Revalidation of inferior petrosal sinus sampling: the latest results from a single-center experience

Cushing's disease (CD), which manifests as excess cortisol secretion, is caused by adrenocorticotrophic hormone (ACTH)-secreting pituitary adenomas. Such adenomas are occasionally difficult to identify on magnetic resonance imaging (MRI), and thorough endocrinological examination may be required to detect them. Inferior petrosal sinus (IPS) sampling (IPSS) has been the gold standard test for distinguishing CD from ectopic ACTH syndrome (EAS). However, IPSS is an invasive procedure, and proper catheterization is occasionally challenging due to anatomical variations. Thus, there have been ongoing debates regarding the necessity of this procedure. Here, we present our recent IPSS data derived from the analysis of 65 patients who were referred to us for possible CD between April 2018 and December 2020 after undergoing meticulous endocrinological testing. Even with detailed MRI, no obvious lesions were identified in 19 patients. IPSS performed on these 19 individuals identified an IPS-to-peripheral ACTH gradient in 15 of them. The four patients who lacked this gradient were subjected to a classical algorithm using concurrently measured prolactin levels, the results of which were consistent with their ultimately confirmed diagnoses: two true-positive and two true-negative diagnoses. These findings support the validity of the algorithm and demonstrate that the prolactin-adjusted IPS-to-peripheral ACTH ratio can improve the differentiation between CD and EAS. We had no false-negative results, but three patients were false-positive. Consequently, those three patients in which no apparent tumor was clarified during surgery could not have any endocrinological improvement postoperatively.

Two Distinctive POMC Promoters Modify Gene Expression in Cushing Disease

CONTEXT

Mechanisms underlying pituitary corticotroph adenoma adrenocorticotropin (ACTH) production are poorly understood, yet circulating ACTH levels closely correlate with adenoma phenotype and clinical outcomes.

OBJECTIVE

We characterized the 5' ends of proopiomelanocortin (POMC) gene transcripts, which encode the precursor polypeptide for ACTH, in order to investigate additional regulatory mechanisms of POMC gene transcription and ACTH production.

METHODS

We examined 11 normal human pituitary tissues, 32 ACTH-secreting tumors, as well as 6 silent corticotroph adenomas (SCAs) that immunostain for but do not secrete ACTH.

RESULTS

We identified a novel regulatory region located near the intron 2/exon 3 junction in the human POMC gene, which functions as a second promoter and an enhancer. In vitro experiments demonstrated that CREB binds the second promoter and regulates its transcriptional activity. The second promoter is highly methylated in SCAs, partially demethylated in normal pituitary tissue, and highly demethylated in pituitary and ectopic ACTH-secreting tumors. In contrast, the first promoter is demethylated in all POMC-expressing cells and is highly demethylated only in pituitary ACTH-secreting tumors harboring the ubiquitin-specific protease 8 (USP8) mutation. Demethylation patterns of the second promoter correlate with clinical phenotypes of Cushing disease.

CONCLUSION

We identified a second POMC promoter regulated by methylation status in ACTH-secreting pituitary tumors. Our findings open new avenues for elucidating subcellular regulation of the hypothalamic-pituitary-adrenal axis and suggest the second POMC promoter may be a target for therapeutic intervention to suppress excess ACTH production.

Hormonal aggressiveness according to the expression of cellular markers in corticotroph adenomas

PURPOSE

The molecular mechanisms underlying tumor growth in Cushing's disease (CD) still remain a challenge. Moreover, clinical manifestations of CD may vary depending on hormonal activity; however, factors involved in the hormonal aggressiveness of adrenocorticotropic hormone (ACTH)-secreting pituitary tumors have not been fully clarified. We investigated the association between the expression of cellular markers regarding pituitary tumor progression and initial or postoperative hormone levels in patients with CD.

METHODS

Tumor tissues from 28 corticotroph adenomas (female 26, male 2, mean age 39.21 ± 10.39 years) were subject to immunohistochemical study using the following antibodies: pituitary tumor-transforming gene 1 (PTTG1), cyclin D1, p16, p27, brahma related-gene 1 (Brg1), and Ki-67. We then analyzed the relationship between each cellular marker expression and hormone levels, including 24 h urinary free cortisol (UFC), plasma ACTH, and serum cortisol.

RESULTS

PTTG1 and Ki-67 were expressed in 100% and 50% of patients, respectively. However, the levels did not reflect initial hormonal activity. The cyclin D1-negative group showed higher serum cortisol levels compared to the cyclin D1-positive group (p = 0.01). The 24 h UFC levels were significantly higher in the p27-negative group than in the p27-positive group (p = 0.04), whereas the Brg1-positive group revealed higher serum cortisol levels than in the Brg1-negative group (p = 0.02).

CONCLUSIONS

Although PTTG1 and Ki-67 play an essential role in developing ACTH-secreting tumors, cyclin D1, p27, and Brg1 may be better biomarkers to determine hormonal aggressiveness of the tumor. Further research is needed to understand the influence of cellular markers on hormonal activity in CD.

Clinical characteristics and surgical outcome in USP8-mutated human adrenocorticotropic hormone-secreting pituitary adenomas

PURPOSE

somatic mutations in the ubiquitin-specific protease 8 (USP8) gene have recently been described in patients with Cushing's disease (CD). The aim of the study is to verify whether USP8 mutation may predict early and late outcome of pituitary surgery in patients with CD operated at a single institution.

METHODS

We performed a retrospective genetic analysis of 92 adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas. Specimens were screened for USP8 hotspot mutations in the exon 14 with Sanger sequencing. Hormonal and surgical data were compared between USP8 variant carriers and wild-type tumors.

RESULTS

USP8 variants were detected in 22 adenomas (23.9%) with higher prevalence in women (28.9% vs. 5.3% in men; p < 0.05). No significant difference in hormonal levels and tumoral features in relation to USP8 status was observed. Interestingly, USP8-variant carriers were more likely to achieve surgical remission than wild-type adenomas (100% vs. 75.7%; p = 0.01). Conversely, recurrence of CD occurred in 23% of USP8-mutated patients and in 13% of patients with wild-type adenoma. The recurrence-free survival did not differ significantly between the two groups (p = 0.42).

