The Nelson's syndrome... revisited

Prevalence of Nelson's syndrome after bilateral adrenalectomy in patients with cushing's disease: a systematic review and meta-analysis

PURPOSE

Bilateral adrenalectomy (BA) still plays an important role in the management of Cushing's disease (CD). Nelson's syndrome (NS) is a severe complication of BA, but conflicting data on its prevalence and predicting factors have been reported. The aim of this study was to determine the prevalence of NS, and identify factors associated with its development.

DATA SOURCES

Systematic literature search in four databases.

STUDY SELECTION

Observational studies reporting the prevalence of NS after BA in adult patients with CD.

DATA EXTRACTION

Data extraction and risk of bias assessment were performed by three independent investigators.

DATA SYNTHESIS

Thirty-six studies, with a total of 1316 CD patients treated with BA, were included for the primary outcome. Pooled prevalence of NS was 26% (95% CI 22-31%), with moderate to high heterogeneity (I² 67%, P < 0.01). The time from BA to NS varied from 2 months to 39 years. The prevalence of NS in the most recently published studies, where magnet resonance imaging was used, was 38% (95% CI 27-50%). The prevalence of treatment for NS was 21% (95% CI 18-26%). Relative risk for NS was not significantly affected by prior pituitary radiotherapy [0.9 (95% CI 0.5-1.6)] or pituitary surgery [0.6 (95% CI 0.4-1.0)].

CONCLUSIONS

Every fourth patient with CD treated with BA develops NS, and every fifth patient requires pituitary-specific treatment. The risk of NS may persist for up to four decades after BA. Life-long follow-up is essential for early detection and adequate treatment of NS.

Multivariable analysis of 63 contemporary patients diagnosed with nelson's syndrome: A nationwide readmission database study

INTRODUCTION

Nelson's syndrome (NS) is a rare complication involving enlargement of an adrenocorticotropic hormone (ACTH) producing tumor in the pituitary following bilateral adrenalectomy in Cushing's syndrome. Here, we explore the epidemiology, complication profiles, and readmission statistics of 63 patients diagnosed with NS.

METHODS

The Nationwide Readmission Database was retrospectively queried for all patients diagnosed with NS (n = 63) or receiving total bilateral adrenalectomy (TBA) surgery (n = 275) between 2016 and 2017. Complications, demographics, and predictive factors were queried for all patients involved. Statistical analysis used Mann-Whitney U nonparametric testing was to compare basic demographics and gaussian-fitted multivariable regression analysis with post hoc odds ratios to compare patient predictors of development of NS and complication rates between the two cohorts.

RESULTS

We report the largest contemporary patient series of NS through a nationally-representative inpatient database and explore the clinical characteristics of modern NS patients. Modeling revealed that the absence of primary hypertension served as a significant predictor for NS when compared to the TBA control cohort (OR = 0.88; 95%CI = 0.79-0.99; p = 0.037). In addition, analysis of complications between NS and TBA cohortsrevealed that NS patients have significantly higher rates of hypoosmolarity/hyponatremia (OR = 1.42; 95%CI = 1.19-1.71; p = 0.00021), hypopituitarism (OR = 1.94; 95%CI = 1.60-2.36; p < 0.0001), and sepsis (OR = 1.51; 95%CI = 1.14-2.00; p = 0.0046).

CONCLUSION

Contemporary NS is a rare complication of TBA, and modern cases of NS may differ significantly from cases of NS reported in the mid-1900s. As such, a thorough understanding of patient complications and predictive factors for NS are necessary to fully guide patient management in the modern era.

Stereotactic radiosurgery before bilateral adrenalectomy is associated with lowered risk of Nelson's syndrome in refractory Cushing's disease patients

BACKGROUND

Nelson's syndrome is a rare but challenging sequelae of Cushing's disease (CD) after bilateral adrenalectomy (BLA). We sought to determine if stereotactic radiosurgery (SRS) of residual pituitary adenoma performed before BLA can decrease the risk of Nelson's syndrome.

METHODS

Consecutive patients with CD who underwent BLA after non-curative resection of ACTH secreting pituitary adenoma and had at least one follow-up visit after BLA were studied. Nelson's syndrome was diagnosed based on the combination of rising ACTH levels, increasing volume of the pituitary adenoma and/or hyperpigmentation.

RESULTS

Fifty patients underwent BLA for refractory CD, and 43 patients (7 men and 36 women) had at least one follow-up visit after BAL. Median endocrine, imaging, and clinical follow-up were 66 months, 69 months, and 80 months, respectively. Nine patients (22%) were diagnosed with the Nelson's syndrome at median time after BLA at 24 months (range: 0.6-119.4 months). SRS before BLA was associated with reduced risk of the Nelson's syndrome (HR = 0.126; 95%CI [0.022-0.714], p=0.019), while elevated ACTH level within 6 months after BLA was associated with increased risk for the Nelson's syndrome (HR = 9.053; 95%CI [2.076-39.472], p=0.003).

CONCLUSIONS

SRS before BLA can reduce the risk for the Nelson's syndrome in refractory CD patients requiring BLA and should be considered before proceeding to BLA. Elevated ACTH concentration within 6 months after BLA is associated with greater risk of the Nelsons' syndrome. When no prior SRS is administered, those with a high ACTH level shortly after BLA may benefit from early SRS.

