Transient efficacy of octreotide and pasireotide (SOM230) treatment in GIP-dependent Cushing's syndrome

Clinical, pathophysiologic, genetic and therapeutic progress in Primary Bilateral Macronodular Adrenal Hyperplasia

Patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) usually present bilateral benign adrenocortical macronodules at imaging and variable levels of cortisol excess. PBMAH is a rare cause of primary overt Cushing's syndrome, but may represent up to one third of bilateral adrenal incidentalomas with evidence of cortisol excess. The increased steroidogenesis in PBMAH is often regulated by various G-protein coupled receptors aberrantly expressed in PBMAH tissues; some receptor ligands are ectopically produced in PBMAH tissues creating aberrant autocrine/paracrine regulation of steroidogenesis. The bilateral nature of PBMAH and familial aggregation, led to the identification of germline heterozygous inactivating mutations of the ARMC5 gene, in 20-25% of the apparent sporadic cases and more frequently in familial cases; ARMC5 mutations/pathogenic variants can be associated with meningiomas. More recently, combined germline mutations/pathogenic variants and somatic events inactivating the KDM1A gene were specifically identified in patients affected by GIP-dependent PBMAH. Functional studies demonstrated that inactivation of KDM1A leads to GIP-receptor (GIPR) overexpression and over or down-regulation of other GPCRs. Genetic analysis is now available for early detection of family members of index cases with PBMAH carrying identified germline pathogenic variants. Detailed biochemical, imaging, and co-morbidities assessment of the nature and severity of PBMAH is essential for its management. Treatment is reserved for patients with overt or mild cortisol/aldosterone or other steroid excesses taking in account co-morbidities. It previously relied on bilateral adrenalectomy; however recent studies tend to favor unilateral adrenalectomy, or less frequently, medical treatment with cortisol synthesis inhibitors or specific blockers of aberrant GPCR.

Current approach of primary bilateral adrenal hyperplasia

PURPOSE OF REVIEW

To discuss the most recent findings on the pathophysiology, the genetic and molecular causes of primary bilateral adrenal hyperplasia (PBAH). The diagnostic approach of patients with PBAH will also be presented in detail with an emphasis on the emerging diagnostic tools and finally, the treatment of PBAH will be discussed with an emphasis on the newest surgical and medical treatment approaches.

RECENT FINDINGS

PBAH is a highly heterogeneous condition mostly detected incidentally on abdominal imaging. Based on the size of the nodules, PBAH is subdivided into primary bilateral macronodular adrenal hyperplasia (PBMAH) and micronodular adrenal hyperplasia. A substantial proportion of patients with PBMAH harbor a germline mutation of the armadillo repeat containing 5 tumor suppression gene and therefore genetic testing is strongly recommended. Measurements of plasma or urinary multisteroid profiles show promising results in that PBMAH has a distinctive plasma steroid fingerprint that can help in diagnosis and subtyping of PBMAH. Finally, although surgery is the mainstay of treatment of patients with PBAH, medical therapy is increasingly emerging as an alternative option.

SUMMARY

PBAH is a poorly studied and therefore a challenging disease to diagnose and treat. Hopefully with these newest diagnostic and therapeutic tools, a more comprehensive approach will be adopted.

Cushing´s syndrome due to bilateral adrenal cortical disease: Bilateral macronodular adrenal cortical disease and bilateral micronodular adrenal cortical disease

Cushing´s syndrome (CS) secondary to bilateral adrenal cortical disease may be caused by bilateral macronodular adrenal cortical disease (BMACD) or by bilateral micronodular adrenal cortical disease (miBACD). The size of adrenal nodules is a key factor for the differentiation between these two entities (>1cm, BMACD and <1cm; miBACD). BMACD can be associated with overt CS, but more commonly it presents with autonomous cortisol secretion (ACS). Surgical treatment of BMACD presenting with CS or with ACS and associated cardiometabolic comorbidities should be the resection of the largest adrenal gland, since it leads to hypercortisolism remission in up to 95% of the cases. Medical treatment focused on the blockade of aberrant receptors may lead to hypercortisolism control, although cortisol response is frequently transient. miBACD is mainly divided in primary pigmented nodular adrenocortical disease (PPNAD) and isolated micronodular adrenocortical disease (i-MAD). miBACD can present at an early age, representing one of the main causes of CS at a young age. The high-dose dexamethasone suppression test can be useful in identifying a paradoxical increase in 24h-urinary free cortisol, that is a quite specific in PPNAD. Bilateral adrenalectomy is generally the treatment of choice in patients with overt CS in miBACD, but unilateral adrenalectomy could be considered in cases with asymmetric disease and mild hypercortisolism. This article will discuss the clinical presentation, genetic background, hormonal and imaging features and treatment of the main causes of primary bilateral adrenal hyperplasia associated with hypercortisolism.

