[Clinical case of the month. Anterior mediastinal mass in a patient with acromegaly]

The discovery of an anterior asymptomatic mediastinal mass with acromegaly creates a dilemma for the clinician. As acromegaly can be due to a pituitary tumor but also to an ectopic production of GHRH, the first diagnostic step consists of finding the etiology of the disease in order to use adequate treatment. This can be complicated by the fact that acromegaly can be associated with other tumors (for instance in MEN-1 disease and Carney Complex) and because chronic GH hypersecretion can stimulate tumor overgrowth and perhaps tumor formation. We describe the case of a 44-year-old acromegalic woman with an anterior mediastinal mass. We present the different diagnoses and a review of the literature.

The treatment of sporadic versus MEN1-related pituitary adenomas

The treatment of pituitary tumours strongly depends on their clinical presentation. In general, the treatment aims are reducing tumour volume and/or decreasing hormone hypersecretion. It relies on single or a combination of three different methods: surgery, medication and radiotherapy. The rationale for deciding the treatment are many but include the aggressiveness of the tumour. The aetiologies of sporadic pituitary adenomas are not fully understood. However, several causes have been identified resulting in specific familial phenotypes like multiple endocrine neoplasia type I (MEN1). MEN1 is related to mutations in the MEN1 gene, a tumour suppressor gene localized on chromosome 11q13 and which encodes menin, a 610 amino acid protein. During the last years, an evidence progressively emerged that MEN1-related adenomas were more aggressive and less responsive to therapy than their sporadic counterparts. In this article, we review the differences between sporadic and MEN1-related adenomas and suggest specific ways of treatment and follow-up for MEN1-related tumours.

Oral administration of the growth hormone secretagogue NN703 in adult patients with growth hormone deficiency

OBJECTIVE

Little is known of the usefulness of GH secretagogues (GHSs) in GH-deficient (GHD) adults. The objective of this study was to determine the number of responders to treatment with NN703 in GHD adults.

DESIGN

A multicentre, randomized, double-blind, and placebo-controlled study.

PATIENTS

Ninety-seven GHD adults were included.

MEASUREMENTS

The GH response before and after 1 week of oral treatment with NN703 (n = 83) or placebo (n = 14) was determined. The first and last dose of NN703 was 3 mg/kg, whereas the dose of NN703 was 1.5 mg/kg/day during the 6 days between the first and last doses. Furthermore, all 97 patients received 1 micro g/kg GH-releasing hormone (GHRH) 3 weeks after the last dose of NN703.

RESULTS

Serum GH peak and area under curve (AUC) values after the first NN703 administration were greater than those after placebo administration (P < 0.05). However, after correction for the lower body mass index (BMI) in the NN703 group, this difference lost statistical significance. After 1 week of therapy, GH peak and AUC values were similar following the final doses of NN703 and placebo. Serum peak and AUC values of other anterior pituitary hormones were similar between the NN703 and placebo groups both after the first and last administration of study drug. Nine of the 83 patients (11%) responded with a serum peak GH concentration >or= 5 micro g/l after the first and/or last NN703 administration, whereas no patient responded after placebo administration. Serum IGF-I was unaffected by 1-week NN703 treatment, whereas serum IGFBP-3 was increased (P < 0.05 vs. placebo) also after correction for BMI. Mean serum peak GH concentration after GHRH administration was 2.1 micro g/l (+/-0.3, SEM), which was higher than that after the first NN703 administration (1.32 +/- 0.3, P < 0.05).

CONCLUSION

NN703 administration was generally well tolerated. Eleven per cent of the GHD adult patients responded with a peak GH response >or= 5 micro g/l after the first and/or last administration of oral NN703. Although a majority of GHD adults will not respond to NN703, the present results suggest that oral NN703 treatment could be useful in some adult patients with moderately severe GHD. These patients may be identified by a test dose of GHS.