Recurrence after pituitary surgery in adult Cushing's disease: a systematic review on diagnosis and treatment

PURPOSE

Recurrence after pituitary surgery in Cushing's disease (CD) is a common problem ranging from 5% (minimum) to 50% (maximum) after initially successful surgery, respectively. In this review, we give an overview of the current literature regarding prevalence, diagnosis, and therapeutic options of recurrent CD.

METHODS

We systematically screened the literature regarding recurrent and persistent Cushing's disease using the MESH term Cushing's disease and recurrence. Of 717 results in PubMed, all manuscripts in English and German published between 1980 and April 2020 were screened. Case reports, comments, publications focusing on pediatric CD or CD in veterinary disciplines or studies with very small sample size (patient number < 10) were excluded. Also, papers on CD in pregnancy were not included in this review.

RESULTS AND CONCLUSIONS

Because of the high incidence of recurrence in CD, annual clinical and biochemical follow-up is paramount. 50% of recurrences occur during the first 50 months after first surgery. In case of recurrence, treatment options include second surgery, pituitary radiation, targeted medical therapy to control hypercortisolism, and bilateral adrenalectomy. Success rates of all these treatment options vary between 25 (some of the medical therapy) and 100% (bilateral adrenalectomy). All treatment options have specific advantages, limitations, and side effects. Therefore, treatment decisions have to be individualized according to the specific needs of the patient.

ACTH increment post total bilateral adrenalectomy for Cushing's disease: a consistent biosignature for predicting Nelson's syndrome

PURPOSE

Nelson's syndrome (NS) is regarded as an aggressive complication of total bilateral adrenalectomy (TBA) for Cushing's disease (CD). This challenge may be addressed by using clinical criteria to guide frequency of neuroimaging to enable timely management of NS and also avoid unnecessary frequent imaging.

METHODS

All patients (n = 43) with CD subjected to TBA over 35 years at a tertiary care centre were included. NS was defined as a newly appearing or expanding (> 2 mm) pituitary adenoma with or without ACTH levels exceeding 500 pg/ml. Pre-and post-TBA parameters like clinical symptomatology, cortisol, ACTH and radiology were analysed for the prediction of NS.

RESULTS

NS developed in 39.5% (n = 17) patients with a median follow-up of 7 years. Half of them had new appearance, while rest had an expansion of pre-existing pituitary tumour. Majority (90%) had ACTH above 500 pg/ml. On Cox proportional hazards analysis, frequent discriminatory features of protein catabolism (≥ 4) (HR 1.15, CI 0.18, 7.06), proximal myopathy (HR 8.82, CI 1.12, 69.58) and annual ACTH increment of 113 pg/ml (HR 12.56, CI 1.88, 88.76) predicted NS. First post-operative year ACTH indices predicting NS included ACTH rise of 116 pg/ml and absolute ACTH of 142 pg/ml (sensitivity, specificity exceeding 90%). Annual ACTH increment exceeding 113 pg/ml, ≥ 4 discriminatory features and uncontrolled hypertension had the best overall prediction.

CONCLUSION

Patients who developed NS had higher rebound rise of ACTH following TBA and a more severe disease phenotype at baseline. Consistent ACTH increment can be used as a marker for predicting the development of NS.

Gamma Knife radiosurgery for the treatment of Nelson's syndrome: a multicenter, international study

OBJECTIVE

Nelson's syndrome is a rare and challenging neuroendocrine disorder, and it is associated with elevated adrenocorticotrophic hormone (ACTH) level, skin hyperpigmentation, and pituitary adenoma growth. Management options including resection and medical therapy are traditional approaches. Ionizing radiation in the form of Gamma Knife radiosurgery (GKRS) is also being utilized to treat Nelson's syndrome. In the current study the authors sought to better define the therapeutic role of stereotactic radiosurgery (SRS) in Nelson's syndrome.

METHODS

Study patients with Nelson's syndrome were treated with single-fraction GKRS (median margin dose of 25 Gy) at 6 different centers as part of an International Radiosurgery Research Foundation (IRRF) investigation. Data including neurological function, endocrine response, and radiological tumor response were collected and sent to the study-coordinating center for review. Fifty-one patients with median endocrine and radiological follow-ups of 91 and 80.5 months from GKRS, respectively, were analyzed for endocrine remission, tumor control, and neurological outcome. Statistical methods were used to identify prognostic factors for these endpoints.

RESULTS

At last follow-up, radiological tumor control was achieved in 92.15% of patients. Endocrine remission off medical management and reduction in pre-SRS ACTH level were achieved in 29.4% and 62.7% of patients, respectively. Improved remission rates were associated with a shorter time interval between resection and GKRS (p = 0.039). Hypopituitarism was seen in 21.6% and new visual deficits were demonstrated in 15.7% of patients.

CONCLUSIONS

GKRS affords a high rate of pituitary adenoma control and improvement in ACTH level for the majority of Nelson's syndrome patients. Hypopituitarism is the most common adverse effect from GKRS in Nelson's syndrome patients and warrants longitudinal follow-up for detection and endocrine replacement.

Long-term outcome after bilateral adrenalectomy in Cushing's disease with focus on Nelson's syndrome

OBJECTIVE

We analyzed the clinical, biochemical, and imaging findings of adrenalectomized patients with Cushing's disease (CD) in order to compare the characteristics of those who developed Nelson's syndrome (NS) versus those who did not develop this complication (NNS), aiming to identify possible predictive factors for its occurrence.