Bilateral Adrenal Hyperplasia: Pathogenesis and Treatment

Bilateral adrenal hyperplasia is a rare cause of Cushing’s syndrome. Micronodular adrenal hyperplasia, including the primary pigmented micronodular adrenal dysplasia (PPNAD) and the isolated micronodular adrenal hyperplasia (iMAD), can be distinguished from the primary bilateral macronodular adrenal hyperplasia (PBMAH) according to the size of the nodules. They both lead to overt or subclinical CS. In the latter case, PPNAD is usually diagnosed after a systematic screening in patients presenting with Carney complex, while for PBMAH, the diagnosis is often incidental on imaging. Identification of causal genes and genetic counseling also help in the diagnoses. This review discusses the last decades’ findings on genetic and molecular causes of bilateral adrenal hyperplasia, including the several mechanisms altering the PKA pathway, the recent discovery of ARMC5, and the role of the adrenal paracrine regulation. Finally, the treatment of bilateral adrenal hyperplasia will be discussed, focusing on current data on unilateral adrenalectomy.

Role of unilateral adrenalectomy in bilateral adrenal hyperplasias with Cushing's syndrome

Primary bilateral adrenocortical hyperplasias are rare forms of pituitary ACTH-independent Cushing's syndrome (CS). They are divided between primary bilateral macronodular adrenal hyperplasia (PBMAH) and micronodular adrenal hyperplasia (MiBAH), which is subdivided in primary pigmented nodular adrenocortical disease (PPNAD) and isolated micronodular adrenocortical disease (i-MAD). One of the most debated aspects surrounding these entities is their most appropriate therapy. Although bilateral adrenalectomy (BA) has previously been the most utilized therapy for patients with overt CS, recent studies have indicated that unilateral adrenalectomy (UA) can be effective in patients with PBMAH and some with MiBAH with fewer long-term side effects. Medical therapies can also be used for bridging to surgery or rarely in the long-term for these patients. We review the various degrees of CS resulting from PBMAH and MiBAH, with a special focus on their respective therapies including UA, taking into account the recent pathophysiological and genetics findings.

Adrenally Directed Medical Therapies for Cushing Syndrome

CONTEXT

Endogenous Cushing syndrome (CS) is characterized by excess cortisol secretion, which is driven by tumorous secretion of corticotropin in the majority of patients. Untreated, CS results in substantial morbidity and mortality. Tumor-directed surgery is generally the first-line therapy for CS. However, hypercortisolism may persist or recur postoperatively; in other cases, the underlying tumor may not be resectable or its location may not be known. Yet other patients may be acutely ill and require stabilization before definitive surgery. In all these cases, additional interventions are needed, including adrenally directed medical therapies.

EVIDENCE ACQUISITION

Electronic literature searches were performed to identify studies pertaining to adrenally acting agents used for CS. Data were abstracted and used to compile this review article.

EVIDENCE SYNTHESIS

Adrenally directed medical therapies inhibit one or several enzymes involved in adrenal steroidogenesis. Several adrenally acting medical therapies for CS are currently available, including ketoconazole, metyrapone, osilodrostat, mitotane, and etomidate. Additional agents are under investigation. Drugs differ with regards to details of their mechanism of action, time course of pharmacologic effect, safety and tolerability, potential for drug-drug interactions, and route of administration. All agents require careful dose titration and patient monitoring to ensure safety and effectiveness, while avoiding hypoadrenalism.

CONCLUSIONS

These medications have an important role in the management of CS, particularly among patients with persistent or recurrent hypercortisolism postoperatively or those who cannot undergo tumor-directed surgery. Use of these drugs mandates adequate patient instruction and close monitoring to ensure treatment goals are being met while untoward adverse effects are minimized.