[Medullary thyroid cancer: how tumor markers and genetics determine preventive measures]

Medullary thyroid cancer (MTC) arises from parafollicular C cells secreting calcitonin. MTC occurs both as sporadic tumors and as part of specific inherited autosomal dominant syndromes in which point mutations within a discrete set of RET codons were described. Total thyroidectomy and aggressive neck dissection represents the only chance for cure in the affected patients. Therefore, all patients with thyroid nodular disease should undergo measurement of calcitonin plasma levels to allow preclinical diagnosis of the disease and early appropriate surgery ("secondary prevention"). In case of proband patient for inherited disease, all the family members should be genetically screened to detect the disease gene carriers. Patients with germline mutation would benefit either from earlier surgery at the stage of C-cell hyperplasia or microcarcinoma or prophylactic surgery (total thyroidectomy without neck dissection) (primary prevention) before the onset of any C-cells pathology. The ideal age for performance of such prophylactic surgery is determined by the genotypic features of the disease.

The changing spectrum of TSH-secreting pituitary adenomas: diagnosis and management in 43 patients

OBJECTIVE

Our aim was to report the recent changes in diagnosis and management of TSH-secreting pituitary adenomas.

METHODS

We retrieved 43 consecutive patients with TSH-secreting pituitary tumors (23 male and 20 female) among 4400 pituitary adenomas followed between 1976 and 2001 in six Belgian and French centers.

RESULTS

TSH was elevated in 18/43 and alpha subunit in 13/32 patients. In patients with intact thyroid (n=30), mean free tri-iodothyronine was 13.1 pmol/l (range 3.5-23) and mean free thyroxine was 38.4 pmol/l (range 10.2-62.7). Hyperprolactinemia and acromegaly were associated in 9/43 and 8/43 cases. The number of associated hypersecretions was higher in macroadenomas than in microadenomas (Chi square = 11.2, P<0.01). Two women had sporadic multiple endocrine neoplasia type 1-associated syndrome. The proportion of microadenomas versus macroadenomas was 1/11 (period 1974-1986) and 8/32 (period 1987-2001). Bilateral petrosal sinus sampling, (111)In-pentreotide scintigraphy and ((11)C)-l-methionine positron emission tomography scan confirmed diagnosis in four questionable microadenomas. Macroadenomas with extrasellar extension (31 cases) had a tendency to be medially located. Medical treatment with somatostatin analogs was initiated as first-line treatment in 26 patients. TSH levels were reduced by more than 50% in 23/26 cases. A tumoral shrinkage of more than 20% was observed in 5/13 cases. Surgery was performed in 36 patients. After 1 year, 21 of them (58.3%) met the criteria of surgical favorable outcome. Pituitary radiotherapy (n=8) and somatostatin analogs allowed normalization in cases not cured by surgery.

CONCLUSION

Ultrasensitive methods for TSH measurement led to an earlier recognition of TSH-secreting pituitary tumors. In this series, we observed that TSH-secreting pituitary tumors are today more frequently found at the stage of microadenomas, medially located, without associated hypersecretions and needing new exploration methods as compared with older series. This changing spectrum in the presentation of TSH-secreting pituitary tumors and the excellent response to somatostatin analogs has been accompanied by an improvement in the prognosis of the disease.

[Inflammatory diseases of the pituitary during pregnancy]

Well-known pituitary inflammatory diseases (sarcoidosis, Wegener granulomatosis, Langerhans and non-Langerhans histiocytosis, inflammatory pseudotumors) may occur during pregnancy or apart from it. Moreover, some inflammatory diseases, such as lymphocytic hypophysitis occur most of the time during pregnancy. In this chapter, we shall consider these different pathologies as well as the specific treatment of lymphocytic hypophysitis.

[Acromegaly and pregnancy]

Acromegaly usually results from GH hypersecretion by a somatotroph adenoma. The fertility of acromegalic patients is often impaired. Several factors may impact the course of pregnancy in acromegaly. Disturbed pituitary function might lead to infertility or spontaneous abortion. GH is a powerful insulin antagonist, and pregnant acromegalic patients are prone to added glucose intolerance and diabetes. Pregnancy itself might also impact the course of the pituitary tumor. During pregnancy, the normal pituitary increases in size due to estrogens-mediated hyperplasia. Therefore, tumors are at risk for hemorrhage due to enhanced vascularity, and might compress the optic chiasm. In this article we summarize the data on the literature on the reciprocal influences between acromegaly and pregnancy, we discuss therapeutic options and advance diagnostic and surveillance schedules of acromegaly during pregnancy.

