Somatostatin analogs in ectopic corticotropin production

The Mount Sinai Clinical Pathway for the Diagnosis and Management of Hypercortisolism due to Ectopic ACTH Syndrome

Neoplasms that secrete ectopic ACTH may cause severe, life-threatening hypercortisolism. These tumors are often difficult to localize and treat, requiring a comprehensive and systematic management plan orchestrated by a multidisciplinary team. The Mount Sinai Adrenal Center hosted an interdisciplinary retreat of experts in adrenal disorders and neuroendocrine tumors with the aim of developing a clinical pathway for the management of Cushing syndrome due to ectopic ACTH production. The result was institutional recommendations for the diagnosis, localization, surgical approaches to intrathoracic tumors and bilateral adrenalectomy, perioperative and postoperative medical management of hypercortisolism and its sequelae. Specific recommendations were made regarding the timing and selection of therapies based on the considerations of our team as well as a review of the current literature. Our clinical pathway can be applied by other institutions directly or serve as a guide for institution-specific management.

Challenging Case of Ectopic ACTH Secretion from Prostate Adenocarcinoma

Cushing’s syndrome (CS) secondary to ectopic adrenocorticotrophic hormone (ACTH)-producing prostate cancer is rare with less than 50 cases reported. The diagnosis can be challenging due to atypical and variable clinical presentations of this uncommon source of ectopic ACTH secretion. We report a case of Cushing’s syndrome secondary to prostate adenocarcinoma who presented with symptoms of severe hypercortisolism with recurrent hypokalaemia, limb oedema, limb weakness, and sepsis. He presented with severe hypokalaemia and metabolic alkalosis (potassium 2.5 mmol/L and bicarbonate 36 mmol/L), with elevated 8 am cortisol 1229 nmol/L. ACTH-dependent Cushing’s syndrome was diagnosed with inappropriately normal ACTH 57.4 ng/L, significantly elevated 24-hour urine free cortisol and unsuppressed cortisol after 1 mg low-dose, 2-day low-dose, and 8 mg high-dose dexamethasone suppression tests. 68Ga-DOTANOC PET/CT showed an increase in DOTANOC avidity in the prostate gland, and his prostate biopsy specimen was stained positive for ACTH and markers for neuroendocrine differentiation. He was started on ketoconazole, which was switched to IV octreotide in view of liver dysfunction from hepatic metastases. He eventually succumbed to the disease after 3 months of his diagnosis. It is imperative to recognize prostate carcinoma as a source of ectopic ACTH secretion as it is associated with poor clinical outcomes, and the diagnosis can be missed due to atypical clinical presentations.

Mifepristone Improves Octreotide Efficacy in Resistant Ectopic Cushing's Syndrome

A 30-year-old Caucasian man presented with severe Cushing's syndrome (CS) resulting from ectopic adrenocorticotropin syndrome (EAS) from a metastatic pancreatic neuroendocrine tumor. The patient remained hypercortisolemic despite treatment with steroidogenesis inhibitors, chemotherapy, and octreotide long-acting release (LAR) and was enrolled in a 24-week, phase 3 clinical trial of mifepristone for inoperable hypercortisolemia. After mifepristone was added to ongoing octreotide LAR treatment, EAS symptoms essentially resolved. Cortisol decreased dramatically, despite mifepristone's competitive glucocorticoid receptor antagonist effects. The clinical and biochemical effects reversed upon mifepristone discontinuation despite the continued use of octreotide LAR therapy. Substantial improvement in octreotide LAR efficacy with mifepristone use was noted in this patient with ectopic CS, consistent with upregulation of somatostatin receptors previously downregulated by hypercortisolemia.

Treatment of Cushing's Syndrome: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for treating Cushing's syndrome.

PARTICIPANTS

Participants include an Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. The European Society for Endocrinology co-sponsored the guideline.