The pathogenic role of the GIP/GIPR axis in human endocrine tumors: emerging clinical mechanisms beyond diabetes

The glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone produced in the gastrointestinal tract in response to nutrients. GIP has a variety of effects on different systems, including the potentiation of insulin secretion from pancreatic β-cells after food intake (i.e. incretin effect), which is probably the most important. GIP effects are mediated by the GIP receptor (GIPR), a G protein-coupled receptor expressed in several tissues, including islet β-cells, adipocytes, bone cells, and brain. As well as its involvement in metabolic disorders (e.g. it contributes to the impaired postprandial insulin secretion in type 2 diabetes (T2DM), and to the pathogenesis of obesity and associated insulin resistance), an inappropriate GIP/GIPR axis activation of potential diagnostic and prognostic value has been reported in several endocrine tumors in recent years. The ectopic GIPR expression seen in patients with overt Cushing syndrome and primary bilateral macronodular adrenal hyperplasia or unilateral cortisol-producing adenoma has been associated with an inverse rhythm of cortisol secretion, with low fasting morning plasma levels that increase after eating. On the other hand, most acromegalic patients with an unusual GH response to oral glucose suppression have GIPR-positive somatotropinomas, and a milder phenotype, and are more responsive to medical treatment. Neuroendocrine tumors are characterized by a strong GIPR expression that may correlate positively or inversely with the proliferative index MIB-1, and that seems an attractive target for developing novel radioligands. The main purpose of this review is to summarize the role of the GIP/GIPR axis in endocrine neoplasia, in the experimental and the clinical settings.

Mifepristone Treatment in Four Cases of Primary Bilateral Macronodular Adrenal Hyperplasia (BMAH)

CONTEXT

Primary bilateral macronodular adrenal hyperplasia (BMAH) is a rare form of adrenal Cushing syndrome conventionally treated with adrenalectomy. Medical treatment is often reserved for patients not eligible for surgery. However, to date there have been few studies about the efficacy of mifepristone for the treatment of BMAH associated with hypercortisolism.

OBJECTIVE

To describe a series of patients with hypercortisolism due to BMAH treated with mifepristone from multiple medical practices.

DESIGN

We retrospectively assessed four patients treated with mifepristone for hypercortisolism due to BMAH who had either failed unilateral adrenalectomy, declined surgery, or were poor surgical candidates.

RESULTS

Mifepristone induced clinical improvement and remission of the signs and symptoms of hypercortisolism in all described patients with BMAH. The median treatment duration at the time of efficacy response assessment was 5 months (range: 3 to 18 months). Improvement in cardiometabolic parameters was observed as early as 2 weeks after treatment was started. All patients achieved improvements in glycemic control and hypertension and had significant weight loss. The most common adverse event observed with mifepristone therapy was fatigue. Increases in TSH level occurred in two patients.

CONCLUSION

Mifepristone can be an effective medical alternative to surgery in patients with hypercortisolism due to BMAH.

Study of abnormal adrenal receptors in subjects with ACTH-independent Cushing's syndrome and nodular adrenal hyperplasia

INTRODUCTION

ACTH-independent Cushing's Syndrome (AICS) accounts for 15-20% of cases of Cushing's syndrome, with <1% due to abnormal receptors. Our aim is to study the presence of abnormal receptors in subjects diagnosed with AICS with nodular adrenal hyperplasia in a 14-year period (2002-2016), as well as its clinical-biological and evolutive characteristics.

MATERIAL AND METHODS

A multicentre descriptive study of a 15-case series of AICS with nodular adrenal hyperplasia (study period: 2002-2016). In these cases, abnormal receptor screening was performed by means of stimulation tests, with a plasma cortisol increase of ≥ 25% from baseline being considered pathologic.

RESULTS

Of the 15 cases, 13 were female, with a mean age at diagnosis of 56.8 years. In 12 of the 15 cases studied, positivity was detected with stimulation tests, and, of them, 25% were positive for the meal test, 58.3% for posture walking test, 33.3% for desmopressin; 25% for terlipressin; 33.3% for GnRH; 25% for LH and 50% for metoclopramide. Regarding treatment, bilateral adrenalectomy was performed in 16.7% and unilateral adrenalectomy in 41.7%. The rest continue under observation with periodic follow-up (41.7%).

CONCLUSIONS

In most of the cases studied with AICS and nodular adrenal hyperplasia (80%), an abnormal cortisol response is detected due to the presence of abnormal receptors. The test with the highest percentage of positivity was the postural walking test (58.3%).