[Pituitary diseases in elderly patients with chronic renal insufficiency]

Chronic renal failure (CRF) in the elderly is a cause of multiple endocrine dysfunctions. The three most common pituitary axes involved are the thyrotrope, lactotrope and gonadotrope axes. Thyroid dysfunction may be the consequence of thyroid or pituitary failure. Hyperprolactinemia results in gonadal failure and is present in 30% of patients. Early presentation of menopause and andropause are common in patients with CRF. Sexual hormonal replacement is controversial and must be individually tailored. We propose a systematic screening in the elderly with CRF: determination of TSH, TPO antibodies and cervical palpation, measures of PRL, LH, FSH and testosterone to explore lactotrope and gonadotrope axis.

[Differential diagnosis and medical treatment in Cushing's disease]

Cushing's disease remains a difficult diagnosis in spite of new technical procedures such as pituitary MRI, selective bilateral petrosal or cavernous sampling, (111)In pentreotide scan and 18 Flurodeoxyglucose pituitary PET scan. In this article, we review biological diagnostic procedures of Cushing's disease and corticotroph adenomas. According to our experience and the literature, we summarize the approach in medical treatment of Cushing's disease.

[Cushing's disease and corticotroph adenoma: anterior pituitary function before and after trans-sphenoidal microsurgery]

BACKGROUND AND PURPOSE

Cushing's disease is characterized by an overproduction of ACTH inducing an hypersecretion of corticosteroids. We assessed the non-corticotrophic pituitary functions before and after microsurgical resection of the corticotrophic adenoma.

METHODS

We reviewed retrospectively a series of 98 patients (19 males, 79 females) undergoing transsphenoidal surgery between 1974 and 2001. Prolactin levels, somatrotrophic, gonadotrophic and thyroidotrophic functions were assessed and compared before and after resection of the adenoma.

RESULTS

Before surgery, we observed an elevation of prolactin and a reduction of the GH, TSH, LH and FSH levels. These modifications were not linked to the volume of the adenoma but depended on the systemic effect of the hypercorticism or on local paracrine mechanisms. Selective adenomectomy usually restored altered corticotrophic and also, unlike (partial or total) hypophysectomy, the non-corticotrophic functions.

CONCLUSIONS

Non-corticotrophic functions are often altered in Cushing's disease but can be restored after selective adenomectomy.

[Cushing's disease and corticotrophic adenoma: results of pituitary microsurgery]

Between November 1994 and June 2001, 194 patients with Cushing's disease underwent transsphenoidal surgery: 167 patients had adenomectomy, 14 had ante hypophysectomy, 5 had subtotal hypophysectomy, 4 had hemihypophysectomy 4 had central hypophysectomy. Complications occurred in 18 patients (9.3%), including 4 deaths (three were apparently not related to surgery). Remission of disease was achieved in 162 of 190 (85.3%) patients analyzed. Surgical failures were associated with lack of pituitary adenoma, size of the tumor and invasiveness. Among patients with confirmed adenomas, the rate of remission was significantly higher (p<0.01) in patients with microadenomas (92.6%) than in patients with macroadenomas (66.7%). Reoperation in 6 failures was followed by remission in 4 cases. The overall remission rate was 87.4%. In the 162 patients with immediate success, duration of follow-up was 10.0 +/- 5.9 years (m +/- DS; median=10.0). Recurrence of the disease occurred in 24 (14.8%) of 162 patients at a mean 4.8 years (range: 0.8-12.0 years). Our longest sustained remission is 25.6 years. Actuarial analysis indicates that the probability of a patient remaining well 12 years after surgery is 80.0%. It is 86.2% in microadenomas versus 52.5% in macroadenomas and 94.5% in the patients with postoperative hypocortisolism versus 59.2% in the others.

