Petrosal sinus sampling for Cushing syndrome: anatomical and technical considerations. Work in progress

Bilateral inferior petrosal sinus sampling in the differential diagnosis of ACTH-dependent Cushing's syndrome: A reappraisal

Cushing's syndrome (CS) is a rare disorder, once exogenous causes have been excluded. However, when diagnosed, the majority of cases are adrenocorticotropic hormone (ACTH)-dependent, of which a substantial minority are due to a source outside of the pituitary, ectopic ACTH syndrome (EAS). Differentiating among pituitary-dependent CS, Cushing's disease (CD) and an ectopic source can be problematic. Because non-invasive tests in the evaluation of CS patients often lack adequate sensitivity and specificity, bilateral inferior petrosal sinus sampling (BIPSS), a minimally invasive procedure performed during the investigation of ACTH-dependent CS, can be extremely helpful. BIPSS is considered to be the gold standard for differentiating CD from the EAS. Furthermore, although such differentiation may indeed be challenging, BIPSS is itself a complex investigation, especially in recent times due to the widespread withdrawal of corticotrophin-releasing hormone and its replacement by desmopressin. We review current published data on this investigation and, in the light of this and our own experience, discuss its appropriate use in diagnostic algorithms.

Bilateral Inferior Petrosal Sinus Sampling Without Lateralization Is Less Accurate for the Diagnosis of Cushing Disease

Context

During bilateral inferior petrosal sinus sampling (BIPSS), the side-to-side adrenocorticotropic hormone (ACTH) ratio, referred to as sampling lateralization, was used to predict pituitary adenoma localization.

Objective

To investigate the potential different diagnostic accuracy of BIPSS for differentiating Cushing disease (CD) and ectopic ACTH secretory syndrome (EAS) patients with low lateralization (inferior petrosal sinus [IPS]:IPS ≤ 1.4) and high lateralization (IPS:IPS > 1.4).

Methods

This single-center retrospective study (2011-2021) included (all patients had BIPSS results and confirmed pathologic diagnoses) 220 consecutive CD patients (validation set), 30 EAS patients, and 40 of the CD patients who had digital subtraction angiography (DSA) videos (discovery set).

Results

In the discovery set, the low-lateralization CD group (n = 11) had a higher median plasma ACTH concentration (62.2, IQR 44.7-181.0 ng/L) than the high-lateralization CD group (n = 29) (33.0, IQR 18.5-59.5, P = .013). Lower IPS to peripheral ratios were observed in the low-lateralization group during BIPSS, both before and after stimulation (P = .013 and P = .028). The sensitivity of BIPSS before stimulation in differentiating CD from EAS was lower in the low-lateralization group than the high-lateralization group (54.6% vs 93.1%, P = .003), as validated in the validation set. DSA videos revealed higher vascular area difference visible in the 2 sides of the pituitary in low lateralization (median 1.2 × 105 pixels, IQR 0.5-1.8) than the high-lateralization group (0.4 × 105 pixels, IQR 0.1-0.7, P = .008). The vascular area ratio of the 2 sides was also significantly higher in low (1.55, IQR 1.31-2.20) than high lateralization (1.19, IQR 1.07-1.35, P = .010).

Conclusion

Our study suggested that low lateralization in CD patients may reduce the diagnostic sensitivity of BIPSS, which might be potentially associated with peripituitary vascular anatomy.

Clinical features, diagnosis and treatment outcomes of Cushing's disease in children: A multicenter study

OBJECTIVE

Since Cushing's disease (CD) is less common in the paediatric age group than in adults, data on this subject are relatively limited in children. Herein, we aim to share the clinical, diagnostic and therapeutic features of paediatric CD cases.

DESIGN

National, multicenter and retrospective study.

PATIENTS

All centres were asked to complete a form including questions regarding initial complaints, physical examination findings, diagnostic tests, treatment modalities and follow-up data of the children with CD between December 2015 and March 2017.

MEASUREMENTS

Diagnostic tests of CD and tumour size.

RESULTS

Thirty-four patients (M:F = 16:18) from 15 tertiary centres were enroled. The most frequent complaint and physical examination finding were rapid weight gain, and round face with plethora, respectively. Late-night serum cortisol level was the most sensitive test for the diagnosis of hypercortisolism and morning adrenocorticotropic hormone (ACTH) level to demonstrate the pituitary origin (100% and 96.8%, respectively). Adenoma was detected on magnetic resonance imaging (MRI) in 70.5% of the patients. Transsphenoidal adenomectomy (TSA) was the most preferred treatment (78.1%). At follow-up, 6 (24%) of the patients who underwent TSA were reoperated due to recurrence or surgical failure.

CONCLUSIONS

Herein, national data of the clinical experience on paediatric CD have been presented. Our findings highlight that presenting complaints may be subtle in children, the sensitivities of the diagnostic tests are very variable and require a careful interpretation, and MRI fails to detect adenoma in approximately one-third of cases. Finally, clinicians should be aware of the recurrence of the disease during the follow-up after surgery.

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.

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.

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.

Lateralization of inferior petrosal sinus sampling in Cushing's disease correlates with cavernous sinus venous drainage patterns, but not tumor lateralization

Background

Inferior petrosal sinus sampling (IPSS) is known as the gold standard to distinguish whether excessive adrenocorticotropin hormone (ACTH) production origins from the pituitary gland or an ectopic source. However, due to a number of factors, the value of IPSS for adenoma lateralization may be limited. Aim of this study was to evaluate the influence of parasellar venous drainage (VD) patterns on IPSS findings in predicting lateralization of pituitary microadenomas.

Methods

We retrospectively reviewed records of confirmed cases of Cushing's disease which were evaluated by IPSS prior to endoscopic tansnasal trans-sphenoidal surgery (ETSS) to assess the ability of IPSS to predict adenoma laterality.

Results

Seventeen patients with pathologically confirmed Cushing's disease were retrospectively reviewed. The median age of the included patients was 37 years. Laterality of parasellar VD perfectly associated with lateralization as measured by IPSS. Symmetrical VD was associated with symmetrical ACTH gradient on IPSS. However, lateralization measured by IPSS did not show any significant correlation with lateralization detected during ETSS.

Conclusion

Our study suggests that IPSS lateralization results strongly depend on parasellar VD pattern but show no significant correlation with the adenoma lateralization found during ETSS. Thus, IPSS does not appear to be an appropriate modality to predict adenoma lateralization.

High positive predictive value of the combined pituitary dynamic enhanced MRI and high-dose dexamethasone suppression tests in the diagnosis of Cushing's disease bypassing bilateral inferior petrosal sinus sampling

The purpose of the study is to evaluate the positive predictive value of the combined pituitary dynamic enhanced MRI (dMRI) and high-dose dexamethasone suppression tests (HDDST) in the diagnosis of Cushing's disease (CD) bypassing bilateral inferior petrosal sinus sampling (BIPSS). A total of 118 patients with Cushing's syndrome (CS), who underwent pituitary dMRI, HDDST and BIPSS were included. Positive predictive value of pituitary dMRI, HDDST, BIPSS and the combined test were calculated and tumor lateralization accuracy was further analyzed. The positive predictive value of the combined pituitary dMRI and HDDST was 98.6%, higher than that of BIPSS. There were 96.8% of patients, who had either negative findings in pituitary dMRI or HDDST, showing centralizing BIPSS results. For tumor lateralization, the accuracy by pituitary dMRI was 88.6%, whereas BIPSS was 57.5%. Therefore, CS patients with both positive findings in pituitary dMRI and HDDST need no further invasive evaluation to establish the definite diagnosis of CD. BIPSS will improve the diagnostic accuracy when negative findings were found in either pituitary dMRI or HDDST.

