The diagnostic yield of inferior petrosal sinus sampling in Cushing syndrome in the era of ovine CRH shortage

PURPOSE

The ovine corticotropin-releasing hormone (oCRH) stimulation test has been routinely used in the diagnostic work-up of ACTH-dependent Cushing syndrome (CS). With oCRH currently being out-of-stock in Europe, we aimed at evaluating the diagnostic performance of inferior petrosal sinus sampling (IPSS) without oCRH stimulation.

METHODS

We compared the values of 40 patients with ACTH-dependent CS and negative MRI findings in whom ACTH was measured before and after oCRH stimulation.

RESULTS

The ratio of central-to-peripheral ACTH measurement (IPS:P) before the combined 3, 5, and 10 min of oCRH stimulation yielded diminished sensitivity (85% vs. 97%), alongside markedly decreased specificity (57% vs. 71%), as well as reduced positive and negative predictive values (90% vs. 94% and 44% vs. 83%), respectively.

CONCLUSIONS

With the current drug shortages in Europe, ACTH measurements without oCRH stimulation in IPSS cannot be recommended. Thus, we call for desmopressin or the commercially available human CRH as a potential alternative in the confirmation of ACTH excess by IPSS in equivocal MRI findings.

Interpetrosal sphingosine-1-phosphate ratio predicting Cushing's disease tumor laterality and remission after surgery

Background

Cushing's disease (CD) poses significant challenges in its treatment due to the lack of reliable biomarkers for predicting tumor localization or postoperative clinical outcomes. Sphingosine-1-phosphate (S1P) has been shown to increase cortisol biosynthesis and is regulated by adrenocorticotropic hormone (ACTH).

Methods

We employed bilateral inferior petrosal sinus sampling (BIPSS), which is considered the gold standard for diagnosing pituitary sources of CD, to obtain blood samples and explore the clinical predictive value of the S1P concentration ratio in determining tumor laterality and postoperative remission. We evaluated 50 samples from 25 patients who underwent BIPSS to measure S1P levels in the inferior petrosal sinuses bilaterally.

Results

Serum S1P levels in patients with CD were significantly higher on the adenoma side of the inferior petrosal sinus than on the nonadenoma side (397.7 ± 15.4 vs. 261.9 ± 14.88; P < 0.05). The accuracy of diagnosing tumor laterality with the interpetrosal S1P and ACTH ratios and the combination of the two was 64%, 56% and 73%, respectively. The receiver operating characteristic curve analysis revealed that the combination of interpetrosal S1P and ACTH ratios, as a predictor of tumor laterality, exhibited a sensitivity of 81.82% and a specificity of 75%, with an area under the curve value of 84.09%. Moreover, we observed that a high interpetrosal S1P ratio was associated with nonremission after surgery. Correlation analyses demonstrated that the interpetrosal S1P ratio was associated with preoperative follicle-stimulating hormone (FSH), luteinizing hormone (LH), and postoperative ACTH 8 am levels (P < 0.05).

Conclusion

Our study demonstrated a significant association between the interpetrosal S1P ratio and tumor laterality, as well as postoperative remission in CD, suggesting that the interpetrosal S1P ratio could serve as a valuable biomarker in clinical practice.

Enhancing Cushing's disease diagnosis: exploring the impact of desmopressin on ACTH gradient during BIPSS

Introduction

The differential diagnosis between Cushing's disease (CD) and ectopic ACTH syndrome (EAS) is complex, and bilateral inferior petrosal sinus sampling (BIPSS) is considered the gold-standard test. However, BIPSS with corticotropin-releasing hormone (CRH) stimulation is rarely available.

Objective

This retrospective cohort study aimed to assess the accuracy of the inferior petrosal sinus to peripheral ACTH gradient (IPS:P) before and after desmopressin stimulation for the differential diagnosis of ACTH-dependent Cushing's syndrome (CS), applying different cutoff values.

Methods

A total of 50 patients (48 with CD and 2 with EAS) who underwent BIPSS were included in this study. The sensitivity and specificity of IPS:P in BIPSS before and after desmopressin stimulation were evaluated. Various cutoff values for IPS:P were examined to determine their diagnostic accuracy.

Results

Using the traditional IPS:P cutoff, the sensitivity was 85.1% before stimulation, 89.6% after stimulation, and a combined sensitivity of 91.7%. Applying cutoff values of IPS:P >1.4 before and >2.8 after stimulation, the sensitivity was 87.2% and 89.6%, respectively, with a combined sensitivity of 91.7%. Receiver operating characteristic (ROC) curve analysis determined optimal cutoff values of 1.2 before stimulation and 1.57 after stimulation, resulting in a sensitivity of 93.6% and 93.8%, respectively, with a combined sensitivity of 97.9%. Specificity remained at 100% throughout all analyses. Among the 43 patients who responded positively to stimulation, 42 (97.7%) did so within the first three minutes, and all 43 (100%) did so within the first five minutes. None of the assessed clinical variables predicted the ACTH response to stimulation in BIPSS with statistical significance.

Discussion

ACTH stimulation with desmopressin during BIPSS improves the accuracy of IPS:P, making it a valuable tool for investigating ACTH-dependent Cushing's syndrome. Considering the low risk of complications, we recommend the use of desmopressin stimulation during BIPSS for the differential diagnosis of ACTH-dependent CS.

Biochemical testing to differentiate Cushing's disease from ectopic ACTH syndrome

The differential diagnosis of ACTH-dependent Cushing's syndrome is often a diagnostic challenge that has been debated in numerous studies. In this short article, we will discuss the performance and main drawbacks of the biochemical tests used for this diagnosis.

A noninvasive scoring model for the differential diagnosis of ACTH-dependent Cushing's syndrome: a retrospective analysis of 311 patients based on easy-to-use parameters

OBJECTIVES

The differential diagnosis of ACTH-dependent Cushing's disease (CS) is challenging. The gold standard approach bilateral inferior petrosal sinus sampling (BIPSS) is expensive and invasive, while other noninvasive tests, like the high-dose dexamethasone suppression test (HDDST), provide unsatisfactory diagnostic accuracy. This study aimed to find a new noninvasive practical approach with higher diagnostic accuracy to differently diagnose ACTH-dependent CS, which can be used in centers where BIPSS cannot be applied.

METHODS

264 Cushing's disease (CD) patients and 47 ectopic ACTH secretion syndrome (EAS) patients were analyzed in this single-center retrospective study (2011-2021). The multivariate logistic model was used to construct the scoring model.

RESULTS

Female (adjusted OR 3.030, 95%CI 1.229-7.471), hypokalemia (0.209, 0.076-0.576), ACTH (0.988, 0.982-0.994), MRI pituitary lesion positive (8.671, 3.521-21.352), and HDDST positive (2.768, 1.139-6.726) have a strong association with the differential diagnosis of ACTH-dependent CS and were included in the final multivariable logistic regression model. A -14-to-14-point noninvasive scoring model was built on the model. The AUC of the noninvasive scoring model was 0.915 (95% CI 0.869-0.960), significantly higher than the AUC of HDDST (0.756, 95% CI 0.685-0.825, P = 0.004). The optimal cutoff of the model was ≥0 to diagnose CD. The sensitivity of the noninvasive scoring model was 91.3% (95% CI 87.3%-94.1%), and the specificity was 80.9% (95% CI 67.5%-89.6%). When the model's sensitivity was 100.0%, the cutoff was ≥ -10 with a specificity of 19.2%; when the model's specificity was 100.0%, the cutoff was ≥ 13 with a sensitivity of 22.7%.

