Proposed diagnostic criteria for subclinical Cushing's syndrome associated with adrenal incidentaloma

Biochemical Evaluation by Confirmatory Tests after Unilateral Adrenalectomy for Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. Unilateral PA can be cured using unilateral adrenalectomy (Adx). PA surgery outcome (PASO) criteria, which include clinical and biochemical outcomes, have been proposed to evaluate PA cure after Adx. However, clinical outcomes are often inconsistent with biochemical outcomes. In addition, although confirmatory tests are included as endpoints of biochemical outcomes in the PASO criteria, their clinical usefulness has not yet been established. We evaluated clinical parameters and confirmatory test results before and after Adx in 16 patients with PA and assessed the usefulness of the confirmatory tests. The following were the clinical outcomes after Adx: 37.5% complete success, 62.5% partial success, and 0% absent success. The ratio of biochemical complete success was as follows: 69% aldosterone/renin ratio and basal plasma aldosterone concentration, 19% as assessed by the captopril challenge test, 47% as assessed by the saline infusion test, 30% as assessed by the furosemide upright test, and 100% urine aldosterone. Of these, biochemical complete success was judged in four cases by aldosterone/renin ratio and basal plasma aldosterone concentration, one case by captopril challenge test, five cases by saline infusion test, and one case by furosemide upright test. Although clinical outcomes and urine aldosterone levels improved after Adx, confirmatory tests failed to improve in some cases. The current criteria are not considered useful for biochemical evaluation after Adx. To determine whether additional treatment with mineralocorticoid receptor antagonists is required, more accurate biochemical criteria should be established after Adx.

Apparent failed and discordant adrenal vein sampling: A potential confounding role of cortisol cosecretion?

OBJECTIVE

Adrenal vein sampling (AVS) and computed tomography (CT) often show confusingly discordant lateralisation results in primary aldosteronism (PA). We tested a biochemical algorithm using AVS data to detect cortisol cosecretion as a potential explanation for discordant cases.

DESIGN

Retrospective analysis from a large PA + AVS database.

PATIENTS

All patients with PA and AVS, 2005-2020.

MEASUREMENTS

An algorithm using biochemical data from paired AVS + CT images was devised from physiological first principles and informed by data from unilateral, AVS-CT concordant patients. The algorithm involved calculations based upon the expectation that low cortisol levels exist in adrenal vein effluent opposite an aldosterone-and-cortisol-producing adrenal mass and may reverse lateralisation due to inflated aldosterone/cortisol ratios.

MAIN OUTCOMES

The algorithm was applied to cases with discordant CT-AVS lateralisation to determine whether this might be a common or explanatory finding. Clinical and biochemical characteristics of identified cases were collected via chart review and compared to CT-AVS concordant cases to detect evidence of biological plausibility for cortisol cosecretion.

RESULTS

From a total of 588 AVS cases, 141 AVS + CT pairs were clear unilateral PA cases, used to develop the three-step algorithm for AVS interpretation. Applied to 88 AVS + CT discordant pairs, the algorithm suggested possible cortisol cosecretion in 40%. Case review showed that the proposed cortisol cosecretors, as identified by the algorithm, had low/suppressed adrenocorticotropic hormone levels, larger average nodule size and lower plasma aldosterone.

CONCLUSIONS

Pending external validation and outcome verification by surgery and tissue immunohistochemistry, cortisol cosecretion from aldosteronomas may be a common explanation for discordant CT-AVS results in PA.

Current challenges in laboratory diagnostics of autonomous cortisol secretion in adrenal incidentalomas

Adrenal incidentalomas are unexpectedly identified adrenal masses without prior suspicion of the existence of adrenal disease. The majority of adrenal incidentalomas are benign adrenal adenomas (80-90%), and they are non-functioning adrenocortical adenomas in more than 70% of cases. Mild hypercortisolemia is the most common finding in hormonally active adrenal incidentalomas. It is defined as autonomous cortisol secretion in up to 15% of patients. Despite a lot of research that anticipated higher cardiometabolic risk in patients with autonomous cortisol secretion, there is still no clear consensus on biochemical criteria for an autonomous cortisol secretion diagnosis in patients with adrenal incidentalomas. This review delineates the advantages and limitations of different laboratory tests recommended for the diagnosis of autonomous cortisol secretion in adrenal incidentalomas.

Association between Neutrophilic Granulocyte Percentage and Diabetes Mellitus in Cushing's Syndrome Patients: A Cross-Sectional Study

BACKGROUND

Glucose metabolism is frequently impaired in patients with Cushing's syndrome (CS) due to chronic exposure to excess glucocorticoids. Inflammation plays an essential role in the pathophysiology of diabetes mellitus (DM). The present study aimed to investigate the potential associations of inflammatory blood cell parameters, including white blood cell (WBC) count, neutrophil count, neutrophilic granulocyte percentage (NEUT%), lymphocyte count (LYM), and lymphocyte proportion (LYM%), with diabetes mellitus in Cushing's syndrome patients.