Hypermethylator Phenotype and Ectopic GIP Receptor in GNAS Mutation-Negative Somatotropinomas

CONTEXT

Besides GNAS gene mutations, the molecular pathogenesis of somatotroph adenomas responsible for gigantism and acromegaly remains elusive.

OBJECTIVE

To investigate alternative driver events in somatotroph tumorigenesis, focusing on a subgroup of acromegalic patients with a paradoxical increase in growth hormone (GH) secretion after oral glucose, resulting from ectopic glucose-dependent insulinotropic polypeptide receptor (GIPR) expression in their somatotropinomas.

DESIGN, SETTING, AND PATIENTS

We performed combined molecular analyses, including array-comparative genomic hybridization, RNA/DNA fluorescence in situ hybridization, and RRBS DNA methylation analysis on 41 somatotropinoma samples from 38 patients with acromegaly and three sporadic giants. Ten patients displayed paradoxical GH responses to oral glucose.

RESULTS

GIPR expression was detected in 13 samples (32%), including all 10 samples from patients with paradoxical GH responses. All GIPR-expressing somatotropinomas were negative for GNAS mutations. GIPR expression occurred through transcriptional activation of a single allele of the GIPR gene in all GIPR-expressing samples, except in two tetraploid samples, where expression occurred from two alleles per nucleus. In addition to extensive 19q duplications, we detected in four samples GIPR locus microamplifications in a certain proportion of nuclei. We identified an overall hypermethylator phenotype in GIPR-expressing samples compared with GNAS-mutated adenomas. In particular, we observed hypermethylation in the GIPR gene body, likely driving its ectopic expression.

CONCLUSIONS

We describe a distinct molecular subclass of somatotropinomas, clinically revealed by a paradoxical increase of GH to oral glucose related to pituitary GIPR expression. This ectopic GIPR expression occurred through hypomorphic transcriptional activation and is likely driven by GIPR gene microamplifications and DNA methylation abnormalities.

Clinical Characteristics of Acromegalic Patients With Paradoxical GH Response to Oral Glucose Load

CONTEXT

A paradoxical GH response to oral glucose (OG) is often found in acromegaly. However, the clinical characteristics of patients with acromegaly and a paradoxical GH response to OG (OG responders) remain unclear.

OBJECTIVE

The aim of the present study was to define the clinical characteristics of OG responders with acromegaly.

DESIGN

Retrospective study.

SETTING

Hospitalized care at Osaka University Hospital.

PATIENTS AND METHODS

Of 63 patients with acromegaly admitted to our hospital from January 2006 to January 2017, 19 were classified as OG responders and 44 as nonresponders. The clinical characteristics of these groups were compared.

RESULTS

Before surgery, OG responders had substantially greater IGF-1 SD scores than nonresponders (P < 0.05), although no difference was found in basal GH levels between the two groups (P = 0.46). Regarding glucose metabolism, 120-minute plasma glucose and immunoreactive insulin after OG administration and hemoglobin A1c were significantly greater in OG responders than in nonresponders (P < 0.01, P < 0.05, P < 0.05, respectively). GH levels during octreotide or bromocriptine testing were decreased more significantly in OG responders than in nonresponders (P < 0.05, P < 0.05, respectively). The proportion of pituitary tumors with hypointensity on T2-weighted MRI was significantly greater in OG responders than in nonresponders (P < 0.05). The difference in IGF-1 and parameters of glucose metabolism described disappeared between the two groups after surgery.

CONCLUSIONS

The paradoxical GH response reflected the clinical characteristics, especially IGF-I level, glucose metabolism, and drug efficacy in acromegaly. A paradoxical GH response, in addition to the nadir GH levels, to OG load is potentially useful for evaluation of the clinical characteristics of acromegaly.

Advances in the medical treatment of Cushing's syndrome

Cushing's syndrome is associated with multisystem morbidity and, when suboptimally treated, increased mortality. Medical therapy is an option for patients if surgery is not successful and can be classified into pituitary-directed drugs, steroid synthesis inhibitors, and glucocorticoid receptor antagonists. In the last decade there have been new developments in each drug category. Targeting dopamine and somatostatin receptors on corticotroph adenomas with cabergoline or pasireotide, or both, controls cortisol production in up to 40% of patients. Potential new targets in corticotroph adenomas include the epidermal growth factor receptor, cyclin-dependent kinases, and heat shock protein 90. Osilodrostat and levoketoconazole are new inhibitors of steroidogenesis and are currently being evaluated in multicentre trials. CORT125134 is a new selective glucocorticoid receptor antagonist under investigation. We summarise the drug therapies for various forms of Cushing's syndrome and focus on emerging drugs and drug targets that have the potential for new and effective tailor-made pharmacotherapy for patients with Cushing's syndrome.