CONCLUSIONS

ACTH-secreting pituitary adenomas carrying somatic USP8 mutations are associated with a greater likelihood of surgical remission in patients operated by a single neurosurgeon. Recurrence rates are not related with USP8-variant status.

Cushing's syndrome: comparison between Cushing's disease and adrenal Cushing's

PURPOSE

The most common etiology of Cushing's syndrome (CS) is an ACTH-producing pituitary adenoma (pitCS), reported as 2-3 times more frequent than primary adrenal CS (adrCS). We aimed to analyze and compare features of patients with pitCS and adrCS.

METHODS

A retrospective file review of 196 consecutive patients (age 46.8 ± 15.6 years, 76% female) diagnosed with CS in 2000-2017 and followed for 5.2 ± 4.2 years; 109 (55.6%) had pitCS and 76 (38.8%) adrCS. Epidemiologic, clinical and biochemical factors were compared between and within the pitCS and adrCS groups.

RESULTS

The relative proportion of pitCS to adrCS (1.4) was lower than previously reported and gradually decreased during the study years to only 1.2 in 2012-2017. The most common reason for CS screening was weight-gain in the pitCS group (48.6%) and adrenal incidentaloma in the adrCS group (39.5%). The pitCS patients were diagnosed at younger age (42.5 ± 15.1 vs. 51.6 ± 15.1 years, p < 0.001) and had lower prevalence of hypertension (51.4 vs. 74%, p = 0.005). There was no between-group difference in severity of hypercortisoluria. Within the adrCS group, patients diagnosed after detection of an adrenal incidentaloma had milder hypercortisoluria than the remaining patients, presented with smaller adrenal lesions (35.9 ± 16.3 vs. 49.1 ± 33.7 cm, p = 0.04), and received post-adrenalectomy glucocorticoid treatment for shorter periods (13 ± 11.6 vs. 31 ± 40 months, p = 0.04).

CONCLUSIONS

The relative proportion of adrCS to pitCS is rising, probably because of an increasing detection of cortisol-secreting adrenal incidentalomas associated with milder hypercortisolism. There is no difference between pitCS and adrCS in the severity of hypercortisoluria, although significant clinical differences were found.

Perioperative serum cortisol levels in ACTH sufficient and ACTH deficient patients during transsphenoidal surgery of pituitary adenoma

PURPOSE

No previous study has analyzed serum cortisol levels during transsphenoidal endoscopic pituitary surgery in patients with and without hydrocortisone (HC) substitution.

METHODS

A total of 15 patients undergoing surgery for a pituitary adenoma were studied. Those with normal ACTH function were either not given HC (n = 7) or received 50 mg intravenous HC at the start of surgery (n = 4). Patients with ACTH deficiency received intravenous HC of 100 mg in the morning before surgery (n = 4) with the additional 50 mg for an afternoon operation (n = 2). Propofol and remifentanil were used as anesthetics. Serum cortisol was measured at the start of and every 30 min during surgery.

RESULTS

Among 7 patients with normal ACTH function without HC substitution, cortisol levels before surgery were 126-244 nmol/L, among the 4 patients undergoing surgery in the morning, whereas the 3 who underwent surgery in the afternoon had lower levels, 38-76 nmol/L. During nose/sinus surgery cortisol levels decreased to 79-139 and 24-54 nmol/L, respectively. At intrasellar manipulation a distinct rise was noted. Also, in the 4 ACTH sufficient patients receiving HC, cortisol levels decreased during nose/sinus surgery, but only with a slight increase during intrasellar surgery. In the 4 ACTH deficient patients cortisol peaked at 1914-2582 nmol/L.

CONCLUSIONS

Patients with normal ACTH function without HC substitution had very low cortisol levels during the first part of surgery, likely suppressed by the anesthetics. After mechanical impact in the sella, a marked increase in cortisol was noted. Supraphysiological cortisol levels were achieved with our routine HC substitution, advising us to reduce the supplementation.

Consensus-driven in-hospital cortisol assessment after ACTH-secreting pituitary adenoma resection

PURPOSE

Remission from Cushing disease (CD) after pituitary adenoma resection may be predicted by a postoperative reduction in serum cortisol level. A 2008 consensus statement recommends assessing morning cortisol levels during the first postoperative week, and replacing glucocorticoid (GC) if cortisol nadir of < 2 or < 5 µg/dL is achieved. We sought to evaluate adherence to consensus recommendations following adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma resection at our tertiary medical center, and assess time to cortisol nadir to better define the window for assessment and intervention.

METHODS

We retrospectively analyzed data extracted from in-hospital electronic medical records for CD surgeries between January 1991 and September 2015. We compared cortisol levels and collection times, ACTH measurement, and postoperative and discharge GC treatment before and after consensus statement publication in July 2008.

RESULTS

107 surgeries were performed in 92 patients with CD. After 2008, more surgeries had at least one cortisol value assessed (67.9% before vs. 91.3% after, p = 0.033), with median initial cortisol measurement at 14 h post-surgery. However, ACTH measurement remained unchanged (42.9% vs. 43.5%; p > 0.99). Cortisol collection during GC treatment tended to increase (32.7% vs. 57.1%; p = 0.068). Of surgeries performed without prior GC treatment, 31.7 and 55.0% had a cortisol nadir of < 2 and < 5 µg/dL, respectively, within 72 h postoperative.

CONCLUSIONS

Our physicians were more diligent in measuring in-hospital postoperative cortisol levels consistent with 2008 consensus recommendations. Better management of cortisol measurements and their timing is an opportunity for improvement.