MATERIALS AND METHODS

The cross-sectional study was conducted in Zhongshan Hospital of Fudan University, China. A total of 150 patients with Cushing's syndrome were retrospectively screened from 2017 to 2019. The demographic data, clinical data, and blood samples (lipids, adrenal, glucose, and inflammatory blood cell parameters) were recorded. Statistical analyses were carried out by using the SPSS software package, version 13.0.

RESULTS

In this study, the prevalence of diabetes mellitus was 38.7% in patients with Cushing's syndrome. Patients with DM had higher WBC, neutrophil, NEUT% levels than patients without DM (p < 0.05). As the NEUT% increased, a stepwise increase in glucose and glycated hemoglobin (HbA1c) level was observed. In addition, in the multivariate logistic regression, NEUT% was a significant independent risk factor for DM, regardless of gender, age, body mass index (BMI), and triglyceride and 12 midnight cortisol (12 MN cortisol) level (OR = 2.542, 95% CI 1.337-4.835, p < 0.001).

CONCLUSIONS

In conclusion, elevated NEUT% level was linked to diabetes in patients with Cushing's syndrome. The neutrophilic granulocyte percentage may be referred to as a new predictor for diabetes in Cushing's syndrome patients.

Application of adrenal maximum standardized uptake value to 131I-6β-iodomethyl-19-norcholesterol SPECT/CT for characterizing unilateral hyperfunctioning adrenocortical masses

PURPOSE

To evaluate the maximum standardized uptake value (SUVmax) by ¹³¹I-6β-iodomethyl-19-norcholesterol (NP-59) single-photon emission computed tomography (SPECT)/computed tomography (CT) for characterizing unilateral hyperfunctioning adrenocortical masses.

METHODS

Ten patients underwent NP-59 SPECT/CT to evaluate the following unilateral adrenocortical hyperfuncting masses: three with Cushing's syndrome (CS), three with subclinical CS, and four with primary aldosteronism (PA). Visual and quantitative or semiquantitative analyses (noncontrast CT HU [Hounsfield units], lesion SUVmax, contralateral SUVmax, and SUVmax ratio [lesion SUVmax/contralateral adrenal SUVmax]) were performed. The Mann-Whitney U test or Chi-squared test was used appropriately to assess differences between quantitative variables or compare categorical data. Diagnostic performance was evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

All adrenal tumors were diagnosed as cortical adenomas. On visual analysis, unilateral uptake was noted in three patients with CS and one patient with subclinical CS, whereas bilateral uptake was noted in four patients with PA and two patients with subclinical CS (p = 0.046). No significant difference was observed in CT HU (p = 0.055). The lesion SUVmax and SUVmax ratio were significantly higher and the contralateral SUVmax was significantly lower in six patients with CS than in four patients with PA (each, p < 0.05). The area under the ROC curve and accuracy for differentiating between CS and PA were, respectively, 0.92 and 90.0 % for the lesion SUVmax, 1.00 and 100 % for the contralateral SUVmax, and 0.92 and 90.0 % for the SUVmax ratio.

CONCLUSIONS

Quantitative or semiquantitative analysis using the adrenal SUVmax in adrenocortical NP-59 SPECT/CT has potential for characterizing unilateral hyperfunctioning adrenocortical masses.

Genetic and epigenetic analyses of aldosterone-producing adenoma with hypercortisolemia

DNA methylation is associated with excess cortisol and aldosterone. The DNA encoding aldosterone synthase (CYP11B2) and 11β-hydroxylase (CYP11B1), which catalyzes the final step of cortisol biosynthesis, is less methylated in aldosterone-producing adenomas (APA) and cortisol-producing adenomas (CPA), respectively. Several studies have reported specific gene mutations in APA and CPA, and some APAs also cause hypercortisolemia. The aim of this study was to clarify the molecular mechanisms of cortisol co-production in APA using genetic and epigenetic analyses. We evaluated 16 patients with APA between 2011 and 2018 at Kanazawa University Hospital (Ishikawa, Japan). The diagnostic criteria for hypercortisolemia were based on the guideline from the Endocrine Society. Gene mutation and DNA methylation analyses of the CYP11B2 and CYP11B1 promoters in APA were performed. Of the 16 patients with APA, six also had hypercortisolemia. In the genetic analysis, all six APAs with hypercortisolemia as well as eight of the 10 APAs without hypercortisolemia had a KCNJ5 mutation. In the epigenetic analyses, the methylation status of the CYP11B2 promoter was similar in the APAs with and without hypercortisolemia. However, in the APAs with hypercortisolemia, the CYP11B1 promoter was significantly less methylated, especially at two CpG sites near the Ad1/cAMP response element binding site within the CYP11B1 promoter. In conclusion, the genetic analysis revealed no association between hypercortisolemia and the evaluated gene mutations. However, the epigenetic analysis suggested that DNA methylation of the CYP11B1 promoter plays a role in concurrent hypercortisolemia and APA.