SUBJECTS AND METHODS

We performed a retrospective review of the clinical records of a group of patients with CD who underwent TBA between 1974 and 2011.

RESULTS

Out of 179 patients with CD, 13 (7.3%) underwent TBA. NS occurred in 6 of them (46%) after a mean of 24 months from the total bilateral adrenalectomy (TBA). Age at diagnosis, duration of Cushing's syndrome (CS) until TBA, and steroid replacement doses were similar in both groups. Initial urinary cortisol levels (24-hour urinary free cortisol [UFC]) were significantly higher in the NS group than in the NNS group (p = 0.009). Four patients in the NS group and three of those in the NNS group received radiotherapy before TBA (p = 0.26). Three patients in the NS group presented residual tumors before TBA, compared with none in the NNS group (p = 0.04). At 1 year after TBA, the median ACTH level was 476 ng/L (240-1500 ng/L) in the NS group and 81 ng/L (48-330 ng/L) in the NNS group (p = 0.0007).

CONCLUSION

In conclusion, a residual tumor before TBA, higher 24-hour UFC at diagnosis, and increasing ACTH levels within 1 year after TBA emerged as predictive factors of development of NS.

Recent advances in understanding corticotroph pituitary tumor initiation and progression

Cushing’s disease is the most frequent form of hypercortisolism and is caused by hypophyseal corticotroph adenomas secreting excessive amounts of adrenocorticotropic hormone. Most of the tumors develop sporadically and only a limited number of corticotroph adenomas have been found to be associated with different neuroendocrine syndromes or with familial isolated pituitary adenomas. The pathogenic mechanisms of corticotroph adenomas are largely unknown, but the discovered aberrant chaperoning activity of heat shock protein 90 on the one hand and the presence of ubiquitin-specific protease 8 mutations on the other hand partially explained the causes of their development. Corticotroph tumors arise initially as benign microadenomas but with time form invasively growing aggressive macroadenomas which can switch to corticotroph carcinomas in extremely rare cases. The mechanisms through which corticotroph tumors escape from glucocorticoid negative feedback are still poorly understood, as are the processes that trigger the progression of benign corticotroph adenomas toward aggressive and malignant phenotypes. This review summarizes recent findings regarding initiation and progression of corticotroph pituitary tumors.

The USP8 mutational status may predict long-term remission in patients with Cushing's disease

OBJECTIVE

Almost half of the cases of Cushing's disease (CD) tumours carry recurrent activating somatic mutations in the ubiquitin-specific protease eight gene (USP8). The USP8 mutational status could predict remission in patients with CD, so our objective was to correlate the presence of somatic USP8 mutations with the rate of recurrence after transsphenoidal surgery (TSS) retrospectively.

DESIGN

Biochemical, radiological and clinical data were retrospectively assessed in 48 patients. USP8 mutational status was determined from corticotroph tumour samples. Association between USP8 mutational status, remission and recurrence was investigated.

PATIENTS

Patients with Cushing's disease from a single-centre cohort who underwent TSS between 1991 and 2012.

MEASUREMENTS

Long-term remission and recurrence rate after TSS with at least 6 months follow-up. Biochemical, radiological and clinical data, including sex, age at diagnosis, tumour size and pre-operative hormonal levels. USP8 mutational status.

RESULTS

Patients with USP8 mutant corticotroph tumours (18 of 48; 37%) were diagnosed significantly earlier (mean ± SD 46 ± 10 years vs 53 ± 11 years; P = 0.028) and presented with higher pre-operative 24-hour urinary-free cortisol levels (median IQR μg/24 hours 1174.0, 1184.5 vs 480.0, 405.3; P = 0.045). The incidence of recurrence in a 10-year follow-up was significantly higher in patients with USP8 mutant tumours after the initial remission (58% vs 18% P = 0.026). Recurrence appeared significantly earlier in these patients (months 70, 44-97 95% CI vs 102, 86-119 95% CI; P = 0.019).

CONCLUSION

Recurrence appears to be more frequent and earlier after TSS in patients with USP8 mutant corticotroph tumours.

A prospective longitudinal study of Pasireotide in Nelson's syndrome

PURPOSE

Nelson's syndrome is a challenging condition that can develop following bilateral adrenalectomy for Cushing's disease, with high circulating ACTH levels, pigmentation and an invasive pituitary tumor. There is no established medical therapy. The aim of the study was to assess the effects of pasireotide on plasma ACTH and tumor volume in Nelson's syndrome.

METHODS

Open labeled multicenter longitudinal trial in three steps: (1) a placebo-controlled acute response test; (2) 1 month pasireotide 300-600 μg s.c. twice-daily; (3) 6 months pasireotide long-acting-release (LAR) 40-60 mg monthly.

RESULTS

Seven patients had s.c. treatment and 5 proceeded to LAR treatment. There was a significant reduction in morning plasma ACTH during treatment (mean ± SD; 1823 ± 1286 ng/l vs. 888.0 ± 812.8 ng/l during the s.c. phase vs. 829.0 ± 1171 ng/l during the LAR phase, p < 0.0001). Analysis of ACTH levels using a random intercept linear mixed-random effects longitudinal model showed that ACTH (before the morning dose of glucocorticoids) declined significantly by 26.1 ng/l per week during the 28-week of treatment (95% CI - 45.2 to - 7.1, p < 0.01). An acute response to a test dose predicted outcome in 4/5 patients. Overall, there was no significant change in tumor volumes (1.4 ± 0.9 vs. 1.3 ± 1.0, p = 0.86). Four patients withdrew during the study. Hyperglycemia occurred in 6 patients.

