A critical analysis of the value of simultaneous inferior petrosal sinus sampling in Cushing's disease and the occult ectopic adrenocorticotropin syndrome

Comparison of the preoperative diagnostic accuracy of BIPSS versus MRI for Cushing disease: a single-centre experience

BACKGROUND

Cushing disease (CD) arises due to a pituitary corticotroph adenoma, which is the most common cause of Cushing syndrome (CS). Bilateral inferior petrosal sinus sampling (BIPSS) is a safe method for differentiating CD from ectopic adrenocorticotropic hormone (ACTH)-dependent CS. Enhanced high-resolution magnetic resonance imaging (MRI) can localize tiny pituitary lesions. The aim of this study was to compare the preoperative diagnostic accuracy of BIPSS versus MRI for CD in CS patients. We performed a retrospective study of patients who underwent BIPSS and MRI between 2017 and 2021. Low- and high-dose dexamethasone suppression tests were performed. Blood samples were collected simultaneously from the right and left catheter and femoral vein before and after desmopressin stimulation. MRI images were obtained, and endoscopic endonasal transsphenoidal surgery (EETS) was performed in confirmed CD patients. Dominant sides of ACTH secretion during BIPSS and MRI were compared with surgical findings.

RESULTS

Twenty-nine patients underwent BIPSS and MRI. CD was diagnosed in 28 patients, 27 of whom received EETS. Localizations of microadenomas by MRI and BIPSS agreed with the EETS findings in 96% and 93% of the cases, respectively. BIPSS and EETS were successfully performed on all patients.

CONCLUSION

BIPSS was the most accurate method (gold standard) for establishing a preoperative diagnosis of pituitary-dependent CD and was more sensitive than MRI in diagnosing microadenoma. High-resolution MRI with enhancement had an advantage over BIPSS in microadenoma lateralization diagnostics. The combined use of MRI and BIPSS could improve the preoperative diagnosis accuracy in ACTH-dependent CS patients.

Diagnostic accuracy of bilateral inferior petrosal sinus sampling using desmopressin or corticotropic- releasing hormone in ACTH-dependent Cushing's syndrome: A systematic review and meta-analysis

The current gold standard diagnostic method for Cushing disease (CD) is bilateral inferior petrosal sinus sampling (BIPSS) after corticotropin-releasing hormone (CRH) stimulation. Due to shortages of CRH, BIPSS has been performed with desmopressin (DDAVP) instead. The objective of this systematic review and meta-analysis was to estimate the diagnostic accuracy of BIPSS using DDAVP or CRH for the differential diagnosis of Cushing's syndrome (CS). A literature review was done in PubMed, Scopus, EMBASE, and google scholar databases to derive summary estimates of the overall diagnostic sensitivity and accuracy of BIPSS using DDAVP or CRH in Cushing's syndrome. Pooled sensitivity, specificity, diagnostic odds ratio and summary receiver operating characteristic curves (SROC) for differential diagnosis of Cushing's syndrome in the random-effects models, were computed. Overall, 11 different studies with a total of 612 participants, were eligible for the analysis. Five articles with data on BIPSS using DDAVP, 5 papers on BIPSS using CRH, and another one evaluated the results of stimulation using DDAVP, with or without CRH, for differential diagnosis of Cushing's syndrome. The pooled (95% CI) sensitivity and specificity of BIPSS using DDAVP, were 96% (91-98%) and 1.00 (0.00-1.00), respectively. The area under the SROC curve was 0.95. The pooled (95% CI) sensitivity and specificity of BIPSS using CRH, were 98% (92-99%) and 1.00 (0.00-1.00), respectively, and the area under the SROC curve was 0.98. The I² index (95% CI) was 0% (0-100%) for both BIPSS using DDAVP and using CRH. As a result, DDAVP stimulation is a safe, effective, less expensive, valuable and available alternative to CRH in the setting of BIPSS for all age groups of patients with CS. Registration code in PROSPERO: CRD42021292531.

Acute elevation of interleukin 6 and matrix metalloproteinase 9 during the onset of pituitary apoplexy in Cushing's disease

PURPOSE

Pituitary apoplexy is a rare endocrine emergency. The purpose of this study is to characterize physiological changes involved in pituitary apoplexy, especially during the acute phase.

METHODS

A Cushing's disease patient experienced corticotroph releasing hormone (CRH)-induced pituitary apoplexy during inferior petrosal sinus sampling (IPSS). The IPSS blood samples from the Cushing's disease patient were retrospectively analyzed for cytokine markers. For comparison, we also analyzed cytokine markers in blood samples from two pituitary ACTH-secreting microadenoma patients and one patient with an ectopic ACTH-secreting tumor.

RESULTS

Acute elevation of interleukin 6 (IL-6) and matrix metalloproteinase 9 (MMP9) was observed in the IPSS blood sample on the apoplectic hemorrhagic site of the tumor. In contrast, such a change was not observed in the blood samples from the contralateral side of the apoplexy patient and in other IPSS samples from two non-apoplexy Cushing's disease patient and a patient with ectopic Cushing's syndrome.

CONCLUSION

IL-6 and MMP9 may be involved in the acute process of pituitary apoplexy in Cushing's disease.

Inferior petrosal sinus sampling in Cushing's syndrome: usefulness and pitfalls

In patients with ACTH-dependent Cushing's syndrome (CS), the differentiation between Cushing's disease (CD) and ectopic ACTH secretion (EAS) can often be challenging. The traditionally used biochemical tests have limited diagnostic accuracy and imaging modalities may fail to detect the culprit lesion. Inferior petrosal sinus sampling (IPSS) was introduced more than 3 decades ago as a test with optimal diagnostic accuracy and has since become the gold standard in the differential diagnosis between CD and EAS. However, several, albeit rare, pitfalls may limit its diagnostic accuracy and awareness is needed to avoid incorrect interventions. Moreover, it is an invasive and demanding procedure, available in a limited number of centers worldwide. This review aims to critically present the usefulness and pitfalls of IPSS and define strategies for its optimal place in the contemporary management of CS.

A case series of bilateral inferior petrosal sinus sampling with desmopressin in evaluation of ACTH-dependent Cushing's syndrome in Iran

BACKGROUND

Differentiating the etiology of ACTH-dependent Cushing's syndrome (CS) has remained challenging due to the limited accuracy of noninvasive assays. Nowadays, bilateral inferior petrosal sinus sampling (BIPSS) with corticotropin-releasing hormone (CRH) is the gold standard method in the diagnostic work-up of complex CS. However, this method is as yet far from being widespread. The limited utility of this method could be due to many factors such as limited availability of an experienced interventionist, limited availability of CRH, and cost of the procedure. So far, very few studies have been conducted using desmopressin instead of CRH. In this study, we report the use of BIPSS with desmopressin as a diagnostic tool in a series of patients with suspected Cushing's disease (CD) and equivocal imaging in a tertiary referral center in Iran.