Changes in glucose metabolism based on 75-g oral glucose tolerance tests before and after surgery for adrenal Cushing's syndrome

Adrenal Cushing's syndrome (CS) is caused by cortisol-producing adrenal adenoma and is frequently accompanied by glucose metabolism disorders, which are characterized by increased insulin resistance and insufficient β-cell compensation. However, considering the rarity of CS, few studies have assessed whether the glucose metabolism disorders could be ameliorated by surgical treatment. In this case series, we evaluated glucose metabolism before and after surgery in 11 patients (10 women and 1 man) who underwent unilateral adrenalectomy for overt adrenal CS between 2005 and 2016. Patients with pre-diagnosed diabetes mellitus (DM) were excluded. Pre- and post-operative 75-g oral glucose tolerance tests were performed. Cortisol secretion decreased significantly after surgery (median 24-h urinary free cortisol: 582.0 μg/day [interquartile range: 321.0-743.0 μg/day] to 31.3 μg/day [23.6-40.6 μg/day], p = 0.001). The results of the OGTT generally improved after surgery (normal glucose tolerance/impaired glucose tolerance/DM: 2/8/1 to 8/3/0), with significant decreases in the immunoreactive insulin and glucose levels. We also found a decrease in the median homeostatic model assessment of insulin resistance (2.4 [1.4-2.8] to 1.0 [0.6-1.1], p = 0.002), and increases in the median Matsuda index (3.0 [2.3-4.5] to 8.2 [6.3-11.4], p < 0.001), median insulinogenic index (0.70 [0.22-1.51] to 1.22 [0.78-1.64], p = 0.08), and median disposition index (609.1 [237.8-1,095.2] to 1,286.0 [1,034.6-1,857.6], p = 0.002). These findings indicate that adrenalectomy for adrenal CS without overt DM may help ameliorate glucose metabolism disorders, and improve both insulin resistance and insulin secretion.

Clinical Investigation of Adrenal Incidentalomas in Japanese Patients of the Fukuoka Region with Updated Diagnostic Criteria for Sub-clinical Cushing's Syndrome

Objectives We retrospectively investigated the clinical and endocrinological characteristics of adrenal incidentalomas. Methods We studied 61 patients who had been diagnosed with adrenal incidentalomas and had undergone detailed clinical and endocrinological evaluations while hospitalized. We used common criteria to diagnose the functional tumors, but for sub-clinical Cushing's syndrome, we used an updated set of diagnosis criteria: serum cortisol ≥1.8 μg/dL after a positive response to a 1-mg dexamethasone suppression test if the patient has a low morning adrenocorticotropic hormone (ACTH) level (<10 pg/mL) and a loss of the diurnal serum cortisol rhythm. Results Of the 61 patients, none (0%) had malignant tumors, 8 (13.1%) had pheochromocytoma, and 15 (24.6%) had primary aldosteronism; when diagnosed by our revised criteria, 13 (21.3%) had cortisol-secreting adenomas (Cushing's syndrome and sub-clinical Cushing's syndrome), and 25 (41.0%) had non-functional tumors. Compared with the non-functional tumor group, the primary aldosteronism group and the cortisol-secreting adenoma group were significantly younger and had significantly higher rates of hypokalemia, whereas the pheochromocytoma group had significantly larger tumors and a significantly lower body mass index. Conclusion Our study found a larger percentage of functional tumors among adrenal incidentalomas than past reports, partly because we used a lower serum cortisol level after a dexamethasone suppression test to diagnose sub-clinical Cushing's syndrome and because all of the patients were hospitalized and could therefore receive more detailed examinations. Young patients with hypokalemia or lean patients with large adrenal tumors warrant particularly careful investigation.

The impact of an adrenal incidentaloma algorithm on the evaluation of adrenal nodules

Objective

To determine the impact of the use of an electronic medical record tool on the evaluation of adrenal incidentalomas.

Methods

Retrospective chart review was used to compare rates of hormone testing and follow up imaging for adrenal incidentalomas. Patients whose radiology reports contained an algorithm with recommendations, based on our 2013 clinical guideline for the workup of these nodules, were compared to those whose imaging reports did not contain the algorithm.

Results

For patients whose Radiology reports contained the algorithm, 69% had hormonal testing versus 43% of controls (p < 0.0001). By contrast, 57% of study group patients had a follow up imaging study, compared to 51% of controls (p = 0.1000). However, when the 18% of controls that were given guidance by the radiologist to perform follow-up imaging were excluded from those who received no guidance, there was a statistically significant difference in the rate of follow up imaging (57% vs 48%, p < 0.0001).

Conclusion

Implementation of a clinical algorithm for the evaluation of adrenal incidentalomas in radiology reports and on the intranet site of a major clinical center led to improved rates of hormone testing. There was also a significant increase in the rate of follow up imaging, compared to when no guidance was given. Additional efforts to further improve performance are needed to increase the detection of clinically significant lesions, particularly hormone secreting tumors that should be removed.