CONCLUSIONS

Pasireotide lowers plasma ACTH levels in patients with Nelson's syndrome. A longer period of treatment may be needed to assess the effects of pasireotide on tumor volume.

TRIAL REGISTRATION

Clinical Trials.gov ID, NCT01617733.

Bilateral adrenalectomy for Cushing's syndrome: Pros and cons

AIM

To assess the outcome of patients undergoing bilateral adrenalectomy for Cushing's syndrome (CS).

METHODS

All patients who underwent bilateral adrenalectomy for CS at the Department of Endocrine Surgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences hospital between 1991 and 2013 were included. Medical records were reviewed to obtain patient characteristics and follow-up data.

RESULTS

Twenty-seven patients were studied. Mean age was 28.74 ± 12.95 years (range 9-60), male:female ratio was 1.7:1. About half that is, 48.19% were of Cushing's disease (failed trans-sphenoidal surgery [TSS]), 37.04% were of ectopic CS (ECS), and 14.81% were of CS due to bilateral adrenal pathology. Median follow-up period was 80.5 months. Before surgery, 74.1% patients had body mass index > which after surgery declined to <25 in 75% of them. Hypertension was present in 85.2% and after surgery resolved in 40%. Diabetes mellitus was present in 44.4% and after surgery resolved in 33% of them. Hirsutism and proximal muscle weakness were present in 55.6% and 70.4% patients, respectively, and after surgery improved markedly in all patients. Adrenal crisis developed in 36.3% and Nelson's syndrome in 41.7% patients during follow-up. Three patients died in perioperative period while three succumbed to the disease during follow-up. Two patients developed recurrence of endogenous cortisol production during the follow-up period.

CONCLUSIONS

Bilateral adrenalectomy is a valid treatment option for palliating severe symptoms in Pituitary Cushing's with failed TSS and unlocalized ECS but the procedure is curative for CS due to bilateral adrenal disease. Overall morbidity and mortality is higher than other endocrine operations. Co-morbidities tend to be more severe and are a risk factor for mortality during the time patient survives.

Nelson's syndrome: a review of the clinical manifestations, pathophysiology, and treatment strategies

Nelson's syndrome is a rare clinical manifestation that occurs in 8%-47% of patients as a complication of bilateral adrenalectomy, a procedure that is used to control hypercortisolism in patients with Cushing's disease. First described in 1958 by Dr. Don Nelson, the disease has since become associated with a clinical triad of hyperpigmentation, excessive adrenocorticotropin secretion, and a corticotroph adenoma. Even so, for the past several years the diagnostic criteria and management of Nelson's syndrome have been inadequately studied. The primary treatment for Nelson's syndrome is transsphenoidal surgery. Other stand-alone therapies, which in many cases have been used as adjuvant treatments with surgery, include radiotherapy, radiosurgery, and pharmacotherapy. Prophylactic radiotherapy at the time of bilateral adrenalectomy can prevent Nelson's syndrome (protective effect). The most promising pharmacological agents are temozolomide, octreotide, and pasireotide, but these agents are often administered after transsphenoidal surgery. In murine models, rosiglitazone has shown some efficacy, but these results have not yet been found in human studies. In this article, the authors review the clinical manifestations, pathophysiology, diagnostic criteria, and efficacy of multimodal treatment strategies for Nelson's syndrome.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushing's syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

Management Strategies for Aggressive Cushing's Syndrome: From Macroadenomas to Ectopics

Cushing's syndrome (CS) is a rare but severe clinical condition represented by an excessive endogenous cortisol secretion and hence excess circulating free cortisol, characterized by loss of the normal feedback regulation and circadian rhythm of the hypothalamic-pituitary axis due to inappropriate secretion of ACTH from a pituitary tumor (Cushing's disease, CD) or an ectopic source (ectopic ACTH secretion, EAS). The remaining causes (20%) are ACTH independent. As soon as the diagnosis is established, the therapeutic goal is the removal of the tumor. Whenever surgery is not curative, management of patients with CS requires a major effort to control hypercortisolemia and associated symptoms. A multidisciplinary approach that includes endocrinologists, neurosurgeons, oncologists, and radiotherapists should be adopted. This paper will focus on traditional and novel medical therapy for aggressive ACTH-dependent CS. Several drugs are able to reduce cortisol levels. Their mechanism of action involves blocking adrenal steroidogenesis (ketoconazole, metyrapone, aminoglutethimide, mitotane, etomidate) or inhibiting the peripheral action of cortisol through blocking its receptors (mifepristone “RU-486”). Other drugs include centrally acting agents (dopamine agonists, somatostatin receptor agonists, retinoic acid, peroxisome proliferator-activated receptor γ “PPAR-γ” ligands) and novel chemotherapeutic agents (temozolomide and tyrosine kinase inhibitors) which have a significant activity against aggressive pituitary or ectopic tumors.