The Optimal Cut-off of BIPSS in Differential Diagnosis of ACTH-dependent Cushing's Syndrome: Is Stimulation Necessary?

CONTEXTS

Bilateral inferior petrosal sinus sampling (BIPSS) can differentiate Cushing's disease (CD) and ectopic adrenocorticotropin (ACTH) syndrome (EAS). The traditional cutoff of inferior petrosal sinus to peripheral (IPS:P) ACTH gradient was 2 before stimulation and 3 after stimulation, which yielded unsatisfactory sensitivity in some studies.

OBJECTIVES

To determine the optimal cutoff in BIPSS before or after desmopressin stimulation and to evaluate the necessity of stimulation.

DESIGN AND SETTING

Single-center retrospective study (2011-2018) along with meta-analysis.

PATIENTS

226 CD and 24 EAS patients with confirmed diagnosis who underwent BIPSS with desmopressin stimulation.

RESULTS

In the meta-analysis of 25 studies with 1249 CD and 152 EAS patients, the traditional cutoff yielded sensitivity of 86% and 97% and specificity of 98% and 100% before and after stimulation, respectively. We then analyzed the data from our center. With the traditional cutoff, the sensitivity was 87.2% (197/226) and 96.5% (218/226) before and after stimulation, and specificity was both 100% (25/25), which were close to the results of meta-analysis. Receiver operating characteristic analysis revealed that the optimal cutoff was 1.4 before stimulation and 2.8 after stimulation. With the new cutoff, the sensitivity was 94.7% (214/226) and 97.8% (221/226) while the specificity remained 100% (25/25) before and after stimulation. Among the 7 CD patients (7/226; 3.1%) for whom stimulation was necessary to get correct diagnosis, none has a pituitary lesion >6 mm by magnetic resonance imaging, and their sampling lateralization rate (P = .007) and peak ACTH level at dominant inferior petrosal sinus (P = .011) were lower than those among CD patients with IPS:P >1.4 before stimulation.

CONCLUSIONS

The optimal cutoff for IPS:P in BIPSS is different from the commonly-used one. The optimal cutoff value can yield satisfactory accuracy even without stimulation, and stimulation may be unnecessary for those with pituitary adenoma >6 mm.

Validity of discharge ICD-10 codes in detecting the etiologies of endogenous Cushing's syndrome

OBJECTIVE

To investigate the validity of discharge ICD-10 codes in detecting the etiology of endogenous Cushing's syndrome (CS) in hospitalized patients.

METHODS

We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CS etiology-related ICD-10 codes or code combinations by comparing hospital discharge administrative data (DAD) with established diagnoses from medical records.

RESULTS

Coding for patients with adrenocortical adenoma (ACA) and those with bilateral macronodular adrenal hyperplasia (BMAH) demonstrated disappointingly low sensitivity at 78.8% (95% CI: 70.1-85.6%) and 83.9% (95% CI: 65.5-93.9%), respectively. BMAH had the lowest PPV of 74.3% (95% CI: 56.4-86.9%). In confirmed ACA patients, the sensitivity for ACA code combinations was higher in patients initially admitted to the Department of Endocrinology before surgery than that in patients directly admitted to the Department of Urology (90.0 vs 73.1%, P = 0.033). The same phenomenon was observed in the PPV for the BMAH code (100.0 vs 60.9%, P = 0.012). Misinterpreted or confusing situations caused by coders (68.1%) and by the omission or denormalized documentation of symptomatic diagnosis by clinicians (26.1%) accounted for the main source of coding errors.

CONCLUSIONS

Hospital DAD is an effective data source for evaluating the etiology of CS but not ACA and BMAH. Improving surgeons' documentation, especially in the delineation of symptomatic and locative diagnoses in discharge abstracts; department- or disease-specific training for coders and more multidisciplinary collaboration are ways to enhance the applicability of administrative data for CS etiologies.

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.

Demographic Characteristics, Etiology, and Comorbidities of Patients with Cushing's Syndrome: A 10-Year Retrospective Study at a Large General Hospital in China

PURPOSE

To investigate the demographic characteristics, etiology, and comorbidities of Cushing's syndrome (CS) patients at a large medical center in China.

METHODS

Records on CS patients discharged from 2008 to 2017 were retrieved from the hospital discharge abstract database (DAD) using ICD-10 codes. Demographic characteristics, etiology, and comorbidity data were analyzed.

RESULTS

Cushing's disease (CD) accounted for 63.0% of CS patients, followed by adrenocortical adenoma (ACA) (20.9%), primary bilateral macronodular adrenal hyperplasia (BMAH) (6.2%), ectopic ACTH syndrome (EAS) (5.9%), primary pigmented nodular adrenocortical disease (PPNAD) (1.8%), and adrenocortical carcinoma (ACC) (1.0%). CD, ACA, ACC, and PPNAD presented marked preponderances in women (4.1 : 1, 10.5 : 1, 4.3 : 1, and 2.3 : 1, respectively), while BMAH (59.8%) and EAS (51.0%) showed slightly higher preponderances in men. CD patients were younger than ACA and EAS patients (36.1 ± 12.9 years vs. 39.4 ± 12.7 years and 36.1 ± 12.9 years vs. 41.0 ± 15.8, P < 0.001); PPNAD patients were the youngest (24.2 ± 10.8 years, P < 0.001), and BMAH patients were the oldest (51.3 ± 9.9 years, P < 0.001). Hypertension, diabetes mellitus, osteoporosis without fractures, osteoporotic fractures, dyslipidemia, and fatty liver occurred more frequently in CD patients than in ACA patients (P < 0.001 for all). Osteoporotic fractures were observed more frequently in PPAND than in ACA (26.7% vs. 9.0%, P < 0.001) and BMAH (26.7% vs. 4.9%, P < 0.001) patients. EAS patients had more severe and diverse comorbidities, with higher prevalences of hypokalemia (52.0%), diabetes mellitus (61.2%), and osteoporotic fractures (28.6%). When adjusted for age, male CD patients were associated with hypertension (OR = 2.266, 95% CI: 1.524-3.371, and P < 0.001), osteoporotic fractures (OR = 2.274, 95% CI: 1.568-3.298, and P < 0.001), fatty liver (OR = 1.435, 95% CI: 1.028-2.003, and P = 0.034), and hypokalemia (OR = 1.944, 95% CI: 1.280-2.951, and P = 0.002).

CONCLUSIONS

The proposed method efficiently evaluates CS patients' epidemiological profiles using hospital DADs with ICD-10 codes and thus may enrich the limited epidemiological data and contribute to clinical practice for CS.

Pediatric Cushing's Disease: Dichotomy in Lateralization between Imaging and Inferior Petrosal Sinus Sampling with Review of Literature

Inferior petrosal sinus sampling (IPSS) is a minimally invasive method done in adrenocorticotrophic hormone (ACTH)-dependent pituitary adenoma cases where magnetic resonance imaging (MRI) either gives equivocal results or fails to localize it. A 12-year-girl with cushingoid features and raised ACTH levels presented to us with two consecutive MRI’s done outside showing gross change in the morphology of a left-sided pituitary adenoma. Hence, a bilateral IPSS was done which showed a higher IPS/periphery ACTH ratio on the right side as compared to left. Transsphenoidal endoscopic excision of the left pituitary adenoma along with right hemihypophysectomy was performed. ACTH levels fell postoperatively. This case stands distinct in highlighting the discordance in lateralization of pituitary adenoma on MRI and IPSS. Review of literature tells us that while IPSS is more sensitive in accurately diagnosing Cushing’s disease, MRI provides better accuracy in lateralizing the site of adenoma.