New diagnostic criteria of adrenal subclinical Cushing's syndrome: opinion from the Japan Endocrine Society

New diagnostic criteria and the treatment policy for adrenal subclinical Cushing's syndrome (SCS) are proposed on behalf of the Japan Endocrine Society. The Japanese version has been published, and the essential contents are presented in this English-language version. The current diagnostic criteria for SCS have elicited two main problems: (i) the relatively low reliability of a low range of serum cortisol essential for the diagnosis by an overnight 1-mg dexamethasone suppression test (DST); (ii) different cutoff values for serum cortisol after a 1-mg DST compared with those of other countries. Thus, new criteria are needed. In the new criteria, three hierarchical cortisol cutoff values, 5.0, 3.0 and 1.8 μg/dL, after a 1-mg DST are presented. Serum cortisol ≥5 μg/dL after a 1-mg DST alone is considered sufficient to judge autonomous cortisol secretion for the diagnosis of SCS, and the current criterion based on serum cortisol ≥3 μg/dL after a 1-mg DST can continue to be used. Clinical evidence suggests that serum cortisol ≥1.8-2.9 μg/dL after a 1-mg DST is not always normal, so cases who meet the cutoff value as well as a basal adrenocorticotropic hormone (ACTH) level <10 pg/mL (or poor ACTH response to corticotropin-releasing hormone (CRH)) and nocturnal serum cortisol ≥5 μg/dL are proposed to have SCS. We suggest surgery if cases show serum cortisol ≥5 μg/dL after a 1-mg DST (or are disheartened by treatment-resistant problems) or suspicious cases of adrenal cancer according to tumor imaging.

In the overnight dexamethasone suppression test, 1.0 mg loading is superior to 0.5 mg loading for diagnosing subclinical adrenal Cushing's syndrome based on plasma dexamethasone levels determined using liquid chromatography-tandem mass spectrometry

The low-dose dexamethasone suppression test (DST) is one of the commonly used initial tests for endogenous Cushing's syndrome (CS). However, there are two loading dose regimens (0.5-mg and 1-mg), which may cause some confusion in daily practice in Japan; furthermore, there are no reports regarding whether 0.5-mg DST is a better loading dose for detecting adrenal subclinical CS (SCS) based on the plasma dexamethasone (DEX) levels. Therefore, the aims of this study were (a) to develop a novel assay to measure DEX by using liquid chromatography tandem-mass spectrometry (LC-MS/MS) and (b) to compare between the 0.5-mg and 1-mg DST for SCS diagnosis based on the DEX levels. The study retrospectively analyzed 52 consecutive subjects hospitalized for diagnosis of adrenal incidentaloma but who did not exhibit an overt CS phenotype; eight (15.4%) patients were affected with adrenal SCS. Inter-individual variability of DEX levels after the DST was high, but intra-individual variability was low. DEX levels after 1-mg loading in each patient was around two times higher than those after 0.5-mg loading (ρ = 0.853 and p < 0.001). There were 45 (86.5%) and 17 (32.7%) subjects with DEX levels ≤2.2 ng/mL after the 0.5-mg and 1-mg DST, respectively (p < 0.001). Twenty-eight (93.3%) of 30 subjects and four (21.1%) of 19 subjects with detectable ACTH levels after the 0.5-mg and 1.0-mg DST, respectively, did not exhibit DEX levels >2.2 ng/mL. These results clearly indicate that the 1-mg DST is superior to 0.5-mg loading for the diagnosis of adrenal SCS.

A Novel Method: Super-selective Adrenal Venous Sampling

Primary aldosteronism (PA) and subclinical Cushing's syndrome (SCS) are conditions in which the adrenal glands autonomously produce excessive amounts of aldosterone and cortisol, respectively. The conventional adrenal venous sampling (cAVS) method collects blood samples from both adrenal central veins and is useful for identifying the laterality of excess hormone production in a unilateral lesion(s), as documented in PA cases. In cAVS, plasma cortisol concentrations (PCCs) are used to normalize plasma aldosterone concentrations (PACs). A novel "super-selective" adrenal venous sampling (ssAVS) method was developed using a micro-catheter, which collects blood samples from adrenal tributary veins (TVs). PACs in ssAVS samples do not require PCC normalization because samples contain a limited amount of systemic venous blood, if any. The ssAVS method enabled segmental lesion(s) to be detected in both adrenal glands, which may be treated by bilateral adrenalectomy, thereby sparing lesion-free segment(s). Right and left adrenals typically have three TVs each, i.e., the superior, lateral, and inferior TVs in the right adrenal as well as the superior-median, superior-lateral, and lateral TVs in the left adrenal. In the ssAVS method, specific parent catheters and a technique to handle them are required, and have been described herein. Furthermore, ssAVS results from three cases of PA are presented: bilateral aldosterone-producing adenoma (APA) (Case #1), left APA and right possible cortisol-producing adenoma causing SCS (Case #2), and idiopathic hyperaldosteronism in which bilateral adrenal segments produced excessive amounts of aldosterone (Case #3). The ssAVS method is not difficult for expert angiographers, and, thus, is recommended worldwide to treat PA cases for which cAVS does not represent a viable surgical treatment option.

Cushing's syndrome: a practical approach to diagnosis and differential diagnoses

Diagnosis of Cushing's syndrome (CS) and identification of the aetiology of hypercortisolism can be challenging. The Endocrine Society clinical practice guidelines recommends one of the four tests for initial screening of CS, namely, urinary-free cortisol, late night salivary cortisol, overnight dexamethasone suppression test or a longer low-dose dexamethasone suppression test, for 48 hours. Confirmation and localisation of CS requires additional biochemical and radiological tests. Radiological evaluation involves different imaging modalities including MRI with or without different radio-nuclear imaging techniques. Invasive testing such as bilateral inferior petrosal sinus sampling may be necessary in some patients for accurate localisation of the cause for hypercortisolism. This best practice review discusses a practical approach for the diagnostic evaluation of CS with a brief discussion on differential diagnoses, and cyclical CS, to enhance the skills of clinicians and laboratory personnel.