[Recent progress in the treatment of Cushing's disease]

Transsphenoidal surgery, possibly through the endoscopic approach, remains the first line treatment. Opposing cortisol action with mifepristone proved efficacious in some individual cases but but with major monitoring difficulties. Combined treatment with three anticortisolic drugs (metyrapone, ketokonazole, O,p'DDD) is particularly attractive in severe cases. The Nelson's syndrome has been revisited, and the corticotroph tumor progression should rather be cautiously assessed after bilateral adrenalectomy. Two molecules potentially act directly to suppress the ACTH secretion by the corticotroph adenoma: agonists of the D2 Dopamine receptor and of the somatostatin receptor type 5. Their efficacy remains modest (20 to 30% of the patients actually normalize urinary cortisol). Pituitary radiotherapy can be efficiently performed by stereotaxic approach.

Cushing's disease in a patient with steroid 21-hydroxylase deficiency

Cushing's disease rarely appears as a consequence of hereditary disease. However, familial diseases with diminished glucocorticoid feedback are associated with secondary hypercorticotropinism and have been shown to give rise to pituitary adenomas. We here describe the rare case of a 30-year old female patient with congenital adrenal hyperplasia who also showed clinical signs and a typical history of hypercortisolism that was specified as Cushing's disease. After removal of a pituitary microadenoma, serum-cortisol levels fell below normal and the symptoms improved. However, after four years the menstrual cycle was irregular again and ACTH levels were in the upper range of normal. A corticotropin challenge showed a minor cortisol response but a marked increase in 17-hydroxyprogesterone serum concentrations. Genetic analysis revealed a homozygous mutation in exon 7 of the CYP21A2 gene (CTG>TTG, p.V281L). We conclude that a marked ACTH drive was able to override insufficient 21-hydroxylation and even to cause hypercortisolism. Although we describe a rare case, the impairment of the glucocorticoid feedback system in the context of congenital adrenal hyperplasia and other diseases may contribute to the development of secondary hypercorticotropinism as well as corticotropin producing adenomas.

Nelson's syndrome

Nelson's syndrome is a potentially life-threatening condition that does not infrequently develop following total bilateral adrenalectomy (TBA) for the treatment of Cushing's disease. In this review article, we discuss some controversial aspects of Nelson's syndrome including diagnosis, predictive factors, aetiology, pathology and management based on data from the existing literature and the experience of our own tertiary centre. Definitive diagnostic criteria for Nelson's syndrome are lacking. We argue in favour of a new set of criteria. We propose that Nelson's syndrome should be diagnosed in any patient with prior TBA for the treatment of Cushing's disease and with at least one of the following criteria: i) an expanding pituitary mass lesion compared with pre-TBA images; ii) an elevated 0800 h plasma level of ACTH (>500 ng/l) in addition to progressive elevations of ACTH (a rise of >30%) on at least three consecutive occasions. Regarding predictive factors for the development of Nelson's syndrome post TBA, current evidence favours the presence of residual pituitary tumour on magnetic resonance imaging (MRI) post transsphenoidal surgery (TSS); an aggressive subtype of corticotrophinoma (based on MRI growth rapidity and histology of TSS samples); lack of prophylactic neoadjuvant pituitary radiotherapy at the time of TBA and a rapid rise of ACTH levels in year 1 post TBA. Finally, more studies are needed to assess the efficacy of therapeutic strategies in Nelson's syndrome, including the alkylating agent, temozolomide, which holds promise as a novel and effective therapeutic agent in the treatment of associated aggressive corticotroph tumours. It is timely to review these controversies and to suggest guidelines for future audit.

Treatment of Nelson's syndrome with temozolomide

A 64-year-old woman was previously treated for Cushing's disease with trans-sphenoidal surgery, external beam radiotherapy and bilateral adrenalectomy. Progression of an aggressive corticotroph adenoma was evident 3 years post-adrenalectomy; involvement of the clivus was treated with surgery and gamma knife radiosurgery. Tumour spread through the skull base, occiput and left ear with persistent facial pain and left ear discharge; progression continued despite second gamma knife treatment. ACTH levels peaked at 2472 and 2265 pmol/l pre- and post-hydrocortisone respectively. Treatment with temozolomide resulted in a significant improvement in symptoms, a reduction of plasma ACTH to 389 pmol/l and regression of tumour on magnetic resonance imaging scan after four cycles of treatment. We propose that temozolomide is an effective and well-tolerated therapeutic tool for the treatment of Nelson's syndrome and a useful addition to the range of therapies available to treat this condition.

Trilostane-induced inhibition of cortisol secretion results in reduced negative feedback at the hypothalamic-pituitary axis

Cushing's disease caused by pituitary corticotroph adenoma in dogs is usually treated by medical treatment, and the efficacy of this treatment has been reported. However, controversy remains as to whether reduced negative feedback through the inhibition of cortisol secretion, similar to Nelson's syndrome, may appear as an adverse effect. The purpose of this study was to investigate the effect of reduced negative feedback through the inhibition of cortisol secretion by daily trilostane administration on the pituitary-adrenal axis in clinically normal dogs. Dogs were administered 5mg/kg trilostane twice a day every day for 8 weeks (n=8) or 16 weeks (n=3). After the initiation of trilostane administration, plasma adrenocorticotropic hormone (ACTH) concentrations were increased remarkably. As assessed by magnetic resonance imaging (MRI) during administration, the pituitary became enlarged. After trilostane administration, the cytoplasmic areas of the pituitary corticotrophs were increased and the ratio of pituitary corticotrophs to all cells in the anterior lobe was greater in the trilostane-treated dogs than that in untreated animals. In addition, histological examinations revealed bilateral adrenal cortical hyperplasia. Using real-time PCR quantification, the expression of proopiomelanocortin (POMC) mRNA in the pituitary and ACTH receptor (ACTH-R) mRNA in the adrenal gland was greater in the dogs treated with trilostane than in untreated dogs. These results indicate that reduced negative feedback induced hyperfunction of the pituitary corticotrophs and pituitary enlargement in healthy dogs. These changes suggest that the inhibition of cortisol secretion by trilostane may increase the risk for accelerating the growth of corticotroph adenomas in dogs with Cushing's disease.