EVIDENCE

The Task Force used the Grading of Recommendations, Assessment, Development, and Evaluation system to describe the strength of recommendations and the quality of evidence. The Task Force commissioned three systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

The Task Force achieved consensus through one group meeting, several conference calls, and numerous e-mail communications. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines.

CONCLUSIONS

Treatment of Cushing's syndrome is essential to reduce mortality and associated comorbidities. Effective treatment includes the normalization of cortisol levels or action. It also includes the normalization of comorbidities via directly treating the cause of Cushing's syndrome and by adjunctive treatments (eg, antihypertensives). Surgical resection of the causal lesion(s) is generally the first-line approach. The choice of second-line treatments, including medication, bilateral adrenalectomy, and radiation therapy (for corticotrope tumors), must be individualized to each patient.

Hormonal secretion and quality of life in Nelson syndrome and Cushing disease after long acting repeatable octreotide: a short series and update

Clinical management of persistent adrenocorticotropin hormone (ACTH) excess in Nelson syndrome (NS) and Cushing disease (CD) remains a challenge. Somatostatin and its analogs as octreotide decrease ACTH secretion through somatostatin receptors of pituitary cells. To our knowledge, there are no reports on the effect of long-acting repeatable octreotide (oct-lar) on hormonal secretion and quality of life in patients with NS and CD who failed conventional therapy. Herein, we describe the effects of treatment with oct-lar (20 mg/month intramurally) in 1 woman with NS and 2 women with persistent CD. Oct-lar therapy reduced ACTH secretion and improved the quality of life in NS patient. By contrast, in CD patients, it failed to control ACTH and cortisol secretion, and the quality of life remained unchanged.

A new therapeutic approach in the medical treatment of Cushing's syndrome: glucocorticoid receptor blockade with mifepristone

OBJECTIVE

Cushing's syndrome (CS) is a serious endocrine disorder caused by prolonged exposure to high cortisol levels. Initial treatment of this condition is dependent upon the cause, but is generally surgical. For patients whose hypercortisolism is not cured by surgery, medical therapy is often required. Drugs that have typically been used for CS medical therapy act by decreasing cortisol levels. Mifepristone is a glucocorticoid receptor antagonist now available for use in patients with CS. Unlike other agents, mifepristone does not decrease cortisol levels, but directly antagonizes its effects. Our objective is to review the pharmacology and clinical use of this novel agent and to discuss detailed guidance on the management of CS patients treated with mifepristone.

METHODS

We review the literature regarding mifepristone use in CS and recently published clinical trial data. Detailed information related to clinical assessment of mifepristone use, potential drug interactions, drug initiation and dose titration, and monitoring of drug tolerability are provided.

RESULTS

Clinical trial data have shown that mifepristone improves glycemic control and blood pressure, causes weight loss and a decrease in waist circumference, lessens depression, and improves overall wellbeing. However, adverse effects include adrenal insufficiency, hypokalemia, and endometrial thickening with vaginal bleeding. These findings are supported by the earlier literature case reports.

CONCLUSION

This article provides a review of the pharmacology and clinical use of mifepristone in Cushing's syndrome, as well as detailed guidance on the management of patients treated with this novel agent.

A rare case of Cushing syndrome by cyclic ectopic-ACTH

ACTH-dependent Cushing syndrome (CS) due to ectopic ACTH production is most times difficult to manage. The identification of the source of ACTH may take many years. Surgery or chemotherapy for the primary tumor is not always possible. Control of Cushing symptoms is many times achieved using medication, or bilateral adrenalectomy in refractory cases. This case presents a Brazilian male who showed severe hypertension, mood changes, muscle weakness, darkening of skin, and increased abdominal fat. An investigation for Cushing syndrome was carried out and, after a four-year follow-up, a carotid glomus tumor (chemodectoma) was confirmed, a rare ectopic ACTH-producing tumor. Besides, the patient presented cyclic Cushing syndrome that was exacerbated by diverticulitis episodes. This case presents interesting pitfalls on diagnosis and management of ACTH-dependent CS. This is the only report of a chemodectoma that produced ACTH in the literature.