Measuring cortisol in serum, urine and saliva - are our assays good enough?

Cortisol is a steroid hormone produced in response to stress. It is essential for maintaining health and wellbeing and leads to significant morbidity when deficient or present in excess. It is lipophilic and is transported bound to cortisol-binding globulin (CBG) and albumin; a small fraction (∼10%) of total serum cortisol is unbound and biologically active. Serum cortisol assays measure total cortisol and their results can be misleading in patients with altered serum protein concentrations. Automated immunoassays are used to measure cortisol but lack specificity and show significant inter-assay differences. Liquid chromatography - tandem mass spectrometry (LC-MS/MS) offers improved specificity and sensitivity; however, cortisol cut-offs used in the short Synacthen and Dexamethasone suppression tests are yet to be validated for these assays. Urine free cortisol is used to screen for Cushing's syndrome. Unbound cortisol is excreted unchanged in the urine and 24-h urine free cortisol correlates well with mean serum-free cortisol in conditions of cortisol excess. Urine free cortisol is measured predominantly by immunoassay or LC-MS/MS. Salivary cortisol also reflects changes in unbound serum cortisol and offers a reliable alternative to measuring free cortisol in serum. LC-MS/MS is the method of choice for measuring salivary cortisol; however, its use is limited by the lack of a single, validated reference range and poorly standardized assays. This review examines the methods available for measuring cortisol in serum, urine and saliva, explores cortisol in disease and considers the difficulties of measuring cortisol in acutely unwell patients and in neonates.

Disorganized Steroidogenesis in Adrenocortical Carcinoma, a Case Study

Most adrenocortical carcinomas (ACCs) produce excessive amounts of steroid hormones including aldosterone, cortisol, and steroid precursors. However, aldosterone- and cortisol-producing cells in ACCs have not yet been immunohistochemically described. We present a case of ACC causing mild primary aldosteronism and subclinical Cushing's syndrome. Removal of the tumor cured both conditions. In order to examine the expression patterns of the steroidogenic enzymes responsible for adrenocortical hormone production, 10 tumor portions were immunohistochemically analyzed for aldosterone synthase (CYP11B2), 11β-hydroxylase (CYP11B1, cortisol-synthesizing enzyme), 3β-hydroxysteroid dehydrogenase (3βHSD, upstream enzyme for both CYP11B2 and CYP11B1), and 17α-hydroxylase/C17-20 lyase (CYP17, upstream enzyme for CYP11B1, but not for CYP11B1). CYP11B2, CYP11B1, and 3βHSD were expressed sporadically, and their expression patterns varied significantly among the different tumor portions examined. The expression of these enzymes was random and not associated with each other. CYP17 was expressed throughout the tumor, even in CYP11B2-positive cells. Small tumor cell populations were aldosterone- or cortisol-producing cells, as judged by 3βHSD coinciding with either CYP11B2 or CYP11B1, respectively. These results suggest that the tumor produced limited amounts of aldosterone and cortisol due to the lack of the coordinated expression of steroidogenic enzymes, which led to mild clinical expression in this case. We delineated the expression patterns of steroidogenic enzymes in ACC. The coordinated expression of steroidogenic enzymes in normal and adenoma cells was disturbed in ACC cells, resulting in the inefficient production of steroid hormones in relation to the large tumor volume.

Immunohistochemistry of aldosterone synthase leads the way to the pathogenesis of primary aldosteronism

Our group previously purified human and rat aldosterone synthase (CYP11B2 and Cyp11b2, respectively) from their adrenals and verified that it is distinct from steroid 11β-hydroxylase (CYP11B1 or Cyp11b1), the cortisol- or corticosterone-synthesizing enzyme. We now describe their distributions immunohistochemically with specific antibodies. In rats, there is layered functional zonation with the Cyp11b2-positive zona glomerulosa (ZG), Cyp11b1-positive zona fasciculata (ZF), and Cyp11b2/Cyp11b1-negative undifferentiated zone between the ZG and ZF. In human infants and children (<12 years old), the functional zonation is similar to that in rats. In adults, the adrenal cortex remodels and subcapsular aldosterone-producing cell clusters (APCCs) replace the continuous ZG layer. We recently reported possible APCC-to-APA transitional lesions (pAATLs) in 2 cases of unilateral multiple adrenocortical micro-nodules. In this review, we present 4 additional cases of primary aldosteronism, from which the extracted adrenals contain pAATLs, with results of next generation sequencing for these lesions. Immunohistochemistry for CYP11B2 and CYP11B1 has become an important tool for the diagnosis of and research on adrenocortical pathological conditions and suggests that APCCs may be the origin of aldosterone-producing adenoma.