Nelson's Syndrome

Nelson's syndrome is a potentially severe complication of bilateral adrenalectomy performed in the treatment of Cushing's disease, and its management remains difficult. Of all of the features of Nelson's syndrome, the one that causes most concern is the development of a locally aggressive pituitary tumour, which, unusually for pituitary disease, may occasionally cause death from the tumour itself. This feature is especially pertinent given the increasing use in Cushing's disease of laparoscopic bilateral adrenal surgery as a highly effective treatment modality to control cortisol-excess. Despite numerous studies and reports, there is no formal consensus of what defines Nelson's syndrome. Thus, some will define Nelson's syndrome according to the classical description with an evolving pituitary mass after bilateral adrenalectomy, whereas others will rely on increasing plasma ACTH levels, even in the absence of a clear pituitary mass lesion on MRI. These factors need to be borne in mind when considering the reports of Nelson's syndrome, as there is great heterogeneity, and it is likely that overall the modern 'Nelson's syndrome' represents a different disease entity from that of the last century. In the present paper, clinical and epidemiological features of Nelson's syndrome, as well as its treatment modalities, are reviewed.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Treatment of adrenocorticotropin-dependent Cushing's syndrome: a consensus statement

OBJECTIVE

Our objective was to evaluate the published literature and reach a consensus on the treatment of patients with ACTH-dependent Cushing's syndrome, because there is no recent consensus on the management of this rare disorder.

PARTICIPANTS

Thirty-two leading endocrinologists, clinicians, and neurosurgeons with specific expertise in the management of ACTH-dependent Cushing's syndrome representing nine countries were chosen to address 1) criteria for cure and remission of this disorder, 2) surgical treatment of Cushing's disease, 3) therapeutic options in the event of persistent disease after transsphenoidal surgery, 4) medical therapy of Cushing's disease, and 5) management of ectopic ACTH syndrome, Nelson's syndrome, and special patient populations.

EVIDENCE

Participants presented published scientific data, which formed the basis of the recommendations. Opinion shared by a majority of experts was used where strong evidence was lacking.

CONSENSUS PROCESS

Participants met for 2 d, during which there were four chaired sessions of presentations, followed by general discussion where a consensus was reached. The consensus statement was prepared by a steering committee and was then reviewed by all authors, with suggestions incorporated if agreed upon by the majority.

CONCLUSIONS

ACTH-dependent Cushing's syndrome is a heterogeneous disorder requiring a multidisciplinary and individualized approach to patient management. Generally, the treatment of choice for ACTH-dependent Cushing's syndrome is curative surgery with selective pituitary or ectopic corticotroph tumor resection. Second-line treatments include more radical surgery, radiation therapy (for Cushing's disease), medical therapy, and bilateral adrenalectomy. Because of the significant morbidity of Cushing's syndrome, early diagnosis and prompt therapy are warranted.

Cushing's Syndrome

Cushing's syndrome is a rare endocrine disease characterized by cortisol hypersecretion, induced mainly by a pituitary tumor (Cushing's disease) or, rarely, by an adrenal or an ectopic neuroendocine tumor. Cushing's syndrome is associated with severe morbidities and an increased mortality. The major systemic complications and the main cause of death are represented by cardiovascular disease. The prognosis of the disease is mainly affected by the difficulties in the diagnosis and treatment of the disease, which remain a considerable challenge.

Nelson syndrome: comprehensive review of pathophysiology, diagnosis, and management

Nelson syndrome (NS) is a rare clinical manifestation of an enlarging pituitary adenoma that can occur following bilateral adrenal gland removal performed for the treatment of Cushing disease. It is characterized by excess adreno-corticotropin secretion and hyperpigmentation of the skin and mucus membranes. The authors present a comprehensive review of the pathophysiology, diagnosis, and management of NS. Corticotroph adenomas in NS remain challenging tumors that can lead to significant rates of morbidity and mortality. A better understanding of the natural history of NS, advances in neurophysiology and neuroimaging, and growing experience with surgical intervention and radiation have expanded the repertoire of treatments. Currently available treatments include surgical, radiation, and medical therapy. Although the primary treatment for each tumor type may vary, it is important to consider all of the available options and select the one that is most appropriate for the individual case, particularly in cases of lesions resistant to intervention.

Prise en charge du syndrome de Nelson: données actuelles

PURPOSE

Nelson's syndrome is a severe complication of bilateral adrenalectomy performed in the treatment of some Cushing's diseases, and its management remains difficult. Trough the observation of a patient suffering from a severe form of Nelson's syndrome for more than 10 years, the authors review the literature and discuss the main current therapeutic possibilities.