Tumour lateralization in Cushing's disease by inferior petrosal sinus sampling with desmopressin

BACKGROUND

Bilateral inferior petrosal sinus sampling (IPSS) with corticotropin-releasing hormone (CRH) is currently the gold standard in the diagnosis of Cushing's disease (CD) and has also been used in tumour lateralization. Our objective was to determine the diagnostic value and lateralization accuracy of IPSS with desmopressin.

METHODS

We retrospectively analysed 91 patients with Cushing's syndrome who had either negative findings on pituitary dynamic enhanced magnetic resonance imaging (MRI) or nonsuppressed high-dose dexamethasone suppression tests (HDDST). Thin-slice thoracoabdominal computed tomography (CT) and octreotide receptor imaging of whole body were also negative to rule out ectopic adrenocorticotropin hormone (ACTH) syndrome. All patients went through IPSS with desmopressin. Afterwards, transsphenoidal pituitary surgery, light microscope pathology and immunohistological staining for ACTH were performed in all patients.

RESULTS

Diagnosis of CD. Among the 91 patients included, 90 were confirmed with CD, of whom 89 had positive IPSS findings, therefore the sensitivity was 98.9%. The one patient who was negative for CD also had negative IPSS findings, therefore the specificity was 100%. Tumour lateralization. Among the 51 patients who were ultimately diagnosed with CD and whose lateralization by IPSS and surgery was either left or right, 37 had IPSS lateralization in concordance with surgery, therefore the concordance rate was 72.5%. Patients in the concordant group had a higher frequency of right lateralization by surgery.

CONCLUSIONS

IPSS with desmopressin is a sensitive approach in the diagnosis of CD and has moderate accuracy in tumour lateralization, making it an alternative choice to IPSS with CRH.

Diagnosis and Outcomes of 341 Patients with Cushing's Disease Following Transsphenoid Surgery: A Single-Center Experience

BACKGROUND

Transsphenoid surgery (TSS) is a standard treatment modality for Cushing's disease (CD). However, postoperative remission and recurrence rates vary among studies. Here we analyze the diagnosis and outcomes of 341 patients with a preoperative diagnosis of CD undergoing TSS in a single center over a 3-year period.

METHODS

A total of 341 patients were enrolled. Clinical manifestations, imaging results, laboratory workups, and results of inferior petrosal sinus sampling (IPSS) were obtained. Outcomes were obtained with a follow-up length from 12 to 36 months.

RESULTS

The tumors were mainly of Knosp level 0 (68.57%). The sensitivity of MRI, combined low-dose and high-dose dexamethasone suppression test and IPSS in the diagnosis were 90.83%, 88.53% and 95.57%. The concordance of lateralization by MRI and by IPSS were 78.96% and 61.34% compared with surgery. 2.

OUTCOMES

The overall remission rate was 78.89% (N = 289). Patients undergoing the first TSS (N = 234) had a remission rate of 86.36% for macroadenomas (N = 22) and 83.2% for microadenomas (N = 212). Patients undergoing a second TSS (N = 55) had lower rate of remission of 50.00% for macroadenomas (N = 6) and 61.22% for microadenomas (N = 49). For patients with invasive tumors, the overall remission rate was 26.92% (N = 26), 20.0% for macroadenomas (n = 20) and 50.0% for microadenomas (N = 6). The recurrence rate was 2.42%.

CONCLUSIONS

Pituitary imaging, endocrinological workups and IPSS are sensitive and specific diagnostic modalities for CD, but the lateralization efficacy of MRI and IPSS are unsatisfactory. A higher rate of remission relies on gross resections of tumors.

Inferior Petrosal Sinuses Sampling

Quando il prelievo dei seni petrosi inferiori (IPS) per la diagnosi differenziale della sindrome di Cushing fu introdotto negli ultimi anni 70, la sua validità fu sottostimata a causa della non compresa necessityà di un prelievo bilaterale. Oltrettutto, il valore di una emiipofisectomia cieca quando nessun tumore sia identificato al tavolo operatorio non è stato apprezzato fino a che non e stato introdotto il prelievo simultaneo bilaterale.

Il prelievo dei seni petrosi è meglio eseguito mediante puntura bilaterale delle vene femorali, sebbene in particolari circostanze, le vene giugulari interne possano essere direttamente cateterizzate.

La valvola presente alla giunzione tra vena giugulare interna sinistra e vena innominata può essere difficile da superare specie in pazienti con accentuata lipomatosi mediastinica che disloca la vena innominata. I seni petrosi inferiori drenano nella parete mediale delle vene giugulari interne nel tratto immediatamente caudale alla base cranica.

Il catetere deve essere posizionato alla giunzione tra segmento verticale e orizzontale del seno petroso inferiore al di sopra della confluenza del plesso venoso vertebrale (VVP).

I prelievi dal seno petroso rifletteranno il drenaggio dal seno cavernoso omolaterale solo quando l'iniezione retrograda di mezzo di contrasto opacizzera il seno cavernosa. Cateteri con curve terminali prefissate, quali quelli con configurazione «viscerale» o «a Cobra», tendono a entrare nel plesso venoso vertebrale. Prelievi da queste vene porterebbero ad una diagnosi erronea di sindrome di Cushing ectopica.

Gradienti unilaterali si riscontrano nel 40% dei pazienti con comprovato adenoma ipofisario corticotropo cosicchè il prelievo bilaterale è essenziale. Il posizionamento routinario di un catetere Tracker nel seno cavernoso non è necessario e aggiunge considerevoli costi.

Cateteri Tracker possono essere usati per attraversare i seni intercavernosi allo scopo di ottenere campionamenti bilaterali in pazienti con una vena giugulare interna ostruita.

Per quanto riguarda la nostra esperienza, il successo del prelievo bilaterale dei seni petrosi supera il 98%. Nel 30% circa dei casi, il seno petroso inferiore si connette con la vena giugulare interna attraverso un plesso di vene e in tali casi l'uso di un catetere Tracker si può rendere necessaria. In meno del 2% dei pazienti non c'è connessione tra il seno petroso inferiore e la vena giugulare interna di un lato.

Dopo la raccolta di campioni basali, viene eseguita la stimolazione con CRH (corticotropin-releasing hormone) somministrato alla dose di 1 ug/Kg di peso corporeo e prelievi bilaterali dai seni petrosi vengono eseguiti a tre minuti.

Abbiamo routinariamente eseguito prelievi a 5 e 10 minuti dopo la stimolazione con CRH, ma i massimi gradienti si sono sempre riscontrati nei campioni raccolti a tre minuti.

Il prelievo bilaterale dei seni petrosi è un test estremamente accurato. Senza stimolazione con CRH, il test ha una affidabilita diagnostica del 95% nel distinguere un Cushing ipofisario da una sindrome da iperincrezione ectopica di ACTH utilizzando un gradiente centrale/periferico di 2/1.