[Multihormonal bilateral petrosal sinus sampling in Cushing's disease: radiological, surgical and pathological correlations]

Multihormonal bilateral petrosal sinus sampling (BPSS) has been proposed to improve corticotroph microadenomas prediction of lateralisation. Few series have simultaneously compared data of pituitary MRI, surgical findings and multihormonal BPSS. Seven patients (6F/1M) with Cushing's disease, mean age at diagnosis of 35 years (range 24-55) were prospectively studied to compare radiological and multihormonal BPSS data with surgical and pathological findings. In untreated patients, simultaneous measures of ACTH, TSH and prolactine (PRL) were done at time 0, 7, 15, 22 minutes after CRH (500 microgram) and TRH (200 microgram) stimulation. An intersinus gradient of 1.4 was considered as a lateralisation. All microadenomas were identified during surgery, diameters ranged from 2 to 7 mm. All patients were in long-term surgical remission. Pathological studies confirmed a tumoral tissue with ACTH immunostaining in 6/7 cases and PRL in 3/7 cases. Pituitary MRI correctly identified tumors in 4 cases, the remaining tumors were not seen. Basal and stimulated intersinus gradients of ACTH, TSH and PRL were homolateral in 6/7 cases and were coincident with surgical findings in 4/7 cases. The other three cases were contralateral to MRI and surgical data. In conclusion, simultaneous gradient of ACTH, PRL and TSH did not improve lateralisation prediction in this series. Hormonal hypersecretion was homolateral in six cases whereas pathological studies demonstrated a mixed secretion in only three cases. A preferential pituitary draining could explain these discordances. Data from our series and from others (done with CRH stimulation and ACTH-PRL measures) strongly suggest a paracrine interaction between tumoral and normal pituitary tissue.

Efficacy of the new long-acting formulation of lanreotide (lanreotide Autogel) in the management of acromegaly

Lanreotide Autogel is a new long-acting aqueous preparation of lanreotide for the treatment of acromegaly and is administered by deep sc injection from a small volume, prefilled syringe. The aim of this study was to evaluate the efficacy and safety of this new long-acting formulation in a large population of acromegalic patients previously responsive to lanreotide 30 mg, im (sustained release microparticle formulation). Lanreotide Autogel was administered by deep sc injection every 28 d to 107 patients (54 males and 53 females; mean age, 54 +/- 1.2 yr). All patients had been treated with lanreotide (30 mg) for at least 3 months before study entry and had a mean GH level less than 10 ng/ml after at least 4 subsequent im injections every 14 d (48%), 10 d (32%), or 7 d (20%). Treatment was switched from lanreotide 30 mg injected every 14, 10, or 7 d to 60, 90, or 120 mg lanreotide Autogel, respectively, every 28 d. After three fixed dose injections of lanreotide Autogel, mean lanreotide levels were similar to those obtained at steady state with lanreotide 30 mg. During lanreotide Autogel treatment, the control of acromegalic symptoms was comparable with that previously achieved during lanreotide 30 mg treatment. After 3 injections of lanreotide Autogel, mean GH (2.87 +/- 0.22 ng/ml) and IGF-I (317 +/- 15 ng/ml) values were comparable with those recorded at the end of lanreotide 30 mg treatment (GH, 2.82 +/- 0.19 ng/ml; IGF-I, 323 +/- 16 ng/ml). GH levels below 2.5 ng/ml and age-/sex-normalized IGF-I were achieved in 33% and 39% of patients during lanreotide 30 mg and lanreotide Autogel treatment, respectively. Diarrhea, abdominal pain, and nausea were reported by 38%, 22%, and 18% of patients during lanreotide 30 mg treatment and by 29%, 17%, and 9% of patients, respectively, during lanreotide Autogel treatment. In conclusion, this clinical study shows that lanreotide Autogel is at least as efficacious and well tolerated as lanreotide 30 mg. This new long-acting lanreotide formulation, lanreotide Autogel, which is administered from a small volume, prefilled syringe by deep sc injection, is therefore likely to improve the acceptability of medical treatment for patients requiring long-term somatostatin analog therapy.