Coexistence of Myelolipoma and Primary Bilateral Macronodular Adrenal Hyperplasia With GIP-Dependent Cushing's Syndrome

Introduction: Adrenal myelolipomas are usually isolated benign adrenal lesions, but can be adjacent to steroid-secreting adrenocortical tumors. We studied the aberrant regulation of cortisol secretion in a 61 year-old woman with combined bilateral myelolipomas and primary bilateral macronodular adrenal hyperplasia (BMAH) causing Cushing's syndrome. Materials and Methods: Cortisol response was measured during in vivo tests that transiently modulated the levels of ligands for potential aberrant receptors, including GIP. Response to medical therapies decreasing GIP was monitored. Expression of ACTH and of GIP receptors were examined in resected adrenal tissues by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Results: In vivo, cortisol increased in response to mixed meals (+353%), oral 75 g glucose (+71%), GIP infusion (+416%), and hLH IV (+243%). Suppression of GIP by pasireotide improved cortisol secretion but produced hyperglycemia. The left adrenal was predominantly composed of myelolipoma and strands of BMAH, while the right was mainly composed of BMAH with some foci of myelolipoma on pathology. No ACTH was detectable by immunohistochemistry in BMAH or myelolipomas tissue. Ectopic GIP receptor was confirmed by RT-PCR and immunohistochemistry in BMAH tissues but not in the myelolipomas. No germline mutations were identified in the ARMC5 gene of the patient's leucocyte DNA. Conclusion: This is the first report of interspersed myelolipoma and BMAH with GIP-dependent Cushing's syndrome. In contrast with the BMAH tissues, myelolipoma tissue did not express specific GIP receptors. The potential mechanisms responsible for the interspersed growth of those two lesions remain to be identified.

La chirurgie d’épargne surrénalienne : du cortex à la médulla

The 2017 Endocrine Society annual meeting included several communications and debates on the conservative adrenal surgery in bilateral hereditary pheochromocytomas (BHP), bilateral adrenal macronodular hyperplasia (BAMH) and primary hyperaldosteronism (PHA). The general principle is to preserve a part of the adrenal cortex to prevent the occurrence of a definitive adrenal insufficiency. In BHP, cortical sparing surgery allows more than 50% of patients to maintain normal corticotropic function at 10 years with a low recurrence rate (~ 10%). Since the adrenal medulla cannot be removed entirely, recurrence seems inevitable and long-term follow-up is essential. Individual risk of malignancy must be taken into account. In BAMH responsible for Cushing syndrome, unilateral adrenalectomy induces a normalization of urinary free cortisol in 92 to 100% of cases and even corticotropic insufficiency in 40 to 100% of cases. This is most often transient. Late recurrences of Cushing's syndrome may occur in 13 to 60% of cases. Prolonged patient monitoring is therefore essential. In PAH with lateralized aldosterone production, minimally invasive partial adrenal surgery, which consists of removing only the adrenal adenoma visualized at TDM, allows an improvement blood pressure in about 94% of patients. However, failure or recurrence may occur. Its place therefore remains marginal in the treatment of the lateralized PAHs.

Aberrant G-protein coupled hormone receptor in adrenal diseases

The regulation of cortisol or aldosterone production when ACTH of pituitary origin or the renin-angiotensin systems are suppressed in primary adrenal Cushing's syndrome or in primary aldosteronism is exerted by diverse genetic and molecular mechanisms. In addition to recently identified mutations in various genes implicated in the cyclic AMP or ion channel pathways, steroidogenesis is not really autonomous as it is frequently regulated by the aberrant adrenocortical expression of diverse hormone receptors, particularly G-protein coupled hormone receptors (GPCR) which can substitute for the normal function of ACTH or angiotensin-II. In addition, paracrine or autocrine production of ligands for the aberrant GPCR such as ACTH or serotonin is found in some adrenal tumors or hyperplasias and participates in a complex regulatory loop causing steroid excess. Targeted therapies to block the aberrant ligands or their receptors could become useful in the future, particularly for patients with bilateral source of steroid excess.