Practical guide to supportive care of patients with functional neuroendocrine tumors

Supportive care of patients with functional neuroendocrine tumors (NETs) has evolved to include the use of multiple targeted agents to control paraneoplastic states and newer surgical and interventional radiologic techniques to reduce tumor bulk. Challenges encountered by the clinician are the recognition of specific symptom complexes, selecting the relevant laboratory tests and radiologic/scintigraphic scans, and the timing of intervention(s). Individual variables such as the severity of symptoms in the context of primary and metastatic disease sites, tumor bulk, comorbidities, and previous treatment are factors determining the prioritization of specific treatment regimens for patients with functional NETs. Symptoms such as flushing, secretory diarrhea, hypercalcemia, hyper /hypoglycemia, hypercortisolism, and peptic ulcers should improve with decreasing the elevated amino acid and/or peptide levels produced by NETs. These paraneoplastic symptoms may be accompanied by complaints related to tumor burden such as fatigue, pain, early satiety, anorexia, weight loss, night sweats, and/or symptoms secondary to adverse drug effects such as mucositis, dysgeusia, diarrhea, rash, hypertension, and myelosuppression. Developing a comprehensive continuum of care plan early in disease management assists in controlling the presenting signs and symptoms, and in minimizing disease- and/or treatment-related side effects. This guide serves as a framework to manage the signs and symptoms of metastatic functional neuroendocrine tumors.

Neuroendocrine tumors presenting with thyroid gland metastasis: a case series

Introduction

Autopsy series have shown that metastasis to the thyroid gland has occurred in up to 24% of patients who have died of cancer. Neuroendocrine tumors may metastasize to thyroid gland.

Case presentations

Case 1 was a 17-year-old Turkish woman who was referred from our Endocrinology Department for a thyroidectomy for treatment of neuroendocrine tumor metastasis. She was treated with a bilateral total thyroidectomy. Histopathological examination results were consistent with a neuroendocrine tumor; neoplastic cells showed strong immunoreactivity to chromogranin A and synaptophysin, but the immunohistochemical profile was inconsistent with medullary thyroid carcinoma in that the tumor was negative for calcitonin, carcinoembryonic antigen, and thyroid transcription factor-1.

Case 2 was a 54-year-old Turkish woman who presented with a 3-cm nodule on her right thyroid lobe. She had undergone surgery for a right lung mass four years previously. After a right pneumonectomy, thymectomy and lymph node dissection, a typical carcinoid tumor was diagnosed. Under ultrasonographic guidance, fine needle aspiration biopsy of her right thyroid pole nodule was performed and the biopsy was compatible with a neuroendocrine tumor metastasis. She was treated with a bilateral total thyroidectomy. Histopathological examination indicated three nodular lesions, 5 cm and 0.4 cm in diameter in her right lobe and 0.1 cm in diameter in her left lobe. The tumors were consistent with a neuroendocrine phenotype, showing strong immunoreactivity to chromogranin A and synaptophysin.

Conclusion

Thyroid nodules detected during follow-up of neuroendocrine tumor patients should be thoroughly investigated. A fine needle aspiration biopsy of the thyroid confirms the diagnosis in most cases and leads to appropriate management of those patients and may prevent unnecessary treatment approaches.

Long-term management with octreotide or cabergoline in ectopic corticotropin hypersecretion: case report and literature review

OBJECTIVE

To describe the corticotropin response to long-term octreotide or cabergoline administration in a patient with ectopic corticotropin secretion who underwent adrenalectomy.

METHODS

We describe the clinical, radiologic, and biochemical findings of the study patient over the course of 18 years.