Biomechanical and morphological types of the linea alba and its possible role in the pathogenesis of midline incisional hernia

OBJECTIVE

To review the tensile strength of the different histological types of fibres in the linea alba and correlate the anatomical features of the anterior abdominal wall with the tensile strength of the linea alba to see whether the tensile strength of the linea alba might contribute to the development of midline incisional hernias.

DESIGN

Laboratory study.

SETTING

University hospital, Germany.

SUBJECTS

46 cadavers in part one, and 9 freshly frozen and 38 formalin-fixed cadavers in part two.

INTERVENTIONS

In the first part of the study the histological examination was by binocular dissection microscopy, magnification x10, but this was not sufficiently reproducible so in the second part we used an Olympus BX50 microscope, magnification x20, and Optimas 5.22 picture processing software. Tensile strength was measured using a Loosenhausen ZHP 1-6 tensiometer.

MAIN OUTCOME MEASURES

Correlation between anatomical features and tensile strength.

RESULTS

The method used in part one of the study failed to differentiate between the three types of fibres in the linea alba (weak, intermediate, and compact). In the second part of the study we found that the fibres were irregular, with no systematic crossing of the fibres of the aponeurosis. There was a significant correlation between the thickness and density of fibres in the linea alba and its tensile strength (r = 0.9). The thickness of fibres ranged from 21.9-38.2 microm and the density from 48% to 90%. The tensile strength ranged from 3-25 kp.

CONCLUSION

A combination of low density and thin fibres in the linea alba could be a predisposing factor for development of midline incisional hernias

Extensive inflammatory pseudotumor of the pituitary

A 40-yr-old female presented with an extensive lesion of the sellar area and the sphenoid sinus, spreading to the optic nerves and associated with pachymeningitis. Histological findings were consistent with an inflammatory pseudotumor, and steroid treatment allowed the disappearance of all the lesions. Inflammatory pseudotumors of the pituitary are very rare. This case appears unique with regard to the extension of the lesions and the dramatic response to medical treatment. The differential diagnosis of inflammatory lesions of the pituitary is difficult. It relies mainly on histological analysis and includes sarcoidosis, Wegener's granulomatosis, histiocytosis (Langerhans, Rosai-Dorfman, and Erdheim-Chester diseases) and lymphocytic hypophysitis.

ACTH silent adenoma shrinking under cabergoline

OBJECTIVES

The authors present a case report that proposes the use of cabergoline treatment in silent ACTH adenoma, an unusual member of the heterogeneous group of the so-called clinically non-functioning pituitary adenomas.

DESIGN

Following the clinical and radiological improvement of a recurrent silent ACTH adenoma in a 77-year-old patient treated with cabergoline (0.5 mg every 2 days for 2 years), in vitro studies of the original tumor were performed.

METHODS

The original tumor from the patient was studied by in situ hybridization and dopamine D2 receptor autoradiography. It was compared with four macroprolactinomas and two macroadenomas from patients with Cushing's disease.

RESULTS

The D2 receptor mRNA signal of the reported case was intense and of the same order of magnitude as that observed in control prolactinomas. Dopamine D2 receptor autoradiography was twice that of control corticotroph adenomas and was close to that observed in prolactinomas.

CONCLUSIONS

This is the first description of an in vivo shrinkage of an ACTH silent adenoma under cabergoline. We demonstrate in vitro, the presence of D2 receptors in the primitive tumor in concentrations similar to those found in control prolactinomas. These results suggest that therapeutic trials with cabergoline might be undertaken in recurring cases of ACTH silent tumors and more generally, non-functioning pituitary adenomas.