Successful Treatment of Estrogen Excess in Primary Bilateral Macronodular Adrenocortical Hyperplasia with Leuprolide Acetate

Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) is an uncommon cause of adrenal Cushing syndrome (CS) in which cortisol and occasionally other steroid hormones can be secreted under the influence of aberrantly expressed G-protein coupled receptors (GPCRs) in the adrenal cortex. We describe the unique case of a 64-year-old postmenopausal female with PBMAH whose adrenal lesions expressed luteinizing hormone receptors (LHr). She presented initially with CS and underwent right adrenalectomy; a few years later she presented with macromastia and mastodynia, possibly due to estrogen excess from her remaining left adrenocortical masses. Testing before and after treatment with quarterly leuprolide acetate therapy and immunohistochemistry on tissue and targeted sequencing of the genes of interest were performed. Tissue from the patient's right adrenal was tested for P450 aromatase (CYP19A1) and LHr expression; both were expressed throughout the hyperplastic cortex, although expression was more intense in the adenomatous areas. Targeted sequencing revealed a pathogenic PDE11A mutation, as well as variants in the ARMC5 and INHA genes. PDE11A expression was decreased in the adenoma but there was no loss of heterozygosity for the PDE11A locus. Because of the clinical presentation and LHr expression, quarterly leuprolide acetate therapy was started. Shortly after initiation of therapy, the patient reported decreased breast size and pain; she remains well controlled to date, after 10 years of treatment. This is the first description of a patient with PBMAH presenting with severe macromastia and mastodynia from what appears to be excess estrogen production from her adrenal tumor. The patient had a long-lasting response to chronic leuprolide acetate treatment, showing that drug therapy exploiting the aberrant receptor expression in PBMAH is possible even in the absence of cortisol overproduction.

Adrenal GIPR expression and chromosome 19q13 microduplications in GIP-dependent Cushing's syndrome

GIP-dependent Cushing's syndrome is caused by ectopic expression of glucose-dependent insulinotropic polypeptide receptor (GIPR) in cortisol-producing adrenal adenomas or in bilateral macronodular adrenal hyperplasias. Molecular mechanisms leading to ectopic GIPR expression in adrenal tissue are not known. Here we performed molecular analyses on adrenocortical adenomas and bilateral macronodular adrenal hyperplasias obtained from 14 patients with GIP-dependent adrenal Cushing's syndrome and one patient with GIP-dependent aldosteronism. GIPR expression in all adenoma and hyperplasia samples occurred through transcriptional activation of a single allele of the GIPR gene. While no abnormality was detected in proximal GIPR promoter methylation, we identified somatic duplications in chromosome region 19q13.32 containing the GIPR locus in the adrenocortical lesions derived from 3 patients. In 2 adenoma samples, the duplicated 19q13.32 region was rearranged with other chromosome regions, whereas a single tissue sample with hyperplasia had a 19q duplication only. We demonstrated that juxtaposition with cis-acting regulatory sequences such as glucocorticoid response elements in the newly identified genomic environment drives abnormal expression of the translocated GIPR allele in adenoma cells. Altogether, our results provide insight into the molecular pathogenesis of GIP-dependent Cushing's syndrome, occurring through monoallelic transcriptional activation of GIPR driven in some adrenal lesions by structural variations.

Multiple aberrant hormone receptors in Cushing's syndrome

The mechanisms regulating cortisol production when ACTH of pituitary origin is suppressed in primary adrenal causes of Cushing's syndrome (CS) include diverse genetic and molecular mechanisms. These can lead either to constitutive activation of the cAMP system and steroidogenesis or to its regulation exerted by the aberrant adrenal expression of several hormone receptors, particularly G-protein coupled hormone receptors (GPCR) and their ligands. Screening for aberrant expression of GPCR in bilateral macronodular adrenal hyperplasia (BMAH) and unilateral adrenal tumors of patients with overt or subclinical CS demonstrates the frequent co-expression of several receptors. Aberrant hormone receptors can also exert their activity by regulating the paracrine secretion of ACTH or other ligands for those receptors in BMAH or unilateral tumors. The aberrant expression of hormone receptors is not limited to adrenal CS but can be implicated in other endocrine tumors including primary aldosteronism and Cushing's disease. Targeted therapies to block the aberrant receptors or their ligands could become useful in the future.