CONCLUSIONS

We developed a noninvasive scoring model to distinguish CD and EAS in ACTH-dependent CS patients with higher diagnostic utility than HDDST in the same cohort. The noninvasive scoring model might be applied in areas where BIPSS is unavailable, the CRH is hard to obtain, or the desmopressin stimulation is not widely applied. It also provided a triage tool for selecting patients that might benefit the most from a further BIPSS test.

Diagnostic Power of Bilateral Inferior Petrosal Sinus Sampling with Desmopressin in Paediatric Cushing’s Disease

Objective

The aim of this study was to evaluate the diagnostic accuracy of bilateral inferior petrosal sinus sampling (BIPSS) with desmopressin for pediatric Cushing’s disease (CD).

Methods

We reviewed studies performed in children that evaluated the accuracy of BIPSS with desmopressin.

Results

All included studies were case series of children with adrenocorticotropin hormone (ACTH)-dependent Cushing’s syndrome. The overall accuracy of BIPSS before stimulation was 84.1% (37/44), and after stimulation it was 92.3% (36/39). The overall lateralizing accuracy of BIPSS was 50.0%.

Conclusion

Considering that available evidence is limited, it appears that BIPSS with desmopressin stimulation is accurate for the diagnosis of pediatric CD, but its lateralizing accuracy is probably not suitable for pediatric clinical practice.

Diagnostic workup of Cushing's syndrome

Cushing's syndrome (CS) is a rare but detrimental endocrine disorder. Early diagnosis and prompt treatment are essential since the duration of hypercortisolism has an adverse impact on the extent of comorbidities and overall survival. The diagnostic approach involves a stepwise process that includes (1) screening and confirming the diagnosis and (2) establishing the aetiology of CS. The tests currently used to confirm the diagnosis of CS include urinary free cortisol measurements, the dexamethasone suppression test and late- night salivary cortisol or midnight serum cortisol measurements. None of these tests are ideal; all have pitfalls and require careful interpretation. Following confirmation of CS, measurement of ACTH discriminates between ACTH-dependent and non-ACTH dependent causes of CS. Adrenal imaging provides clues for the aetiology of non-ACTH dependent forms. Differentiation between the ACTH-dependent forms that involve pituitary corticotroph adenomas and ectopic ACTH sources is more complex and include pituitary MRI imaging, the high dose dexamethasone suppression test, the CRH test, bilateral inferior petrosal sinus sampling and, when required imaging modalities to detect ectopic ACTH secreting lesions. This review, which is part of a special issue on "Update of Cushing's syndrome: 100 years after Minnie G" will provide an update on our current diagnostic workup for the confirmation and differential diagnosis of CS.

Case Report: Micro-RNAs in Plasma From Bilateral Inferior Petrosal Sinus Sampling and Peripheral Blood From Corticotroph Pituitary Neuroendocrine Tumors

Objective

Circulating miRNAs are found in bodily fluids including plasma and can serve as biomarkers for diseases. The aim of this study was to provide the first insight into the landscape of circulating miRNAs in close proximity to the adrenocorticotropic hormone (ACTH) secreting PitNET. To achieve this objective next-generation sequencing of miRNAs in plasma from bilateral inferior petrosal sinus sampling (BIPSS) - a gold standard in diagnosing ACTH-secreting PitNETs was carried out and selected miRNA candidates were further tested by RT-qPCR in independent patient cohorts.

Methods

Sinistral (left) and dextral (right) BIPSS blood samples of the patient were collected in three time points: before the administration of corticotropin-releasing hormone, 5 and 15 minutes after stimulation. In differential expression analysis, sinistral plasma was compared with dextral. The selected miRNA candidates were tested in plasma by RT-qPCR in two patient groups: 1) in five ACTH secreting PitNET patients with plasma samples taken before and 24 hours after surgery, 2) in 12 ACTH secreting PitNET patients vs. 9 non-functioning PitNET patients.

Results

BIPSS concluded that the highest amount of ACTH was released in the sinistral side at the 5th minute mark indicating a presence of a tumor. The highest amount of differentially expressed miRNAs was observed 5 minutes after stimulation (20 upregulated, 14 downregulated). At the 5th minute mark in sinistral plasma, two miRNAs were identified: hsa-miR-7-5p and hsa-miR-375-3p that were highly upregulated compared to other BIPSS samples and peripheral plasma samples. Further testing by qPCR revealed significant reduction of miR-7-5p in plasma 24 hours after surgery and upregulation in plasma of ACTH secreting PitNET patients compared to non-functioning PitNET patients (P =0.0013).

Conclusions

By stimulating the ACTH secreting PitNET with CRH a rapid increase of two miRNAs (hsa-mir-7-5p, hsa-mir-375-3p) and ACTH can be observed in sinistral inferior petrosal (tumor side). A decrease of miR-7-5p in plasma after surgery and upregulation in plasma of ACTH secreting PitNET patients was discovered implying that further studies of this miRNA as diagnostic marker is needed.

Rare case of renal Ewing sarcoma presenting as ectopic Cushing syndrome in a 12-year-old girl

We present a 12-year-old girl with recent onset weight gain and purple striae over the abdomen. Examination revealed her to be hypertensive. On evaluation for Cushing syndrome (CS), her cortisol and adrenocorticotropic hormone (ACTH) were found to be high. MRI brain showed a suspicious lesion (thought to be pituitary microadenoma). Inferior petrosal sinus sampling was not conclusive of pituitary source of ACTH. High dose dexamethasone suppression test confirmed an ectopic source of ACTH secretion and CT scan revealed a mass in the right kidney which was laparoscopically excised. Histopathology and immunohistochemistry confirmed Ewing sarcoma. Our case highlights the rare presentation of renal Ewing sarcoma (RES) as CS. To the best of our knowledge, this is only the second case report of RES/primitive neuroectodermal tumour of the kidney presenting as CS in paediatric age group and first with a concomitant pituitary incidentaloma.

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.

Lateral one-third gland resection in Cushing patients with failed adenoma identification leads to low remission rates: long-term observations from a small, single-center cohort

BACKGROUND

Currently, there are no guidelines for neurosurgeons treating patients with Cushing's disease (CD) when intraoperative adenoma identification is negative. Under these circumstances, a total hypophysectomy or hemi-hypophysectomy on the side indicated by inferior petrosal sinus sampling (IPSS) is the approach being used, although there is a subsequent risk of hypopituitarism. Data on whether one-third lateral pituitary gland resection results in cure of hypercortisolism and low rates of hypopituitarism remain inconclusive.

METHODS

Retrospective single-center study of CD patients with failed intraoperative adenoma identification and subsequent resection of the lateral one-third of the pituitary gland as predicted by IPSS. We assessed (i) histopathological findings, (ii) early and long-term remission rates, and (iii) rates of additional pituitary hormone insufficiency.

RESULTS

Ten women and three men met the inclusion criteria. At 3 months, remission was noted in six (46%) patients: three (23%) had histologically confirmed adenomas, two (15%) had ACTH hyperplasia, and one patient (8%) was positive for Crooke's hyaline degeneration. New pituitary hormone deficits were noted in two patients (15%). After a median (±SD) follow-up of 14±4 years, recurrence was noted in two (15%) patients. Long-term control of hypercortisolism was attained by 10 patients (77%), with additional therapies required in nine (69%) of them.