CURRENT KNOWLEDGE AND KEY POINTS

Many molecules have been used with variable results. In our observation cabergoline at 2 mg per week seems to be efficient after a 3 and a half years follow-up, in accordance with some recent publications. More than bromocriptine, this dopamine agonist provides interesting prospects for this disease's management. Moreover, if the conventional treatments as valproic acid or cyproheptadine are not very efficient, somatostatin analogs seem to be of some therapeutic interest.

FUTURE PROSPECTS AND PROJECTS

New molecules are currently evaluated, but studies are difficult to conduct because of the low disease prevalence. Tumour receptors analysis undoubtedly constitutes an attractive way to find new therapeutic targets.

Nelson syndrome: historical perspectives and current concepts

✓The appearance of an adrenocorticotropic hormone (ACTH)–producing tumor after bilateral adrenalectomy for Cushing disease was first described by Nelson in 1958. The syndrome that now bears his name was characterized by hyperpigmentation, a sellar mass, and increased plasma ACTH levels. The treatment of Cushing disease has changed drastically since the 1950s, when the choice was adrenalectomy. Thus, the occurrence, diagnosis, and treatment of Nelson syndrome have changed as well. In the modern era of high-resolution neuroimaging, transsphenoidal microneu-rosurgery, and stereotactic radiosurgery, Nelson syndrome has become a rare entity. The authors describe the history of the diagnosis and treatment of Nelson syndrome. In light of the changes described, the authors believe this disease must be reevaluated in the contemporary era and a modern paradigm adopted.

Improved quality of life after bilateral laparoscopic adrenalectomy for Cushing's disease: a 10-year experience

OBJECTIVE

To determine long-term quality of life after bilateral adrenalectomy for persistent Cushing's disease after transsphenoidal pituitary tumor resection.

SUMMARY BACKGROUND DATA

Bilateral adrenalectomy for symptomatic relief of persistent hypercortisolism appears to be an effective treatment option. However, few studies have examined long-term outcomes in this patient population.

METHODS

Retrospective review of 39 patients treated by bilateral laparoscopic adrenalectomy for Cushing's disease from 1994 to 2004. Patients completed a follow-up phone survey, including our Cushing-specific questionnaire and the SF-12v2 health survey. Patients then refrained from taking their steroid replacement for 24 hours, and serum cortisol and ACTH levels were measured.

RESULTS

Three patients died at 12, 19, and 50 months following surgery from causes unrelated to adrenalectomy. The remaining 36 patients all responded to the study questionnaire (100% response rate). Patients were between 3 months and 10 years post-adrenalectomy. We had zero operative mortalities and a 10.3% morbidity rate. Our incidence of Nelson's syndrome requiring clinical intervention was 8.3%; 89% of patients reported an improvement in their Cushing-related symptoms, and 91.7% would undergo the same treatment again. Twenty of 36 (55%) and 29 of 36 (81%) patients fell within the top two thirds of the national average for physical and mental composite scores, respectively, on the SF-12v2 survey. An undetectable serum cortisol level was found in 79.4% of patients.

CONCLUSIONS

Laparoscopic bilateral adrenalectomy for symptomatic Cushing's disease is a safe and effective treatment option. The majority of patients experience considerable improvement in their Cushing's disease symptoms, and their quality of life equals that of patients initially cured by transsphenoidal pituitary tumor resection.

Pitfalls in the management of Cushing’s disease

Cushing's disease is caused by functional corticotroph adenomas of the pituitary gland, most commonly noninvasive microadenomas. Transsphenoidal microsurgery is an effective means of control for patients with adrenocorticotrophic hormone-producing microadenomas. However, a wide variation of clinical outcomes and recurrence rates has been reported. The major causes of surgical failure in the treatment of Cushing's disease lies in inadequate preoperative evaluation, unsuccessful identification of the adenoma and inexperience of the surgeon. Furthermore, appropriate use of combination therapy, including surgery, radiotherapy, radiosurgery and adrenalectomy can improve the outcome. For optimal results in this rare disease, endocrinological, radiological and surgical procedures should be co-ordinated in a specialized center. In this review, factors affecting preoperative evaluation, surgical success and outcome are outlined in the light of current knowledge.

Ineffectiveness of rosiglitazone therapy in Nelson's syndrome

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists have been proposed as therapy to lower plasma ACTH in Cushing's disease. Cyclical secretion of ACTH may, however, explain some of the responses seen. Patients with Nelson's syndrome have persistently high levels of ACTH and may be a better model for examining new therapies to elevated ACTH levels.

OBJECTIVE

The objective of the study was to assess whether high-dose rosiglitazone therapy reduces circulating ACTH levels in Nelson's syndrome, a model of ACTH hypersecretion for which no established medical therapy exists.

DESIGN

The design was an open-label, prospective, nonrandomized study over 14 wk.

SETTING

The study was conducted at a university teaching hospital.

PATIENTS

Six patients with Nelson's syndrome participated in the study.

METHODS

Patients were assessed at -2, 0, 4, 8, and 12 wk. Rosiglitazone 12 mg/d was administered between 0 and 8 wk. PPAR-gamma immunoreactivity was assessed in pathological tissue.

OUTCOME MEASURE

Plasma ACTH was measured before (0830 h) and 120 min after morning dosing with hydrocortisone (HC).