RESULTS

A 40-year-old woman was evaluated for Cushing syndrome. On the basis of biochemical indices, Cushing disease was diagnosed and pituitary exploration was performed. No cure was achieved. Computed tomography of the chest revealed a right lung nodule due to a lung carcinoid tumor that was then surgically excised. Because of persistent hypercortisolism, total adrenalectomy was performed. Subsequently, corticotropin levels rose dramatically and hyperpigmentation developed while serum cortisol was in the reference range. The patient was treated with octreotide for 3 years and then with cabergoline for 8 years. While taking octreotide, corticotropin values decreased, accompanied by depigmentation and development of signs of adrenal insufficiency, which led to the reinstitution of supplemental hydrocortisone. Cabergoline induced a similar long-lasting effect on the clinical and biochemical parameters observed. Eight years later, she is still treated with cabergoline, and no lung tumor has been detected.

CONCLUSIONS

In this patient with ectopic Cushing syndrome, treatment with either octreotide or cabergoline markedly reduced corticotropin levels and hyperpigmentation.

[Ectopic ACTH-secreting neuroendocrine tumor]

The authors report a case of an ectopic ACTH-syndrome that resulted in severe hypercortisolism, hypokalemia, diabetes mellitus and osteoporosis. The ACTH-secreting tumor tissue was localized in the lung. The tumor was removed by segmentectomy and histological evaluation revealed an ACTH-secreting neuroendocrine tumor. After surgery, however, plasma cortisol and ACTH levels failed to decrease significantly due to subtotal tumor removal. Long-acting somatostatin analogue therapy resulted in a normalization of both plasma cortisol and ACTH levels and the clinical symptoms improved significantly. Residual tumor was removed by repeat surgery and the patient was permanently cured.

Esthesioneuroblastoma (Olfactory Neuroblastoma) with Ectopic ACTH Syndrome: a multidisciplinary case presentation from the Joan Karnell cancer center of Pennsylvania Hospital

The case of a patient with recurrent esthesioneuroblastoma complicated by ectopic adrenocorticotropic hormone production is presented, including the workup and management of this uncommon complication of an uncommon disease.

An ACTH-secreting pituitary adenoma within the sphenoid sinus

A 68-year-old woman developed Cushingoid features three months prior to admission. She was found to have a markedly elevated plasma ACTH-cortisol level. Magnetic resonance imaging (MRI) revealed a mass in the left sphenoidal sinus, which had become enlarged to a point where it could not be removed by transsphenoidal surgery. We decided to proceed with radiation therapy to shrink the tumor. However, it was ineffective. Despite a reduction in serum cortisol levels using metyrapone, she died of septic shock. We describe a rare case of an ACTH-secreting pituitary adenoma within the sphenoid sinus.

Treatment of adrenocorticotropin-dependent Cushing's syndrome: a consensus statement

OBJECTIVE

Our objective was to evaluate the published literature and reach a consensus on the treatment of patients with ACTH-dependent Cushing's syndrome, because there is no recent consensus on the management of this rare disorder.

PARTICIPANTS

Thirty-two leading endocrinologists, clinicians, and neurosurgeons with specific expertise in the management of ACTH-dependent Cushing's syndrome representing nine countries were chosen to address 1) criteria for cure and remission of this disorder, 2) surgical treatment of Cushing's disease, 3) therapeutic options in the event of persistent disease after transsphenoidal surgery, 4) medical therapy of Cushing's disease, and 5) management of ectopic ACTH syndrome, Nelson's syndrome, and special patient populations.

EVIDENCE

Participants presented published scientific data, which formed the basis of the recommendations. Opinion shared by a majority of experts was used where strong evidence was lacking.

CONSENSUS PROCESS

Participants met for 2 d, during which there were four chaired sessions of presentations, followed by general discussion where a consensus was reached. The consensus statement was prepared by a steering committee and was then reviewed by all authors, with suggestions incorporated if agreed upon by the majority.

CONCLUSIONS

ACTH-dependent Cushing's syndrome is a heterogeneous disorder requiring a multidisciplinary and individualized approach to patient management. Generally, the treatment of choice for ACTH-dependent Cushing's syndrome is curative surgery with selective pituitary or ectopic corticotroph tumor resection. Second-line treatments include more radical surgery, radiation therapy (for Cushing's disease), medical therapy, and bilateral adrenalectomy. Because of the significant morbidity of Cushing's syndrome, early diagnosis and prompt therapy are warranted.