CONCLUSIONS

In CD patients with failed intraoperative adenoma visualization, lateral one-third gland resection resulted in low morbidity and long-term remission in 31% of patients without the need for additional therapies. Bearing in mind the sample size of this audit, the indication for lateral one-third-gland resection has to be critically appraised and discussed with the patients before surgery.

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.

Inferior petrosal sinus sampling and stimulation with CRH: 15 years of experience in a tertiary hospital

BACKGROUND

Inferior petrosal sinus sampling (IPSS) is indicated in the diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (CS), especially when the results of the initial diagnostic tests are discordant.

OBJECTIVE

To describe the patients who underwent this invasive functional test in a tertiary hospital.

METHODS

This was an observational study of a retrospective cohort of patients with ACTH-dependent CS and IPSS between 2004 and 2019. We determined their epidemiological, hormonal, radiological and functional characteristics, and evaluated their diagnostic capacity and optimal cut-off points to differentiate between Cushing's disease (CD) and ectopic Cushing's syndrome (ECS).

RESULTS

23 patients were evaluated, of which 65.2% were women with the average age of 42 (36-62) years. ACTH secretion of pituitary origin was evident in 82.6% of the patients and of ectopic origin in 17.4%. Plasma cortisol, urinary free cortisol, and ACTH levels were higher in patients with ECS. Regarding IPSS, the baseline central/peripheral ACTH gradient detected 89.5% of patients with CD and after stimulation with CRH, 100%. The optimal cut-off points in the diagnosis of CD were 2.06 at baseline and 2.49 after CRH stimulation.

CONCLUSION

IPSS with CRH stimulation is a test with a high diagnostic accuracy for correctly classifying patients with CD and ECS. The cut-off points of the gradients may be different from the classic ones. Therefore, we recommend that each center perform its own evaluation.

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.

Molecular Imaging Targeting Corticotropin-releasing Hormone Receptor for Corticotropinoma: A Changing Paradigm

BACKGROUND

Corticotrophin-releasing hormone (CRH) is the major regulator of adrenocorticotrophic hormone (ACTH) secretion from the anterior pituitary and acts via CRH-1 receptors (CRH-1R). Corticotropinoma though autonomous, still retain their responsiveness to CRH and hence, we hypothesize that in vivo detection of CRH-1 receptors on pituitary adenoma using Gallium-68 (68Ga)-tagged CRH can indicate the functionality of adenoma, and combining it with positron emission tomography-computed tomography (PET-CT) can provide requisite anatomical information.

METHODS

Subjects with ACTH-dependent Cushing's syndrome (CS) (n = 27, 24 with Cushing's disease [CD], 3 with ectopic CS [ECS]) underwent 68Ga CRH PET-CT. Two nuclear medicine physicians read these images for adenoma delineation and superimposed them on magnetic resonance imaging (MRI) sella. The information provided was used for intraoperative navigation and compared with operative and histopathological findings.

FINDINGS

68Ga CRH PET-CT correctly delineated corticotropinoma in all the 24 cases of CD, including the 10 cases with adenoma size < 6mm (4 cases were negative on MRI). Corticotropinoma location on 68Ga CRH PET fusion images with MRI were concordant with operative findings and were further confirmed on histopathology. There was no tracer uptake in the pituitary in 2 patients with ECS, while, in another, the diffuse uptake in pituitary suggested ectopic CRH production.

CONCLUSION

68Ga CRH PET-CT represents a novel, noninvasive molecular imaging, targeting CRH receptors that not only delineate corticotropinoma and provides the surgeon with valuable information for intraoperative tumor navigation, but also helps in differentiating a pituitary from an extra-pituitary source of ACTH-dependent CS.

FUNDING

None.

Experience of Ectopic Adrenocorticotropin Syndrome: 88 Cases With Identified Causes

OBJECTIVE

Ectopic adrenocorticotropic hormone syndrome (EAS) is a rare cause of Cushing's syndrome and diagnosis and management remain challenging. The aim of this study was to present the clinical spectrum of a group of EAS cases in a single center to explore better management strategies.

METHODS

A retrospective study was conducted to identify 88 confirmed EAS cases at our hospital from 1984 to 2019. The clinical, biochemical, imaging, and pathological features were analyzed.

RESULTS

Of the 88 eligible patients with EAS, 38 (43.2%) cases of pulmonary neuroendocrine tumors (NETs) and a larger number of thymic/mediastinal NETs (29 cases, 33%) were identified. The clinical and biological features of EAS and Cushing's disease overlapped but were more severe in EAS. Inferior petrosal sinus sampling (97.4%) and computed tomography (85.4%) provided the highest positive diagnostic accuracy. Computed tomography is also a useful tool to identify tumors in chest cavity compared with nonchest lesions (91.2% vs 57.1%). Although a greater tumor size (4.54 cm vs 1.44 cm) and higher rate of insuppressible high-dose dexamethasone suppression test (83.3% vs 51.5%) were found in thymic/mediastinum NETs than in pulmonary NETs, the level of hormone production had no difference.

CONCLUSION

EAS had more common and severe clinical presentations than Cushing's disease, and multiple imaging approaches are required for reliable diagnosis. A higher proportion of thymic/mediastinal NETs was found in our study. For patients without a certain tumor source, long-term follow-up and further evaluations are needed.

An Optimized Pathway for the Differential Diagnosis of ACTH-Dependent Cushing's Syndrome Based on Low-Dose Dexamethasone Suppression Test

CONTEXT

Traditionally, low-dose dexamethasone suppression test (LDDST) was used to confirm the diagnosis of Cushing's syndrome (CS), and high-dose dexamethasone suppression test (HDDST) was used to differentiate Cushing's disease (CD) and ectopic adrenocorticotropin (ACTH) syndrome (EAS), but some studies suggested that HDDST might be replaced by LDDST. For the differential diagnosis of CS, dexamethasone suppression test was usually combined with other tests such as bilateral petrosal sinus sampling (BIPSS) and pituitary magnetic resonance imaging, but the optimal pathway to incorporate these tests is still controversial.

OBJECTIVES

To develop an optimized pathway for the differential diagnosis of CD and EAS based on LDDST.

DESIGN AND SETTING

Single-center retrospective study (2011-2019).

PATIENTS

Two hundred sixty-nine CD and 29 EAS patients with pathological diagnosis who underwent consecutive low- and high-dose DST.

RESULTS

For the differential diagnosis of CD and EAS, the area under curve (AUC) of LDDST using urine free cortisol (0.881) was higher than that using serum cortisol (0.685) (p < 0.001) in head-to-head comparison among a subgroup of 108 CD and 10 EAS. The AUC of LDDST (0.883) was higher than that of HDDST (0.834) among all the included patients. With the cutoff of <26%, the sensitivity and specificity of LDDST were 39.4% and 100%. We designed a new pathway in which BIPSS was only reserved for those patients with unsuppressed LDDST and adenoma <6mm, yielding an overall sensitivity of 97.7% and specificity of 86.7%.

CONCLUSION

LDDST had similar value to HDDST in differentiating CD and EAS using the specific cutoff point. The pathway that combined LDDST and BIPSS could differentiate CD and EAS accurately.