METHODS

A total of 13 patients with ACTH-dependent CS and no significant lesions in their pituitary MRI participated in this retrospective case series. All patients underwent BIPSS with desmopressin, and, following centralization of CS, transsphenoidal surgery (TSS) was carried out and diagnosis of CD was confirmed using standard methods.

RESULTS

Of the 13 patients with confirmed CD (by pathology or biochemical response after surgery), eight (61.5%) were female, with a median age of 32 years (IQR: 26-41). The median duration of disease was 24 months (IQR: 11-48). During BIPSS, all patients had a central-to-peripheral gradient greater than 2 under basal conditions. This central-to-peripheral gradient did not increase to > 3 after desmopressin administration in two of these patients. Based on the gradient after BIPSS, the sensitivity of this modality in the diagnosis of CD was 100%. Eight of the 13 patients had right lateralization in both BIPSS and TSS; therefore, the accuracy rate of lateralization by BIPSS was 61.5%. No complications occurred after BIPSS, the exception being the development of groin hematoma in one patient.

CONCLUSION

No significant benefits of adding desmopressin to BIPSS were observed. The sensitivity of BIPSS in the diagnosis of CD was high, whereas it has moderate accuracy in tumor lateralization.

Image of the month: Diagnostic and therapeutic challenges in the management of ectopic ACTH syndrome: a perfect storm of hypercortisolism, hyperglycaemia and COVID-19

Cushing's syndrome is a rare endocrine disorder requiring a high degree of clinical suspicion and meticulous investigations to diagnose and manage optimally. Delayed diagnosis and suboptimal treatment are associated with increased morbidity and mortality. Uncontrolled hypercortisolism leads to multiple cardiovascular and metabolic complications. Key risk factors identified for COVID-19-related adverse clinical outcomes (such as diabetes, hypertension and obesity) are, in fact, core clinical manifestations of Cushing's syndrome. Occurrence of SARS-CoV-2 infection in someone with uncontrolled hypercortisolism could, therefore, lead to disastrous medical consequences. We report a case highlighting challenges in the diagnosis and management of aggressive Cushing's syndrome secondary to ectopic adrenocorticotropic hormone (ACTH) secretion from an, as yet unidentified, neuroendocrine tumour. Our patient also contracted SARS-CoV-2 infection during investigations, which posed additional difficulties with aggravation of cardiometabolic complications. We also identify lack of clinical evidence to address management of this unique combination of two potentially life-threatening illnesses.

The Effects of Sampling Lateralization on Bilateral Inferior Petrosal Sinus Sampling for Pediatric Cushing's Disease-A Single Endocrinology Centre Experience and Review of the Literature

BACKGROUND

This study aims to analyze the diagnostic accuracy of bilateral inferior petrosal sinus sampling (BIPSS), the gold standard test for the differential diagnosis of ACTH-dependent Cushing's syndrome (CS) in a group of pediatric patients with Cushing's disease (CD).

METHODS

This is a retrospective analysis which include 12 patients with hypercortisolemia and inconclusive pituitary MRI, who underwent bilateral inferior petrosal sinus sampling (BIPSS) and transsphenoidal surgery (TSS) from 2004 to 2020 in the Children's Memorial Health Institute (CMHI) Warsaw, Poland. Pituitary origin of ACTH secretion was considered if baseline central to peripheral (C/P) ACTH level ratio was ≥ 2 or C/P ratio was ≥ 3 after human corticotropin-releasing hormone (hCRH) stimulation. The diagnosis was histologically confirmed in almost all cases after TSS.

RESULTS

The diagnostic accuracy of BIPSS reached 75% at baseline and 83.3% after CRH stimulation. The compatibility of localization of a microadenoma by BIPSS with the surgical location was 66.7%.

CONCLUSIONS

Owing to its high diagnostic effectiveness, BIPSS remains the best test to differentiate CD from EAS. The indications for the procedure should be carefully considered, because EAS in the pediatric population, unlike in adults, is extremely rare. Moreover BIPSS has only limited value for indicating tumor localization.

Differential diagnostic value of bilateral inferior Petrosal sinus sampling (BIPSS) in ACTH-dependent Cushing syndrome: a systematic review and Meta-analysis

BACKGROUND

Previous studies have shown inconsistent results about the usefulness of bilateral inferior petrosal sinus sampling (BIPSS) in differential diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome. This meta-analysis evaluated the diagnostic value of BIPSS via the published literature.

METHODS

This study searched PubMed, Embase, Web of Science, Cochrane library, and Wanfang database for published data on the use of BIPSS in Cushing syndrome differential diagnosis as of October 2019. Sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and receiver operating characteristic (ROC) curves were calculated based on the relevant data.

RESULTS

This meta-analysis included a total of 23 studies with 1642 patients. The calculated sensitivity, specificity, PLR, and NLR were 0.94 (95% confidence interval, CI: 0.91-0.96), 0.89 (95% CI: 0.79-0.95), 8.8 (95% CI: 4.3-17.9), and 0.07 (95% CI: 0.04-0.11), respectively. The pooled DOR and area under the ROC curve were 129 (95% CI: 48-345) and 0.97 (95% CI: 0.95-0.98), respectively.

CONCLUSION

This meta-analysis indicated that BIPSS had high diagnostic value for detecting ACTH in patients with ACTH-dependent Cushing syndrome, and BIPSS should be used as an effective method to identify ACTH-secretion sources.

Severe ectopic Cushing's syndrome

We present a rare case of severe ectopic Cushing's syndrome in a 39-year-old woman with a rapid onset of signs and symptoms and severe hypokalemia. Further workup demonstrated an adrenocorticotropic hormone-secreting metastatic high-grade neuroendocrine carcinoma.