Dopamine receptor expression and function in corticotroph ectopic tumors

BACKGROUND

Dopamine receptor (DR) expression and dopamine agonist (DA) effectiveness have never been demonstrated in neuroendocrine tumors associated with ectopic ACTH syndrome (EAS).

AIM

The aim of the current study was to evaluate DR and particularly D2 subtype expression in neuroendocrine tumors associated with EAS and to evaluate the in vivo effectiveness of the DA cabergoline in the treatment of EAS.

PATIENTS AND METHODS

Six ACTH-secreting neuroendocrine tumors, including four lung, one pancreatic, and one thymic carcinoid, were used for the evaluation of D2 expression by immunohistochemistry. DR subtypes and D2 isoforms and number were evaluated by RT-PCR in three cases of persistent EAS after surgery. These patients were treated with cabergoline at the dose of 3.5 mg/wk for 6 months. Clinical parameters, hormonal levels, and tumor size were monitored during the treatment period.

RESULTS

At immunohistochemistry, D2 was expressed in five (83.3%) tumors. At RT-PCR, D2 was confirmed in all three cases but at variable numbers, whereas D4 was expressed in two cases. D(2long) was expressed in all three cases, together with D(2short) in one case. A normalization of urinary cortisol levels was found in two patients (66.7%) after 3 months of treatment. However, treatment escape was demonstrated in one of these patients afterward.

CONCLUSION

The results of this study demonstrated that DR are expressed in neuroendocrine tumors associated with EAS and that cabergoline treatment could be effective in controlling cortisol excess in a subgroup of patients with EAS. Further studies on a larger number of patients are mandatory to confirm the usefulness of DA in EAS.

Ectopic Cushing' syndrome caused by a neuroendocrine carcinoma of the mesentery

Background

ACTH overproduction within the pituitary gland or ectopically leads to hypercortisolism. Here, we report the first case of Cushing' syndrome caused by an ectopic ACTH-secreting neuroendocrine carcinoma of the mesentery. Moreover, diagnostic procedures and pitfalls associated with ectopic ACTH-secreting tumors are demonstrated and discussed.

Case presentation

A 41 year-old man presented with clinical features and biochemical tests suggestive of ectopic Cushing's syndrome. First, subtotal thyroidectomy was performed without remission of hypercortisolism, because an octreotide scan showed increased activity in the left thyroid gland and an ultrasound revealed nodules in both thyroid lobes one of which was autonomous. In addition, the patient had a 3 mm hypoenhancing lesion of the neurohypophysis and a 1 cm large adrenal tumor. Surgical removal of the pituitary lesion within the posterior lobe did not improve hypercortisolism and we continued to treat the patient with metyrapone to block cortisol production. At 18-months follow-up from initial presentation, we detected an ACTH-producing neuroendocrine carcinoma of the mesentery by using a combination of octreotide scan, computed tomography scan, and positron emission tomography. Intraoperatively, use of a gamma probe after administration of radiolabeled ¹¹¹In-pentetreotide helped identify the mesenteric neuroendocrine tumor. After removal of this carcinoma, the patient improved clinically. Laboratory testing confirmed remission of hypercortisolism. An octreotide scan 7 months after surgery showed normal results.

Conclusion

This case underscores the diagnostic challenge in identifying an ectopic ACTH-producing tumor and the pluripotency of cells, in this case of mesenteric cells that can start producing and secreting ACTH. It thereby helps elucidate the pathogenesis of neuroendocrine tumors. This case also suggests that patients with ectopic Cushing's syndrome and an octreotide scan positive in atypical locations may benefit from explorative radioguided surgery using ¹¹¹In-pentetreotide and a gamma probe.