The 4Ds of ectopic ACTH syndrome: diagnostic dilemmas of a difficult disease

Cushing's syndrome (CS) is an uncommon condition that leads to high morbidity and mortality. The majority of endogenous CS is caused by excessive ACTH secretion, mainly due to a pituitary tumor - the so-called Cushing's disease (CD) - followed by ectopic ACTH syndrome (EAS), an extra-pituitary tumor that produces ACTH; adrenal causes of CS are even rarer. Several methods are used to differentiate the two main etiologies: specific laboratory tests and imaging procedures, and bilateral inferior petrosal sinus sampling (BIPSS) for ACTH determination; however, identification of the source of ACTH overproduction is often a challenge. We report the case of a 28-year-old woman with clinical and laboratory findings consistent with ACTH-dependent CS. All tests were mostly definite, but several confounding factors provoked an extended delay in identifying the origin of ACTH secretion, prompting a worsening of her clinical condition, with difficulty controlling hyperglycemia, hypokalemia, and hypertension. During this period, clinical treatment was decisive, and measurement of morning salivary cortisol was a differential for monitoring cortisol levels. This report shows that clinical reasoning, experience and use of recent methods of nuclear medicine were decisive for the elucidation of the case.

The effects of sampling lateralization on bilateral inferior petrosal sinus sampling and desmopressin stimulation test for pediatric Cushing's disease

PURPOSE

Bilateral inferior petrosal sinus sampling (BIPSS) is useful for differential diagnosis of adult Cushing's disease (CD) but may not be so reliable in pediatric cases. The purpose of this study was to evaluate the sensitivity of BIPSS before and after desmopressin stimulation in pediatric CD, and to explore related factors of false-negative results and meanings of sampling lateralization.

METHODS

We retrospectively analyzed 16 pediatric CD patients who underwent 17 BIPSS procedures from 2006 to 2017. CD was diagnosed if inferior petrosal sinus (IPS) to peripheral adrenocorticotropic hormone (ACTH) ratio was >2 at baseline or >3 after desmopressin stimulation. Sampling lateralization was yielded if interpetrosal sinus gradient was >1.4. Magnetic resonance imaging (MRI) was conducted. All the patients underwent surgery and the diagnosis was confirmed.

RESULTS

The sensitivity was 64.7% (11/17) at baseline and 83.3% (10/12) after desmopressin stimulation. After stimulation, BIPSS reached its best sensitivity at 3 min. Sampling lateralization rate was 62.5% and 63.6% before and after stimulation, and the accordant rate with actual tumor lateralization was 50.0% and 42.9%, respectively. The accuracy of MRI in predicting the tumor lateralization was 80.0%. Sampling lateralization rate (81.8% in true-positive, 20.0% in false-negative, p = 0.036) and ACTH at dominant IPS (p = 0.001) was lower among false-negative patients.

CONCLUSIONS

The sensitivity of BIPSS in pediatric CD was low at baseline, but increased after desmopressin stimulation. Sampling lateralization cannot accurately indicate the tumor lateralization, but the absence of sampling lateralization with low ACTH at IPS is a hint of false-negative cases in BIPSS.

Combined Ovarian and Adrenal Venous Sampling in the Localization of Adrenocorticotropic Hormone-Independent Ectopic Cushing Syndrome

CONTEXT

Cushing syndrome is rarely caused by the secretion of cortisol from ovarian tumors. In clinical decision-making, it is important to determine whether the ovarian tumor is capable of secreting cortisol. Selective ovarian and adrenal venous sampling is scarcely reported in the localization of ACTH-independent ectopic Cushing syndrome.

CASE DESCRIPTION

We present a case of 40-year-old Chinese woman who had weight gain, hirsutism, hypertension, and menstrual disorder over 6 months. Her physical examination and biochemical assessment revealed adrenocorticotropic hormone-independent Cushing syndrome. Adrenal computed tomography scan indicated no abnormality. A mass of 5.7 cm × 4.2 cm × 3.4 cm was discovered by pelvic ultrasonography. Somatostatin receptor scintigraphy revealed no abnormal radioactivity intake. Combined ovarian and adrenal venous sampling together with a cortisol assay were conducted. Results revealed cortisol concentration of the right-side ovarian vein, left-side ovarian vein, and peripheral vein of 268.60, 29.00, and 35.18 μg/dL, respectively, suggesting a right-side ovarian origin. A right-side salpingo-oophorectomy was performed and the pathological diagnosis revealed ovarian steroid cell tumor, not otherwise specified. The cortisol level was substantially lower after the patient underwent surgery and symptoms of Cushing syndrome disappeared. At 3-year follow-up, the patient remained disease free, and no tumor was observed on pelvic ultrasonogram.

CONCLUSION

Combined ovarian and adrenal venous sampling is valuable in the localization of adrenocorticotropic hormone-independent ectopic Cushing syndrome.

A pitfall in diagnosing Cushing's disease: ectopic ACTH-producing pituitary adenoma in the sphenoid sinus

PURPOSE

To show a rare case of Cushing's disease and possible cause of failed transsphenoidal surgery.

METHOD

We report on a 50-year-old woman suffering from ACTH-dependent Cushing's syndrome. Endocrinological work-up including low-dose/high-dose dexamethasone test (Liddle-test) and CRH test were clearly compatible with pituitary origin. Although an MRI showed no pituitary tumor, CRH-stimulated petrosal sinus sampling revealed a significant central-peripheral gradient in ACTH concentrations, rendering Cushing's disease very likely. The patient underwent transsphenoidal surgery with negative exploration of the pituitary gland. After intraoperative re-evaluation of the preoperative MRI, a "polyp" at the bottom of the sphenoid sinus was identified. The intraoperative microscopic aspect as well as instantaneous sections and cytology of a biopsy confirmed an adenoma, which was then removed. Histological analysis demonstrated an ACTH-producing pituitary adenoma adjacent to respiratory mucous membrane consisting of ciliated epithelium with submucous connective tissue. Postoperatively, ACTH concentrations were decreased and intermittent hydrocortisone substitution treatment was initiated. At the 3-month follow up, Cushing's stigmata were found to be alleviated and the hydrocortisone dosage could be reduced.

CONCLUSION

Ectopic pituitary adenoma tissue causing Cushing's disease is extremely rare but a potential cause for surgical failure or re-evaluation.

Rapid Recovery of Hypothalamic-Pituitary Axis after Successful Resection of an ACTH-secreting Neuroendocrine Tumor

We describe a 30-year-old man with ectopic adrenocorticotropic hormone (ACTH) syndrome. Before the operation, there was no diurnal variation of ACTH, and ACTH did not respond to CRH or dexamethasone suppression tests. These abnormalities disappeared after the removal of a neuroendocrine tumor in the lung. In addition, plasma ACTH was measureable at as early as postoperative day 3 with ACTH levels increasing thereafter. Furthermore, an insulin tolerance test and inferior petrosal sinus sampling indicated that ACTH was secreted from the pituitary. This case indicates that the hypothalamic-pituitary function can recover within a couple of weeks after curative surgery for ectopic ACTH syndrome.