Cushing's syndrome

Chronic exposure to excess glucorticoids results in diverse manifestations of Cushing's syndrome, including debilitating morbidities and increased mortality. Genetic and molecular mechanisms responsible for excess cortisol secretion by primary adrenal lesions and adrenocorticotropic hormone (ACTH) secretion from corticotroph or ectopic tumours have been identified. New biochemical and imaging diagnostic approaches and progress in surgical and radiotherapy techniques have improved the management of patients. The therapeutic goal is to normalise tissue exposure to cortisol to reverse increased morbidity and mortality. Optimum treatment consisting of selective and complete resection of the causative tumour is necessay to allow eventual normalisation of the hypothalamic-pituitary-adrenal axis, maintenance of pituitary function, and avoidance of tumour recurrence. The development of new drugs offers clinicians several choices to treat patients with residual cortisol excess. However, for patients affected by this challenging syndrome, the long-term effects and comorbidities associated with hypercortisolism need ongoing care.

An analysis of different therapeutic options in patients with Cushing's syndrome due to bilateral macronodular adrenal hyperplasia: a single-centre experience

CONTEXT

Bilateral macronodular adrenal hyperplasia (BMAH) is a rare form of Cushing's syndrome (CS). A variety of in vivo tests to identify aberrant receptor expression have been proposed to guide medical treatment. Unilateral adrenalectomy (UA) may be effective in selected patients, but little is known about recurrence during follow-up.

OBJECTIVE

To describe a series of patients with BMAH and CS treated by different approaches, with a particular focus on the benefit of UA.

DESIGN AND PATIENTS

We retrospectively assessed 16 patients with BMAH and CS (11 females, five males), analysing the in vivo cortisol response to different provocative tests. Twelve of the 16 patients underwent UA and were monitored over the long term.

RESULTS

Based on in vivo test results, octreotide LAR or propranolol was administered in one case of food-dependent CS and two patients with a positive postural test. A significant improvement in biochemical values was seen in all patients but with limited clinical response. UA was performed in 12 patients, producing long-term remission in three (106 ± 28 months; range: 80-135), recurrence in eight (after 54 ± 56 months; range 12-180) and persistence in one other. Four patients subsequently underwent contralateral adrenalectomy for overt CS, one received ketoconazole, and four other patients remain under observation for subclinical CS.

CONCLUSIONS

Medical treatment based on cortisol response to provocative tests had a limited role in our patients, whereas UA was useful in some of them. Although recurrence is likely, the timing of onset is variable and close follow-up is mandatory to identify it.

Long-term low-dose ketoconazole treatment in bilateral macronodular adrenal hyperplasia

Medical therapy for Cushing's syndrome due to bilateral macronodular adrenal hyperplasia (BMAH) is generally administered for a limited time before surgery. Aberrant receptors antagonists show inconsistent efficacy in the long run to prevent adrenalectomy. We present a patient with BMAH, treated for 10 years with low doses of ketoconazole to control cortisol secretion. A 48-year-old woman presented with headaches and hypertension. Investigations showed the following: no clinical signs of Cushing's syndrome; enlarged lobulated adrenals; normal creatinine, potassium, and aldosterone; normal urinary aldosterone and metanephrines; elevated urinary free cortisol and steroid metabolites; and suppressed plasma renin activity and ACTH. A screening protocol for aberrant adrenal receptors failed to show any illegitimate hormone dependence. Ketoconazole caused rapid normalisation of cortisol and ACTH that persists over 10 years on treatment, while adrenals show no change in shape or size. Ketoconazole decreases cortisol in patients with Cushing's syndrome, and may prevent adrenal overgrowth. Steroid secretion in BMAH is inefficient as compared with normal adrenals or secreting tumours and can be controlled with low, well-tolerated doses of ketoconazole, as an alternative to surgery.

Pasireotide monotherapy in Cushing's disease: a single-centre experience with 5-year extension of phase III Trial

PURPOSE

A recent phase III randomized controlled trial (NCT00434148) showed efficacy of pasireotide in the treatment of patients with Cushing's disease (CD). Patients were invited to participate in an extension phase of the protocol and a subgroup had a sustained response. We report the experience with 4 patients in our center of which 2 full responders have completed 5.5 and 4.25 years of treatment with disease control.

METHODS

The trial protocol was described previously. The extension phase consisted of 3-monthly visits with clinical, biochemical, and imaging evaluation and investigator-driven pasireotide titration. Research charts were retrospectively analyzed.