Circulating Plasma microRNA to Differentiate Cushing's Disease From Ectopic ACTH Syndrome

Corticotropinomas and adrenocorticotropic hormone (ACTH)-secreting neuroendocrine tumors exhibit differential levels of some microRNAs (miRs) compared to normal tissue. Because miRs can be released from tissues into circulation, they offer promise as novel disease biomarkers. Objective: To evaluate whether miRs are differentially detected in plasma samples of patients with ACTH-dependent Cushing's syndrome (CS). Design: Case-control study. Methods: Morning fasting plasma samples were collected from 41 consecutive patients with confirmed ACTH-dependent CS and 11 healthy subjects and stored at -80°C. Twenty-one miRs previously reported to be differentially expressed in ACTH-secreting tumors vs. healthy tissue samples were quantified in plasma by qPCR. Results: Among enrolled subjects, 28 were confirmed to have Cushing's disease (CD), 13 had ectopic ACTH secretion (EAS) and 11 were healthy controls. We found statistically significant differences in the circulating levels of miR-16-5p [45.04 (95% CI 28.77-61.31) in CD vs. 5.26 (2.65-7.87) in EAS, P < 0.001; q = 0.001], miR-145-5p [0.097 (0.027-0.167) in CD vs. undetectable levels in EAS, P = 0.008; q = 0.087] and differences in miR-7g-5p [1.842 (1.283-2.400) in CD vs. 0.847 (0.187-1.507) in EAS, P = 0.02; q = 0.14]. The area under the receiver-operator (ROC) curve was 0.879 (95% CI 0.770-0.987), p < 0.001, when using miR-16-5p to distinguish between CD and EAS. Circulating levels of miR-16-5p in the healthy control group differed from that of both the CD and EAS groups. Conclusions: Plasma miR levels differ in patients with CD and EAS. In particular, miR-16-5p, miR-145-5p and miR-7g-5p are promising biomarkers for further research to differentiate ACTH-dependent CS.

Pediatric pituitary adenomas

BACKGROUND

Pediatric pituitary adenomas are a rare medical entity that makes up a small portion of intracranial tumors in children and adolescents. Although benign, the majority of these lesions are secreting functional tumors with the potential for physiological sequela that can profoundly affect a child's development.

FOCUS OF REVIEW

In this review, we discuss the medical and surgical management of these tumors with a focus on clinical presentation, diagnostic identification, surgical approach, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to treat these tumors. The management of pituitary tumors requires a multidisciplinary team of surgeons, endocrinologists, and neuroanesthesiologists as well as neurocritical care specialists to deliver comprehensive care.

Pediatric Pituitary Adenoma: Case Series, Review of the Literature, and a Skull Base Treatment Paradigm

Background  Pediatric pituitary adenoma is a rare skull base neoplasm, accounting for 3% of all intracranial neoplasms in children and 5% of pituitary adenomas. Compared with pituitary tumors in adults, secreting tumors predominate and longer disease trajectories are expected due to the patient age resulting in a natural history and treatment paradigm that is complex and controversial. Objectives  The aims of this study were to describe a large, single-institution series of pediatric pituitary adenomas with extensive long-term follow-up and to conduct a systematic review examining outcomes after pituitary adenoma surgery in the pediatric population. Methods  The study cohort was compiled by searching institutional pathology and operative reports using diagnosis and site codes for pituitary and sellar pathology, from 1956 to 2016. Systematic review of the English language literature since 1970 was conducted using PubMed, MEDLINE, Embase, and Google Scholar. Results  Thirty-nine surgically managed pediatric pituitary adenomas were identified, including 15 prolactinomas, 14 corticotrophs, 7 somatotrophs, and 4 non-secreting adenomas. All patients underwent transsphenoidal resection (TSR) as the initial surgical treatment. Surgical cure was achieved in 18 (46%); 21 experienced recurrent/persistent disease, with secondary treatments including repeat surgery in 10, radiation in 14, adjuvant pharmacotherapy in 11, and bilateral adrenalectomy in 3. At the last follow-up (median 87 months, range 3-581), nine remained with recurrent/persistent disease (23%). Thirty-seven publications reporting surgical series of pediatric pituitary adenomas were included, containing 1,284 patients. Adrenocorticotropic hormone (ACTH)-secreting tumors were most prevalent (43%), followed by prolactin (PRL)-secreting (37%), growth hormone (GH)-secreting (12%), and nonsecreting (7%). Surgical cure was reported in 65%. Complications included pituitary insufficiency (23%), permanent visual dysfunction (6%), chronic diabetes insipidus (DI) (3%), and postoperative cerebrospinal fluid (CSF) leak (4%). Mean follow-up was 63 months (range 0-240), with recurrent/persistent disease reported in 18% at the time of last follow-up. Conclusion  Pediatric pituitary adenomas are diverse and challenging tumors with complexities far beyond those encountered in the management of routine adult pituitary disease, including nuanced decision-making, a technically demanding operative environment, high propensity for recurrence, and the potentially serious consequences of hypopituitarism with respect to fertility and growth potential in a pediatric population. Optimal treatment requires a high degree of individualization, and patients are most likely to benefit from consolidated, multidisciplinary care in highly experienced centers.

Arginine vasopressin (AVP): a review of its historical perspectives, current research and multifunctional role in the hypothalamo-hypophysial system

INTRODUCTION

This publication reviews the function of arginine vasopressin and focuses on the morphologic and functional correlation between the hormone and its effect on stress, the hypophysial-adrenocortical axis, neuroimmune responses, renal function and corticotroph pituitary tumors.

MATERIALS AND METHODS

A literature review was performed using various search engines for information regarding the morphology and the multifunctional role of arginine vasopressin.

RESULTS

Although a large number of studies were published discussing these interactions, there are several important areas that are still obscure.

CONCLUSION

The questions of how does arginine vasopressin affect the morphology and function of these various areas, and how does the secretion of ACTH and adrenocortical hormones influence the morphology of arginine vasopressin-producing cells and their hormone secretion requires further investigation.

Bilateral inferior petrosal sinus sampling

Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing's syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88-100% and 67-100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50-70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres.

Etiology and clinical profile of patients with Cushing's syndrome: A single center experience

BACKGROUND

There is little published literature on the profile of patients with Cushing's syndrome (CS) from India. The aim of this study was to compile data of CS patients treated at this hospital.

MATERIALS AND METHODS

Patients referred to the endocrine services of this hospital for diagnosis/treatment of CS from January 1985 to July 2012 were the subjects for this study. All patients had detailed medical history, physical examination and biochemical and hormonal assays (which changed with availability of tests and changing views). Assays for plasma adrenocorticotropic hormone (ACTH) (late 90s), salivary cortisol estimation, IJV sampling for ACTH and corticotrophin releasing hormone stimulation tests were added on later. Imaging included computed tomography (CT), magnetic resonance imaging (since the late 80's) and (68)Ga DOTA-TOC/FDG PET-CT (2008).

RESULTS

Three hundred sixty-four patients (250 females, 114 males, age 6 months to 65 years, mean 28 years + 12 years) were diagnosed to have CS during this period. Two hundred and ninety-three patients (80.5%) were ACTH dependent (CD 215, ectopic ACTH syndrome 22, occult ACTH source 56) while 71 (19.5%) were ACTH independent (adrenal carcinoma 36, adenoma 30, primary pigmented nodular adrenal disease 4, AIMAH 1). Pituitary macro adenoma was seen in 14% of the CD cases. The most common presenting complaints were hypertension and diabetes mellitus. A total of 63% patients complained of weight gain while 15% had lost weight. Myopathy, infections, skeletal fractures and psychiatric problems were the other common observations in our patients.