Clinical utility of plasma POMC and AgRP measurements in the differential diagnosis of ACTH-dependent Cushing's syndrome

CONTEXT

Distinguishing between pituitary [Cushing's disease (CD)] and ectopic causes [ectopic ACTH syndrome (EAS)] of ACTH-dependent Cushing's syndrome can be challenging. Inferior petrosal sinus sampling (IPSS) best discriminates between CD and occult EAS but is a specialized procedure that is not widely available. Identifying adjunctive diagnostic tests may prove useful. In EAS, abnormal processing of the ACTH precursor proopiomelanocortin (POMC) and the accumulation of POMC-derived peptides might be expected and abnormal levels of other neuropeptides may be detected.

OBJECTIVE

The objective of the study was to evaluate the diagnostic utility of POMC measurements for distinguishing between CD and occult EAS in patients referred for IPSS. Another objective of the study was to evaluate in parallel the diagnostic utility of another neuropeptide, agouti-related protein (AgRP), because we have observed a 10-fold elevation of AgRP in plasma in a patient with EAS from small-cell lung cancer.

DESIGN AND PARTICIPANTS

Plasma POMC and AgRP were measured in 38 Cushing's syndrome patients presenting for IPSS, with either no pituitary lesion or a microadenoma on magnetic resonance imaging, and in 38 healthy controls.

RESULTS

Twenty-seven of 38 patients had CD; 11 of 38 had EAS. The mean POMC was higher in EAS vs CD [54.5 ± 13.0 (SEM) vs 17.2 ± 1.5 fmol/mL; P < .05]. Mean AgRP was higher in EAS vs CD (280 ± 76 vs 120 ± 16 pg/mL; P = .01). Although there was an overlap in POMC and AgRP levels between the groups, the POMC levels greater than 36 fmol/mL (n = 7) and AgRP levels greater than 280 pg/mL (n = 3) were specific for EAS. When used together, POMC greater than 36 fmol/mL and/or AgRP greater than 280 pg/mL detected 9 of 11 cases of EAS, indicating that elevations in these peptides have a high positive predictive value for occult EAS.

CONCLUSIONS

Expanding upon previous observations of high POMC in EAS, this study specifically demonstrates elevated POMC levels can identify occult ectopic tumors. Elevations in AgRP also favor the diagnosis of EAS, suggesting AgRP should be further evaluated as a potential neuroendocrine tumor marker.

Volume interpolated 3D-spoiled gradient echo sequence is better than dynamic contrast spin echo sequence for MRI detection of corticotropin secreting pituitary microadenomas

BACKGROUND

Various techniques have been attempted to increase the yield of magnetic resonance imaging (MRI) for localization of pituitary microadenomas in corticotropin (ACTH)-dependent Cushing's syndrome (CS).

OBJECTIVE

To compare the performance of dynamic contrast spin echo (DC-SE) and volume interpolated 3D-spoiled gradient echo (VI-SGE) MR sequences in the diagnostic evaluation of ACTH-dependent CS.

DESIGN

Data was analysed retrospectively from a series of ACTH-dependent CS patients treated over 2-year period at a tertiary care referral centre (2009-2011).

PATIENTS

Thirty-six patients (24 female and 12 male) were diagnosed to have ACTH-dependent CS during the study period. All patients underwent MRI by both sequences during a single examination. Cases with negative and equivocal pituitary MR imaging underwent corticotropin-releasing hormone (CRH) stimulated bilateral inferior petrosal sinus sampling (BIPSS) to confirm pituitary origin of ACTH excess state. Thirty patients were finally diagnosed to have Cushing's disease (CD) [based on histopathology proof of adenoma and/or remission (partial/complete) of hypercortisolism postsurgery]. Six patients were diagnosed to have histopathologically proven ectopic CS.

RESULTS

Of 30 patients with CD, 24 patients had microadenomas and 6 patients had macroadenomas. DC-SE MRI sequence was able to identify microadenomas in 16 of 24 patients, whereas postcontrast VI-SGE sequence was able to identify microadenomas in 21 of 24 patients. All six patients of ectopic CS had negative pituitary MR imaging by both techniques (specificity: 100%).

CONCLUSION

VI-SGE MR sequence was better for localization of pituitary microadenomas particularly when DC-SE MR sequence is negative or equivocal and should be used in addition to DC-SE MR sequence for the evaluation of ACTH-dependent CS.

Chronic necrotising aspergillosis mimicking ACTH-secreting tumour in a case of Cushing's disease

An 18-year-old man presenting with speech and behaviour disorders was found to suffer from Cushing's syndrome. Ectopic ACTH secretion was initially suspected on the basis of very high cortisoluria and ACTH concentrations, severe hypokalemia, a lung hypermetabolic lesion and a normal pituitary on conventional magnetic resonance imaging (MRI). After lung surgery, this lesion proved to be chronic necrotising aspergillosis (CNA). Diagnostic reevaluation by bilateral inferior petrosal sinus sampling disclosed a right-sided petrosal sinus gradient consistent with Cushing's disease (CD). A new high resolution thin-section MRI demonstrated a 5 mm pituitary adenoma, which could be removed successfully. Thus, a lung mass associated with several clues in favour of ectopic ACTH secretion may hide a diagnosis of CD. Such a mass can be CNA, an opportunistic infection favoured by immunosuppression, which to our knowledge, is the first case reported in CD.

Adrenocorticotrophin-dependent hypercortisolism: imaging versus laboratory diagnosis

INTRODUCTION

Cushing's syndrome results from inappropriate exposure to excessive glucocorticoids. Untreated, it has significant morbidity and mortality.

CASE OUTLINE

A 38-year-old woman with a typical appearance of Cushing's syndrome was admitted for further evaluation of hypercortisolism. The serum cortisol level was elevated without diurnal rhythm, without adequate suppression of cortisol after 1 mg dexamethasone suppression test. 24-hour urinary-free cortisol level was elevated. Differential diagnostic testing indicated adrenocorticotrophin (ACTH)-dependent lesion of the pituitary origin. Pituitary abnormalities were not observed during repeated MRI scanning. Inferior petrosal sinus sampling (IPSS) was performed: 1) Baseline ratio ACTH inferior petrosal sinus/peripheral was <2; 2) Corticotropin-releasing hormone (CRH) stimulated ratio ACTH inferior petrosal sinus/peripheral was <3; 3) Baseline intersinus ratio of ACTH was <1.4; 4) Increase in inferior petrosal sinus and peripheral ACTH of more than 50 percent above basal level after CRH; 5) Baseline ratio ACTH vena jugularis interna/peripheral was >1.7. Transsphenoidal exploration and removal of the pituitary tumor was performed inducing iatrogenic hypopituitarism. Postoperative morning serum cortisol level was less than 50 nmol/l on adequate replacement therapy with hydrocortisone, levothyroxine and estro-progestagen.

CONCLUSION

No single test provides absolute distinction, but the combined results of several tests generally provide a correct diagnosis of Cushing's syndrome.

Diagnosis and therapy for Cushing's disease with negative dynamic MRI finding: a single-centre experience

OBJECTIVE

Most patients with Cushing's disease (CD) will have evidence of an adenoma on high-resolution magnetic resonance imaging (MRI). However, a significant minority of patients with CD and biochemical hypercortisolaemia have no visible adenoma on MRI. The purpose of this study was to evaluate the diagnostic value of preoperative biochemical assessment and accuracy of MRI findings on surgical outcome.

DESIGN

Retrospective data set analyses. PATIENTS AND MEASUREMENT: The clinical, endocrinological, histopathological and surgical outcomes of 24 consecutive CD patients with negative MRI findings were compared with those of 95 consecutive age- and sex-matched CD patients with pituitary adenomas on MRI.