Predictors of silent corticotroph adenoma recurrence; a large retrospective single center study and systematic literature review

PURPOSE

Silent corticotroph adenomas (SCAs) are clinically silent and non-secreting, but exhibit positive adrenocorticotropic hormone (ACTH) immunostaining. We characterized a single center cohort of SCA patients, compared the SCAs to silent gonadotroph adenomas (SGAs), identified predictors of recurrence, and reviewed and compared the cohort to previously published SCAs cases.

METHODS

Retrospective review of SCA and SGA surgically resected patients over 10 years and 6 years, respectively. Definitions; SCA-no clinical or biochemical evidence of Cushing's syndrome and ACTH positive immunostaining, and SGA-steroidogenic factor (SF-1) positive immunostaining. A systematic literature search was undertaken using Pubmed and Scopus.

RESULTS

Review revealed 814 pituitary surgeries, 39 (4.8%) were SCAs. Mean follow-up was 6.4 years (range 0.5-23.8 years). Pre-operative magnetic resonance imaging demonstrated sphenoid and/or cavernous sinus invasion in 44%, 33% were > 50% cystic, and 28% had high ACTH levels pre-operatively. Compared to SGAs (n = 70), SCAs were of similar size and invasiveness (2.5 vs. 2.9 cm, p = 0.2; 44 vs. 41%, p = 0.8, respectively), but recurrence rate was higher (36 vs. 10%, p = 0.001) and more patients received radiation therapy (18 vs. 3%, p = 0.006). Less cystic tumors (0 vs. 50%, p < 0.001) and higher pre-operative ACTH levels (54 vs. 28 pg/ml, p = 0.04) were predictors of recurrence for SCAs.

CONCLUSION

This review is unique; a strict definition of SCA was used, and single center SCAs were compared with SGAs and with SCAs literature reviewed cases. We show that SCAs are aggressive and identify predictors of recurrence. Accurate initial diagnosis, close imaging and biochemical follow up are warranted.

Perioperative hypothalamic pituitary adrenal function in patients with silent corticotroph adenomas

BACKGROUND

Silent corticotroph adenomas (SCAs) are characterized by strong ACTH immunostaining without clinical manifestations of hypercortisolism. Patients with SCAs often present with mechanical symptoms related to tumor growth. This study investigates the hypothalamic pituitary adrenal axis (HPA) characteristics after adenomectomy in patients with SCAs.

METHODS

Biochemical parameters of HPA function were monitored frequently after surgical resection of non-functioning macroadenomas. Levels of ACTH, cortisol, DHEA and DHEA-S were measured frequently for 48 h after adenomectomy. HPA data of patients with SCAs (n = 38) were compared to others (Controls) with non-secreting, ACTH-negative immunostaining adenomas of similar age and gender distribution (n = 182) who had adenomectomy.

RESULT

Plasma ACTH increased (P < 0.0001) equally in patients with SCA and controls reaching a peak at 3 h (238 ± 123 vs. 233 ± 96 ng/L, respectively) after extubation declining thereafter to baseline values 24-36 h. Similarly, serum cortisol levels increased (P < 0.0001) equally in both groups reaching a maximum at 7 h (36.8 ± 13.9 vs. 39.3 ± 13.3 ug/dL). Serum DHEA also increased (P < 0.001) equally in both groups in parallel to the rise in serum cortisol. Serum DHEA-S levels similarly increased (P < 0.001) from their respective baseline (105.9 ± 67.5 and 106.5 ± 58.7 ug/dL) reaching their peak (154.5 ± 69.5 and 153.5 ± 68.6 ug/dL; respectively) at 15 h after extubation. None of the patients acquired any hormone deficits.

CONCLUSIONS

Under the maximal stimulation of the peri-operative stress, HPA function in patients with SCA behaved in an identical manner to others with ACTH-negative macroadenomas. Thus, despite the strong ACTH-positive immunostaining of these tumors, SCAs are truly non- functional.

Clinical significance of screening for subclinical Cushing's disease in patients with pituitary tumors

Cushing's syndrome (CS) is a clinical state caused by chronic excess of glucocorticoid, and results in hypertension, impaired glucose tolerance, and dyslipidemia. Recently, a mild state of pituitary CS without typical Cushingoid appearance (subclinical Cushing's disease; SCD) has been identified. However, the true prevalence of SCD and its effect on metabolic disorders remain obscure. The aim of this prospective study was to determine the prevalence of SCD according to the guideline proposed by the working group of the Japanese Ministry of Health, Welfare and Labor, and to assess the outcome of surgery on metabolic disorders. The prevalence of SCD was investigated in 105 consecutive patients diagnosed with pituitary adenomas by MRI. ACTH-dependent hypercortisolism was diagnosed based on the results of the 0.5 mg dexamethasone suppression test (serum cortisol >3.0 μg/dL) plus one positive finding of the following two tests: midnight serum cortisol level >5.0 μg/dL or ACTH increase >50% after 1-deamino-5-D-arginine vasopressin (DDAVP) challenge. The final diagnosis of SCD was established by positive staining for ACTH in surgically-excised pituitary adenoma. Three patients (4.8%) were diagnosed with SCD among 62 patients with pituitary adenoma. Transsphenoidal adenomectomy partially resulted in improvement of blood pressure and glucose metabolism in SCD patients. Our results emphasize the importance of SCD screening in patients with pituitary tumors, especially in those patients with metabolic disorders.

Perioperative thromboprophylaxis in Cushing's disease: What we did and what we are doing?

PURPOSE

Cushing's disease (CD) is associated with an increased risk of thrombotic events, particularly after surgery. No guidelines are available on the management of patients with CD undergoing pituitary transsphenoidal surgery (TSS). We aimed to compare the effectiveness of different prophylactic procedures on the prevention of thrombotic events after surgery in CD.

METHODS

We retrospectively collected data on 78 consecutive patients who underwent TSS for CD between 2001 and 2012 at Padova's Neurosurgical Unit, recording their hemostatic, hormonal and anthropometric parameters. Patients were divided into two groups according to their perioperative management. Group A (34 patients) received fractionated heparin for a maximum of 14 days after surgery. Patients in group B (44 patients) were given no early glucocorticoid replacement therapy, and treated with subcutaneous enoxaparin 4,000-8,000 U/daily (depending on their weight) for 30 days plus graduated elastic stockings until mobilization, and early ambulation.