Dopo stimolazione con CRH, il prelievo petrosa ha una sensibilità del 100% (gradiente minimo 3/1) in presenza di malattia di Cushing.

Pazienti con sindrome da iperincrezione ectopica di ACTH non mostrano gradienti di ACTH nei seni petrosi né prima né dopo stimolazione. Tuttavia, il prelievo dai seni petrosi è veritiero solo quando la normale secrezione ipofisaria di ACTH sia soppressa. Pertanto, pazienti con sindrome ciclica o di pseudo-Cushing e pazienti in terapia soppressiva non devono mai essere campionati.

In una revisione dei nostri primi 265 casi di malattia di Cushing confermata chirurgicamente e in 20 casi di provata sindrome di iperincrezione ectopica di ACTH, il prelievo dei seni petrosi è risultato aver una sensibilita del 98% prima del CRH e del 100% dopo CRH.

Nei nostri primi 265 pazienti non si sono avute complicazioni ad eccezione di occasionali ematomi inguinali. Abbiamo successivamente modificato la configurazione del catetere angolandolo di 90° a 2 cm dalla punta. Nelle successive 150 indagini, un paziente ha presentato una emorragia pontina e due altri pazienti hanno accusato sintomi transitori di disfunzione pontina, scomparsi immediatamente dopo il ritiro del catetere. I sintomi da disfunzione pontina, vale a dire perdita della sensibilità periorale, sensazione di «lingua grossa», fuggevoli alterazioni del sensoria, sono aspecifici e facilmente confondibili con ansia eccessiva.

Con l'abbandono dei cateteri con angolazione fissa mediale non abbiamo più registrato complicanze nei successivi 250 pazienti. Noi raccomandiamo il prelievo dei seni petrosi in tutti i pazienti con syndrome di Cushing ACTH-dipendente e con Risonanza Magnetica sellare normale. In tali circostanze, il prelievi dai seni petrosi può escludere un carcinoide bronchiale secernente ACTH, simulante un'origine ipofisaria del Cushing.

I carcinoidi bronchiali sono la causa più frequente di iperincrezione ectopica di ACTH e metà di essi simula esattamente un adenoma corticotropo ipofisario. In aggiunta, quando il neurochirurgo non sia in grado di identificare un microadenoma durante un'esplorazione per via trans-nasosfenoidale, l'emiipofisectomia basata sui gradienti petrosi è risolutiva nell'80% dei pazienti (in base a una casistica di più di 50 casi in cui una tale resezione cieca è stata eseguita).

Raccomandiamo inoltre il prelievo dai seni petrosi in tutti i pazienti con sindrome di Cushing ACTH-dipendente, con RM sellare positiva o dubbia, e test biochimici incerti (negativi i test di soppressione col Dexamethasone o di stimolazione col CRH).

Nella popolazione femminile compresa tra 20–35 anni, si ha un riscontro di «incidentaloma» ipofisario nel 10%. Il prelievo dei seni petrosi è necessaria per escludere un incidentaloma ipofisario in presenza di una sindrome da iperincrezione ectopica di ACTH.

In conclusione, il prelievo dai seni petrosi è una metodica estremamente accurata e un test sicuro per la differenziazione tra ipercortisolismo ACTH-dipendente ectopico o ipofisario utile inoltre ad offrire una opportunità chirurgica quando l'esplorazione transsfenoidale risulti negativa.

I prelievi venosi nella sindrome di Cushing

I prelievi venosi dai seni petrosi inferiori sono utilizzati nella diagnostica differenziale della sindrome di Cushing per dimostrare l'origine ipofisaria o ectopica dell'ipersecrezione di ACTH.

Il drenaggio venoso dell'adenoipofisi avviene attraverso due plessi venosi, il destro ed il sinistro, che coprono la superficie della ghiandola e scaricano nel seno cavernoso omolaterale, direttamente o attraverso i seni intercavernosi. I seni petrosi inferiori rappresentano le principali vie di deflusso dei seni cavernosi; essi sono cateterizzabili con relativa facilità, allo scopo di eseguire prelievi peril dosaggio degli ormoni ipofisari.

La nostra tecnica prevede il cateterismo per via transfemorale; utilizziamo cateteri da 4 o 5 French, retti, con estremo distale ricurvo a 45°, senza fori laterali.

Sono indispensabili accurati controlli flebografici per dimostrare l'esatta posizione dei cateteri prima dell'esecuzione dei prelievi.

In letteratura viene riportata un'alta accuratezza diagnostica dei prelievi dai seni petrosi nella diagnosi differenziale tra malattia di Cushing e sindrome da ACTH ectopico, mentre assai minore è la specificità di una corretta localizzazione delle lesioni ipofisarie. Riteniamo che gli errori di lateralizzazione possano essere so1tanto ridotti, ma non eliminati da una corretta esecuzione dell'indagine: infatti dipendono da variabilità anatomiche, dalla sede dell'adenoma e, verosimilmente, da asimmetrie di flusso attraverso le vene di drenaggio ipofisario.

Cushing's disease: pathobiology, diagnosis, and management

Cushing's disease (CD) is the result of excess secretion of adrenocorticotropic hormone (ACTH) by a benign monoclonal pituitary adenoma. The excessive secretion of ACTH stimulates secretion of cortisol by the adrenal glands, resulting in supraphysiological levels of circulating cortisol. The pathophysiological levels of cortisol are associated with hypertension, diabetes, obesity, and early death. Successful resection of the CD-associated ACTH-secreting pituitary adenoma is the treatment of choice and results in immediate biochemical remission with preservation of pituitary function. Accurate and early identification of CD is critical for effective surgical management and optimal prognosis. The authors review the current pathophysiological principles, diagnostic methods, and management of CD.

Clinical Guidelines for the Diagnosis and Treatment of Cushing's Disease in Korea

Cushing's disease (CD) is a rare disorder characterized by the overproduction of adrenocorticotropic hormone due to a pituitary adenoma that ultimately stimulates excessive cortisol secretion from the adrenal glands. Prior to the detection of pituitary adenomas, various clinical signs of CD such as central obesity, moon face, hirsutism, and facial plethora are usually already present. Uncontrolled hypercortisolism is associated with metabolic, cardiovascular, and psychological disorders that result in increased mortality. Hence, the early detection and treatment of CD are not only important but mandatory. Because its clinical manifestations vary from patient to patient and are common in other obesity-related conditions, the precise diagnosis of CD can be problematic. Thus, the present set of guidelines was compiled by Korean experts in this field to assist clinicians with the screening, diagnoses, and treatment of patients with CD using currently available tests and treatment modalities.

Physiological basis for the etiology, diagnosis, and treatment of adrenal disorders: Cushing's syndrome, adrenal insufficiency, and congenital adrenal hyperplasia

The hypothalamic-pituitary-adrenal (HPA) axis is a classic neuroendocrine system. One of the best ways to understand the HPA axis is to appreciate its dynamics in the variety of diseases and syndromes that affect it. Excess glucocorticoid activity can be due to endogenous cortisol overproduction (spontaneous Cushing's syndrome) or exogenous glucocorticoid therapy (iatrogenic Cushing's syndrome). Endogenous Cushing's syndrome can be subdivided into ACTH-dependent and ACTH-independent, the latter of which is usually due to autonomous adrenal overproduction. The former can be due to a pituitary corticotroph tumor (usually benign) or ectopic ACTH production from tumors outside the pituitary; both of these tumor types overexpress the proopiomelanocortin gene. The converse of Cushing's syndrome is the lack of normal cortisol secretion and is usually due to adrenal destruction (primary adrenal insufficiency) or hypopituitarism (secondary adrenal insufficiency). Secondary adrenal insufficiency can also result from a rapid discontinuation of long-term, pharmacological glucocorticoid therapy because of HPA axis suppression and adrenal atrophy. Finally, mutations in the steroidogenic enzymes of the adrenal cortex can lead to congenital adrenal hyperplasia and an increase in precursor steroids, particularly androgens. When present in utero, this can lead to masculinization of a female fetus. An understanding of the dynamics of the HPA axis is necessary to master the diagnosis and differential diagnosis of pituitary-adrenal diseases. Furthermore, understanding the pathophysiology of the HPA axis gives great insight into its normal control.