RESULTS

The total remission rate was 86.6%. Among all patients, 87 had concordant positive endocrine tests and underwent neurosurgery, while bilateral inferior petrosal sinus sampling (BIPSS) was performed in 12 and 50 other patients with negative and positive MRI, respectively. A pituitary adenoma, confirmed by pathological examination, was found in 83.3% and 93.6% of patients with negative and positive MRI, respectively. The remission rate was not different between patients with negative and positive MRI (87.5 % and 86.3%, respectively; P > 0.05) or between patients who did not undergo BIPSS with negative MRI and patients with positive MRI (P > 0.05). The remission rate of patients who underwent BIPSS with negative MRI was not different from those not undergoing BIPSS (P > 0.05). The recurrence rate was higher, although not statistically different, in patients with negative MRI compared to positive ones.

CONCLUSIONS

Based on the findings outlined, MRI-negative CD may be a surgically remediable syndrome, with a pathophysiological basis that primarily involves a pituitary cause of the hypercortisolaemia.

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.

Diagnosis and treatment of Cushing's disease in children

Cushing's disease (CD) is rare in the paediatric age range, but presents a diagnostic and therapeutic challenge. Most paediatric endocrinologists have limited experience managing children or adolescents with CD and thus benefit from close consultation with adult colleagues. A diagnostic protocol for investigation is required which broadly follows the model for adult patients. Treatment strategies for CD are described and critically appraised. The management of paediatric CD patients after cure also presents challenges for optimizing growth, bone health, reproduction and body composition from childhood into and during adult life.

Contrast extravasation after bilateral inferior petrosal sinus sampling masquerading as venous subarachnoid haemorrhage

When performed properly, bilateral inferior petrosal sinus sampling (BIPSS) for adrenocorticotropic hormone (ACTH) is rarely associated with complications. Major complications reported to date include thromboembolism, brain stem infarction, pontine haemorrhage, isolated sixth nerve palsy and venous subarachnoid haemorrhage. We describe a rare case where a predominant contrast extravasation into the subarachnoid space, admixed with a small quantity of venous blood, occurring during BIPSS in a 58-year-old woman with ACTH-dependent Cushing's syndrome, was misinterpreted as venous subarachnoid haemorrhage.

Effect of injectable bromocriptine in patients with Cushing's disease

The therapeutic efficacy of sustained dopaminergic stimulation in Cushing's disease (CD), was investigated performing a three-month trial with monthly 50-100 mg injections of a bromocriptine depot preparation (Parlodel LAR, Sandoz) in six patients with CD. Dopaminergic treatment did not consistently influence pituitary-adrenal activity, as judged by plasma ACTH, cortisol and urinary free cortisol levels as well as by clinical findings. Interestingly, treatment with bromocriptine was associated with reappearance of menses in the three patients who were amenorrheic. In the five patients submitted to inferior petrosal sinus sampling, a parallelism between ACTH and PRL concentrations could be observed with a PRL rise, ipsilateral to that of ACTH, ensuing in three patients after administration of corticotropin-releasing hormone. In one patient a 55% reduction in the size of the pituitary adenoma was demonstrated by MRI carried out at the end of treatment. Our findings lead to the following conclusions: a) administration of depot injections of bromocriptine to patients with CD appears unable to correct hypercortisolism, although it can induce restoration of menses in amenorrheic patients; b) enhanced PRL concentrations at the pituitary level are probably involved in the amenorrhea often accompanying Cushing's disease.

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.

[Reversible metabolic syndrome]

A 52-year-old male patient was admitted to the emergency department with dyspnea and hypertensive urgency. During the previous 6 months, the patient had noticed leg edema, weight gain (particularly in the face and abdomen), and impotence. 1.5 years ago, he was diagnosed with hypertension resistant to medication. After an accident at work 1 year ago, osteoporosis was diagnosed with vertebral and rib fractures. Measurement of sleeping midnight salivary cortisol levels together with 24-h urine free cortisol excretion and an overnight low-dose 1-mg dexamethasone suppression test proved overt hypercortisolism. The high-dose 8-mg dexamethasone suppression suggested an adrenal or ectopic source of hypercortisolism. By contrast, elevated adreno-corticotropic hormone (ACTH) levels and a corticotropin-releasing hormone stimulation test gave evidence for a pituitary source of hypercortisolism. However, pituitary magnetic resonance imaging failed to reveal a pituitary adenoma. Moreover, computed tomography scans of thorax and abdomen were negative. In this situation, an inferior petrosal vein sampling was performed and revealed an ACTH gradient (central-systemic) >3 with lateralization to the right side. The patient underwent a selective, partial, transsphenoidal resection and was cured from clinical signs and symptoms caused by hypercortisolism. Subsequent hormonal replacement therapy of postoperative pituitary insufficiency was necessary.

Dual bronchial carcinoids and Cushing's syndrome with a paradoxical response to dexamethasone and a false positive outcome of inferior petrosal sinus sampling

CONTEXT

Establishing the cause of Cushing's syndrome (CS) can be a considerable challenge, in particular in ectopic adrenocorticotropic hormone (ACTH) syndrome, and often requires a combination of biochemical tests and imaging procedures.

SUBJECT

A 27-year-old man presented with signs of CS. P-ACTH levels were three times above the upper limit of normal (ULN) and free urinary cortisol around 2000 nmol/24 h. The work-up showed remarkable results.

RESULTS

A 2-day low-dose dexamethasone suppression test demonstrated paradoxical increases in cortisol. Sampling from the bilateral inferior petrosal sinus sampling (BIPSS) showed a central to peripheral ACTH ratio of 4.7 after corticotrophin-releasing hormone (CRH) stimulation, i.e. indicated pituitary disease, but magnetic resonance imaging of the pituitary was normal. Computed tomography (CT) scan of the lungs showed two oval-shaped masses, 1.3 x 1.8 and 1.3 x 2 cm, in the middle lobe. Both were positive at somatostatin receptor scintigraphy, compatible with tumors or inflammatory lesions. Subsequently, (11)C-5-hydroxytryptophan-PET showed distinct uptake in the tumors but not elsewhere. Two carcinoids situated 3 cm apart, both staining for ACTH, were removed at surgery.

CONCLUSION

This unique case with dual bronchial carcinoids inducing hypercortisolism illustrates the problems with identifying the source of ACTH in CS. Possibly, an abnormal regulation of ACTH production in response to dexamethasone, or steroid-induced tumor necrosis, explains the paradoxical outcome at dexamethasone suppression, and the false positive result at BIPSS reflects an unusual sensitivity of the pituitary corticotrophs to CRH in this patient. The work-up illustrates the great value of (11)C-5-hydroxytryptophan-PET as a diagnostic procedure when other investigations have produced ambiguous results.

Work-up and management of paediatric Cushing's syndrome

PURPOSE OF REVIEW

Paediatric Cushing's syndrome presents a diagnostic and therapeutic challenge. Most paediatric endocrinologists have limited experience in managing children or adolescents with Cushing's syndrome and thus benefit from close consultation with adult colleagues. A protocol for investigation of the child with suspected Cushing's syndrome is presented followed by principles of management.