RESULTS

The whole cohort of patients had clotting and anticoagulant factors significantly higher than the normal range. The two groups were comparable for age, BMI, ACTH, urinary free cortisol levels, outcome of surgery, and main clotting parameters. The surgical procedure did not change during the study period. Three venous thrombotic events [venous thromboembolic events (VTE), 2 associated with pulmonary embolism] were recorded in group A, none in group B (p = 0.079). No hemorrhagic events were reported.

CONCLUSIONS

Provoked thrombotic events pose a major problem in the management of CD patients after surgery, regardless of the procedure's outcome. The prophylactic regimen proposed in this paper afforded an efficacy prophylaxis against postoperative VTE in patients with CD. Due to the rarity of CD, a multicenter study on a larger sample of cases would be warranted in order to collect more thrombotic events.

A gender-dependent analysis of Cushing's disease in childhood: pre- and postoperative follow-up

OBJECTIVE

To analyse gender differences in the clinical presentation and recovery of paediatric patients with Cushing's disease (CD) after transsphenoidal surgery (TSS). Indeed, gender differences between paediatric patients with CD during presentation, after TSS and postoperative recovery have not been adequately studied.

DESIGN

Data were obtained and retrospectively analysed from clinical reports and biochemical tests at the time of presentation, 5-9 days after TSS and at the 6 and 12 months postoperative follow-up visits to determine hypothalamic-pituitary-adrenal axis (HPAA) recovery.

PATIENTS

Data from 102 paediatric patients (48 females, 54 males, mean age 12.9 ± 3.0) with CD who underwent TSS at the National Institute of Health (NIH) Clinical Center between 1997 and 2011.

RESULTS

There was equal distribution of paediatric CD between males and females (53% vs 47%; n = 102, P = 0.484). Males were more likely than females to present with higher mean BMI Z-scores (2.2 ± 0.7 vs 1.9 ± 0.6, P = 0.0079), lower mean height Z-scores (-1.2 ± 1.3 vs -0.7 ± 1.1, P = 0.0467) and higher median plasma ACTH (12.2 vs 8.5 pmol/l; P = 0.0495). Females did not present more frequently with any single sign or symptom. No significant differences were found between males and females for CD cure rates 5-9 days after TSS (87.0% males vs 87.5% females, P = 1.0), long-term cure rates (86.5% vs 93.7%; n = 69; P = 0.4374) and HPAA recovery time (11.2 ± 2.5 vs 11.7 ± 2.5 months; n = 47; P = 0.1992).

CONCLUSIONS

Paediatric CD is found to have equal distribution between males and females, but male patients present with elevated BMI and potentially shorter height and higher plasma ACTH. There is no significant difference in the cure rate or HPAA recovery time after TSS between males and females.

Gamma knife radiosurgery for Cushing's disease and Nelson's syndrome

PURPOSE

This paper presents our 18 years of experience in treating ACTH secreting adenomas (Cushing's disease and Nelson's syndrome) using the Leksell gamma knife (LGK) irradiation.

METHODS

Twenty-six patients with Cushing's disease were followed-up after LGK irradiation for 48-216 months (median 78 months). Seventeen patients had undergone previous surgery, in nine patients LGK irradiation was the primary therapy. Furthermore, 14 patients with Nelson's syndrome were followed-up for 30-204 months (median 144 months).

RESULTS

LGK treatment resulted in hormonal normalization in 80.7 % of patients with Cushing's disease. Time to normalization was 6-54 months (median 30 months). The volume of the adenoma decreased in 92.3% (in 30.7% disappeared completely). There was no recurrence of the disease. In all 14 patients with Nelson's syndrome ACTH levels decreased (in two patients fully normalized) their ACTH levels. When checked up 5-10 years after irradiation regrowth of the adenoma was only detected in one patient (9.1%), in 27.3% adenoma volume remained unchanged, in 45.4% adenoma volume decreased and in 18.2% adenoma completely disappeared. Hypopituitarism did not develop in any patient where the critical dose to the pituitary and distal infundibulum was respected.

CONCLUSION

LGK radiation represents an effective and well-tolerated option for the treatment of patients with Cushing's disease after unsuccessful surgery and may be valuable even as a primary treatment in patients who are not suitable for, or refuse, surgery. In the case of Nelson's syndrome it is possible to impede tumorous growth and control the size of the adenoma in almost all patients.

Pituitary-directed medical therapy in Cushing's disease

Transsphenoidal surgery remains the first line therapy in Cushing's disease, but a large number of patients will not be cured or disease will recur over time. Repeat pituitary surgery, bilateral adrenalectomy, and radiation have limitations with respect to efficacy and/or side effects. Therefore, there is a clear need for an effective medical treatment. The studies reviewed here suggest a role for pituitary-directed therapies, applying multireceptor ligand somatostatin analogs like pasireotide or second-generation dopamine agonists. Retinoic acid has been also studied in a small prospective study. These compounds target ACTH-secretion at the pituitary level and possibly inhibit corticotrope proliferation. Specific side effects of these compounds need to be considered, especially when used as long-term therapy. These novel approaches could provide options for treatment of patients in whom surgery has failed or is not possible, and while awaiting effects of radiation therapy. Preoperative use to decrease cortisol excess, potentially reducing perioperative complications, needs to be further studied.

Diagnosis of Cushing's disease

Diagnosis of Cushing's disease frequently remains a challenge. In this review we critically appraise the clinical features, biochemical tests, and imaging modalities used for this purpose. We outline recommendations for approaches to clinical investigation, with a particular focus on developments made within the last two years.