Contralateral adrenal suppression on adrenocortical scintigraphy provides good evidence showing subclinical cortisol overproduction from unilateral adenomas

Unilateral and/or predominant uptake on adrenocortical scintigraphy (ACS) may be related to autonomous cortisol overproduction in patients with subclinical Cushing's syndrome (SCS). However, there is no information regarding whether increased tracer uptake on the tumor side or decreased uptake on the contralateral side on ACS is more greatly associated with inappropriate cortisol production. Therefore, we evaluated the relationship between quantitative ¹³¹I-6β-iodomethyl-norcholesterol (¹³¹I-NP-59) uptake in both adrenal glands and parameters of autonomic cortisol secretion and attempted to set a cut off for SCS detection. The study included 90 patients with unilateral adrenal adenoma who fulfilled strict criteria. The diagnosis of SCS was based on serum cortisol ≥3.0 μg/dL after 1-mg dexamethasone suppression test (DST) with at least 1 other hypothalamus-pituitary-adrenal axis function abnormality. Twenty-two (27.7%) subjects were diagnosed with SCS. The uptake rate on the affected side in the SCS group was comparable to that in the non-functioning adenoma group. In contrast, the uptake rate on the contralateral side was lower and the laterality ratio significantly higher in the SCS group. The two ACS indices were correlated with serum cortisol levels after a 1-mg DST, but uptake on the tumor side was not. Tumor size was also important for the functional statuses of adrenal tumors and NP-59 imaging patterns. The best cut-off point for the laterality ratio to detect SCS was 3.07. These results clearly indicate that contralateral adrenal suppression in ACS is good evidence showing subclinical cortisol overproduction.

GNAS mutations in adrenal aldosterone-producing adenomas

Mutations in GNAS, which encodes Gsα, have been documented in detail, particularly in human pituitary GH-secreting adenomas. Mutations have also recently been reported in adrenal cortisol-producing adenomas (CPAs), in addition to those in the PRKACA gene. However, mutations have not yet been examined in aldosterone-producing adenomas (APAs). Therefore, we herein investigated mutations in the GNAS gene in APAs. Two of the 15 (13%) CPAs with overt Cushing's syndrome and one of the 9 (11%) CPAs with subclinical Cushing's syndrome examined had the somatic mutations, p.R201S and p.R201C in the GNAS gene. We identified mutations in the GNAS gene (p.R201C) in 2 out of the 33 (6%) APAs tested, both of which showed autonomous cortisol secretion, while 24 APAs had mutations in the KCNJ5 gene (18 with p.G151R and 6 with p.L168R). These GNAS and KCNJ5 mutations were mutually exclusive in these adenomas. We herein demonstrated for the first time the presence of GNAS mutations in APAs, as well as in some cortisol-secreting adenomas. Our results suggest that these mutations, in addition to mutations in the KCNJ5 gene and other genes such as ATP1A1, ATP2B3 and CACNA1D, may be responsible for the tumorigenesis of APAs and CPAs with subclinical Cushing's syndrome.

Serum Adiponectin Level as a Predictor of Subclinical Cushing's Syndrome in Patients with Adrenal Incidentaloma

Subclinical Cushing's syndrome (SCS) is a condition of slight but chronic cortisol excess in patients with adrenal incidentaloma (AI) without typical signs and symptoms of Cushing's syndrome. Adiponectin has potent roles in modulating energy balance and metabolic homeostasis and acts in opposition to glucocorticoids. This study aimed to evaluate adiponectin level in SCS and nonfunctional AI (NAI) patients and its relation with metabolic parameters. Patients with AI (n = 40) and metabolically healthy controls (n = 30) were included. In AI patients and controls, detailed medical history assessment, physical examinations, anthropometric measurements, and laboratory measurements were performed. Age, body mass index, waist circumference, and lipid profiles were significantly higher and waist-to-hip ratio and adiponectin level were significantly lower in the AI patients than in the controls. The midnight cortisol and urinary free cortisol levels were significantly higher in the SCS patients (n = 8) than in the NAI patients (n = 32). Adiponectin level of the SCS group was significantly lower than those of the NAI and control groups. The sensitivity and specificity for an adiponectin level of ≤13.00 ng/mL in predicting the presence of SCS were 87.5% and 77.4%, respectively. In conclusion, adiponectin is valuable in predicting the presence of SCS in AI patients.

Update on subclinical Cushing's syndrome

PURPOSE OF REVIEW

The present review summarizes recent findings in the diagnosis and treatment of subclinical Cushing's syndrome, a condition of subtle cortisol dysregulation with a spectrum of clinical and biochemical abnormalities.

RECENT FINDINGS

The diagnosis of subclinical Cushing's syndrome is suggested by abnormal suppression to dexamethasone in a patient with an adrenal mass. The natural history of this disorder includes progression in a minority of cases, and increased cardiovascular disease in patients with more severe and progressive disease, much as is found in overt Cushing's syndrome. In patients with an abnormal response to dexamethasone, additional biochemical and metabolic features increase confidence in the ability of adrenalectomy to reverse clinical abnormalities. In addition, bilateral masses and larger masses are more likely to be associated with hypercortisolism.

SUMMARY

We review the recent literature on subclinical cortisol secretion and suggest that additional studies are needed to define optimal diagnostic and therapeutic approaches.

