed at controlling hormone hypersecretion and tumor size of pituitary adenomas. This Review discusses the long-term efficacy and adverse effects of stereotactic radiosurgery with the Gamma Knife((R)) in secreting and nonsecreting pituitary adenomas. Long-term data confirm the antisecretory efficacy of the procedure (about 50% remission in hypersecreting tumors) but also a previously unknown low risk of recurrence (2-10% of cases). The time to remission is estimated to range from 12 to 60 months. The antitumoral efficacy of this treatment against nonsecreting tumors is observed in about 90% of cases. Hypopituitarism is the main adverse effect, observed in 20-40% of cases. Comparisons with conventional fractionated radiotherapy reveal a lower rate of remission with Gamma Knife((R)) radiosurgery, counterbalanced by a more rapid efficacy and a lower rate of hypopituitarism. Short-term follow-up results on stereotactic fractionated radiotherapy suggest a risk of hypopituitarism similar to the one observed with radiosurgery. Therefore, stereotactic radiosurgery is probably still useful to treat some cases of pituitary adenoma, despite the fact that antisecretory drugs, particularly for acromegaly and prolactinomas, are becoming more effective and are well tolerated, thus increasing the probability of success with nonsurgical therapy.

Endonasal transsphenoidal surgery and multimodality treatment for giant pituitary adenomas

OBJECTIVE

Giant pituitary adenomas (> or =40 mm) pose a major management challenge. We describe the experience of a single surgeon and a dedicated neuro-endocrine team with multimodality treatment of these tumours in three specialized institutions.

DESIGN

Retrospective data set analyses.

PATIENTS

Fifty-one consecutive patients with a giant adenoma (39 endocrine-inactive, 12 endocrine-active; mean tumour diameter 45 mm) treated over 10 years by an endonasal transsphenoidal approach were included. All patients had surgical resection followed by radiotherapy and/or medical therapy as judged necessary.

MEASUREMENTS

Hormonal and visual status, extent of resection, tumour control rates, complications and use of medical and radiotherapy were evaluated.

RESULTS

Surgery resulted in gross total, near total and subtotal removal in21 (41%), 10 (20%) and 20 (39%) patients respectively. Complete tumour removal was associated with absence of cavernous sinus invasion (P < 0.001). Long-term endocrine function improved in 49% of patients and new endocrinopathy occurred in 14.6%; 76% required long-term hormone replacement therapy. Vision improved in 81.5% of the patients and there was no visual worsening. At the last follow up (median 30 months), tumour control was achieved in 96% of patients: 59% with surgery alone, 20% with surgery plus focussed radiotherapy, 18% with surgery and medical therapy and two with all three modalities.

CONCLUSIONS

Endonasal surgery provides effective initial treatment for patients with giant adenomas. Multimodality therapy was needed in almost 50% of patients and this rate will likely increase with longer follow up. Close collaboration of neurosurgeons with endocrinologists and radiation oncologists is essential for optimal treatment of patients with these challenging tumours.

Incidentally discovered pituitary masses: pituitary incidentalomas

With the widespread use of computed tomography and MRI, the incidental discovery of pituitary incidentalomas is increasing in frequency. The most common cause of a pituitary mass is a pituitary adenoma (90% of all pituitary masses); however, the differential diagnosis remains extensive. The challenge is to distinguish those that can or will cause morbidity/mortality from those that will not. Opinions on approaching management of these lesions vary. This article will review current data regarding the prevalence, natural history and potential morbidity associated with this entity and describe an epidemiological approach based on four questions: does an incidental mass put the patient at increased risk for an adverse outcome? Can individuals with treatable syndromes be accurately diagnosed? Is the treatment of these syndromes more effective in presymptomatic patients? And do the beneficial effects of presymptomatic detection and treatment of these patients justify the costs incurred? We recommend the following approach: recognizing that one size does not fit all and that the approach should be tailored to the needs of the particular case. If the mass was discovered on a computed tomography, an enhanced MRI is recommended. Detailed history and physical examination should be carried out to look for signs of functional or 'subclinically' functional tumor. Size and structure should be assessed, especially proximity to the optic chiasm. Laboratory evaluation with a serum prolactin for small tumors is cost effective, other lab testing is indicated if metabolic problems are present. Care should be taken to assess for hypopituitarism, clinically and biochemically, if the mass is large, that is, more than 1 cm, visual field testing is also recommended. Note that the vast majority of patients with pituitary incidentalomas that are microadenomas die with them, not from them.

Comparison of multiple methods for identification of hyperprolactinemia in the presence of macroprolactin

BACKGROUND

Macroprolactin is a large, heterogeneous form of prolactin with limited bioavailability. Detection of macroprolactin by different immunoassays varies widely. The objectives of this study were to determine the immunoreactivity of macroprolactin by the Ortho Clinical Diagnostics Vitros((R)) ECi prolactin immunoassay, establish the most effective method for interpreting the prolactin concentration after PEG-precipitation, and correlate the clinical features of hyperprolactinemia with the presence of macroprolactin.

METHODS

PEG-precipitation was performed on 120 hyperprolactinemic specimens. Of these, 31 specimens with a recovery<80% were fractionated by GFC. Four different approaches for identifying true hyperprolactinemia were investigated. Clinical symptoms of hyperprolactinemia were determined by chart review.

RESULTS

Macroprolactin was detected by the Vitros ECi prolactin immunoassay. Use of a PEG modified prolactin reference interval was effective for identifying hyperprolactinemia in the presence of macroprolactin. There was no difference in the prevalence of abnormal menses, galactorrhea, or abnormal MRI between those with and without macroprolactin (p>0.05). Accounting for macroprolactin in patients with hyperprolactinemia reduced the number of idiopathic cases.

CONCLUSIONS

The Vitros ECi prolactin immunoassay detects macroprolactin. PEG-precipitation is an acceptable surrogate to detect hyperprolactinemia in the presence of macroprolactin when using a prolactin reference interval derived from PEG precipitated reference sera. Although testing for macroprolactin should not substitute for standard evaluation of hyperprolactinemia, identification of macroprolactin may clarify a diagnosis and direct appropriate therapy.