Imaging of the pituitary and sella turcica

The pituitary gland is housed in the sella turcica and has vital endocrinologic functions. It lies in close proximity to numerous vital structures, including the optic chiasm, sphenoid sinus, cavernous sinus and hypothalamus. An understanding of the function, anatomy and embryology of the pituitary gland and its surrounding structures is vital to understanding its normal appearance, as well as in evaluating the broad spectrum of pathology that can involve the pituitary gland. Imaging of pathology in the sellar region, including pituitary adenomas, meningiomas, craniopharyngiomas and aneurysms, plays an important role in guiding treatment decisions. Modern imaging techniques are also important in evaluating the pituitary gland after surgery.

Diagnostic value of super-selective bilateral cavernous sinus sampling with hypothalamic stimulating hormone loading in patients with ACTH-producing pituitary adenoma

AIMS

Early diagnosis and early treatment by transsphenoidal surgery is desirable for ACTH-producing pituitary microadenoma, but accurate localization of the functional lesion is not always possible before surgery because magnetic resonance (MR) imaging may provide false negative and/or positive findings. The diagnostic value of super-selective bilateral cavernous sinus sampling with the administration of corticotropin-releasing hormone (CRH) was assessed in patients with functioning ACTH-producing pituitary adenoma.

METHODS

Fifteen patients with pituitary adenoma (14 with microadenoma) aged from 23 to 74 years (mean 46.7 years) underwent cavernous sinus sampling with or without the CRH loading test and subsequent transsphenoidal surgery in our institute from October 1997 through to November 2002. MR imaging including dynamic scan failed to detect the adenomatous lesion in all patients. To eliminate the bias due to uneven blood flow in the cavernous sinuses and the multi-hormonal response to CRH administration, the ACTH/FSH ratios were evaluated. The inter-cavernous gradient (ICG) was calculated as the higher/lower ACTH venous blood levels in the right and left cavernous sinuses with or without CRH loading. The adjusted ICG was calculated using the ACTH/FSH ratios. The results were compared with the surgical findings. An ICG of 1.4 or greater was considered to indicate the localization of the responsible lesion.

RESULTS

Transsphenoidal surgery revealed the functioning lesion on the right in five cases, the left in six, the midline in three and the bilateral lateral wings (double adenoma) in one. Adjusted ICG with CRH loading had a localization accuracy of 93.3% (14/15), which was significantly higher than that of 73.3% (11/15) using ICG without hypothalamic stimulating hormone loading (p = 0.0402).

CONCLUSIONS

Super-selective cavernous sinus sampling with hypothalamic stimulating hormone administration can provide accurate localization of the responsible lesion in patients with ACTH-producing pituitary adenoma.

The lateralization accuracy of inferior petrosal sinus sampling in 501 patients with Cushing's disease

CONTEXT

It is often difficult to find an adenoma in patients with Cushing's disease (CD) whose preoperative magnetic resonance imaging (MRI) is normal. Better localizing modalities are needed.

OBJECTIVE

The aim of this study was to determine the accuracy of inferior petrosal sinus sampling (IPSS) in predicting adenoma lateralization.

DESIGN AND SETTING

We conducted a prospective observational study at a tertiary care clinical research center.

PATIENTS

A total of 501 consecutive patients (363 female) with confirmed ACTH adenomas and IPSS were included.

MAIN OUTCOME MEASURE

We measured the accuracy of IPSS to predict the intrasellar location of an adenoma.

RESULTS

IPSS confirmed a pituitary source of ACTH secretion in 491 patients (98%). All 10 patients with false-negative results had peak IPSS ACTH concentrations (before or after CRH) of < 400 pg/ml. Interpetrosal (side-to-side) ratios were ≥ 1.4 in 491 patients (98%). This ratio correctly predicted lateralization in 273 of 396 patients (positive predictive value = 69%) with a lateral adenoma. Left-sided IPSS lateralization (P = .008) and consistent lateralization before and after CRH administration (P = .02) were associated with enhanced accuracy. When positive, preoperative MRI correlated with adenoma location in 171 of 201 patients (positive predictive value = 86%).

CONCLUSIONS

Potential false-negative results, the most common type of diagnostic error with IPSS for the differential diagnosis of CS, can be identified by peak IPSS ACTH values < 400 pg/ml. When MRI is normal, IPSS can be used to guide surgical exploration in patients with negative preoperative imaging. However, because of the limited accuracy of lateralization, thorough exploration of the pituitary gland is required when an adenoma is not readily discovered based on predicted location.

Imaging of pediatric pituitary endocrinopathies

Accurate investigation of the hypothalamic-pituitary area is required in pediatric patients for diagnosis of endocrine-related disorders. These disorders include hypopituitarism, growth failure, diencephalic syndrome, delayed puberty, precocious puberty, diabetes insipidus, syndrome of inappropriate antidiuretic hormone (SIADH) secretion, and hyperpituitarism. Magnetic resonance imaging (MRI) is the modality of choice to visualize hypothalamic-pituitary axis and associated endocrinopathies. Neuroimaging can be normal or disclose abnormalities related to pituitary-hypothalamic axis like (i) congenital and developmental malformations; (ii) tumors; (iii) cystic lesions; and (iv) infectious and inflammatory conditions. Classical midline anomalies like septo-optic dysplasias or corpus callosum agenesis are commonly associated with pituitary endocrinopathies and also need careful evaluation. In this radiological review, we will discuss neuroendocrine disorders related to hypothalamic pituitary-axis.

Prolactin measurement during inferior petrosal sinus sampling improves the localization of pituitary adenomas in Cushing's disease

OBJECTIVE

Inferior petrosal sinus sampling (IPSS) distinguishes pituitary-dependent Cushing's disease (CD) from ectopic ACTH syndrome with a high degree of certainty, but has not been reliable in predicting the location of an adenoma within the pituitary gland. We investigated whether prolactin measurements during IPSS would improve pituitary tumour localization.

METHODS

Fifty-four patients with suspected ACTH-dependent Cushing's syndrome who underwent IPSS between 1997 and 2009 were studied retrospectively. Twenty-eight patients who had an identifiable tumour that stained for ACTH on histopathology are the subject of this study. Intersinus ACTH gradients before and after adjustment for prolactin were compared with surgical findings and pathology.