[62 year-old patient with rapid progressive edema, low potassium and hypertension]

A 62 year-old patient was admitted to hospital with rapid progressive edema, low potassium and hypertension. This symptoms are caused by Cushing's syndrome through ectopic paraneoplastic ACTH-production. Primary neoplasm is a small cell cancer. A Sertoli-cell-tumor of the testis was diagnosed as an additional carcinoma. Palliative chemotherapy and adrenostatic agents did not improve the clinical findings and the patient died eight weeks after admission.

Ectopic Cushing's syndrome caused by an esthesioneuroblastoma

OBJECTIVE

To report a case of florid Cushing's hormone (ACTH) secretion related to the presence of an esthesioneuroblastoma (ENB).

METHODS

We present clinical, laboratory, and pathologic findings in a 36-year-old Caucasian man presenting with Cushing's syndrome. Results of computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) scanning, and somatostatin receptor scintigraphy are presented, along with tumor pathology findings.

RESULTS

After initial biochemical studies suggestive of ectopic Cushing's syndrome, CT of the chest and abdomen revealed multiple cavitated pulmonary lesions, an ischiorectal mass, and bilateral adrenal hyperplasia. MRI of the pituitary gland revealed normal findings. Both PET scanning with [18 F]-flurodeoxyglucose (FDG) and somatostatin receptor scintigraphy with 111 indium-penetetreotide (Octreoscan) revealed strong tracer uptake in the ethmoid region. CT and MRI of the sinuses and brain subsequently localized a 5-cm mass in the ethmoid sinuses with intracranial extension. On biopsy, pathology results were consistent with a diagnosis of ENB, and immunohistochemical analysis revealed that tumor cells were strongly positive for ACTH, synaptophysin, and S-100, providing definitive diagnosis of ACTH-producing ENB. Hypercortisolemia was initially controlled by metyrapone, then by external beam radiation therapy (RT).

CONCLUSION

This case illustrates the usefulness of nuclear imaging in the diagnosis of ENB, and the importance of prompt control of hypercortisolemia in Cushing's syndrome.

Is there a therapeutic role for octreotide in patients with ectopic Cushing's syndrome?

Cushing's syndrome (CS) due to ectopic ACTH secretion (EAS) has a high morbidity and mortality, because of the underlying tumor and the sequelae of severe hypercortisolemia. Therefore, rapid treatment of ectopic CS is mandatory. Scintigraphy shows that up to 80% of ectopic ACTH-producing tumors have somatostatin receptors. While this suggests that somatostatin analogs may reduce ACTH production and treat patients with EAS, the therapeutic role of these agents is still evolving. Here we demonstrate the spectrum of responses to octreotide therapy in 3 patients with EAS. Diagnostic imaging with the 111In-pentetreotide scan did not predict the therapeutic response to octreotide. Two patients with positive somatostatin receptor scintigraphy failed to respond to octreotide, while one with a negative scan reached eucortisolemia on a maintenance dose of 75 microg octreotide twice daily or octreotide LAR 30 mg per month. We conclude that octreotide is not a first line agent to control hypercortisolemia but may be a useful agent when other inhibitors of steroidogenesis fail or parenteral administration is required. Before therapy an octreotide challenge test may predict therapeutic response. Cortisol levels should be monitored regularly on somatostatin analog therapy, because of its unpredictable long-term pharmacodynamic profile.

Somatostatin analogs

Somatostatin is a hypothalamic peptide hormone that inhibits the secretion of growth hormone, glucagon, insulin, gastrin and secretin, and also plays a role in neural transmission. Because of its wide range of possible clinical applications hundreds of somatostatin analogs have been synthesized and bioassayed to date. This review gives a historical perspective, summarizing approximately 30 years of research on somatostatin. The main focus is on the structure-activity relationships and conformational studies of the last generation of somatostatin agonists and their selectivity for five somatostatin receptor subtypes. Achievements in the synthesis of nonpeptide somatostatin analogs, as well as the first somatostatin antagonists, are also discussed. Finally, the use of a cyclic somatostatin scaffold to design ligands for other G-protein-coupled receptors, such as opioid and melanocortin receptors, is mentioned.