Pituitary tumours: pituitary incidentalomas

Clinically non-functioning pituitary adenomas range from being completely asymptomatic, and therefore being detected either at autopsy or as incidental findings on head magnetic resonance imaging (MRI) or computed tomography (CT) scans performed for other reasons (often referred to as 'pituitary incidentalomas'), to causing significant hypothalamic/pituitary dysfunction and visual field compromise due to their large size. Patients with pituitary incidentalomas should all be screened for hypersecretion (prolactin (PRL), IGF-1, midnight salivary cortisol), and those with macroadenomas should also be screened for hypopituitarism (macroadenomas) and for visual field defects if the tumour abuts the optic chiasm. Growth of non-functioning pituitary adenomas without treatment occurs in about 10% of microadenomas and 24% of macroadenomas. In the absence of hypersecretion, hypopituitarism or visual field defects, patients may be followed up by periodic screening by MRI for enlargement. Growth of a pituitary incidentaloma is an indication for surgery.

Pituitary tumours: inflammatory and granulomatous expansive lesions of the pituitary

Inflammatory and granulomatous diseases of the pituitary are rare causes of sellar masses. Lymphocytic hypophysitis is the most relevant of these disorders, and it is characterised by autoimmune pathogenesis with focal or diffuse inflammatory infiltration and varying degrees of pituitary gland destruction. Endocrine symptoms may include partial or total hypopituitarism, with adrenocorticotropic hormone (ACTH) deficiency being the earliest and most frequent alteration. Pituitary abscess is a rare but potentially life-threatening disease and, in 30-50% of patients, anterior pituitary hormone deficiencies or central diabetes insipidus (DI) at onset may be observed: the earliest manifestation being growth hormone deficiency (GHD), followed by follicle-stimulating hormone (FSH)/luteinising hormone (LH), thyroid-stimulating hormone (TSH) and ACTH deficiencies. Fungal infections of the pituitary are also very rare and include aspergillosis and coccidioidomycosis. Concerning pituitary involvement in systemic diseases, in sarcoidosis endocrine complications are rare, but the hypothalamus and pituitary are the glands most commonly affected. DI is reported in approximately 25-33 % of all neurosarcoidosis cases and is the most frequently observed endocrine disorder. Hyperprolactinaemia and anterior pituitary deficiencies may also occur. Rarely, partial or global anterior pituitary dysfunction may be present also in Wegener's granulomatosis, either at onset or in the course of the disease, resulting in deficiency of one or more of the pituitary axes. Other forms of granulomatous pituitary lesions include idiopathic giant cell granulomatous hypophysitis, Takayasu's disease, Cogan's syndrome and Crohn's disease. The hypotalamic-pituitary system is involved mainly in children with Langerhans' cells histiocytosis who develop DI, which is the most common endocrine manifestation. Anterior pituitary dysfunction is found more rarely and is almost invariably associated with DI. Pituitary involvement may also be observed in another form of systemic hystiocitosis, that is, Erdheim-Chester disease. Tuberculosis is a rare cause of hypophysitis, which may present with features of anterior pituitary dysfunction, such as hypopituitarism with hyperprolactinaemia. In conclusion, in patients with a sellar mass and unusual clinical presentation (DI, neurological symptoms), aggressiveness and onset and in the presence of systemic diseases, inflammatory and granulomatous pituitary lesions should be carefully considered in differential diagnosis.

Should macroprolactin be measured in all hyperprolactinaemic sera?

Macroprolactin is a nonbioactive prolactin isoform usually composed of a monomer of prolactin and a IgG molecule which has a prolonged clearance rate similar to that of the immunoglobulins. Macroprolactinaemia, hyperprolactinaemia entirely accounted for by the presence of macroprolactin, is estimated to account for approximately 10% of all hyperprolactinaemia coming to clinical attention in the United Kingdom and the United States. Failure to recognize that macroprolactinaemia can explain hyperprolactinaemia, leads to unnecessary investigation, incorrect diagnosis and inappropriate treatment. Screening of hyperprolactinaemic sera for the presence of misleading concentrations of macroprolactin is readily performed in biochemistry laboratories although the procedures have not been automated. The most widely employed method is to treat the hyperprolactinaemic sera with polyethylene glycol which precipitates out high-molecular weight constituents including immunoglobulins. Re-assay of the sera for prolactin will then identify those sera which yield values within the relevant normal range indicative of macroprolactinaemia and not true hyperprolactinaemia. The case for the routine screening of all hyperprolactinaemic sera for macroprolactin is compelling. The consequences of failure to recognize macroprolactinaemia are significant, the problem is frequently encountered, the means of addressing it are immediately available and it is cost effective.

Long-term results of stereotactic radiosurgery in secretory pituitary adenomas

CONTEXT

To date, no study reported long-term follow-up results of gamma knife stereotactic radiosurgery (SR).

OBJECTIVE

The aim of the study was to determine long-term efficacy and adverse effects of SR in secreting pituitary adenomas.

DESIGN

We conducted a retrospective study of patients treated by SR in the center of Marseille, France, with a follow-up of at least 60 months.

PATIENTS

A total of 76 patients were treated by SR for acromegaly (n = 43), Cushing's disease (CD; n = 18), or prolactinoma (n = 15) as a primary (n = 27) or adjunctive postsurgical treatment (n = 49).

MAIN OUTCOME MEASURES

After withdrawal of antisecretory drugs, patients were considered in remission if they had mean GH levels below 2 ng/ml and normal IGF-I (acromegaly), normal 24-h urinary free cortisol, and cortisol less than 50 nmol/liter after low-dose dexamethasone test (CD) or two consecutive normal samplings of prolactin levels (prolactinoma).