RESULTS

Magnetic resonance imaging localized a pituitary adenoma in 17/28 (61%) patients. Using a maximum intersinus ACTH gradient of ≥1·4 before or after CRH stimulation, we could diagnose the tumour location correctly in 15/28 (54%) patients. By comparison, tumour lateralization by means of a dominant (≥1·4) prolactin-adjusted ACTH intersinus gradient was correct in 21/28 (75%) patients (P = 0·041). Tumour localization was correct in 23/28 (82%) patients when MRI and prolactin-adjusted ratio data were combined. Fourteen patients with proper bilateral IPS venous sampling (as determined by concurrent IPS to peripheral prolactin ratio ≥1·8) either had correct localization of the tumour (n = 12) or had a central lesion (n = 2). In none of these 14 patients was the dominant prolactin-adjusted ACTH ratio associated with a tumour on the opposite side of the gland.

CONCLUSION

Prolactin measurement, during IPSS, improves our ability to correctly localize the pituitary adenoma site in CD.

Bilateral inferior petrosal sinus sampling by unilateral femoral venous approach

Purpose

Bilateral inferior petrosal sinus sampling (IPSS) is a direct method of distinguishing between pituitary and ectopic ACTH secretion. We present unilateral femoral route technique avoiding bilateral femoral venous puncture using two 4F catheters into both sides of IPSS in these obese patients.

Materials and Methods

Unilateral femoral puncture using 9F guiding catheter allowed two 4F catheters which can be introduced in each side of inferior petrosal sinus. To reduce bleeding in the gap between 2 catheters at the diaphragm of the 9F femoral sheath, we introduced a short guidewire provided along with femoral sheath. After removing the 9F sheath after procedure, we applied manual compression as usual. We evaluated any technical difficulty and other complications including the presence of hematoma at the puncture site 1 day and 30 days later.

Results

Bilateral IPSS by using two 4F catheters in both inferior petrosal sinuses was possible via unilateral femoral route via 9F sheath. There was no technical difficulty introducing 4F catheters into each IPS of both sides. After removing 9F femoral sheath, there was no other complication and no hematoma at the puncture site at 1 day and 30 days later.

Conclusion

Unilateral femoral venous approach with a 9-French sheath can be used in IPSS. This technique allowed to pass two 4F catheters for IPSS at both sides and could avoid unnecessary bilateral femoral puncture in these obese patients without any hematoma formation after the procedure.

The role of interventional venous sampling in localising neuroendocrine tumours

PURPOSE OF REVIEW

This review focuses on the role of interventional venous sampling in the diagnosis and localization of neuroendocrine tumours (NETs), and its role in relation to conventional and novel imaging techniques.

RECENT FINDINGS

Imaging of NETs has evolved together with advances in imaging technology. Imaging localization plays an important role in the subsequent management of these tumours. This article provides an overview of the application of venous sampling in the localization of NETs, presented with current evidence to support its continued role in the diagnostic work-up of pituitary, parathyroid, pancreatic, adrenal and ovarian endocrine disease.

SUMMARY

Interventional venous sampling continues to be a highly sensitive modality in the localization of NETs. Although significant advances in noninvasive anatomic and functional imaging modalities have reduced the reliance of this well established technique, the latest literature continues to support its important role in the diagnostic armament of these unique and rare tumours.

Venous structures at the craniocervical junction: anatomical variations evaluated by multidetector row CT

The aim of this study was to evaluate the anatomy of and normal variations in the craniocervical junction veins. We retrospectively reviewed 50 patients who underwent contrast-enhanced CT with a multidetector scanner. Axial and reconstructed images were evaluated by two neuroradiologists with special attention being paid to the existence and size of veins and their relationships with other venous branches around the craniocervical junction. The venous structures contributing to craniocervical junction venous drainage, including the inferior petrosal sinus (IPS), transverse-sigmoid sinus, jugular vein, condylar vein, marginal sinus and suboccipital cavernous sinus were well depicted in all cases. The occipital sinus (OS) was identified in 18 cases, including 4 cases of prominent-type OS. The IPS showed variations in drainage to the jugular vein through the jugular foramen or intraosseous course of occipital bone via the petroclival fissure. In all cases, the anterior condylar veins connected the anterior condylar confluence to the marginal sinus; however, a number of cases with asymmetry and agenesis in the posterior and lateral condylar veins were seen. The posterior condylar vein connected the suboccipital cavernous sinus to the sigmoid sinus or anterior condylar confluence. The posterior condylar canal in the occipital bone showed some differences, which were accompanied by variations in the posterior condylar veins. In conclusion, there are some anatomical variations in the venous structures of the craniocervical junction; knowledge of these differences is important for the diagnosis and treatment of skull base diseases. Contrast-enhanced CT using a multidetector scanner is useful for evaluating venous structures in the craniocervical junction.

The role of bilateral inferior petrosal sinus sampling in the diagnosis of Cushing's syndrome

Adrenocorticotropin hormone (ACTH)-dependent Cushing's syndrome is most often due to a pituitary corticotroph adenoma, with ectopic ACTH-secreting tumors representing approximately 15% of cases. Biochemical and radiological techniques have been established to help distinguish between these two entities, and thus aid in the localization of the neoplastic lesion for surgical resection. The test that offers the highest sensitivity and specificity is bilateral inferior petrosal sinus sampling (BIPSS). BIPSS is an interventional radiology procedure in which ACTH levels obtained from venous drainage very near the pituitary gland are compared to peripheral blood levels before and after corticotropin hormone (CRH) stimulation. A gradient between these two locations indicates pituitary Cushing's, whereas the absence of a gradient suggests ectopic Cushing's. Accurate BIPSS results require hypercortisolemia to suppress normal corticotroph ACTH production and hypercortisolemia at the time of the BIPSS to assure excessive ACTH secretion. In some cases, intrapituitary gradients from side-to-side can be helpful to localize small corticotroph adenomas within the sella. BIPSS has rare complications and is considered safe when performed at centers with experience in this specialized technique.

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

BACKGROUND AND PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

The role of desmopressin in bilateral and simultaneous inferior petrosal sinus sampling for differential diagnosis of ACTH-dependent Cushing's syndrome

OBJECTIVE

Bilateral inferior petrosal sinus sampling (BIPSS) with corticotrophin-releasing hormone (CRH) stimulation is currently the gold standard test for the differential diagnosis of ACTH-dependent Cushing's syndrome. Reports on the use of desmopressin in this approach are limited. The aim of this study was to evaluate the use of desmopressin during BIPSS in a cohort of patients with ACTH-dependent Cushing's syndrome.

DESIGN

A retrospective case-record study.

PATIENTS

Fifty-six patients with confirmed ACTH-dependent Cushing's syndrome underwent BIPSS with desmopressin stimulation when presenting negative pituitary tumour imaging.

MEASUREMENTS

Central to peripheral (CEN:PER) ACTH gradient, lateralization of the ACTH source and surgical tumour confirmation were evaluated.

RESULTS

A CEN:PER ACTH gradient was found in 40 patients under basal conditions (CEN:PER >or= 2) and in 47 patients after desmopressin stimulation (CEN:PER >or= 3). Ectopic ACTH-producing tumours (three lung carcinoid tumour, one thymus carcinoid tumour and one thymus hyperplasia) were confirmed in five out of nine patients without the CEN:PER ACTH gradient, and four cases were false negative for Cushing's disease. Lateralization (IPS:IPS >or= 1.4) was observed in 80.8% of patients under basal conditions (38/47) and in 97.8% after desmopressin (46/47), and it was surgically confirmed in 78.7%. There were no false-positive cases. Sensitivity and specificity were 92.1% and 100%, respectively.