RECENT FINDINGS

Cushing's syndrome is rare in childhood, but causes serious morbidity. Investigations have evolved and now include new genetic and imaging techniques as well as classical endocrine studies. In Cushing's disease trans-sphenoidal surgery has transformed management, although only a few surgeons have experience in children. Pituitary radiotherapy is effective second-line therapy.

SUMMARY

Early diagnosis and treatment of Cushing's syndrome is vital for long-term outcome. The overall prognosis for Cushing's syndrome is good but challenges remain to ensure normal postcure growth and body composition.

The application of the combined corticotropin-releasing hormone plus desmopressin stimulation during petrosal sinus sampling is both sensitive and specific in differentiating patients with Cushing's disease from patients with the occult ectopic adrenocorticotropin syndrome

CONTEXT

Although bilateral inferior petrosal sinus sampling (BIPSS) with CRH stimulation is the most accurate procedure for the differential diagnosis of ACTH-dependent Cushing's syndrome (CS), 4-15% of patients with Cushing's disease (CD) fail to demonstrate diagnostic gradients. Preliminary data suggest that a more potent stimulation by the combined administration of CRH plus desmopressin during BIPSS may provide some diagnostic advantage. A crucial issue, however, is whether such an amplified stimulation may affect the specificity of the procedure, and this was the main aim of the present study.

OBJECTIVE

We investigated the diagnostic accuracy of BIPSS performed by CRH plus desmopressin stimulation.

DESIGN AND SETTING

A retrospective analysis was conducted at a single tertiary care center.

PARTICIPANTS

Fifty-four patients were admitted for the investigation of ACTH-dependent CS. CD was diagnosed in 47 patients; occult ectopic ACTH syndrome (oEAS) was histologically confirmed in seven patients.

INTERVENTION(S)

All patients underwent BIPSS with CRH plus desmopressin administration. Additional noninvasive tests included CRH test, high-dose dexamethasone suppression test, desmopressin test, and pituitary magnetic resonance imaging.

MAIN OUTCOME MEASURES

Gradients of inferior petrosal sinus (IPS) to peripheral (IPS/P) ACTH were calculated before and after stimulation with CRH plus desmopressin.

RESULTS

The sensitivity for a basal IPS/P gradient greater than 2 was 61.7%, with 100% specificity and a diagnostic accuracy of 66.7%. After stimulation with CRH plus desmopressin, receiver operating characteristic (ROC) curve analysis showed that a cutoff gradient of more than 2 offers the best test performance. In total, 46 of 47 patients with CD had an IPS/P gradient greater than 2, but none of the patients with oEAS, resulting in a sensitivity of 97.9%. The specificity was 100%, diagnostic accuracy was 98.2%, and the positive and negative predictive values were 100 and 87.5%, respectively. A subgroup of 18 patients (16 with CD and two with oEAS) had contradictory responses to routine tests with CRH and/or high-dose dexamethasone suppression test; sensitivity, specificity, and accuracy of BIPSS in this subgroup were 100%.

CONCLUSIONS

The application of a combined stimulation with CRH plus desmopressin during BIPSS is associated with a high sensitivity but no loss of specificity.

[Evaluation of the accuracy of inferior petrosal sinus sampling in the differential diagnosis of ACTH-dependent Cushing's syndrome]

The differentiation of adrenocorticotropic hormone producing pituitary adenoma (Cushing's disease) from the ectopic ACTH syndrome is always a complex and difficult task, and in rare cases it is not possible to differentiate between the two disorders, even with the use of dynamic endocrine tests and the most advanced imaging techniques. Inferior petrosal sinus sampling (IPSS) with subsequent ACTH measurements became the gold-standard method of the differential diagnostic process. 34 patients with ACTH dependent Cushing's syndrome in whom the source of ACTH secretion couldn't be identified unambiguously with imaging techniques and/or dynamic endocrine tests underwent altogether 41 IPSS between 1999 and 2005. The sensitivity of the method was calculated on the basis of 31 samplings of 25 patients who had definite endocrinological diagnosis confirmed by the recovery from Cushing's syndrome after surgical intervention and/or by histological examinations (22 patients with ACTH-producing pituitary adenoma and 3 patients with ectopic ACTH syndrome). As a result of IPSS, pituitary-dependent Cushing's disease was diagnosed with a baseline central to peripheral ACTH ratio of >2.0 or with a ratio of >3.0 after corticotropin releasing hormone (CRH) administration. IPSS correctly identified ACTH-producing pituitary adenoma in 20 of 28 sampling procedures, with a sensitivity of 71.4%. Three patients had true negative and 8 had false negative results. There was no false positive result. Four of the 8 patients with false negative first sampling had a repeat sampling procedure leading to true positive result in each patient. In patients with Cushing's disease having true positive interventions, the basal and 5 minutes post-CRH ACTH concentrations were diagnostic in 14 and 19 cases, respectively. The sensitivity of IPSS within this series, reported for the first time from Hungary, was lower than it was found in much larger series published in international literature. In addition to technical difficulties, the lower sensitivity can be accounted also for the highly selected nature of the patient group.

experience

INTRODUCTION

An overlap in the clinical and biochemical features of the more common pituitary Cushing's disease and the rare ectopic ACTH secreting tumors often leads to a diagnostic dilemma. High quality computed imaging modalities have a poor sensitivity and do not always help in localising the tumor. Inferior petrosal sinus sampling (IPSS) with measurement of ACTH levels localizes the source of excess ACTH secretion and aids in the differential diagnosis of ACTH dependant Cushing's syndrome.

AIMS AND OBJECTIVES

To analyze the efficacy of inferior petrosal sinus sampling in the basal state and its role in the diagnostic evaluation in patients of Cushing's syndrome.

MATERIAL AND METHODS

Forty four patients of proven Cushing's syndrome underwent HDDS and pituitary imaging followed by IPSS (unstimulated). The data was analysed in 39 patients with definite histopathological diagnosis which included 34 patients with Cushing's disease, four with ectopic Cushing's syndrome and one with adrenal carcinoma. A centre:periphery ratio of plasma ACTH levels of > or =2 was considered diagnostic of Cushing's disease.

RESULTS

Cannulation rate was 100%. No neurological complications were encountered. IPSS could correctly localize the lesion in 23 of 34 patients of Cushing's disease (sensitivity: 67.6%). All patients of ectopic Cushing's syndrome and adrenal carcinoma had a ratio of <2 (specificity: 100%). IPSS helped in localization of the lesion and improved the diagnostic yield from 26.7% to 73.5%.

CONCLUSIONS

IPSS helps in localization in patients of Cushing's syndrome with a diagnostic dilemma and should be carried out only in centers with suitable expertise.

Factors influencing cure by transsphenoidal selective adenomectomy in paediatric Cushing's disease

OBJECTIVE

Early diagnosis and effective treatment of paediatric Cushing's disease (CD) is necessary to minimise associated morbidity. Accepted first-line treatment is selective transsphenoidal microadenomectomy (TSS), which can be technically difficult, and cure rates vary considerably between centres. In our paediatric CD patient group we have assessed the possible factors which may influence cure by TSS.