RESULTS

After a mean follow-up of 96 months, 44.7% of the patients were in remission. Mean time to remission was 42.6 months. Twelve patients presented late remission at least 48 months after SR. Two patients with CD presented late recurrence 72 and 96 months after SR. Forty percent of patients treated primarily with SR were in remission. Target volume and initial hormone levels were significant predictive factors of remission in univariate analysis. Radiation-induced hypopituitarism was observed in 23% patients; in half of them, hypopituitarism was observed after a mean time of 48 to 96 months. Twenty-four patients were followed for more than 120 months; rates of remission and hypopituitarism were similar to the whole cohort.

CONCLUSIONS

SR is an effective and safe primary or adjunctive treatment in selected patients with secreting pituitary adenomas.

Long-term outcome of patients with macroprolactinomas initially treated with dopamine agonists

OBJECTIVE

Dopamine agonists are the first line therapy for the treatment of prolactinomas. The aim of this study was to assess the outcome of macroprolactinomas during long-term follow-up after initial treatment with dopamine agonists.

DESIGN

Retrospective follow-up study.

PATIENTS

We included 72 consecutive patients (age 39+/-17 years, men 46%) diagnosed with macroprolactinoma, and initially treated with dopamine agonists between 1980 and 2004.

RESULTS

Initial presentation included headache in 49%, and visual field defects in 38% of the patients. Nine patients were already treated with dopamine agonists at presentation. Median prolactin level of the untreated patients was 460 microg/L (range 96-35,398 microg/L) at presentation. Hypopituitarism, other than hypogonadism, was present in 6% of the patients. Mean duration of follow-up was 10.2+/-6.1 years. Additional transsphenoidal surgery was necessary in 35% of the patients, because of resistance and/or intolerance of dopamine agonists. Postoperative radiotherapy was provided to 18% of all patients. During long-term follow-up, normoprolactinemia was present in 85% of the patients, but biochemical remission (normal prolactin levels in the absence of dopamine agonists) was present in only 22% of the patients. Tumor shrinkage was evident on MRI in 57% of the patients. Hypopituitarism developed in 39% of the patients, especially in those who received additional surgery with or without radiotherapy.

CONCLUSION

Dopamine agonists are effective in normalizing prolactin values, and inducing tumor shrinkage. However, in one-third of the patients, additional therapy was necessary due to dopamine agonist resistance and/or intolerance, associated with a high incidence of hypopituitarism.

Slow-growing craniopharyngioma masquarading as early-onset eating disorder: two cases

BACKGROUND

Craniopharyngiomas are slow-growing tumors, which can either be asymptomatic or present themselves with visual, neuropsychiatric or endocrine disturbances. Eating disorders (EDs) are syndromes with unknown etiology, associated with multiple endocrine abnormalities. In pediatric cases the presentation of EDs may differ markedly from those of adults.

OBJECTIVE

We report on two pediatric patients with craniopharyngioma misinterpreted as ED.

METHOD

Available patient records, psychiatric examinations, neuro-radiographic imaging, and biochemical data were evaluated.

DISCUSSION

The reported cases illustrate the importance to consider slow-growing craniopharyngioma in ED. Especially in atypical ED, neuro-radiographic, ophthalmologic and endocrine examination should be carried out. Furthermore, structural hypothalamic lesions in these cases mimicking features of ED, suggesting the possibility of an as yet unidentified structural hypothalamic disorder to be implicated in the etiopathogeny of ED.

Recurrence of hyperprolactinemia after withdrawal of long-term cabergoline therapy

CONTEXT

Recurrence of hyperprolactinemia after cabergoline withdrawal ranges widely from 36 to 80%. The Pituitary Society recommends withdrawal of cabergoline in selected patients.

OBJECTIVE

Our aim was to evaluate recurrence of hyperprolactinemia in patients meeting The Pituitary Society guidelines.

DESIGN

Patients were followed from the date of discontinuation to either relapse of hyperprolactinemia or the day of last prolactin test.

SETTING

We conducted the study at an academic medical center.

PATIENTS

Forty-six patients meeting Pituitary Society criteria (normoprolactinemic and with tumor volume reduction after 2 or more years of treatment) participated in the study.

INTERVENTIONS

After withdrawal, if prolactin returned above reference range, another measurement was obtained within 1 month, symptoms were assessed by questionnaire, and magnetic resonance imaging was performed.

MAIN OUTCOME MEASURES

We measured risk of and time to recurrence estimates as well as clinical predictors of recurrence.

RESULTS

Mean age of patients was 50 +/- 13 yr, and 70% were women. Thirty-one patients had microprolactinomas, 11 had macroprolactinomas, and four had nontumoral hyperprolactinemia. The overall recurrence was 54%, and the estimated risk of recurrence by 18 months was 63%. The median time to recurrence was 3 months (range, 1-18 months), with 91% of recurrences occurring within 1 yr after discontinuation. Size of tumor remnant prior to withdrawal predicted recurrence [18% increase in risk for each millimeter (95% confidence interval, 3-35; P = 0.017)]. None of the tumors enlarged in the patients experiencing recurrence, and 28% had symptoms of hypogonadism.

CONCLUSIONS

Cabergoline withdrawal is practical and safe in a subset of patients as defined by The Pituitary Society guidelines; however, the average risk of long-term recurrence in our study was over 60%. Close follow-up remains important, especially within the first year.

Spontaneous cerebrospinal fluid rhinorrhoea as the presenting feature of an invasive macroprolactinoma

A 29-year-old male university student, with no prior history of trauma, presented with a 1 year history of clear fluid leaking intermittently from his left nostril. His past medical history included bilateral gynaecomastia since age 12, and recent low libido. β2-transferrin analysis of the nasal fluid confirmed a diagnosis of cerebrospinal fluid (CSF) rhinorrhoea. The serum prolactin was grossly elevated at 42 700 mU/l and brain magnetic resonance imaging (MRI) revealed a large parasellar/sellar mass. A diagnosis of invasive macroprolactinoma complicated by spontaneous CSF rhinorrhoea was made. The patient was commenced on treatment with cabergoline, but while awaiting surgery to repair the CSF leak he developed streptococcus mitis and sanguis meningitis. He made an uncomplicated recovery with antibiotic treatment. Immediately following this episode, the CSF rhinorrhoea resolved spontaneously. Subsequently, a repeat MRI scan revealed dramatic involution of the pituitary mass and the serum prolactin had fallen to 604 mU/l.