CONCLUSIONS

Desmopressin improves the differential diagnosis of ACTH-dependent Cushing's syndrome by amplifying the CEN:PER and IPS:IPS ACTH gradients, and is therefore a useful ACTH secretagogue in BIPSS.

Evaluation and treatment of Cushing's syndrome

Cushing's syndrome results from sustained pathologic hypercortisolism caused by excessive corticotropin (ACTH) secretion by tumors in the pituitary gland (Cushing's disease, 70%) or elsewhere (15%), or by ACTH-independent cortisol secretion from adrenal tumors (15%). The clinical features are variable, and no single pattern is seen in all patients. Those features most specific for Cushing's syndrome include abnormal fat distribution, particularly in the supraclavicular and temporal fossae, proximal muscle weakness, wide purple striae, and decreased linear growth with continued weight gain in a child. Patients with characteristics of glucocorticoid excess should be screened with measurements of saliva or urine cortisol or dexamethasone suppression testing. The diagnosis of Cushing's syndrome should be followed by the measurement of plasma ACTH concentration to determine whether the hypercortisolism is ACTH-independent. In ACTH-dependent patients, bilateral inferior petrosal sinus sampling with measurement of ACTH before and after administration of ACTH-releasing hormone most accurately distinguishes pituitary from ectopic ACTH secretion. Surgical resection of tumor is the optimal treatment for all forms of Cushing's syndrome; bilateral adrenalectomy, medical treatment, or radiotherapy are sought in inoperable or recurrent cases. The medical treatment of choice is ketoconazole. The prognosis is better for Cushing's disease and benign adrenal causes of Cushing's syndrome than adrenocortical cancer and malignant ACTH-producing tumors.

[Cushing's disease in the 90's: a review]

Since 1932 when Cushing's disease has been described, several important advances have been made in diagnosis and management. However several points remain obscure and there is no general agreement among authors. An accurate biological diagnosis is one of the difficulties found when we face a patient with hypercortisolism. In addition, corticotropin dependent syndrome should be distinguished from the independent one, as well as identifying the source of ACTH hypersecretion. The main problem in Cushing's disease is to localise the secreting adenoma and at the moment there is not any diagnostic method with absolute sensibility and specificity. Magnetic Resonance Imaging shows a sensibility of 77% and 87% especificity; inferior petrosal sinus sampling may help in localising the side, where the adenoma lies, although an appropriate technique is mandatory. New developing techniques, such as intraoperative doppler and assessment of ACTH levels in the peripituitary veins may help us in localising the source of ACTH hypersecretion. Sometimes the adenoma cannot be identified and a surgical exploration of the pituitary is required. If an adenoma is found, a 89% probility of curation has been reported; on the contrary, incomplete tumor removal, no tumor found at surgery, or the presence of the so-called corticotrop hyperplasia where followed of bad results and may explain the failed surgery. Then, hypofisectomy, hemi-hypofisectomy, radiotherapy, photon knife or gamma knife, may be of help in the control of this condition. We reviewed the recent literature and analysed the diagnostic strategies and teatments currently available for this illness. In addition we propose an algohritm for diagnosis and treatment and analyze our results in a consecutive series of 38 patients.

Direct intraoperative micromethod for hormone measurements of pituitary tissue in Cushing's disease

BACKGROUND

During transsphenoidal surgery (TSS) for Cushing's disease, the surgeon depends on experience to find minute adenomas. Cytological slide preparations or frozen sections, even when successful, are not specific concerning the hormone activity. In an attempt to improve accurate localization of minute ACTH adenomas, we evaluated a new intraoperative method of ACTH measurements in adenoma and anterior lobe microsamples. As most ACTH adenomas are monohormonal, the possible benefit of a GH measurement was investigated.

METHODS

We included pituitary tissue of 32 patients, 22 with Cushing's disease and 10 endocrine inactive pituitary adenomas as control. All patients underwent TSS by one surgeon. Preoperative data, intraoperative and perioperative hormone measurements of homogenized, weighed pituitary tissue samples, and histological findings are presented.

RESULTS

In ACTH adenomas, the median ACTH content was found to be 1,688 ng/mg, minimum 345 ng/mg. The median GH was measured at 36 ng/mg. Anterior lobe tissue contained median 80 ng ACTH/mg, maximum 279 ng/mg. Median GH was 2,200 ng/mg. In hormonally inactive adenomas ACTH was less than 0.1 ng/mg, median GH was 5.5 ng/mg. There was no overlap of ACTH content in the tissues investigated. Therefore, by adopting 300 ng ACTH/mg as a cutoff level, a clear discrimination is given. Additional GH measurements are not necessary.

CONCLUSION

This new intraoperative method permits a clear differentiation between adenoma and pituitary tissue. In addition to intraoperative cytology and histology, this method can serve as a specific proof that the ACTH adenoma has been identified during surgery. This may be valuable in difficult cases with unclear intraoperative findings, especially after previously negative exploration.

Cavernous sinus sampling in patients with adrenocorticotrophic hormone-dependent Cushing's syndrome with emphasis on inter- and intracavernous adrenocorticotrophic hormone gradients

OBJECT

As an alternative method to inferior petrosal sinus sampling with administration of corticotropin-releasing hormone (CRH), the authors have developed a method of selective venous sampling directly from the cavernous sinus, which is performed using a superselective catheterization technique. The goal of this study is to assess this method.

METHODS

Catheterization to the cavernous sinus was performed in 44 patients with clinical and biochemical features of Cushing's syndrome. Forty of these patients in whom there was a definite clinical and/or histological diagnosis were evaluated. In 35 patients, a pituitary microadenoma was detected on magnetic resonance imaging and/or during surgery. Ectopic lesions were suspected in five patients, who later developed nonpituitary tumors. The central/peripheral (C/P) ratios of adrenocorticotrophic hormone (ACTH) without CRH administration ranged from 5.2 to 448.1 (mean+/-standard deviation, 66.7+/-91.2) in cavernous sinuses and from 1.1 to 52 (mean+/-standard deviation, 8.5+/-9.9) in the inferior petrosal sinuses. The petrosal sinus sampling contained false negative results in eight patients (23%) based on a cutoff point of 2. On the contrary, patients with ectopic lesions did not show any increase in ACTH levels in either sampling portion. The intercavernous gradients of ACTH, ranging from 1.2 to 506.4, indicated the correct lateralization of microadenoma in the lateral wing in all 30 patients. The interpetrosal gradients, ranging from 1 to 31.4, did not give a sufficient value (> or = 1.4) in four patients (13%) with a lateral lesion. In five cases of midline tumors, the intercavernous and interpetrosal gradients indicated false laterality in three and four cases, respectively. The intracavernous (posterior-anterior) gradients, ranging from 1.04 to 60.7 (mean 14.9), showed a higher concentration of ACTH in the posterior portion of the sinus in all patients.

CONCLUSIONS

These results suggest that 1) cavernous sinus sampling without CRH administration can demonstrate hypersecretion of ACTH from the pituitary gland with a high diagnostic accuracy; 2) intercavernous gradients will indicate the correct lateralization in laterally localized microadenomas; and 3) sampling should be performed from the posterior portion of the cavernous sinus.