[Primary hyperparathyroidism: etiology, diagnosis and treatment]

Primary hyperparathyroidism is a not so infrequent disease that is often overlooked by physicians. Its incidence is estimated to be about 28 in 100.000 subjects, mainly women over seventy years old. Three to four percents of women over seventy are affected. Hyperparathyroidism can be isolated or be a component of a more complex syndrome like multiple endocrine neoplasms (MEN). Patients can be asymptomatic or present with symptoms like asthenia, hypertension or nephrolithiasis. The biological investigation requires the combined measurements of plasmatic ionized calcium and parathormone. In some cases, more specific explorations like calcium loading tests have to be performed in order to confirm the diagnosis.

[Pituitary pathology and MEN 1]

Multiple Endocrine Neoplasia type 1 (MEN 1) is an autosomal dominant syndrome characterized by neoplasia of the parathyroid glands, the endocrine pancreas and the anterior pituitary gland. Recently the identification on chromosome 11 (locus q13) of the gene responsible for MEN 1 has allowed direct genetic diagnosis of MEN 1-affected family members. To date almost 300 families have been described and genetically characterized. The genetic etiology of most pituitary tumours remains unknown. Pituitary adenomas can develop sporadically or as a part of multiple endocrine neoplasia type 1. In this review, the recently published data on the pathology of the MEN 1 syndrome will be summarized. The clinical, morphological and genetic aspects of sporadic and MEN 1-associated pituitary adenomas will be outlined.

Mutation analysis of the MEN1 gene in Belgian patients with multiple endocrine neoplasia type 1 and related diseases

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in parathyroids, enteropancreatic endocrine tissues, anterior pituitary, and other tissues. The gene for MEN1 has recently been cloned and shown to code for a 610-amino acid protein of enigmatic function which probably acts as a tumor suppressor. Several mutations causing the MEN1 phenotype have been recently identified. In order to determine the spectrum of MEN1 gene mutations in a sample of 25 Belgian patients, we have systematically screened the 10 exons and adjacent sequences of the MEN1 gene by means of an automatic sequencing protocol. Twelve different mutations were identified including nonsense, frameshift, splicing, and missense mutations. Two of these mutations (D172Y and 357del4) occurred more than once. A missense mutation was also found in a kindred with familial hyperparathyroidism. We observed no significant correlation between the nature or position of mutation and the clinical status. We have also detected 6 intragenic polymorphisms and DNA sequence variants and have analyzed their frequencies in our population.

Mechanical strain at the pisotriquetral joint

Pain and tenderness on the palmar and ulnar aspects of the wrist in the area of the pisiform bone is fairly common. Chronic pain in the pisiform area may be due to tendinitis of the insertion of the flexor carpi ulnaris, bony fractures or osteoarthrosis of pisotriquetral joint which is the second most common degenerative arthritis in wrist after the scaphotrapezial osteoarthrosis (Fischer, 1988, Radiologe 28:338-344). Subperiostal excision of pisiform bone is customarily performed after unsuccessful initial non-operative treatment (Carroll and Coyle, 1985, J. Hand Surg. 10:703-707; Johnston and Tonkin, 1986, Clin. Orthop. 210:137-142; Nüesch et al., 1993, Handchir. Mikrochir. Plast. Chir. 25:42-45). Although the postoperative results seem to be rather good, possible malfunction based on excision has not been considered previously by investigators. The aim of this study was to improve our understanding of the role of the pisiform and the pisotriquetral joint in the transfer of forces within the carpus. In a first part we examined 112 pisotriquetral joints by qualitative, quantitative and densitometrical analysis of joint surfaces. Secondly, mechanical tests were performed to investigate the distribution of forces within pisiform and the pisotriquetral joint. The results demonstrate that the pisiform mechanically contributes to the stability of the ulnar column of the wrist. The pisiform, and its unique anatomical holding mechanism, discharges two main functions. It holds the triquetrum in a correct position and prevents its subluxation even in extreme extension. Furthermore, it acts as a fulcrum (hypomochlion) while transducing powerful forearm forces to the hand. The excision of pisiform should be reconsidered.