Heregulin regulates prolactinoma gene expression

To investigate the role of p185(her2/neu)/ErbB3 signaling in pituitary tumor function, we examined these receptors in human prolactinomas. Immunofluorescent p185(her2/neu) was detected in almost all (seven of eight), and ErbB3 expression in a subset (four of eight) of tumors (seven adenomas and one carcinoma). Quantitative PCR also showed abundant ErbB3 mRNA in tumor specimens derived from a rarely encountered prolactin-cell carcinoma. Activation of p185(c-neu)/ErbB3 signaling with heregulin, the ErbB3 ligand, in rat lacto-somatotroph (GH4C1) tumor cells specifically induced prolactin (PRL) mRNA expression approximately 5-fold and PRL secretion approximately 4-fold, whereas growth hormone expression was unchanged. Heregulin (6 nmol/L) induced tyrosine phosphorylation and ErbB3 and p185(c-neu) heterodimerization, with subsequent activation of intracellular ERK and Akt. The Akt signal was specific to ErbB3 activation by heregulin, and was not observed in response to epidermal growth factor activation of epidermal growth factor receptor. Gefitinib, the tyrosine kinase inhibitor, suppressed heregulin-mediated p185(c-neu)/ErbB3 signaling to PRL. Heregulin induction of PRL was also abrogated by transfecting cells with short interfering RNA directed against ErbB3. Pharmacologic inhibition of heregulin-induced phosphoinositide-3-kinase/Akt (with LY294002) and ERK (with U0126) signaling, as well as short interfering RNA-mediated mitogen-activated protein kinase-1 down-regulation, showed ERK signaling as the primary transducer of heregulin signaling to PRL. These results show ErbB3 expression in human prolactinomas and a novel ErbB3-mediated mechanism for PRL regulation in experimental lactotroph tumors. Targeted inhibition of up-regulated p185(c-neu)/ErbB3 activity could be useful for the treatment of aggressive prolactinomas resistant to conventional therapy.

Phenotypic variability, neurological outcome and genetics background of 6-pyruvoyl-tetrahydropterin synthase deficiency

This study aimed to investigate the clinical variability and factors implied in the outcome of 6-pyruvoyl-tetrahydropterin synthase deficiency (PTPSd). Biochemical and clinical phenotype, treatment variables, and 6-pyruvoyl-tetrahydropterin synthase (PTS) genotype, were explored retrospectively in 19 Italian patients (12 males and 7 females, aged 4 months to 33 years). According to the level of biogenic amines in cerebrospinal fluid (CSF) at the diagnosis, the patients were classified as mild (6) (normal level) or severe (13) (abnormal low level) form (MF and SF, respectively). Blood Phe ranged from 151 to 1053 micromol/l in MF (mean +/- SD: 698 +/- 403) and 342-2120 micromol/l in SF (mean +/- SD: 1175 +/- 517) (p = 0.063). Patients with MF showed a normal neurological development (a transient dystonia was detected in one), while all SF patients except one presented with severe neurological impairment and only four had a normal neurological development. The outcome of the SF was influenced by the precocity of the treatment. Serial CSF examinations revealed a decline of 5-hydroxyindolacetic acid in MFs and an incomplete restoration of neurotransmitters in SFs: neither obviously affected the prognosis. PTS gene analysis detected 17 different mutations (seven so far unreported) (only one affected allele was identified in three subjects). A good correlation was found between genotype and clinical and biochemical phenotype. The occurrence of brain neurotransmitter deficiency and its early correction (by the therapy) are the main prognostic factors in PTPSd.

Cabergoline Effectively Induced Remission of Prolactinoma in a 9-year-old Japanese Boy

Prolactinomas are rarely diagnosed in children under the age of 10. A 9-yr-old Japanese boy complained of severe headache and progressive visual disturbance. His growth had been retarded for approximately 3 yr, and his serum PRL level was 811.6 ng/ml. Brain magnetic resonance imaging (MRI) revealed an enlarged pituitary (2.8 × 2.6 × 2.1 cm) with heterogeneous enhancement. He was diagnosed as having a macroprolactinoma accompanied by pituitary apoplexy and growth hormone deficiency. A surgical approach was initially undertaken due to the progressive visual deficits, but a residual tumor was observed, and the level of serum PRL was still high after the surgery. Cabergoline was then started, and the dose was gradually increased to 1.5 mg/wk. The serum PRL level decreased from 138.8 ng/ml to 32.5 ng/ml and 17.7 ng/ml after 5 wk and 19 wk, respectively. At 33 wk of cabergoline treatment, brain MRI demonstrated no evidence of the residual tumor. Thereafter, the serum level of PRL decreased to less than 10 ng/ml, and remission was consistently confirmed on repeated MRI. No adverse events have been observed. The present case suggests that cabergoline can be an effective treatment for prolactinomas in prepubertal children as well as in adults.

Long-term cabergoline therapy is not associated with valvular heart disease in patients with prolactinomas

Ergot-derived dopamine receptor agonists, especially pergolide and cabergoline, have been associated with an increased risk of valvular heart disease in patients treated for Parkinson's disease. Cabergoline at lower doses than those employed in Parkinson's disease is widely used in patients with prolactinomas, because of its high efficacy and tolerability; however, its safety with regard to cardiac valve disease is unknown. In order to assess the prevalence of cardiac valve regurgitation in patients with prolactinomas treated with long-term cabergoline, we performed a prospective and multicentric study including four university centers in the province of Quebec. A transthoracic echocardiogram was performed in 70 patients with prolactinomas treated with cabergoline for at least 1 year (duration of treatment, 55 +/- 22 months; cumulative dose 282 +/- 271 mg, mean +/- SD) and 70 control subjects matched for age and sex. Valvular regurgitation was graded according to the American Society of Echocardiography recommendations as mild, moderate, or severe. Moderate valvular regurgitation was found in four patients (5.7%) and five control subjects (7.1%) (P = 0.73). No patient had severe valvular regurgitation. There was no correlation between the presence of significant heart-valve regurgitation and cabergoline cumulative dose, duration of cabergoline treatment, prior use of bromocriptine, age, adenoma size, or prolactin levels. Our results show that low doses of cabergoline seem to be a safe treatment of hyperprolactinemic patients. However, in patients with prolonged cabergoline treatment, we suggest that echocardiographic surveillance may be warranted.