DHEAS for the prediction of subclinical Cushing's syndrome: perplexing or advantageous?

The diagnostic accuracy of dehydroepiandrosterone sulfate (DHEAS) to predict subclinical Cushing's syndrome (sCS) has been a matter of debate. The primary objective of this study was to assess the diagnostic power of DHEAS in predicting sCS. This retrospective study was conducted in a tertiary referral center and based on subjects referred between 2004 and 2014. Data of 249 subjects with adrenal incidentalomas were evaluated. We also reviewed 604 DHEAS measurements from adults, which were performed during the same period in our laboratory (LB group). Adrenocortical function, tumor size, and clinical characteristics were assessed. We diagnosed sCS in 15.2 % of the participants in the presence of ≥2 of the following; 1 mg dexamethasone suppression test >3.0 μg/dl, urinary free cortisol >70 μg/24 h, and corticotrophin (ACTH) <10 pg/ml. DHEAS levels were significantly reduced in patients with sCS (n = 38) compared to sCS (-) (n = 141) and LB groups (n = 604) (27.95, 65.90, and 66.80 µg/dl, respectively, p < 0.001) while age was comparable. The ROC curve analysis showed that the cut-off of the DHEAS with the best diagnostic accuracy for detecting sCS was 40.0 μg/dl (SN, 68 %; SP, 75; PPV, 43 %; NPV, 90 %, AUC: 0.788, p < 0.001). Logistic regression assessed the impact of age, BMI, low DHEAS (<40 μg/dl), bilateral tumors, and tumor size on the likelihood of having sCS. The strongest predictor was low DHEAS, recording an OR of 9.41. DHEAS levels are inversely associated with the extent of cortisol excess. In subjects with intermediate laboratory findings, detection of low DHEAS could be advantageous for distinguishing sCS.

The role of adrenal scintigraphy in the diagnosis of subclinical Cushing's syndrome and the prediction of post-surgical hypoadrenalism

BACKGROUND

Management of subclinical Cushing's syndrome (SCS) remains controversial; it is not possible to predict which patients would benefit from adrenalectomy. In the present study we aimed to evaluate the role of adrenocortical scintigraphy (ACS) in the management of patients with SCS.

METHODS

The medical records of 33 consecutive patients with adrenal "incidentaloma" and proven or suspected SCS who underwent (131)I-19-iodocholesterol ACS between 2004 and 2010 were reviewed. Sixteen underwent laparoscopic adrenalectomy (surgical group-S-group) and 17 were medically managed (medical group-M-group). Follow-up evaluation was obtained by outpatient consultation.

RESULTS

Overall 25 patients (15 in the S-group and 10 in the M-group) had concordant unilateral uptake at ACS (ACS+). In the S-group, the mean follow-up duration was 30.9 ± 16.1 months and, irrespective of the presence of hormonal diagnosis of SCS, in patients who were ACS+ adrenalectomy resulted in a significant increase in HDL cholesterol and decreases in body mass index, glycemia, and blood pressure (BP). One patient reduced antihypertensive medication and three others were able to discontinue it altogether. Prolonged postoperative hypoadrenalism (PH) occurred in 14 patients in the S-group. The overall accuracy in predicting PH was 93.7 % for ACS and 68.7 % for laboratory findings. In the M-group, the mean follow-up duration was 31.5 ± 26.3 months and no patient developed overt Cushing's syndrome, although ACS+ patients experienced a worsening in glycemia and diastolic BP.

CONCLUSIONS

Adrenal scintigraphy seems the most accurate diagnostic test for SCS. It is able to predict the metabolic outcome and the occurrence of PH, identifying the patients who could benefit from adrenalectomy irrespective of hormonal diagnosis.

Activity of selected coagulation factors in overt and subclinical hypercortisolism

It is universally acknowledged that glucocorticoids are hormones that exert a significant effect on hemostasis. The aim of this study was to analyze the activities of coagulation factors VIII, von Willebrand (vW), IX, X, and XI, in patients with overt and subclinical hypercortisolism, as well as to examine possible associations between activities of these factors and the degree of hypercortisolism. Thirty endogenous hypercortisolemic patients were included in the study. Twelve of them were diagnosed with overt Cushing's syndrome (OCS), and eighteen with subclinical Cushing's syndrome (SCS). Healthy, age- and sex-matched volunteers comprised the control group. Activities of coagulation factors VIII, IX, X, and XI were examined using a coagulometric method, and von Willebrand factor (vWF) using an immunoturbidimetric method. Mean activities of examined coagulation factors were significantly higher in OCS patients in comparison to healthy controls. SCS patients had significantly higher mean vWF activities versus controls; and a clear trend toward higher mean activities of other factors in SCS patients versus controls was recorded (but no significant differences). Furthermore, statistically significant positive correlations were found between activities of factor IX and: morning serum cortisol concentrations, 24-hour urinary cortisol excretion values, cortisol concentrations in the overnight suppression test with 1 mg of dexamethasone. Activities of factors X and XI positively correlated with cortisol levels in the overnight suppression test. In endogenous hypercortisolemic patients the coagulation pathway is hyperactivated as indicated by increased activities of coagulation factors. These disorders are evident among patients with overt hypercortisolism.