CONCLUSION

The clinical spectrum was broad. CD was the most common cause for CS.

Periodic hypokalemia associated with cyclic Cushing's syndrome

A 69-year-old woman presented with periodic hypertension, edema, and hypokalemia that occurred within an interval of a few weeks. Her laboratory test values showed autonomously elevated plasma adrenocorticotropic hormone (ACTH) and cortisol concentrations. The patient's Cushingoid features were not evident on first admission. Several weeks later, in spite of constant oral potassium supplementation, severe hypokalemia recurred with Cushingoid features and worsening symptoms of leg edema and pigmentation, which spontaneously disappeared within a few days. Her periodic symptoms occurred in parallel with fluctuations of plasma ACTH and cortisol concentrations. A series of endocrinological and pituitary imaging findings led to a tentative diagnosis of cyclic Cushing's syndrome caused by ectopic ACTH secretion. However, chest and abdominal computed tomography did not reveal any candidate lesion. The patient's periodic hypercortisolemia and symptoms were well controlled after treatment with metyrapone plus dexamethasone. This is a very rare case of periodic hypokalemia and hypertension caused by cyclic Cushing's syndrome.

Hypercortisolism is associated with increased coronary arterial atherosclerosis: analysis of noninvasive coronary angiography using multidetector computerized tomography

BACKGROUND

Observational studies show that glucocorticoid therapy and the endogenous hypercortisolism of Cushing's syndrome (CS) are associated with increased rates of cardiovascular morbidity and mortality. However, the causes of these findings remain largely unknown.

OBJECTIVE

To determine whether CS patients have increased coronary atherosclerosis.

DESIGN

A prospective case-control study was performed.

SETTING

Subjects were evaulated in a clinical research center.

SUBJECTS

Fifteen consecutive patients with ACTH-dependent CS, 14 due to an ectopic source and 1 due to pituitary Cushing's disease were recruited. Eleven patients were studied when hypercortisolemic; 4 patients were eucortisolemic due to medication (3) or cyclic hypercortisolism (1). Fifteen control subjects with at least one risk factor for cardiac disease were matched 1:1 for age, sex, and body mass index.

PRIMARY OUTCOME VARIABLES

Agatston score a measure of calcified plaque and non-calcified coronary plaque volume were quantified using a multidetector CT (MDCT) coronary angiogram scan. Additional variables included fasting lipids, blood pressure, history of hypertension or diabetes, and 24-hour urine free cortisol excretion.

RESULTS

CS patients had significantly greater noncalcified plaque volume and Agatston score (noncalcified plaque volume [mm(3)] median [interquartile ranges]: CS 49.5 [31.4, 102.5], controls 17.9 [2.6, 25.3], P < .001; Agatston score: CS 70.6 [0, 253.1], controls 0 [0, 7.6]; P < .05). CS patients had higher systolic and diastolic blood pressures than controls (systolic: CS 143 mm Hg [135, 173]; controls, 134 [123, 136], P < .02; diastolic CS: 86 [80, 99], controls, 76 [72, 84], P < .05).

CONCLUSIONS

Increased coronary calcifications and noncalcified coronary plaque volumes are present in patients with active or previous hypercortisolism. Increased atherosclerosis may contribute to the increased rates of cardiovascular morbidity and mortality in patients with glucocorticoid excess.

Comparative Analysis of Clinical, Hormonal and Morphological Studies in Patients with Neuroendocrine ACTH-Producing Tumours

This paper highlights the problem of neuroendocrine tumours (NETs) with clinical symptoms of hypercorticism caused by hypersecretion of adrenocorticotropic hormone (ACTH) by tumour cells. In most cases (85%), the tumours were localized in the pituitary gland (Cushing's disease); 15% of the patients had an extrapituitary tumour that manifest as an ectopic ACTH secretion (EAS). Comparative analysis of clinical, hormonal, histological, and immunohistochemical characteristics of pituitary and extrapituitary ACTH-secreting NET was performed. It included 46 patients with CD and 38 ones exhibiting ectopic ACTH secretion (EAS). Results of the study suggest differences between CD and EAS in terms of the severity of clinical manifestations and duration of the disease. Hormonal studies showed that EAS unlike CD was associated with high plasma ACTH and cortisol levels, late-evening salivary cortisol and daily urinary free cortisol, the absence of a 60% or greater reduction of cortisol in the HDDST test, and the presence of a low (less than 2) ACTH gradient in response to desmopressin administration with catheterization of cavernous sinuses. The study of morphofunctional characteristics of the removed NET demonstrated the ability of both pituitary and extrapituitary NETs to express ACTH as well as GH, PRL, LH, and FSH. The angiogenic markers (CD31 and VEGF) were detected with equal frequency regardless of the NET localization. The histological structure of all corticotropinomas suggested their benign origin, but extrapituitary NETs were represented by different morphological types with varying malignancy, invasiveness, and metastatic properties. A higher cell proliferation potential (Ki-67) was documented for NET in patients presenting with an ectopic ACTH secretion compared to those having corticotropinomas.

Diagnosis and Multimodality Management of Cushing's Disease: A Practical Review

Cushing's Disease is caused by oversecretion of ACTH from a pituitary adenoma and results in subsequent elevations of systemic cortisol, ultimately contributing to reduced patient survival. The diagnosis of Cushing's Disease frequently involves a stepwise approach including clinical, laboratory, neuroimaging, and sometimes interventional radiology techniques, often mandating multidisciplinary collaboration from numerous specialty practitioners. Pituitary microadenomas that do not appear on designated pituitary MRI or dynamic contrast protocols may pose a particularly challenging subset of this disease. The treatment of Cushing's Disease typically involves transsphenoidal surgical resection of the pituitary adenoma as a first-line option, yet may require the addition of adjunctive measures such as stereotactic radiosurgery or medical management to achieve normalization of serum cortisol levels. Vigilant long-term serial endocrine monitoring of patients is imperative in order to detect any recurrence that may occur, even years following initial remission. In this paper, a stepwise approach to the diagnosis, and various management strategies and associated outcomes in patients with Cushing's Disease are discussed.

Internal jugular vein: Peripheral vein adrenocorticotropic hormone ratio in patients with adrenocorticotropic hormone-dependent Cushing's syndrome: Ratio calculated from one adrenocorticotropic hormone sample each from right and left internal jugular vein during corticotrophin releasing hormone stimulation test

BACKGROUND

DEMONSTRATION OF CENTRAL: Peripheral adrenocorticotropic hormone (ACTH) gradient is important for diagnosis of Cushing's disease.