Prolactin-Producing Adenoma. Clinical Presentation in Adult Sudanese Patients

Objectives: To describe the clinical features of prolactin-producing pituitary adenoma (prolactinoma) in adult patients.

Methods: In a prospective hospital-based study, adult patients with prolactinoma presenting to the National Center for Neurological diseases and the National Center for cancer in Khartoum, Sudan were enrolled in the period from January 2001 to February 2005. The diagnosis was based on finding a pituitary adenoma on cranial MRI and an associated elevated blood prolactin level above 200 pig/L. The size of the adenoma was classified as either microadenoma ( < 10 mm without sellar enlargement or extrasellar extension) ormacroadema (>10 mm). The hormone profile done on each patient included blood level of prolactinand other pituitary trophic hormones, free triiodothyronine and free thyroxine hormones.

Results: Sixteen (14 females and 2 males) were identified as having a prolactinoma. The female to male ratio was 7:1. Their mean age was 24 ± 5.1 years. The prolactinoma was macroadenoma in 9 cases and microademoma in 7. Galactorrhea, amenorrhea and infertility (primary or secondary) were the commonest presenting symptom followed by headache. Affection of the visual pathway, either as bitemporal hemianopia (41.2%) or optic atrophy (11.8%), was the major neurological deficit. The mean prolactin level in macroadenoma was 2053 ± 442.6 jig/L and in microadenoma was 853.6 ± 77.8 jig/L.

Conclusions: Our prolactinoma patients, when reaching the appropriate medical attention, are more likely having an expanded macroadeoma that is compromising the visual pathway. Early recognition and referral to specialized clinics is necessary and that should have a favorable prognostic implication.

Prospective study of high-dose cabergoline treatment of prolactinomas in 150 patients

CONTEXT

Cabergoline fails to normalize hyperprolactinemia in a considerable proportion of prolactinomas, especially macroadenomas.

OBJECTIVE

We examined the effect of individualized high-dose cabergoline treatment on hyperprolactinemia in prolactinomas.

PATIENTS

The study included 122 women and 28 men (93 microadenomas and 57 macroadenomas). Forty-seven had undergone transsphenoidal surgery. According to the preceding medical treatment, the participants were separated into untreated (group U; n = 60), intolerant (group I; n = 64), and resistant (group R; n = 26) groups.

INTERVENTIONS

We promptly increased cabergoline dose on the basis of individual prolactin levels. Length of treatment was 1 yr.

RESULTS

Cabergoline normalized hyperprolactinemia in all patients except one. The proportion of prolactin normalization in both groups U and I was 83% at 3 months and 95% at 6 months. By contrast, that in group R was 35% at 3 months and 58% at 6 months. Mean cabergoline dose in milligrams per week at the time of prolactin normalization was 2.0 +/- 0.3 in group U, 0.9 +/- 0.1 in group I, and 5.2 +/- 0.6 in group R. Prolactin normalization rate at the 3 mg/wk dose was 84% overall but only 35% in group R. Serum progesterone or testosterone levels, diminished in 122 women or 16 men, respectively, were recovered in all except one resistant and four postmenopausal or panhypopituitary patients.

CONCLUSION

Individualized high-dose cabergoline treatment can normalize hyperprolactinemia and hypogonadism in nearly all prolactinomas irrespective of tumor size or preceding treatments. Hyperprolactinemia could be controlled in poor responders within 1 yr with doses higher than 3 mg/wk.

Clinical practice guideline for hypotalamic-pituitary disturbances in pregnancy and the postpartum period

During pregnancy, the body undergoes a major adaptation process as a result of the interaction between mother, placenta and fetus. Major anatomical and histological changes are produced in the pituitary, with an increase of up to 40% in the size of the gland. There are wide variations in the function of the hypothalamus-pituitary-thyroid axis that effect iodine balance, the overall activity of the gland, as well as transport of thyroid hormones in plasma and peripheral metabolism of thyroid hormones. The incidence of goiter and thyroid nodules increases throughout pregnancy. The management of differentiated thyroid carcinoma should be individually tailored according to tumoral type and pregnancy stage. Given the effects of hypothyroidism on fetal development, both the diagnosis and appropriate therapeutic management of thyroid hypofunction are essential. The most important modification to the hypothalamus-pituitary-adrenal axis during pregnancy is the rise in serum cortisol levels due to an increase in cortisol-binding proteins. Although Cushing's syndrome during pregnancy is infrequent, both diagnosis and treatment of this disorder are especially difficult. Adrenal insufficiency during pregnancy does not substantially differ from that occurring outside pregnancy. However, postpartum pituitary necrosis (Sheehan's syndrome) is a well-known complication that occurs after delivery and, together with lymphocytic hypophysitis, constitutes the most frequent cause of adrenal insufficiency. The management of prolactinoma during pregnancy requires suppression of dopaminergic agonists and their reintroduction if there is tumoral growth. Notable among the neuropituitary disorders that can occur throughout pregnancy is diabetes insipidus, which occurs as a consequence of increased vasopressinase activity.

Serum Total Prolactin and Monomeric Prolactin Reference Intervals Determined by Precipitation with Polyethylene Glycol: Evaluation and Validation on Common ImmunoAssay Platforms

Background: Macroprolactin is an important source of immunoassay interference that commonly leads to misdiagnosis and mismanagement of hyperprolactinemic patients. We used the predominant immunoassay platforms for prolactin to assay serum samples treated with polyethylene glycol (PEG) and establish and validate reference intervals for total and monomeric prolactin.