Medical therapy for Cushing's disease: adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers

Morbidity and mortality in Cushing's disease (CD) patients are increased if patients are not appropriately treated. Surgery remains the first line therapy, however the role of medical therapy has become more prominent in patients when biochemical remission is not achieved/or recurs after surgery, while waiting effects of radiation therapy or when surgery is contraindicated. Furthermore, use of preoperative medical therapy has been also recognized. In addition to centrally acting therapies (reviewed elsewhere in this special issue), adrenal steroidogenesis inhibitors, and glucocorticoid receptor antagonists are frequently used. A PubMed search of all original articles or abstracts detailing medical therapy in CD, published within 12 months (2013-2014), were identified and pertinent data extracted. Although not prospectively studied, ketoconazole and metyrapone have been the most frequently used medical therapies. A large retrospective ketoconazole study showed that almost half of patients who continued on ketoconazole therapy achieved biochemical control and clinical improvement; however almost 20% discontinued ketoconazole due to poor tolerability. Notably, hepatotoxicity was usually mild and resolved after drug withdrawal. Etomidate remains the only drug available for intravenous use. A new potent inhibitor of both aldosterone synthase and 11β-hydroxylase, following the completion of a phase II study LCI699 is being studied in a large phase III with promising results. Mifepristone, a glucocorticoid receptor antagonist, has been approved for hyperglycemia associated with Cushing's syndrome based on the results of a prospective study where it produced in the majority of patients' significant clinical and metabolic improvement. Absence of both a biochemical marker for remission and/or diagnosis of adrenal insufficiency remain, however, a limiting factor. Patient characteristics and preference should guide the choice between different medications in the absence of clinical trials comparing any of these therapies. Despite significant progress, there is still a need for a medical therapy that is more effective and with less adverse effects for patients with CD.

Medical combination therapies in Cushing's disease

INTRODUCTION

There has been growing interest on medical therapy for the management of Cushing's disease (CD), particularly in cases of persistent or recurrent hypercortisolism. Ketoconazole, an inhibitor of adrenal steroidogenesis, is the most widely used drug, whereas cabergoline and pasireotide are the most promising centrally acting agents. The main purpose of this review article is to highlight the options of medical treatment for CD, with a special emphasis on combination therapies, a topic that has only been addressed by a limited number of studies.

CONCLUSIONS

According to the results of these studies, combination therapies involving medications with additive or synergistic effects on ACTH and cortisol secretion seem quite attractive as they yield higher probability of longterm control of the hypercortisolism at lower doses, a lower incidence of side-effects, and possibly a lower rate of treatment escapes. Currently, ketoconazole, cabergoline, and pasireotide are the best drugs to be prescribed in combination.

Bilateral adrenalectomy for Cushing's disease

PURPOSE

Review the indications, outcomes, and consequences of bilateral adrenalectomy (BLA) in patients with Cushing's disease.

METHODS

A literature review was performed.

RESULTS

The primary therapy for Cushing's disease is surgery, with medical therapy and radiation therapy relegated to an adjuvant role. BLA is indicated in cases of persistent disease following pituitary surgery or in situations where rapid normalization of hypercortisolism is required. When performed via the laparoscopic approach, BLA is associated with a significantly reduced morbidity compared to the traditional, open approach. Following BLA, patients are at risk for adrenal crisis and the concern of Nelson's syndrome. However, BLA leads to a rapid resolution of the signs and symptoms of CS and leads to an improved long-term quality of life.

CONCLUSION

BLA should be considered in the treatment algorithm for patients with persistent CD after failed pituitary surgery, especially in patients who have severe consequences of hypercortisolism or desire pregnancy.

Hormone secretion by pituitary adenomas is characterized by increased disorderliness and spikiness but more regular pulsing

CONTEXT

Hormone secretion by functioning pituitary tumors is characterized by increased basal (nonpulsatile) secretion, enhanced pulse frequency, amplified pulse mass, and increased disorderliness.

OBJECTIVE

The objective of the study was to quantify (subtle) abnormalities of hormone secretion by pituitary adenomas and the influence of selective pituitary surgery and suppressive medications on these parameters.

METHODS

Approximate entropy (ApEn) was quantified with a refined algorithm, spikiness by a new method to evaluate sudden short-lived increases in hormone levels, and pulsing regularity, determined with a fully automated deconvolution program. These 3 distinct measures of secretory disruption were compared in untreated and treated patients with acromegaly, prolactinoma, and Cushing's disease together with matching profiles in healthy controls.

RESULTS

ApEn and spikiness were markedly increased in all untreated patient groups and normalized after pituitary surgery in acromegaly and hypercortisolism. In contrast, hormone-suppressive medical treatment in acromegaly and prolactinoma did not normalize ApEn. Spikiness normalized in acromegalic patients but not in prolactinoma. GH and cortisol pulsing regularity was elevated in acromegaly and Cushing's disease, respectively, and normalized after surgery. Medical treatment caused normalization of pulsing regularity in acromegaly but not in prolactinoma patients.

CONCLUSION

This study extends the understanding of disorganized hormone secretion by hyperfunctioning pituitary adenomas. The new findings are increased spikiness in all 3 tumor groups and increased pulsing regularity in GH- and ACTH-secreting adenomas. The mechanisms behind the marked pattern irregularity and the selective normalization by surgical and medical therapies are not established yet but may include diminished feedback signaling in addition to the anatomical and functional disorganization of intrapituitary cell networks.

Silent, but not unseen: multimicrocystic aspect on T2-weighted MRI in silent corticotroph adenomas

OBJECTIVE

Silent corticotroph adenomas (SCAs) present as nonfunctional pituitary tumours in routine pre-operative evaluation. The objective of this study was to evaluate the diagnostic accuracy of MRI T2-weighted sequences for detecting the corticotroph subtype pre-operatively.

DESIGN

The pre-operative T2-weighted MRI sequences were retrospectively evaluated in patients with SCA and two control groups: clinically manifest corticotroph macroadenomas (CSMs) and nonfunctional gonadotroph macroadenomas (NFGMs). All were selected from a registry of 1096 patients in whom transsphenoidal surgery was performed in the same tertiary reference centre. T2-weighted MRI sequences were independently classified by one senior endocrinologist and one senior radiologist who were blinded to the clinical and histological features.