[An immunologic etiology for hyperprolactinemia: macroprolactinemia]

Besides classical etiologies of hyperprolactinaemia (pregnancy, pharmacological treatments, pituitary or hypothalamic perturbations), another less known cause may explain a spectacular idiopathic elevation of plasma concentrations of prolactin hormone. Macroprolactinaemia is characterized by the presence of a circulating high molecular weight complex of prolactin with an immunoglobulin G. In this article, we report the cases of 3 female patients for whom size exclusion chromatography technique permitted to give a precise biological diagnosis and to avoid heavy, expensive, time consuming and unnecessary clinical investigations or therapeutic actions. Patients with macroprolactinaemia do not exhibit clinical features of classical hyperprolactinaemia, notably as regard to menstrual and fertility disturbances.

[Therapeutic controversies: the treatment of Graves' disease]

Hyperthyroidism is a common clinical condition with an annual incidence of about 1%. Approximately, 1 in every 20 women will develop this condition during a lifetime. Most cases are due to Graves'disease. Solitary toxic nodules and toxic multinodular goiters are also important but less frequent causes. In this article, we will consider only the treatment of Graves'disease. Anti-thyroid drugs, surgery and radio-iodine, all represent effective forms of treatment. There is, however, little consensus regarding the treatment of choice for specific cases. This article discusses the advantages and disadvantages of each treatment.

Cabergoline in the treatment of hyperprolactinemia: a study in 455 patients

Cabergoline is a new long-acting dopamine agonist that is very effective and well tolerated in patients with pathological hyperprolactinemia. The aim of this study was to examine, in a very large number of hyperprolactinemic patients, the ability to normalize PRL levels with cabergoline, to determine the effective dose and tolerance, and to assess the effect on clinical symptoms, tumor shrinkage, and visual field abnormalities. We also evaluated the effects of cabergoline in a large subgroup of patients with bromocriptine intolerance or -resistance. We retrospectively reviewed the files of 455 patients (102 males and 353 females) with pathological hyperprolactinemia treated with cabergoline in 9 Belgian centers. Among these patients, 41% had a microadenoma; 42%, a macroadenoma; 16%, idiopathic hyperprolactinemia; and 1%, an empty sella. The median pretreatment serum PRL level was 124 microg/L (range, 16-26,250 microg/L). A subgroup of 292 patients had previously been treated with bromocriptine, of which 140 showed bromocriptine intolerance and 58 showed bromocriptine resistance. Treatment with cabergoline normalized serum PRL levels in 86% of all patients: in 92% of 244 patients with idiopathic hyperprolactinemia or a microprolactinoma and in 77% of 181 macroadenomas. Pretreatment visual field abnormalities normalized in 70% of patients, and tumor shrinkage was seen in 67% of cases. Side effects were noted in 13% of patients, but only 3.9% discontinued therapy because of side effects. The median dose of cabergoline at the start of therapy was 1.0 mg/week but could be reduced to 0.5 mg/week once control was achieved. Patients with a macroprolactinoma needed a higher median cabergoline dose, compared with those with idiopathic hyperprolactinemia or a microprolactinoma: 1.0 mg/week vs. 0.5 mg/week, although a large overlap existed between these groups. Twenty-seven women treated with cabergoline became pregnant, and 25 delivered a healthy child. One patient had an intended abortion and another a miscarriage. In the patients with bromocriptine intolerance, normalization of PRL was reached in 84% of cases, whereas in the bromocriptine-resistant patients, PRL could be normalized in 70%. We confirmed, in a large-scale retrospective study, the high efficacy and tolerability of cabergoline in the treatment of pathological hyperprolactinemia, leaving few patients with unacceptable side effects or inadequate clinical response. Patients with idiopathic hyperprolactinemia or a microprolactinoma, on average, needed only half the dose of cabergoline as those with macroprolactinomas and have a higher chance of obtaining PRL normalization. Cabergoline also normalized PRL in the majority of patients with known bromocriptine intolerance or -resistance. Once PRL secretion was adequately controlled, the dose of cabergoline could often be significantly decreased, which further reduced costs of therapy.