Methods: We used the Architect (Abbott), ADVIA Centaur and Immulite (Siemens Diagnostics), Access (Beckman Coulter), Elecsys (Roche Diagnostics), and AIA (Tosoh) analyzers with samples from healthy males (n = 53) and females (n = 93) to derive parametric reference intervals for total and post-PEG monomeric prolactin. Concentrations of immunoreactive prolactin isoforms in serum samples from healthy individuals were established by gel filtration chromatography (GFC). We then used samples from 22 individuals whose hyperprolactinemia was entirely attributable to macroprolactin and 32 patients with true hyperprolactinemia to compare patient classifications and prolactin concentrations measured by GFC with the newly derived post-PEG reference intervals.

Results: Parametric reference intervals for post-PEG prolactin in male and female serum samples, respectively, were (in mIU/L): 61–196, 66–278 (Centaur); 63–245, 75–381 (Elecsys); 70–301, 92–469 (Access); 72–229, 79–347 (Architect); 73–247, 83–383 (AIA); and 78–263, 85–394 (Immulite). Concordance between GFC and immunoassay-specific post-PEG reference intervals was observed in 311 of 324 cases and for 31 of 32 patients with true hyperprolactinemia and 17 of 22 patients with macroprolactinemia. Results leading to misclassification occurred in a few analyzers for 5 macroprolactinemia patient samples with relatively minor increases in post-PEG prolactin (mean 61 mIU/L).

Conclusions: Our validated normative reference data for sera pretreated with PEG and analyzed on the most commonly used immunoassay platforms should facilitate the more widespread introduction of macroprolactin screening by clinical laboratories.

Rat prolactinoma cell growth regulation by epidermal growth factor receptor ligands

Epidermal growth factor (EGF) regulates pituitary development, hormone synthesis, and cell proliferation. Although ErbB receptor family members are expressed in pituitary tumors, the effects of EGF signaling on pituitary tumors are not known. Immunoprecipitation and Western blot confirmed EGF receptor (EGFR) and p185(c-neu) protein expression in GH3 lacto-somatotroph but not in adrenocorticotropic hormone-secreting AtT20 pituitary tumor cells. EGF (5 nmol/L) selectively enhanced baseline ( approximately 4-fold) and serum-induced (>6-fold) prolactin (PRL) mRNA levels, whereas gefitinib, an EGFR antagonist, suppressed serum-induced cell proliferation and Pttg1 expression, blocked PRL gene expression, and reversed EGF-mediated somatotroph-lactotroph phenotype switching. Downstream EGFR signaling by ERK, but not phosphoinositide-3-kinase or protein kinase C, mediated the gefitinib response. Tumors in athymic mice implanted s.c. with GH3 cells resulted in weight gain accompanied by increased serum PRL, growth hormone, and insulin growth factor 1. Gefitinib decreased tumor volumes and peripheral hormone levels by approximately 30% and restored normal mouse body weight patterns. Mice treated with gefitinib exhibited decreased tumor tissue ERK1/2 phosphorylation and down-regulated tumor PRL and Pttg1 mRNA abundance. These results show that EGFR inhibition controls tumor growth and PRL secretion in experimental lacto-somatotroph tumors. EGFR inhibitors could therefore be useful for the control of PRL secretion and tumor load in prolactinomas resistant to dopaminergic treatment, or for those prolactinomas undergoing rare malignant transformation.

Effect of long-term cabergoline therapy on the immunological pattern and pituitary function of patients with idiopathic hyperprolactinaemia positive for antipituitary antibodies

OBJECTIVE

The occurrence of antipituitary antibodies (APA) in patients with idiopathic hyperprolactinaemia (IH) and the effects of dopamine agonists on these antibodies and long-term pituitary function outcome have been so far not evaluated. This longitudinal study was aimed at investigating, in patients with IH the occurrence of APA and the effect of cabergoline on the pituitary function and behaviour of APA.

DESIGN

Sixty-six patients with IH were studied. APA (by indirect immunofluorescence) and pituitary function were investigated every year for 3 years.

RESULTS

Seventeen patients resulted APA positive (Group 1) and 49 APA negative (Group 2). Eight patients of Group 1 (Group 1a) and 24 of Group 2 (Group 2a) were asymptomatic and then not treated; instead, nine patients in Group 1 (Group 1b) and 25 in Group 2 (Group 2b), showing symptoms of hyperprolactinaemia, were treated with cabergoline for 2 years. Among the untreated patients, during the follow-up, those with APA positive (Group 1a) showed an increase of APA titres and PRL levels with partial pituitary impairment in some of them; instead those with APA negative (Group 2a) persisted negative with normal pituitary function despite persistent hyperprolactinaemia. Among the treated patients, those with APA positive (Group 1b) showed normalization of PRL levels, APA disappearance and recovery of pituitary function (when initially impaired) during cabergoline treatment, persisting also at last observation (off-therapy). Instead all patients of Group 2b persisted with APA negative during the follow-up with normalization of PRL levels and stable normal pituitary function during cabergoline therapy but showing a further increase of PRL at the last observation.

CONCLUSIONS

The presence of APA in some patients with IH suggests a possible occurrence of autoimmune hypophysitis at potential/subclinical stage; an early and prolonged cabergoline therapy could interrupt the progression to an overt clinical stage of the disease. However, the small amount of patients investigated suggests caution against generalization of our assumption and prompts to further controlled studies on a more numerous population to verify these conclusions.

Cabergoline and the risk of valvular lesions in endocrine disease

AIMS

The cardiac valvular risk associated with lower exposure to cabergoline in common endocrine conditions such as hyperprolactinemia is unknown.