AIM

THE AIM WAS TO ASSESS THE UTILITY OF INTERNAL JUGULAR VEIN (IJV): Peripheral vein ACTH ratio for diagnosis of Cushing's disease.

MATERIALS AND METHODS

Patients with ACTH-dependent Cushing's syndrome (CS) patients were the subjects for this study. One blood sample each was collected from right and left IJV following intravenous hCRH at 3 and 5 min, respectively. A simultaneous peripheral vein sample was also collected with each IJV sample for calculation of IJV: Peripheral vein ACTH ratio. IJV sample collection was done under ultrasound guidance. ACTH was assayed using electrochemiluminescence immunoassay (ECLIA).

RESULTS

Thirty-two patients participated in this study. The IJV: Peripheral vein ACTH ratio ranged from 1.07 to 6.99 (n = 32). It was more than 1.6 in 23 patients. Cushing's disease could be confirmed in 20 of the 23 cases with IJV: Peripheral vein ratio more than 1.6. Four patients with Cushing's disease and 2 patients with ectopic ACTH syndrome had IJV: Peripheral vein ACTH ratio less than 1.6. Six cases with unknown ACTH source were excluded for calculation of sensitivity and specificity of the test.

CONCLUSION

IJV: Peripheral vein ACTH ratio calculated from a single sample from each IJV obtained after hCRH had 83% sensitivity and 100% specificity for diagnosis of CD.

Internal jugular vein adrenocorticotropic hormone estimation for diagnosis of adrenocorticotropic hormone-dependent Cushing's syndrome: Ultrasound-guided direct jugular vein sample collection

AIM OF STUDY

To assess the utility of internal jugular vein (IJV) / peripheral adrenocorticotropic hormone (ACTH) gradient in determining the etiology of ACTH- dependent Cushing's syndrome.

MATERIALS AND METHODS

Patients with ACTH-dependent Cushing's syndrome, (except children less than 12 years), had IJV blood collection under ultrasound guidance using a linear 7 MHZ probe. Blood was collected with a 21 G needle at the level of mandible with the patient in supine position. Six ml of blood was collected sequentially from right and left internal jugular veins for ACTH and prolactin estimation. Peripheral blood for ACTH and prolactin was taken from a previously placed IV cannula in the antecubital vein.

RESULTS

Thirty patients (20 F, 10 M, age 14 to 50 yrs) were enrolled for this study. Source of ACTH excess was pituitary in 22, ectopic ACTH in 4, and unknown in 4 cases. Using an IJV: Peripheral ACTH ratio of ≥ 1.6, 15 out of 22 Cushing's disease patients were correctly identified. However, 1 out of 4 ectopic Cushing also had IJV: Peripheral ratio ≥ 1.6. Overall, it had sensitivity of 68% with specificity of 75% while MRI pituitary and HDDST had sensitivity of 86% and 59%, respectively, with specificity of 100% each.

CONCLUSION

IJV: Peripheral ACTH gradient was observed in 68% of patients with Cushing's disease. Simultaneous IJV and peripheral sample collection with CRH stimulation may improve sensitivity and specificity of this test.

The investigation of Cushing syndrome: essentials in optimizing appropriate diagnosis and management

The investigation of Cushing syndrome (CS) should start with careful history taking and clinical examination, and exogenous steroid usage must be excluded. It is essential to confirm hypercortisolism before further investigations are undertaken. The recommended first-line tests include midnight salivary cortisol and/or the 1 mg overnight or low-dose dexamethasone suppression tests. The next step is to differentiate adrenocorticotrophin (ACTH)-dependent from ACTH-independent CS by measuring ACTH. With ACTH-dependence, further investigations should differentiate pituitary-dependent from ectopic ACTH-dependent CS. Many dynamic tests may be considered, but we suggest that bilateral inferior petrosal sinus sampling should be performed in almost all patients with ACTH-dependent CS, except for patients with a pituitary macroadenoma. Imaging should include MR scanning of the pituitary, and CT scanning of the chest and abdomen to look for an ectopic source. Confirmation of the diagnosis of CS and accurate localization of its source are vital to optimize therapy for this complex disorder.

Neuroendocrine ACTH-producing tumor of the thymus--experience with 12 patients over 25 years

CONTEXT

ACTH-producing neuroendocrine tumor (NET) of the thymus is a rare cause of Cushing's syndrome (CS). The literature consists mainly of isolated case reports.

PATIENTS

We studied 12 cases (eight males and four females) diagnosed between 1986 and 2010 with CS and thymic NET who underwent surgical resection.

MAIN OUTCOME MEASURES

We measured time from onset of CS to diagnosis of thymic NET, tumor size, histological grade, time to recurrence, and survival and performed a meta-analysis of other published cases of CS associated with thymic NET.

RESULTS

Eleven of 12 patients presented with classic features of CS at a median age of 21 yr (range, 7-51). Four were children. The 24-h urine free cortisol was greater than 16-fold of normal, and biochemical testing was consistent with ectopic ACTH production in all 11. Another patient presenting with pulmonary embolus had a thymic mass and was later diagnosed with CS. All patients underwent thymectomy, and nine of 10 tumors exhibited positive ACTH immunochemistry. Median tumor diameter was 5 cm (range, 1-11.5). Six patients recurred 20-28 months after surgery with metastases to mediastinal lymph nodes (n = 5), bone (n = 5), liver (n = 1), parotid gland (n = 1), and breast (n = 1). Four of five patients treated with radiation therapy also received chemotherapy. All recurrent patients received ketoconazole; four later underwent bilateral adrenalectomy. Six recurrent patients died 22-90 months (median, 57) after thymectomy. At last review, six patients were alive 14-90 months (median, 49) after thymectomy. These data are similar to those from the meta-analysis.

CONCLUSIONS

Thymic ACTH-producing NET is an aggressive disease that should be considered in CS with ectopic ACTH secretion, particularly in younger patients.

Cushing's Syndrome due to Ectopic ACTH from Bronchial Carcinoid: A Case Report and Review

Despite advances in analytic and imaging techniques, the syndrome of ectopic adrenocorticotrophic hormone (ACTH) secretion from a tumour resulting in Cushing's syndrome continues to pose difficult diagnostic and therapeutic challenges. Dynamic testing may be equivocal and radiology indeterminate. We report a patient presenting with Cushing's syndrome associated with ectopic ACTH secretion from a bronchial carcinoid whose management presented diagnostic and therapeutic challenges.

Endoscopic bilateral adrenalectomy in patients with ectopic Cushing's syndrome

Background

Bilateral adrenalectomy (BLA) is a treatment option to alleviate symptoms in patients with ectopic Cushing’s syndrome (ECS) for whom surgical treatment of the responsible nonpituitary tumor is not possible. ECS patients have an increased risk for complications, because of high cortisol levels, poor clinical condition, and metabolic disturbances. This study aims to evaluate the safety and long-term efficacy of endoscopic BLA for ECS.