PATIENTS

Seventeen patients with SCA, 14 with CSM and 60 with NFGM were included in this study.

MEASUREMENTS

Pituitary MRI with T2-weighted sequences. Two aspects were retained: multiple microcysts (MMs) and the absence of microcysts. Hormonal data included plasma prolactin, IGF-1, testosterone or oestradiol, LH, FT4, TSH, morning plasma cortisol and an ACTH-stimulation test, when available.

RESULTS

Multiple microcysts were present in 76% (13/17) of SCAs, 21% (3/14) of CSMs and 5% (3/60) of NFGMs. The presence of MMs in clinically nonfunctioning macroadenomas had a sensitivity of 76% and a specificity of 95% for predicting SCA.

CONCLUSION

The presence of MMs in T2-weighted MRI is a good diagnostic tool to suggest the corticotroph subtype in an apparently nonfunctional pituitary tumour.

Recurrences of ACTH-secreting adenomas after pituitary adenomectomy can be accurately predicted by perioperative measurements of plasma ACTH levels

BACKGROUND

Adenomectomy is the treatment of choice for ACTH-secreting adenomas. Although the development of ACTH deficiency immediately after adenomectomy suggests surgical success, disease recurrence was reported in patients who developed hypocortisolism postoperatively. In the current study, we examined the value of measuring perioperative plasma ACTH and cortisol levels in predicting disease recurrence of patients with ACTH-secreting adenomas.

METHODS

Consecutive patients (n = 55; 41 females, 14 males) with clinical, biochemical, and histological documentation of ACTH-secreting adenomas were investigated after pituitary adenomectomy. All patients were followed with clinical monitoring and frequent measurements of plasma ACTH and serum cortisol levels, and none received glucocorticoids unless or until they developed symptoms of adrenal insufficiency or when their serum cortisol levels were ≤3 μg/dL.

RESULTS

Postoperative serum cortisol levels reached ≤3 μg/dL in 46 of 55 and were ≥4 μg/dL in the remaining 9. Simultaneously measured plasma ACTH levels in the latter 9 patients were >40 ng/L when the serum cortisol reached its nadir. In contrast, among the 46 patients who had serum cortisol levels of ≤3 μg/dL, plasma ACTH levels measured simultaneously were ≤20 ng/L in 38 of 46 and >20 ng/L in the remaining 8. During a mean follow-up period of nearly 7 years, patients who had a nadir plasma ACTH of >20 ng/L developed recurrences even though their postoperative serum cortisol levels were ≤3 μg/dL.

CONCLUSIONS

Despite profound hypocortisolemia after adenomectomy, a simultaneously measured plasma ACTH level of >20 ng/L in the perioperative period is highly predictive of future recurrence of ACTH-secreting adenomas.

ACTH-secreting pituitary adenomas: size does not correlate with hormonal activity

ACTH-secreting pituitary adenomas (Cushing's disease, CD) are the most frequent cause of Cushing's syndrome. To test whether the size of ACTH-secreting adenomas correlates with the degree of biochemical and clinical features of hypercortisolism, we retrospectively reviewed all newly diagnosed CD patients seen at our institution by two neuro-endocrinologists over a 10-year time period. We documented the number of clinical manifestations and baseline hormonal measurements. There were 37 microadenomas (μAs) and 16 macroadenomas (MAs). We sought to characterize the relationship between tumor size (μA vs. MA) and number of signs and symptoms of hypercortisolism and biochemical assessment of hypercortisolemia. There were no significant differences in mean age, BMI, or prevalence of hypertension and type 2 diabetes between the μA and MA groups. However, the MAs had fewer clinical manifestations of hypercortisolism (29.4% vs. 36.1%, P = 0.02) compared to μAs. There was a higher prevalence of easy bruisability and proximal muscle weakness in the μAs, but otherwise the prevalence of signs and symptoms were similar between groups. The MAs had a lower random serum cortisol (18.2 ± 2.4 vs. 25.9 ± 1.8 mcg/dl, P = 0.018), lower cortisol:ACTH ratio (0.25 ± 0.03 vs. 0.42 ± 0.05, P < 0.048), and lower cortisol:tumor diameter ratio (14.1 ± 2.2 vs. 56.8 ± 7.2, P < 0.0001) than the μAs. We conclude that tumor size does not directly correlate with the extent of hormonal activity in ACTH-secreting adenomas. Biochemical activity and clinical manifestations may be mild even in larger tumors, and therefore a high index of suspicion may be necessary to recognize hypercortisolism in pituitary MAs.

Measurements of serum DHEA and DHEA sulphate levels improve the accuracy of the low-dose cosyntropin test in the diagnosis of central adrenal insufficiency

BACKGROUND AND OBJECTIVES

The diagnosis of central adrenal insufficiency (AI) continues to be challenging, especially when it is partial. We have recently demonstrated the value of measuring serum dehydroepiandrosterone sulfate (DHEA-S) in establishing the diagnosis of central AI. The current investigation examined the added value of measuring serum dehydroepiandrosterone (DHEA) levels during low-dose (1 μg) cosyntropin (LDC) stimulation in patients suspected to have central AI.

METHODS

Baseline and LDC-stimulated cortisol, DHEA, and DHEA-S were measured preoperatively in 155 consecutive patients with pituitary masses and 63 healthy subjects. Hypothalamic-pituitary adrenal (HPA) function was normal (NL-HPA) in 97 of the patients and was impaired (impaired HPA) in 58 patients. Patients with NL-HPA underwent surgical removal of the sellar masses and received no glucocorticoids before, during, or after surgery.