METHODS AND RESULTS

We performed a cross-sectional, case-control echocardiographic study to assess the valvular status in 102 subjects receiving cabergoline for endocrine disorders and 51 matched control subjects. Cabergoline treatment ranged from 12 to 228 months, with a cumulative dose of 18-1718 mg. Valvular regurgitation was equally prevalent in both groups and was almost exclusively mild. Two cabergoline-treated subjects had moderate mitral regurgitation; there was no relationship between cabergoline dose and the presence or severity of mitral valve regurgitation (P=NS). Mitral valve tenting area was significantly greater in the cabergoline group when compared with the control subjects (P=0.03). Mitral valve leaflet thickening was observed in 5.9% of cabergoline-treated subjects; no relationship with the cumulative cabergoline dose was found. No patient had aortic or tricuspid valvular restriction.

CONCLUSION

No significantly increased risk of clinically relevant cardiac valve disorders was found in subjects treated with long-term cabergoline therapy at the doses used in endocrine practice. While exposure to cabergoline appears to be safe during low-dose long-term therapy, an association with subclinical changes in mitral valve geometry cannot be completely excluded.

Diagnosis and management of hyperprolactinemia: results of a Brazilian multicenter study with 1234 patients

OBJECTIVE

The aim of the study was to evaluate clinical and laboratorial features of 1234 patients with different etiologies of hyperprolactinemia, as well as the response of 388 patients with prolactinomas to dopamine agonists.

DESIGN, SETTING, AND PATIENTS

A total of 1234 hyperprolactinemic patients from 10 Brazilian endocrine centers were enrolled in this retrospective study.

MAIN OUTCOME MEASURE

PRL measurement, thyroid function tests, and screening for macroprolactin were conducted.

RESULTS

Patients were subdivided as follows: 56.2% had prolactinomas, 14.5% drug-induced hyperprolactinemia, 9.3% macroprolactinemia, 6.6% non-functioning pituitary adenomas, 6.3% primary hypothyroidism, 3.6% idiopathic hyperprolactinemia, and 3.2% acromegaly. Clinical manifestations were similar irrespective of the etiology of the hyperprolactinemia. The highest PRL levels were observed in patients with prolactinomas but there was a great overlap in PRL values between all groups. However, PRL>500 ng/ml allowed a clear distinction between prolactinomas and the other etiologies. Cabergoline (CAB) was more effective than bromocriptine (BCR) in normalizing PRL levels (81.9% vs 67.1%, p<0.0001) and in inducing significant tumor shrinkage and complete disappearance of tumor mass. Drug resistance was observed in 10% of patients treated with CAB and in 18.4% of those that used BCR (p=0.0006). Side-effects and intolerance were also more common in BCR treated patients.

CONCLUSION

Prolactinomas, drug induced hyperprolactinemia, and macroprolactinemia were the 3 most common causes of hyperprolactinemia. Although PRL levels could not reliably define the etiology of hyperprolactinemia, PRL values >500 ng/ml were exclusively seen in patients with prolactinomas. CAB was significantly more effective than BCR in terms of prolactin normalization, tumor shrinkage, and tolerability.

Hyperprolactinaemia

Hyperprolactinaemia is a frequent cause of reproductive problems encountered in clinical practice. A variety of pathophysiological conditions can lead to hyperprolactinaemia; therefore, pregnancy, drug effects, hypothyroidism and polycystic ovary syndrome should be excluded before investigating for prolactin-secreting pituitary tumours. Prolactinomas are mainly diagnosed in women aged 20-40 years. They present with clinical features of hyperprolactinaemia (galactorrhoea, gonadal dysfunction), and more rarely with large tumours, headache and visual field loss due to optic chiasm compression. Medical therapy with dopamine agonists is the treatment of choice for both micro- and macroprolactinomas. Tumour shrinkage and restoration of gonadal function are achieved in the majority of cases with dopamine agonists. A trial of withdrawal of medical therapy may be considered in many patients with close follow-up. Pituitary surgery and radiotherapy currently have very limited indications. Pregnancies in patients with prolactinomas need careful planning and close monitoring.

Understanding osteoporosis

Osteoporosis is a common skeletal condition that results in significant morbidity, mortality and health care costs. There is an increased awareness of bone health in people with severe mental illness (SMI). These people appear to be at a higher risk of low bone density and fracture, and also have a poorer outcome following hip fracture. The reason for the increased risk of osteoporosis is multifactorial and includes general as well as disease-specific factors, such as antipsychotic medication and hyperprolactinaemia. Clinical history and examination followed by dual energy x-ray absorptiometry are required to assess the risk of osteoporosis. Therapies should begin with lifestyle measures, such as physical activity and dietary supplementation, with the use of bone-specific agents reserved for those at high absolute risk.

Medical causes and consequences of hyperprolactinaemia. A context for psychiatrists

Hyperprolactinaemia is the commonest endocrine disorder of the hypothalamic-pituitary axis and can lead to both short-term sexual dysfunction and galactorrhoea, and long-term loss of bone mineral density. Prolactin is secreted from the anterior pituitary gland under the influence of dopamine, which exerts a tonic inhibitory effect on prolactin secretion. Physiological regulators of prolactin secretion include many different types of 'stress' and sleep. Disruption of the normal control of prolactin secretion results in hyperprolactinaemia from pathological and pharmacological causes. The administration of antipsychotic medication is responsible for the high prevalence of hyperprolactinaemia in people with severe mental illness. Physiological hyperprolactinaemia, such as pregnancy and lactation, should be distinguished from pathological causes to prevent unnecessary investigation and treatment. The causes, consequences and management of hyperprolactinaemia are discussed in this article.

Hyperprolactinemia and prolactinomas

Any process interfering with dopamine synthesis, its transport to the pituitary gland, or its action at the level of lactotroph dopamine receptors can cause hyperprolactinemia. As described in this article, considering the complexity of prolactin regulation, many factors could cause hyperprolactinemia, and hyperprolactinemia can have clinical effects not only on the reproductive axis. Once any drug effects are excluded, prolactinomas are the most common cause of hyperprolactinemia. The most frequent symptom is hypogonadism in both genders. Medical and surgical therapies generally have excellent results, and most prolactinomas are well controlled or even cured in some cases.