Methods

From 1990 to present, 38 patients were diagnosed and treated for ECS in the Erasmus University Medical Center, a tertiary referral center. Twenty-four patients were treated with BLA (21 endoscopic, 3 open), 9 patients were treated medically, and 5 patients could be cured by complete resection of the adrenocorticotropic hormone (ACTH)-producing tumor. The medical records were retrospectively reviewed and entered into a database. For evaluation of the efficacy of BLA, preoperative biochemical and physical symptoms were assessed and compared with postoperative data.

Results

Endoscopic BLA was successfully completed in 20 of the 21 patients; one required conversion to open BLA. Intraoperative complications occurred in two (10%) patients, and postoperative complications occurred in three (14%) patients. Median hospitalization was 9 (2–95) days, and median operating time was 246 (205–347) min. Hypercortisolism was resolved in all patients. Improvements of hypertension, body weight, Cushingoid appearance, impaired muscle strength, and ankle edema were achieved in 87, 90, 65, 61, and 78% of the patients, respectively. Resolution of diabetes, hypokalemia, and metabolic alkalosis was achieved in 33, 89, and 80%, respectively.

Conclusion

Endoscopic BLA is a safe and effective treatment for patients with ectopic Cushing’s syndrome.

The ectopic ACTH syndrome

Ectopic Cushing's syndrome usually relates to the ectopic ACTH syndrome (EAS) and represents ∼20% of ACTH-dependent and ∼10% of all types of Cushing's syndrome (CS). Nearly any neuroendocrine or non-endocrine tumours may be associated with EAS, but the more prevalent tumours are bronchial carcinoids, small cell lung carcinomas, pancreatic carcinoids, thymic carcinoids, medullary carcinomas of the thyroid, and phaeochromocytomas. Occult tumours are highly represented in all the series (12-38%) and constitute the more challenging cases of EAS, requiring long term follow-up. The lack of any completely reliable diagnostic test procedure and imaging to clearly reveal the source of EAS suggests that we should adopt a step-by-step multidisciplinary approach for their diagnosis and therapeutic management. Clinical features are often similar in ACTH-dependent CS, but the rapid onset and progress may suggest an ectopic source. A combination of biochemical tests and imaging studies seems the most appropriate approach for the prompt identification of EAS, even if there are several pitfalls to be avoided along the way. The most appropriate management for cure of EAS, when its source is identified, is surgical excision after controlling the hypercortisolaemia by inhibitors of cortisol secretion and other newer modalities alone or in combination; bilateral adrenalectomy remains an alternative option. Tumour histology, the presence of metastases and the effective control of hypercortisolaemia affect mortality and morbidity. If a source repeatedly fails to be found, the prognosis is often favourable but the identification of a malignant tumour should still be sought during life-long follow-up to avoid the calamity of misdiagnosis.

Inferior petrosal sinus ACTH and prolactin responses to CRH in ACTH-dependent Cushing's syndrome: a single centre experience from the United Kingdom

Inferior petrosal sinus sampling (IPSS) of ACTH with CRH stimulation helps distinguish pituitary ACTH-dependent Cushing's syndrome from the ectopic ACTH syndrome (EAS). The usefulness of the paradoxical response of other pituitary hormones including prolactin to CRH remains controversial. Data from 33 IPSS procedures carried out at the Walton Centre for Neurology and Neurosurgery in Liverpool were analyzed. Patients were selected for this procedure if they had been diagnosed with ACTH dependent Cushing's syndrome and the majority had no obvious pituitary adenoma on Magnetic Resonance Imaging. Satisfactory simultaneous bilateral catheterization was accomplished in 23/33 (success rate 70%). The diagnostic sensitivity of a basal central/peripheral ACTH ratio >2.0 and >3 post-CRH was 94%. In two patients with subsequently confirmed EAS the maximal central/peripheral ACTH ratio was <2.0 on basal samples and did not change following CRH. The maximal central/peripheral prolactin ratio was noted at 5 min post-CRH, coinciding with the maximal central/peripheral ACTH ratio. The intersinus gradient (ISG) of ACTH was paralleled by a consistent ISG of prolactin and in 7 out of 9 patients (with successful bilateral IPSS and unilateral adenomas) the ISG of prolactin correctly lateralized the microadenoma whereas the ISG of ACTH correctly lateralized in 8 out of 9 patients. Neither of the patients with EAS achieved a central/peripheral prolactin ratio >2 in the basal state and >3 post-CRH. Bilateral catheterization of inferior petrosal sinuses can be successful in up to 70% of cases. Prolactin measurements do not have superior lateralizing capability compared with ACTH but may be useful in the differential diagnosis of pituitary-driven from EAS.

Intraoperative optical identification of pituitary adenomas

INTRODUCTION

The main goals of transsphenoidal pituitary surgery are total removal of pituitary adenomas (PAs) and preservation of normal pituitary functions. Achieving these goals is dependent upon the precise localisation of PAs during surgery, particularly secreting microadenomas. However, some microadenomas are invisible on preoperative imaging and during surgery, leading some surgeons to perform total hypophysectomy in many patients to achieve cure at the expense of panhypopituitrism. We have examined optical detection systems to identify PAs intraoperatively. This paper reports our preliminary findings.

METHODS

A prospective observational study design.

TECHNIQUE

Patients were given 20 mg/kg body weight 5-aminolevulinic acid (ALA) mixed in 30 ml of orange juice, orally 3 h before surgery. Surgery was performed in the supine position, under image guidance, through the right nostril using Storz 0 degree endoscope assisted with microsurgery as required. The endoscope was attached to photodiagnostic filters (PD) allowing switching the light from white to blue at the flick of a foot pedal. After the dura of the floor of the sella was incised a laser probe was inserted into the pituitary gland to identify the ALA-induced protoporphyrin IX spectroscopy at 632 nm, using an optical biopsy system (OBS). Once the adenoma was identified by the OBS it was exposed and examined by the PD system to detect fluorescence. The PA was removed and its type was confirmed by histopathology and correlated to the OBS and PD system findings.

PATIENTS

Thirty consecutive patients were studied: 14 were non-functioning macroadenomas (NFA), 12 were secreting PAs and 4 pituitary cysts. The secreting PAs were GH (2), ACTH (3), prolactin (2) and gonadotrophins (5). Six were microadenomas (3 ACTH, 1 GH, 2 prolactin) and 20 were macroadenomas, of which 12 were invading macroadenomas. Twenty-four of these were examined by the OBS and the PD systems and six were examined by the PD system only. The true positive (sensitivity) of the PD and OBS systems were 80.8% (21/26) and 95.5% (21/22) respectively. The true negative (specificity) of PD and OBS were 75% (3/4) and 100% (2/2) respectively. The false negative rate of PD was 19.2% (5/26) and for OBS was 4.5% (1/22), while the false positive rate for PD was 25% (1/4) and for OBS was 0.