Surgical management of adrenocortical tumours

The surgical treatment of adrenal tumours has evolved over the past century, as has our understanding of which hormones are secreted by the adrenal glands and what these hormones do. This article reviews the preoperative evaluation of patients with adrenal tumours that could be benign or malignant, including metastases. The biochemical evaluation of excess levels of hormones is discussed, as are imaging characteristics that differentiate benign tumours from malignant tumours. The options for surgical management are outlined, including the advantages and disadvantages of various open and laparoscopic approaches. The surgical management of adrenocortical carcinoma is specifically reviewed, including controversies in operative approaches as well as surgical management of invasive or recurrent disease.

Pathophysiology and treatment of subclinical Cushing's disease and pituitary silent corticotroph adenomas [Review]

Pituitary adrenocorticotropic hormone (ACTH)-secreting tumor presents with a variety of clinical features. We outlined the features of ACTH release and characteristics of corticotroph adenoma cells. We especially focused on the corticotroph adenomas in patients with no clinical features of Cushing's disease. Subclinical Cushing's disease is defined by ACTH-induced mild hypercortisolism without typical features of Cushing's disease. Silent corticotroph adenomas (SCAs) are defined by normal cortisol secretion and ACTH-immunopositive staining without autonomous ACTH secretion. Clinicians who are not well-informed about the disease may sometimes confuse SCAs (because of their clinically silent nature) with "subclinical Cushing's disease". The recent criteria for diagnosing subclinical Cushing's disease in Japan are presented. Cortisol measurement was recently standardized in Japan, so plasma cortisol cutoff level should be reconsidered for the diagnosis. In patients with uncontrolled diabetes and hypertension despite appropriate treatment, subclinical Cushing's disease may be efficiently detected. Subclinical Cushing's disease may be associated with metabolic change. In subclinical Cushing's disease, mild hypercortisolism due to autonomous secretion of ACTH contributes to metabolic change and treatment of subclinical hypercortisolism can reverse this change.

D-dimer as a significant marker of deep vein thrombosis in patients with subclinical or overt Cushing's syndrome

Venous thromboembolism (VTE) is frequently associated with hypercortisolemia. This retrospective single-center study aimed to clarify the significance of plasma D-dimer levels for VTE screening in patients with subclinical or overt Cushing's syndrome (soCS). A total of 72 consecutive treatment-naïve patients with soCS diagnosed at Kobe University Hospital between 2002 and 2014 were enrolled. Patients with both lower extremity ultrasound and D-dimer measurement data (n = 19) were recruited in study 1 and divided into 2 groups, a deep vein thrombosis (DVT) (-) group (n = 12) and DVT (+) group (n = 7) for a comparison of the associated factors. The age and D-dimer levels were higher in the DVT (+) group than in the DVT (-) group (p = 0.04 and 0.02, respectively). A receiver operating characteristic analysis found that D-dimer level ≥2.6 μg/mL correlated with the presence of DVT (sensitivity, 100%; specificity, 91.7%). Next, patients with D-dimer measurement data (n = 36) were recruited in study 2 and divided into 2 groups according to D-dimer level: D-dimer (-), <1 μg/mL group (n = 23) and D-dimer (+), ≥1 μg/mL group (n = 13); the groups were compared with respect to various VTE-related risk factors. A logistic regression analysis revealed that elevated cortisol level after low-dose dexamethasone suppression was a significant risk factor for D-dimer elevation (OR = 1.21, p = 0.02). In conclusion, these data demonstrate that a D-dimer level ≥2.6 μg/mL is an indicator of DVT in treatment naïve patients with soCS and suggests that relatively high autonomous cortisol secretion may be associated with thrombus formation.

Long-term study of subclinical Cushing's syndrome shows high prevalence of extra-adrenal malignancy in patients with functioning bilateral adrenal tumors

Subclinical Cushing's syndrome (SCS) is characterized by subtle autonomous cortisol secretion from adrenal tumors without specific signs and symptoms of hypercortisolism. Patients with SCS have a high prevalence of "lifestyle-related diseases," such as hypertension, diabetes mellitus, dyslipidemia, and osteoporosis. Long-term follow-up of SCS patients is reportedly indispensable for establishing indications for surgical treatment of SCS. We performed a follow-up survey of 27 patients with SCS (median: 5.3 years) and compared those who had undergone surgical treatment (n=15) with those who had not (n=12). The mean diameter of tumors was 31 mm; 16 (59%) patients had unilateral lesions and 11 (41%) carried bilateral ones. In 67% and 60% of the treatment group, respectively, hypertension and diabetes mellitus improved. We also noticed that eight of 11 (73%) SCS patients with bilateral adrenal tumors had extra-adrenal malignancies in various tissues. Interestingly, among nine SCS patients who had malignancies, eight showed bilateral adrenal uptake in ¹³¹I-aldosterol scintigraphy. The results imply that surgical treatment can reduce cardiovascular risks in SCS patients. Screening for malignancy may be necessary in patients with bilateral adrenal tumors suspected of autonomous hypersecretion of cortisol from both sides.