RESULTS

Baseline and LDC-stimulated serum cortisol, DHEA, and DHEA-S in patients with NL-HPA were similar to those of normal subjects. In contrast, patients with impaired HPA had lower baseline and LDC-stimulated serum cortisol, DHEA, and DHEA-S levels. There were 18 subjects in the latter group whose LDC-stimulated serum cortisol levels were greater than 18.0 μg/dl. In those 18 subjects, baseline and LDC-stimulated DHEA and DHEA-S levels were similar to the whole group of patients with impaired HPA function. The molar ratio of cortisol to DHEA did not change with LDC stimulation in normal subjects and those with NL-HPA. In contrast, patients with impaired HPA had a higher baseline cortisol to DHEA molar ratio that increased further with LDC stimulation.

CONCLUSIONS

Patients with impaired HPA function have a more severe loss in DHEA secretion than that of glucocorticoids. Measurements of serum DHEA levels during LDC simulation provide additional valuable information that improves the diagnostic accuracy of LDC in patients suspected to have central AI. We recommend the inclusion of DHEA and DHEA-S measurements in the laboratory assessment of HPA function.

The dynamics of post-operative plasma ACTH values following transsphenoidal surgery for Cushing's disease

Rapid assessment of adrenal function is critical following transsphenoidal surgery (TSS) for Cushing's disease (CD) in order to determine surgical efficacy. We hypothesize that there may be a role for ACTH measurement as a rapid indicator of adrenal function. Following surgery for CD, glucocorticoids were withheld and paired plasma ACTH and serum cortisol levels were measured every 6 h. Post-operative hypocortisolemia was defined as serum cortisol <2 mcg/dl or a serum cortisol <5 mcg/dl with the onset of symptoms of adrenal insufficiency within 72 h. We studied 12 subjects, all female, mean age 44.6 years (range 25-55), including 13 surgeries: nine subjects attained hypocortisolemia. Plasma ACTH levels decreased more in subjects with hypocortisolemia (0.9 pg/ml/hr, P = 0.0028) versus those with persistent disease (0 0.2 pg/ml/hr, P = 0.26) within the first 48 h after surgery. In contrast to subjects with persistent disease, all subjects with hypocortisolemia achieved a plasma ACTH <20 pg/ml by 19 h (range 1-19 h). Four of the nine subjects with hypocortisolemia achieved plasma ACTH <20 pg/ml by 13 h and the remaining five subjects by 19 h. Hypocortisolemia occurred between 3-36 h following achievement of a plasma ACTH <20 pg/ml. In CD, a reduction in postoperative plasma ACTH levels differentiates subjects with surgical remission versus subjects with persistent disease. The utility of plasma ACTH measurements in the postoperative management of CD remains to be determined.

Intraoperative MRI for transphenoidal procedures: short-term outcome for 100 consecutive cases

BACKGROUND

The majority of pituitary lesions are benign and can be cured with complete surgical resection. However, the transsphenoidal technique (the most common approach for pathology in this region) is limited by poor visualization and anatomical constraints. This can lead to incomplete tumor resection and thus increased recurrence rates. The use of iMRI during these procedures offers the advantage of radiographic confirmation during the procedure and may improve extent of resection. We reviewed our experience with this technology in 100 consecutive cases and compared the outcomes to published results.

METHODS

100 patients were treated via transnasal transsphenoidal approach using the GE Signa SP 0.5Tesla (double doughnut design) iMRI system between July 2002 and August 2009 and followed prospectively. Intraoperative findings, imaging results, postoperative MRI and clinical outcome were evaluated to determine the extent of tumor resection, monitor for recurrence and determine outcome.

RESULTS

There were 100 patients studied, 81 macroadenomas, 9 microadenomas, and 10 other pathological diagnosis. The average extent of resection was 96% with gross total resection based on iMRI in 76 patients (76%). Four patients (4%) all with macroadenomas greater than 4 cm experienced major perioperative complications (hydrocephalus 2, thalamic infarct 1, major arterial bleeding 1), six patients (6%) developed post-operative CSF leaks, one patient (1%) had post-operative worsening of visual fields, and five patients (5%) had abdominal fat graft infections. Nine patients (9%) including five with known residual tumor required post-operative adjuvant treatment during the follow-up period secondary to either disease progression or failure to achieve endocrinological cure.

CONCLUSIONS

iMRI-guided transsphenoidal pituitary surgery provides the surgeon with immediate radiographic feedback during the procedure and aides in overcoming the limitations in direct visualization during such procedures. As a result of this it may enable surgeons to perform such procedures with fewer complications and increased rate of gross total resection. However, the impact of this technology on long-term tumor control still needs to be determined with further follow-up.

Clinical, hormonal and molecular characterization of pituitary ACTH adenomas without (silent corticotroph adenomas) and with Cushing's disease

OBJECTIVE

Silent corticotroph adenomas (SCAs) are rare pituitary tumours immunoreactive for ACTH, but without clinical evidence of Cushing's disease. We characterized SCAs based on clinical, hormonal and molecular data, and compared the characteristics of these tumours with those of macro (MCA)- and micro (mCA)-ACTH adenomas with Cushing's disease.

METHODS

Fifty ACTH adenomas (14 SCAs, 15 MCAs and 21 mCAs) with complete corresponding clinical, radiological and biochemical data were selected. Histological corticotroph differentiation; immunostaining for ACTH, beta-endorphin and beta-LPH; and mRNA expression levels of TPIT, POMC, GRalpha, prohormone convertase 1/3 (PC1/3) and galectin-3 were compared in 21 representative tumours.

RESULTS

Despite the absence of clinical hypercortisolism in patients with SCA, elevated plasma ACTH levels that were similar to those associated with mCA were observed. The cortisol/ACTH ratio was similar between SCA and MCA groups and lower than that found with mCA (P<0.05). This dissociation could be explained by lower expression of PC1/3 in SCA and MCA than in mCA (P<0.05). After an i.v. dexamethasone suppression test, ACTH levels were significantly higher in patients with MCA than in those with mCA (P<0.05). Cytological and immunocytochemical analyses as well as mRNA expression levels of TPIT, POMC and GRalpha confirmed corticotroph differentiation in both mCAs and MCAs and in half of the SCAs, with a strong correlation between TPIT and POMC mRNA expression levels in SCAs (R(2)=0.72; P<0.01) and in MCAs (R(2)=0.65; P<0.05).