CONCLUSION

Intraoperative optical identification of pituitary adenomas is a feasible and reliable way to localize pituitary adenomas during transsphenoidal surgery and it may lead to improved cure rate and preservation of normal pituitary functions.

Selective use of bilateral inferior petrosal sinus sampling in patients with adrenocorticotropin-dependent Cushing's syndrome prior to transsphenoidal surgery

CONTEXT

Few data are available on the selective use of bilateral inferior petrosal sinus sampling (BIPSS) in the presurgical evaluation of patients with ACTH-dependent Cushing's syndrome, so we investigated whether its use only in patients without a clear adenoma on magnetic resonance imaging and/or inconsistent biochemical testing affected remission and long-term outcome after surgery in patients with Cushing's disease (CD).

SETTING

This was a retrospective review of patients treated for CD by one pituitary neurosurgeon at tertiary medical centers in New York City.

PATIENTS

A total of 193 consecutive adult patients who underwent initial transsphenoidal surgery (TS) for presumed CD between 1987 and 2005 were included.

MAIN OUTCOME MEASURES

We examined preoperative pituitary imaging and biochemical data, results of BIPSS and surgical pathology, and outcome based on biochemical tests after initial TS and long term after subsequent therapies.

RESULTS

Remission rate after the first TS was 80.8% overall, 79.1% in the BIPSS group (n = 105), and 83.0% in the No-BIPSS group (n = 88). Recurrences occurred in 13.5% after the first TS at a mean of 4.8 +/- 3.5 yr (range, 0.7-12.4 yr) with no difference between BIPSS and No-BIPSS groups. Long-term remission was achieved after surgeries and radiotherapy in 85% (86.7% of BIPSS group, 83.0% of No-BIPSS group). CD was ultimately confirmed in all but one patient in each group.

CONCLUSIONS

Selective use of BIPSS in the preoperative evaluation of patients with presumed CD did not lead to misdiagnosis in the No-BIPSS group or adversely affect remission rates or long-term outcome.

Surgery for Cushing's syndrome: an historical review and recent ten-year experience

BACKGROUND

Cushing's syndrome (CS), due to multiple etiologies, is a disorder associated with the ravages of cortisol excess. The purpose of this review article is to provide a historical synopsis of surgery for CS, review a recent 10-year period of operative management at a tertiary care facility, and to outline a practical approach to diagnosis and management.

MATERIALS AND METHODS

From 1996 to 2005, 298 patients underwent 322 operative procedures for CS at Mayo Clinic, Rochester, Minnesota. A retrospective chart review was carried out. Data was gathered regarding demographics, preoperative assessment, procedures performed, and outcomes. Data are presented as counts and percentages. Five-year survival rates were calculated where applicable by the Kaplan-Meier method. Statistical analysis was carried out with SAS, version 9 (SAS Institute, Inc., Cary, NC).

RESULTS

Two-hundred thirty-one patients (78%) had ACTH-dependent CS and 67 patients (22%) had ACTH-independent CS. One-hundred ninety-six patients (66%) had pituitary-dependent CS and 35 patients (12%) had ectopic ACTH syndrome. Fifty-four patients (18%) had cortisol-secreting adenomas, 10 patients (3%) had cortisol-producing adrenocortical carcinomas, and 1% had other causes. Cure rates for first time pituitary operations (transsphenoidal, sublabial, and endonasal) were 80% and 55% for reoperations. Most benign adrenal processes could be managed laparoscopically. Five-year survival rates (all causes) were 90%, 51%, and 23% for adrenocortical adenomas, ectopic ACTH syndrome, and adrenocortical carcinomas, respectively.

CONCLUSIONS

Surgery for CS is highly successful for pituitary-dependent CS and most ACTH-independent adrenal causes. Bilateral total adrenalectomy can also provide effective palliation from the ravages of hypercortisolism in patients with ectopic ACTH syndrome and for those who have failed transsphenoidal surgery. Unfortunately, to date, adrenocortical carcinomas are rarely cured. Future successes with this disease will likely depend on a better understanding of tumor biology, more effective adjuvant therapies and earlier detection. Clearly, IPSS, advances in cross-sectional imaging, along with developments in transsphenoidal and laparoscopic surgery, have had the greatest impact on today's management of the complex patient with CS.

Dynamic testing in Cushing's syndrome

Endogenous Cushing's syndrome (CS) results from chronic exposure to excess glucocorticoids. CS can be ACTH-dependent, caused by ACTH-secreting pituitary or ectopic tumours, or ACTH-independent, caused by cortisol-secreting adrenal tumours. CS can be an extremely difficult diagnosis to make, and assessment will include clinical, biochemical and radiological evaluation. Several screening tests are used for the confirmation of hyper-cortisolaemia and its differentiation from other, more frequent, clinical abnormalities, such as simple obesity, hypertension, depression etc. Other dynamic tests are useful for establishing the aetiology. We have reviewed the current literature on the diagnosis of CS, and based on these data and our own experience, suggest the most useful tests and diagnostic criteria to be used. We conclude that even though laboratory testing is a fundamental part of the investigation of patients with CS, the interpretation of the tests should always be performed with extreme care, as none of the tests has proven fully capable of distinguishing all cases of CS. The biochemical results should be interpreted jointly with the clinical aspects and the radiology findings in a probabilistic matrix, and not as part of a uniform algorithm.

The impact of cavernous sinus drainage pattern on the results of venous sampling in patients with suspected cushing syndrome

BACKGROUND AND PURPOSE

Selective venous sampling from the posterior portion of the cavernous sinus (CS) is recommended for the diagnosis of Cushing disease, because samples from the posterior portion yield higher adrenocorticotropic hormone (ACTH) levels than those from the anterior and middle portions. We prospectively assessed this intracavernous gradient of ACTH level to determine which site in the CS yields adequate sampling.

MATERIALS AND METHODS

In 5 patients with Cushing syndrome, cavernous sinography was performed to assess drainage pattern of the CS. Sampling was performed from the anterior, middle, and posterior parts of the CS, inferior petrosal sinus (IPS), and the peripheral vein. The ratio of the concentration in CS and IPS to that in peripheral blood plasma (C/P ratio) was calculated.