SUBJECTS AND METHODS

From 1983-2004, 27 paediatric patients (16 males, 11 females; mean age+/-s.d., 13.1+/-3.2 yr; range, 6.4-17.8 yr) with CD were managed in our centre and underwent TSS. Sixteen patients (59%), seven males and nine females (mean age+/-s.d., 14.2+/-2.5 yr; range, 8.2-17.8 yr), were cured (post-operative serum cortisol < 50 nM). Eleven patients, nine males and two females (mean age+/-s.d., 11.5+/-3.6 yr; range, 6.4-17.8 yr) had post-operative cortisol levels above 50 nM (2-20 days), with mean serum cortisol levels at 09:00 h of 537 nM (range 269-900 nM) indicating a lack of cure. These 11 patients received external beam pituitary radiotherapy (RT). One patient with a pituitary macroadenoma had a post-operative cortisol level of < 50 nM but 0.8 yr later showed an elevated cortisol and residual disease.

RESULTS

The patients cured by TSS alone were significantly older than those not cured (P = 0.038; Student's t test). All patients had CT/MRI pituitary imaging: 14 were reported to have microadenomas and one macroadenoma, while 12 were reported as normal. Bilateral simultaneous inferior petrosal sinus sampling (BSIPSS) with i.v. corticotropin-releasing hormone (CRH) administration was introduced as a pre-operative investigation in 1986 and was performed in 21 patients (78%), on BSIPSS, 16 (76%) had evidence suggesting pituitary adrenocorticotropic hormone (ACTH) secretion (central to peripheral (IPS:P) ACTH ratio after CRH of > or = 3.0) and 16 (76%) showed lateralisation of ACTH secretion (IPSG of > or = 1.4). There was concordance between the BSIPSS finding and the position of the microadenoma at surgery in 17/21 (81%) patients. Of the 16 patients showing lateralisation of ACTH secretion, 12 (75%) were cured by TSS. Of the four without lateralisation of ACTH, suggesting a midline lesion, 3 (75%) were cured by TSS. Post-operative pituitary hormone deficiencies in the patients cured by TSS were: pan-hypopituitarism 1/16, isolated growth hormone deficiency (GHD) (peak GH on glucagon/ITT < 1-17.9 mU/l) 9/16 and diabetes insipidus 3/16.

CONCLUSION

Over a 21-year period selective adenomectomy by TSS cured 59% of all paediatric CD patients, with higher age favouring cure. Introduction of BSIPSS resulted in the demonstration of a high rate of lateralisation of ACTH secretion consistent with the surgical identification of the adenoma, and therefore appears likely to have contributed to the higher surgical cure rate.

A case of seasonal bipolar disorder exacerbated by Cushing's disease

While depression is common in Cushing's syndrome from whatever cause (pituitary, adrenal, or ectopic adrenocorticotropic hormone-secreting tumor or hyperplasia, or exogenous administration of glucocorticoids) and hypercortisolemia is prevalent in major depression, any association between seasonal affective disorder and Cushing's syndrome is unknown. We present a case of seasonal bipolar disorder, gradually worsening for more than 9 years (1985-1994), accompanied by increasing osteoporosis, mild weight gain, and slight truncal obesity in a middle-aged woman. In January 1991, her seasonal affective disorder was successfully treated with light therapy, but in the following year, bipolar mood swings with a seasonal pattern emerged, which were refractory to light therapy and antidepressants but responsive to lithium. In August 1992, she became depressed despite a 1500-mg lithium daily dosage along with light therapy, and, in 1993, a diagnosis of Cushing's disease (Cushing's syndrome as a result of a pituitary adrenocorticotropic hormone-secreting tumor) was made. The pituitary tumor was removed in February 1994, and pituitary function was fully restored by 1996. While the symptoms of Cushing's syndrome subsided, her bipolar illness continued to require maintenance treatment with low doses of lithium but did not require light therapy.

Value of petrosal sinus sampling: coexisting acromegaly, empty sella and meningioma

Simultaneous occurrence of an intracranial meningioma and a growth hormone (GH)-producing pituitary adenoma is exceedingly rare, as is coexistence of an empty sella and acromegaly. We report all these rare entities in the same patient. We evaluated the role of inferior petrosal sinus sampling for lateralisation of an adenoma in this patient.

Identification of patients with Cushing's disease with negative pituitary adrenocorticotropin gradients during inferior petrosal sinus sampling: prolactin as an index of pituitary venous effluent

Inferior petrosal sinus sampling for ACTH differentiates pituitary ACTH-dependent Cushing's (CD) from the ectopic ACTH syndrome (EAS). Petrosal sinus to peripheral (IPS:P) ACTH ratios greater than 2.0 in the basal state or a peak greater than 3.0 after CRH are diagnostic of CD. However, false-negative rates of 1-10% have been reported. We report three patients with features of CD with peak IPS:P ACTH ratios less than 3.0 after CRH suggesting EAS. We compared IPS:P prolactin (PRL) as an index of pituitary venous effluent in these three index cases with 44 patients with CD and five with EAS. The dominant basal IPS:P PRL ratio was greater than 1.8 in all 49 patients but was less than 1.2 in the three index cases. The IPS:P ACTH ratio normalized to IPS:P PRL was greater than 0.8 in all CD patients but was less than 0.6 in EAS patients. The IPS:P ACTH ratios normalized to IPS:P PRL were greater than 1.2 in the index cases, which was similar to those with CD. The three index cases had clinical and biochemical remissions after pituitary surgery.PRL is an index of pituitary venous effluent during inferior petrosal sinus sampling in patients with CD who fail to have a peak IPS:P ACTH ratio greater than 3.0 after CRH. IPS:P PRL should be measured when results indicate EAS.

Cavernous and inferior petrosal sinus sampling in the evaluation of ACTH-dependent Cushing's syndrome

OBJECTIVE

Central venous sampling (CVS) is used frequently in the evaluation of ACTH-dependent Cushing's syndrome. However, several controversies exist including the diagnostic accuracy, the sampling site of choice (cavernous sinus vs. inferior petrosal sinus) and the use of lateralization data in tumour localization. We have analysed our experience with CVS to address these controversies.

DESIGN

We retrospectively reviewed CVS data in patients with ACTH-dependent Cushing's syndrome, in whom cavernous sinus sampling (CSS), inferior petrosal sinus sampling (IPSS) and IPSS after administration of ovine corticotrophin releasing hormone (oCRH) were performed.

PATIENTS

Data on 95 patients were analysed, including 79 patients with suspected Cushing's disease (CD) and 16 patients with suspected ectopic ACTH syndrome (EAS).

RESULTS

For the differential diagnosis of ACTH-dependent Cushing's syndrome, the diagnostic accuracy of IPSS after oCRH stimulation was 97% compared to 86% for CSS. While no single sampling site was perfect in diagnostic accuracy, sampling both CS and IPS achieved a combined diagnostic accuracy of 100%. Lateralization data predicted tumour location in 62-68% of the patients with various central venous drainage patterns and in 77-80% of the patients with symmetrical drainage. CSS was not significantly superior to IPSS in tumour lateralization. In patients with suspected CD based on CVS and in whom an adenoma was not found on magnetic resonance imaging (MRI) and not located by the surgeon intraoperatively, hemihypophysectomy based on lateralization data was successful in only 10 of the 18 patients (56%) with various central venous drainage patterns and in 5 of 10 patients with symmetrical drainage.

CONCLUSION

CVS is a powerful method for differentiating CD from the EAS. CSS without oCRH was not superior to IPSS after oCRH stimulation; however, we achieved a 100% diagnostic accuracy if at least two sites were sampled. Tumour localization by CVS did not accurately predict the tumour site at surgery and should not be used to guide surgical resection.