RESULTS

Four patients with persistent CD following pituitary surgery completed the first 6 months of the trial and 3 continued in the next 6 month open-label phase. Two patients with baseline urinary free cortisol (UFC) 5.3-6.7 times the upper limit of normal had a rapid sustained response to pasireotide and entered the extension phase after 12 months. They remain in clinical and biochemical disease remission and 1 patient now only requires 300 μg daily of pasireotide. All 4 patients developed glucose intolerance; however, the two patients in the extension phase were eventually able to discontinue all diabetes pharmacotherapy. Adverse events included second degree atrioventicular block type 1 without QT prolongation in a patient with pre-existing sinus bradycardia, and symptomatic cholelithiasis requiring cholecystectomy in a second patient.

CONCLUSIONS

Pasireotide therapy can provide normalization of UFC and of clinical symptoms and signs of CD during up to 5 years of follow-up. This study demonstrates the possible recuperation of normoglycemia after continued use of pasireotide and control of underlying hypercortisolemia. Longer-term monitoring for potential adverse events related to continued use of pasireotide is indicated.

Primary bilateral macronodular adrenal hyperplasia

PURPOSE OF REVIEW

Primary bilateral macronodular adrenal hyperplasia is a rare cause of Cushing's syndrome and is more often diagnosed as bilateral adrenal incidentalomas with subclinical cortisol production. We summarize the recent insights concerning its epidemiology, diagnosis, genetics, pathophysiology, and therapeutic options.

RECENT FINDINGS

Recent publications have modified our notions on the genetics and pathophysiology of bilateral macronodular adrenal hyperplasia. Combined germline and somatic mutations of armadillo repeat containing 5 gene were identified in familial cases, in approximately 50% of apparently sporadic cases and in the relatives of index cases; genetic testing should allow early diagnosis in the near future. The recent finding of ectopic adrenocortical production of adrenocorticotropic hormone in clusters of bilateral macronodular adrenal hyperplasia tissues and its regulation by aberrant hormone receptors opens new horizons for eventual medical therapy using melanocortin-2 receptor and G-protein-coupled receptor antagonists. Finally, some medical and surgical treatments have been updated.

SUMMARY

Recent findings indicate that bilateral macronodular adrenal hyperplasia is more frequently genetically determined than previously believed. Considering the role of paracrine adrenocorticotropic hormone production on cortisol secretion, the previous nomenclature of adrenocorticotropic hormone-independent macronodular adrenal hyperplasia appears inappropriate, and this disease should now be named primary bilateral macronodular adrenal hyperplasia.

Management of malignant insulinoma

AIM

Malignant insulinoma is an infrequent functional endocrine tumor of the pancreas. Adequate therapy is a demanding challenge for oncologists and endocrinologists.

OBJECTIVE

To evaluate the results of multidisciplinary management of malignant insulinoma.

MATERIALS AND METHODS

Retrospective review of patients with malignant insulinoma treated from 1995 to 2011.

RESULTS

Seven patients with malignant insulinoma were included: four males and three females; median age was 61.8 years (range 37-78). Six tumors were sporadic and one was diagnosed in a patient with a type 1 multiple endocrine neoplasia (MEN-1). Surgery was performed in six cases and one patient was considered unresectable. Hypoglycemias persisted in all cases and somatostatin analogs, glucocorticoids and diazoxide were used. Two patients received everolimus. Other techniques were chemoembolization and internal radiation therapy with yttrium-90. Successful liver transplant was done in the patient with MEN-1.

CONCLUSION

Hypoglycemia management is complex and requires multiple therapies. Further evaluations will be necessary to determine the best treatment.

Diabetes in Cushing syndrome: basic and clinical aspects

Diabetes mellitus is a frequent complication of Cushing syndrome (CS) which is caused by chronic exposure to glucocorticoid excess, either endogenous or exogenous, and that is characterized by several clinical symptoms such as central obesity, purple striae, proximal muscle weakness, acne, hirsutism and neuropsychological disturbances. Diabetes occurs as a consequence of an insulin-resistant state together with impaired insulin secretion which are induced by glucocorticoid excess. The management of patients with CS and diabetes mellitus includes the treatment of hyperglycemia and, when possible, the correction of glucocorticoid excess. This review focuses on the disorders of glucose metabolism in patients exposed to glucocorticoid excess, addressing both the pathophysiological aspects and the clinical and therapeutic implications.