RESULTS

Cavernous sinography showed that the main drainage route was the IPS in 6 sides and that the pterygoid plexus (PP) was developed to the same extent as the IPS in 3 sides. In 1 patient, the CS drained mainly to the PP. In 1 patient with an ectopic lesion, no increase in ACTH level was detected. In 3 of 4 patients with Cushing disease, the highest C/P ratio was obtained from the posterior portion. In 1 patient whose main drainage route was the PP, the highest C/P ratio was obtained from the anterior portion. In this case, sampling data from the posterior portion and the IPS yielded false-negative results.

CONCLUSION

Understanding the drainage patterns of the CS is essential for interpretation of sampling data from the CS and avoiding false-negative results.

Use of desmopressin as an alternative to corticotropin-releasing hormone during inferior petrosal sinus sampling in a child with Cushing's disease

Cushing's syndrome (CS) is rare in children. Information on bilateral inferior petrosal sinus sampling (BIPSS) in children with CS is limited. In the procedure CRH is always used to stimulate ACTH values. In addition, growth failure is the main complication of pediatric CS, mainly due to a profound GH suppression that persists for a few months after cure of the disease. Early treatment with recombinant GH after CS cure may partly reverse this phenomenon. We report herein a case of Cushing's disease (CD) in a 7-yr-old child, presenting with severe growth failure. No pituitary adenoma was shown on magnetic resonance imaging and a BIPSS using desmopressin allowed the identification of a central to peripheral (C/P) gradient; however transphenoidal surgery (TSS) did not cure the disease thus requiring the performance of bilateral adrenalectomy. After cure of the disease, a partial catch up of the growth delay occurred without any GH treatment. Our case reinforces the fact that BIPSS can be performed safely in very young children with CD. It also suggests for the first time that the use of desmopressin during the procedure gives the same information as CRH, as well as confirming the fact that the success of TSS is poor in very young children. Finally, it suggests that growth failure in children with CS can be partially reversed after surgical cure of the disease without any GH treatment and that the high IGF-I observed during corticosteroid replacement therapy is due to a state of IGF-I resistance.

In vivo response to growth hormone-releasing peptide-6 in adrenocorticotropin-dependent Cushing's syndrome by lung carcinoid tumor is associated with growth hormone secretagogue receptor type 1a mRNA expression

GH secretagogues (GHS) have been used for the differential diagnosis of ACTH-dependent Cushing's syndrome (CS) since 1997 due to their ability to increase ACTH and cortisol levels in Cushing's disease. The aim of this study was to correlate ACTH response to GH-releasing peptide-6 (GHRP-6) in vivo with GH secretagogue receptor type 1a (GHSR-1a) mRNA expression in a patient with lung carcinoid tumor. The patient was a 26-yr-old male with diagnosis of ACTH-dependent CS. He presented negative responses to human CRH and desmopressin tests; yet, a significant increase in ACTH after the GHRP-6 test was observed. Sellar magnetic resonance imaging (MRI) showed slight posterior hypointensity, but bilateral petrosal sinus sampling did not show central gradient. Computed tomography (CT) and MRI of thorax/abdomen/cervical were negative and 111In-pentetreotide scintigraphy depicted abnormal uptake on the right lung. The patient was submitted to right thoracotomy for exeresis of lung nodule and hilar lymph node which were characterized as atypical lung carcinoid tumor and he presented clinical and laboratorial remission after surgery. GHSR-1a mRNA expression was studied with real-time quantitative PCR and tumor data were compared with fragments of normal lung and pituitary. There was a higher GHSR-1a expression in the lung carcinoid tumor as compared with normal tissues. The ACTH response to GHRP-6 in a patient with ectopic ACTH production by a lung carcinoid tumor was associated with GHSR-1a expression in the tumor tissue, suggesting an association between GHSR-1a mRNA overexpression and the in vivo response to GHS.

Multi-step approach in a complex case of Cushing's syndrome and medullary thyroid carcinoma

The diagnosis of Cushing's syndrome (CS) may sometimes be cumbersome. In particular, in ACTH-dependent CS it may be difficult to distinguish between the presence of an ACTH-secreting pituitary adenoma and ectopic ACTH and/or CRH secretion. In such instances, the etiology of CS may remain unknown despite extensive diagnostic workout, and the best therapeutic option for each patient has to be determined. We report here the case of a 54-yr-old man affected by ACTH-dependent CS in association with a left adrenal adenoma and medullary thyroid carcinoma (MTC). He presented with clinical features and laboratory indexes of hypercortisolism associated with elevated levels of calcitonin. Ectopic CS due to MTC was reported previously. In our case hypercortisolism persisted after surgical treatment of MTC. Thorough diagnostic assessment was performed, in order to define the aetiology of CS. He was subjected to basal and dynamic hormonal evaluation, including bilateral inferior petrosal sinus sampling. Extensive imaging evaluation was also performed. Overall, the laboratory data together with the results of radiological procedures suggested that CS might be due to inappropriate CRH secretion. However, the source of CRH secretion in this patient remained unknown. It was then decided to remove the left adenomatous adrenal gland. Cortisol level fell and has remained within the normal range nine months after surgery. This case well depicts the complexity of the diagnostic workout, which is needed sometimes to correctly diagnose and treat CS, and suggests that monolateral adrenalectomy may represent, at least temporarily, a reasonable therapeutic option in occult ACTH-dependent hypercortisolism.

Cushing's disease: a surgical view

The management of adrenocorticotropic hormone (ACTH)-dependent Cushing's disease implies difficulties in the differential diagnosis, in the detection of minute pituitary adenomas, as well as in the radical removal of invasive adenomas. Magnetic resonance imaging (MRI) is unspecific and often negative in minute adenomas of three or less millimeters diameter. The trias of detectable ACTH, suppression of cortisol in the high-dose dexamethasone test, and stimulation in the corticotropin-releasing-hormone (CRH)-test has a high accuracy to prove pituitary dependency. In unclear cases, the use of inferior petrosal sinus sampling (IPSS) or cavernous sinus sampling (CSS) for the exclusion of ectopic ACTH-syndrome is currently advised especially in cases where cranial MRI is negative. The reliability of these methods to localize the mostly lateralized microadenomas is still discussed. Transsphenoidal microsurgical adenomectomy, the accepted primary therapy of Cushing's disease, has been published from experienced pituitary centers with remission rates ranging from 70% to 98% in the last decade. False diagnosis (pseudo-Cushing, ectopic ACTH-syndrome), incorrect adenoma localization by IPSS or CSS, and the rate of minute or non-resectable invasive tumors influence the results. The handling of minute specimen implies problems for surgeon and pathologist. Intraoperative tumor localization was improved by ACTH measurement from the cavernous sinus and the adenoma itself, by cytology, and frozen sections. The histology of the anterior lobe (rate of Crooke's cells) bears information of clinical relevance. Invasive macroadenomas may deserve repeat microsurgery, medical treatment, and radiosurgery.