CONCLUSIONS

Despite the absence of hypercortisolism, SCAs exhibit histological, biochemical and molecular corticotroph differentiation. SCA and MCA show hormonal and molecular similarities differentiating them from mCA.

A corticotroph pituitary adenoma as the initial presentation of familial glucocorticoid deficiency

CONTEXT; Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive ACTH-resistance syndrome characterized by glucocorticoid deficiency in the absence of mineralocorticoid deficiency. Here, we report the case of a young woman with a corticotroph pituitary adenoma as the initial presentation of FGD.

CASE REPORT

A 15-year-old girl was referred to our institution for a 16 mm pituitary adenoma associated with glucocorticoid deficiency. Clinical and biological features were evocative of FGD. DNA sequencing did not identify mutations in either the melanocortin 2 receptor (MC2R) or the MC2R accessory protein genes, indicating type 3 FGD. Despite adequate glucocorticoid replacement, plasma ACTH levels remained increased and pituitary magnetic resonance imaging (MRI) showed a progression of the tumour size resulting in optic chiasm compression with intra-tumoural haemorrhaging. When the patient was 26 years old, it was decided that she would undergo transsphenoidal surgery. The histomorphological analysis identified a well-individualized pituitary adenoma immunoreactive for ACTH. The proband's sister also exhibited type 3 FGD associated with pituitary hyperplasia upon MRI.

CONCLUSION

This case highlights the relationship between FGD and hyperplasia of ACTH-producing cells, potentially leading to histologically proven pituitary corticotroph adenomas. This observation raises the question of the pituitary MRI's significance in the follow-up of FGD.

Response of ACTH to octreotide in a probable corticotropic adenoma associated with Addison's disease

BACKGROUND

Our patient was a 65-year-old woman previously diagnosed with Addison's disease. She presented an empty sella turcica and, at the age of 47, was discovered to have autonomous hypersecretion of adrenocorticotropic hormone (ACTH), suggesting a corticotropic adenoma secondary to Addison's disease, with a lack of response to high levels of dexamethasone. She maintained high ACTH levels despite corticosteroid treatment.

METHODS

The patient underwent a CRH stimulation test using an intravenous bolus (100 microg) with samples every 30 minutes for 3 hours and, the day after, an octreotide infusion (0.1 mg/200 cc saline) for 2 hours with measurements every 30 minutes for 3 hours. The following month she received subcutaneous octreotide 0.1 mg tid., and samples were taken every week.

RESULTS

Thirty minutes after the corticotropic-releasing-hormone (CRH) stimulation test, baseline ACTH levels (1 063 pg/ml) increased to 1530, the other values lying between 1 020-862. After octreotide infusion, baseline ACTH (1 212 pg/ml) was 946-643-1 630-4 600-1 730 at 30-60-90-120-180 minutes. The following month, with octreotide treatment, serum ACTH levels were 454-768-1233-429 pg/ml each week.

DISCUSSION

Octreotide acts mainly on somatostatin type 2 receptors (SSTR2) and has no effect in Cushing's syndrome, although a suppressor effect in some ACTH ectopic hypersecretions and in Nelson's syndrome has been demonstrated. It has been observed that SSTR5 appear more frequently than SSTR2 in corticotropic adenomas and corticosteroids downregulate octreotide sensitivity.

CONCLUSIONS

Octreotide did not suppress secretion of ACTH in suspected corticotropic adenoma. Newer somatostatin analogues, acting mainly on SSTR5, may be able to control ACTH hypersecretion in cases such as this.

Long-term follow-up results of postoperative radiation therapy for Cushing’s disease

OBJECTIVES

Radiotherapy is currently used in patients with residual or recurrent pituitary adenomas after surgery. However, there is little information of long-term outcome of patients with Cushing's disease following radiotherapy. We assessed the long-term efficacy and toxicity of conventional radiotherapy in the control of Cushing's disease after unsuccessful transsphenoidal surgery.

PATIENTS AND METHODS

Forty patients with Cushing's disease were treated with conventional external beam radiotherapy at our Institution between 1988 and 2002. The median age was 38. All patients received radiotherapy following unsuccessful surgery or at tumour recurrence to a dose of 45-50 Gy in 25-28 fractions. The persistence of active disease after surgery was diagnosed by the increased high plasma cortisol levels, high 24 h urinary cortisol levels and absence of cortisol suppression after administration of dexamethasone.

RESULTS

The 5 and 10 year local tumour control was 93% and the 5 and 10 year survival was 97 and 95%. Normalization of plasma cortisol was seen in 28% of patients at 1 year, 73% at 3 years, 78% at 5 years and 84% at 10 years. The average timing to remission was 24 months. The most common side effect was hypopituitarism that increased progressively during the follow-up, being present in 62% and in 76% of patients at 5 and 10 years after RT. There were no other serious complications as radiation induced optic neuropathy or second tumours.

CONCLUSION

Radiotherapy is effective in the long-term tumour- and hormone hypersecretion control of ACTH-secreting pituitary adenomas, however with a high prevalence of hypopituitarism. At the moment, it remains an important treatment option after failure of surgery.

[Cushing's syndrome in children]

In two girls, aged 13 and 16 years, Cushing's syndrome was diagnosed. In addition, the first showed a decrease in linear growth and weight gain; a pituitary adenoma was found, which was surgically excised. The second girl was examined because of a male body-hair pattern and weight increase. She had an adrenal adenoma, visible on MRI, which was excised during laparoscopy. Cushing's syndrome is a rare disease in childhood. A decrease in linear growth and a gain in weight are early recognisable features. Arriving at an aetiological diagnosis may be difficult and is based on the performance and interpretation of endocrinologic function and laboratory tests such as determination of the cortisol level in blood, saliva and urine, a dexamethasone-suppression test, and a corticotropin assay in blood drawn from the cerebral cavernous sinuses.