Operative treatment of prolactinomas: indications and results in a current consecutive series of 212 patients

OBJECTIVE

Medical therapy with dopamine agonists (DA) is the primary treatment of choice in most patients with prolactinomas. 'Classical' surgical indications are intolerance or lack of efficiency of DA therapy. Focusing on a possible shift of recent indications, we retrospectively analyzed our results of surgical treatment in prolactinomas.

PATIENTS AND METHODS

Between 1990 and 2005, we have operated on 212 consecutive patients with prolactinomas. Surgical indications were divided into 'classical' indications and 'modern' indications defined as cystic prolactinomas or patients with microprolactinomas who individually decided on a primary surgical treatment.

RESULTS

Initial overall remission was accomplished in 53.2% including giant prolactinomas. However, in microadenomas, the remission rate was significantly higher with 91.3%. Overall remission at the latest follow-up was 42.7%, but 72.5% in intrasellar tumors, 80% in cystic prolactinomas, and 84.8% in microprolactinomas. The overall recurrence rate was 18.7%. Relapse of hyperprolactinemia in microprolactinomas was 7.1%. In our series, continually less patients were surgically treated for 'classical' indications. By contrast, the number of patients who individually decided on a primary surgical therapy has increased considerably.

CONCLUSION

Remission rates after surgical treatment of prolactinomas remain excellent, particularly in microadenoma and intrasellar macroadenomas, whereas morbidity of transsphenoidal surgery is low in the hands of experienced pituitary surgeons. Our remission rates not only confirm the already interdisciplinarily accepted surgical indications, but also emphasize the value of primary transsphenoidal surgery as a discussion-worthy alternative to dopaminergic therapy in young patients with microprolactinomas or cystic tumors.

Pituitary testing: a reappraisal

Due to the pulsatile pituitary hormone secretion, their involvement in the acute stress response and feed-back with peripheral hormones, baseline pituitary hormone levels may overlap among normal and pathological subjects. Therefore, dynamic testing has been widely used for the diagnosis and follow-up of pituitary diseases. An ideal test should be sensitive, specific, well tolerated, easy to be standardized and performed and cost-effective. Emerging issues are cost and widespread availability of ultrasensitive hormone assays, increased knowledge of the pathophysiological and pharmacological mechanisms regulating pituitary function and need for better discrimination between clinically useful tests and research tools. In this special issue experts from US and Europe practically approached testing in specific pituitary diseases in the context of current guidelines. Drug effects on different axes are discussed since pharmacologic treatments may influence testing outcome.

Hyperprolactinemia

In several respects prolactin is unique among anterior pituitary hormones. The primary regulation of prolactin secretion is mediated through hypothalamic inhibition, and the diagnosis of hyperprolactinemia can be established without the use of stimulation or suppression tests. Documenting the presence of hyperprolactinemia is not difficult-the challenge is in identifying the cause of the hormone hypersecretion. With immunoradiometric assays falsely low levels of prolactin are occasionally seen in patients with macroadenomas and very high serum prolactin (the hook effect). Macroprolactin should be suspected when a patient with hyperprolactinemia does not present with typical clinical symptoms, and all hyperprolactinemic sera should be screened for macroprolactin. With prolactinomas, prolactin levels generally parallel tumor size. Prolactin secreting macroadenomas are typically associated with levels that exceed 250 microg/l and may exceed 1,000 microg/l. Large non-functioning adenomas also lead to hyperprolactinemia but levels virtually never exceed 94 microg/l. Acquired and isolated prolactin deficiency is rare.

Absence of hypogonadism in a male patient with a giant prolactinoma: a clinical paradox

BACKGROUND

Impotence and decreased libido are the cardinal features of prolactinomas in males. We describe the unusual clinical, pathological and biochemical features in a male patient with a giant prolactinoma and normal gonadal function.

CASE REPORT

A 57 year-old man presented with visual symptoms related to a 30x25x60mm tumor of the sella and skull base. Biopsy revealed a pituitary adenoma and subsequent hormone profiles demonstrated grossly elevated serum prolactin (131,412ng/ml), LH at the upper limit of normal and normal testosterone. The patient had no symptoms of decreased libido or impotence related to this giant prolactinoma. Immunohistochemistry revealed a tumor that was positive for prolactin, alpha-subunit and LH. Cabergoline greatly reduced prolactin levels but these remained above normal. LH, testosterone and alpha-subunit levels were decreased in parallel. Loss of libido and impotence became apparent when testosterone fell below normal, a situation that resolved with further cabergoline treatment and prolactin inhibition and testosterone therapy.

CONCLUSIONS

Sexual dysfunction is a hallmark of prolactinomas in males. Tumors that co-secrete prolactin and LH are extremely rare and this is the first such case reported in an adult male. In this case, normal testosterone was maintained by intact LH levels even in the face of the highest prolactin level reported to date.

The epidemiology and management of pituitary incidentalomas

PREVALENCE

The prevalence of pituitary tumors has been a topic of controversy for many years. Autopsy and radiological series show that pituitary incidentalomas may be present in one of six people. Recent epidemiological data suggest that clinically apparent pituitary adenomas have a prevalence of approximately one in 1,000 people in the general population. The disconnect between these two prevalence rates underlines the common clinical quandary of how to manage pituitary incidentalomas, particularly those lacking clinical signs/symptoms or hormonal abnormalities.

MANAGEMENT

The natural history of incidentalomas suggests that periodic hormonal, clinical and radiological follow-up is the optimal approach. In the absence of tumor growth or relevant symptoms, screening can be continued intermittently or curtailed based on the clinical judgment of the physician. In the presence of hormonal hypersecretion, the management of pituitary incidentalomas, whether they are micro- or macroadenomas, should follow accepted clinical guidelines. For incidental pituitary macroadenomas without hormonal hypersecretion, clinical management should also include assessments for visual field impairment or hypopituitarism. In such cases, regular radiological and hormonal follow-up is required to identify tumor growth or the appearance of new symptoms. In the presence of tumor growth or new hormonal abnormalities, surgical options should be considered and discussed with the patient.