Improved diagnostic accuracy of inferior petrosal sinus sampling over imaging for localizing pituitary pathology in patients with Cushing's disease

The majority of patients with Cushing's disease can be cured by transsphenoidal microsurgery; however, precise localization of the pituitary source of ACTH is not always possible by standard imaging techniques. Bilateral venous sampling from the inferior petrosal sinuses (IPSS) is also useful for diagnosing Cushing's disease, but the interpretation of discordant findings between IPSS and imaging remains problematic. We tested the ability of imaging and IPSS to localize an ACTH-secreting pituitary lesion in comparison to definitive histopathological examination of the pituitary in patients with Cushing's disease (n = 37). Bilateral IPS catheterization was technically feasible in 32 patients and provided evidence of lateralization in 31 patients. Histological examination confirmed a corticotropic adenoma in 28 patients and corticotropic hyperplasia in 2 patients; Crooke's hyaline change was found in 7 patients, among whom 1 subsequently was found to have an ectopic sphenoid corticotropic adenoma, and the remainder had suspected microadenomas that were not identified microscopically. Accurate localization of the pituitary lesion was more frequent when based on IPSS results than on imaging studies (70% vs. 49%, P < 0.06). The 2 tests provided directly discrepant results for 8 patients; among these, IPSS was more likely than imaging to agree with final pathology (63% vs. 13%, P < 0.10). Imaging was entirely normal for another 9 patients, in whom IPSS accurately localized the lesion for the majority (89%; 95% confidence interval: 50-99%). We suggest that IPSS is an effective tool for localizing pituitary pathology and planning surgery for patients with Cushing's disease.

Infertility. A clinical guide for the internist

Infertility is a common condition that internists practicing primary care may increasingly encounter. Abnormal male semen parameters, ovulation disorders, and tubal dysfunction account for most cases of infertility. By performing a complete initial evaluation and through appropriate and timely referral, internists can contribute to the care and improve outcomes for couples with this condition (Table 9).

Advances in the diagnosis and treatment of Cushing's syndrome

Excess endogenous glucocorticoid production, whether ACTH-dependent or ACTH-independent, results in the classic clinical and biochemical picture of Cushing's syndrome. The diagnosis requires demonstration of an increased cortisol secretion rate, best achieved using determination of urinary free cortisol as an index. In mild cases, distinction from the hypercortisolism of pseudo-Cushing states may prove difficult. If the physician is in doubt, a dexamethasone/CRH test should be performed. Primary adrenal Cushing's syndrome can be diagnosed on the basis of undetectable plasma ACTH and the results of adrenal imaging procedures. ACTH-dependent Cushing's syndrome can be differentiated using an oCRH test and imaging procedures. In the presence of a discrete pituitary lesion on imaging, a standard oCRH test with results consistent with such a lesion is sufficient to proceed to transsphenoidal surgery. In the absence of such a lesion or if the oCRH test is equivocal, simultaneous BIPSS with oCRH administration should be performed to distinguish between a pituitary or ectopic source. Surgical ablation is the treatment of choice for all types of Cushing's syndrome. In the 5% of cases with Cushing's disease in whom transsphenoidal surgery fails and in the 5% of cases in whom the disease recurs, repeat transsphenoidal surgery or radiation therapy in association with mitotane treatment are reasonable alternatives. Bilateral adrenalectomy effectively cures hypercortisolism if resection of the ACTH-secreting tumour is unsuccessful and radiation/medical therapy fails.

Cushing's syndrome

Cushing's syndrome is usually caused by the secretion of corticotropin or cortisol by a pituitary or adrenal tumor, respectively, or by ectopic secretion of corticotropin. It is possible to determine the specific abnormality in most patients, but it can sometimes be difficult to decide whether the patient has hypercortisolism and whether it is primary or due to major depressive disorder or to the stress of other diseases. Determining the cause of the hypercortisolism involves performing multiple tests in a logical sequence; the results should all be consistent with the same diagnosis. Treatment should aim to cure the hypercortisolism and to eliminate any tumor that threatens the patient's health, while minimizing the chance of an endocrine deficiency or long-term dependence on medications.

Cushing's syndrome in children and adolescents. Presentation, diagnosis, and therapy

BACKGROUND AND METHODS

Cushing's syndrome is rare in children and adolescents. We analyzed the clinical presentation, diagnostic evaluation, and treatment of 59 patients with Cushing's syndrome between the ages of 4 and 20 years who were admitted to the National Institutes of Health during the period from 1982 to 1992. The cause of hypercortisolism was identified by low- and high-dose dexamethasone suppression tests, the ovine corticotropin-releasing hormone (CRH) stimulation test, imaging studies, and bilateral sampling of the inferior petrosal sinuses combined with administration of CRH.

RESULTS

Fifty patients had Cushing's disease, six had primary adrenal disease, and three had ectopic corticotropin secretion. The initial signs were excessive weight gain in 90 percent of the patients and growth retardation in 83 percent. Most patients (81 percent) had normal bone age at the time of diagnosis. Forty-seven percent had hypertension, whereas only 19 percent had mental or behavioral problems. The high-dose dexamethasone suppression test and the CRH stimulation test identified 68 and 80 percent, respectively, of the patients with Cushing's disease. Magnetic resonance imaging of the pituitary indicated the presence of tumor in 52 percent of the patients with pituitary adenomas. The maximal central-to-peripheral ratio of plasma corticotropin during sampling of the interior petrosal sinuses was > or = 2.5 in all the patients with Cushing's disease and < 2.5 in those with ectopic corticotropin secretion. Remission of hypercortisolism was achieved in 48 of the 49 patients who underwent transsphenoidal surgery for Cushing's disease, in all 6 of the patients who underwent adrenalectomy for primary adrenal disease, and in the 2 patients in whom the ectopic source of corticotropin could be identified.

CONCLUSIONS

Weight gain and growth retardation are common clinical characteristics of Cushing's syndrome in children and adolescents. Diagnostic evaluation of such patients with CRH stimulation alone and combined with inferior petrosal sinus sampling and imaging studies is accurate, and therapy is usually successful.

Preliminary observations using endocrine markers of pituitary venous dilution during bilateral simultaneous inferior petrosal sinus catheterization in Cushing's syndrome: is combined CRF and TRH stimulation of value?

OBJECTIVE

We determined whether the measurement of hormones in pituitary blood permits correction for dilution by non-pituitary blood during bilateral simultaneous inferior petrosal sinus blood sampling in Cushing's syndrome.

DESIGN

Bilateral simultaneous inferior petrosal sinus blood sampling was performed after combined hCRF and TRH stimulation. Peak ACTH concentrations were corrected for the TSH and PRL inter-sinus ratio, assuming uniform secretion of both hormones into each inferior petrosal sinus.

PATIENTS

Eight patients with clinical and biochemical features of Cushing's syndrome.

MEASUREMENTS

Basal and stimulated ACTH, TSH and PRL concentrations were measured after bilateral simultaneous inferior petrosal sinus blood sampling and simultaneously from a peripheral forearm vein.

RESULTS

Basal central:peripheral ACTH ratio misdiagnosed four of eight patients as having non-pituitary disease. Peak uncorrected ACTH central:peripheral ratio erroneously suggested two of eight patients had non-pituitary disease. ACTH central:peripheral ratio corrected by TSH and PRL correctly predicted pituitary-dependent disease in all eight cases and provided correct lateralization data in four of five patients with a unilateral pituitary microadenoma.

CONCLUSION

This study suggests that measuring other hormones in pituitary blood after TRH stimulation can offer a simple and reliable method for correcting for dilution by non-pituitary blood during bilateral simultaneous inferior petrosal sinus blood sampling in Cushing's syndrome.