RESULTS

One female withdrew prior to commencing therapy for personal reasons. There was no evidence that ACTH levels changed over time (P = 0.864). The average ACTH level was 1187 ng/liter (95% confidence interval 928-1446) for patients before the HC dose and 432 ng/liter (95% confidence interval 172-692) after the HC dose. PPAR-gamma immunoreactivity was positive in three ACTH-secreting tumors available.

CONCLUSIONS

Rosiglitazone 12 mg/d did not change circulating ACTH over time, despite PPAR-gamma receptor expression in the tumor tissue. However, this does not preclude the possibility that other patients may respond or that higher doses of rosiglitazone or more potent agonists might prove useful treatment.

Nelson’s syndrome after bilateral adrenalectomy for Cushing’s disease

BACKGROUND

Presentation and outcome of Nelson's syndrome after bilateral adrenalectomy is variable.

METHODS

Clinical records of 39 patients who underwent bilateral adrenalectomy for primary or recurrent Cushing's disease during a 15-year period were analyzed for frequency and evolution of Nelson's syndrome.

RESULTS

The study included 32 females and 7 males with a mean age of 31 years; 20 patients had a hypophysectomy as the initial procedure, and 19 had an adrenalectomy. Of the group, 17 patients received prophylactic radiation therapy to the pituitary gland. A total of 11 patients, none of whom had received prophylactic radiation therapy, developed Nelson's syndrome (determined by skin hyperpigmentation, elevated serum ACTH levels, and enlargement of a previous pituitary tumor or development of a new tumor in patients with no previous pituitary abnormality) over a mean follow-up period of 53 months. Treatment for Nelson's syndrome included valproic acid, radiation therapy, and hypophysectomy as monotherapy or combined therapy. Of the remaining 28 patients, 10 (7 without prophylactic radio therapy) developed skin hyperpigmentation and increased ACTH levels without a tumor.

CONCLUSIONS

Nelson's syndrome is a frequent complication after bilateral adrenalectomy in the absence of prophylactic radiotherapy (28%). The syndrome can be successfully controlled by medical treatment and or radiotherapy; patients rarely require hypophysectomy.

Syndrome de Nelson: évolution d'un adénome hypophysaire corticotrope agressif

Nelson's syndrome was defined in 1958 as the association of an expanding pituitary tumor with high ACTH secretion after bilateral adrenalectomy for Cushing's disease. Pituitary MRI and ACTH measurements led to the definition of Nelson's syndrome as the proliferation of a corticotrophic microadenoma or an aggressive and highly proliferative tumor residue induced by the decreased glucocorticoid inhibition after bilateral adrenalectomy. Now, the problem is not the definition of Nelson's syndrome but rather the identification of markers predictive of tumor growth. Based on a typical case and a review of the literature, we point out some predictive markers of tumor growth after bilateral adrenalectomy: young age at diagnosis, presence of tumor residue on pituitary MRI before adrenalectomy, markers of tumor aggressiveness (Ki-67>3%, mitoses, nuclear PTTG) and increase of ACTH levels during the first months following adrenalectomy.

Corticotroph tumor progression after adrenalectomy in Cushing's Disease: A reappraisal of Nelson's Syndrome

CONTEXT

Adrenalectomy is a radical treatment for hypercortisolism in Cushing's disease. However, it may lead to Nelson's syndrome, originally defined by the association of a pituitary macroadenoma and high plasma ACTH concentrations, a much feared complication.

OBJECTIVE

The objective of the study was to reconsider Nelson's syndrome by investigating corticotroph tumor progression based on pituitary magnetic resonance imaging scan and search for predictive factors.

DESIGN

This was a retrospective cohort study.

SETTING

The complete medical records of Cushing's disease patients at Cochin Hospital were studied.

PATIENTS

Patients included 53 Cushing's disease patients treated by adrenalectomy between 1991 and 2002, without previous pituitary irradiation.

MEASUREMENTS

Clinical data, pituitary magnetic resonance imaging data, and plasma ACTH concentrations for all patients and pituitary gland pathology data for 25 patients were recorded. Corticotroph tumor progression-free survival was studied by Kaplan-Meier, and the influence of recorded parameters was studied by Cox regression.

INTERVENTION

There was no intervention.

RESULTS

Corticotroph tumor progression ultimately occurred in half the patients, generally within 3 yr after adrenalectomy. A shorter duration of Cushing's disease (adjusted hazard ratio: 0.884/yr), and a high plasma ACTH concentration in the year after adrenalectomy [adjusted hazard ratio per 100 pg/ml (22 pmol/liter): 1.069] were predictive of corticotroph tumor progression. In one case, corticotroph tumor progression was complicated by transitory oculomotor nerve palsy. During follow-up, corticotroph tumor progression was associated with the increase of corresponding ACTH concentrations (odds ratio per 100 pg/ml of ACTH variation: 1.055).

CONCLUSION

After adrenalectomy in Cushing's disease, one should no longer wait for the occurrence of Nelson's syndrome: modern imaging allows early detection and management of corticotroph tumor progression.

Gamma knife radiosurgery is a successful adjunctive treatment in Cushing's disease

OBJECTIVE

Though transsphenoidal surgery remains the first-line treatment of Cushing's disease, recurrence occurs frequently. Conventional radiotherapy and anticortisolic drugs both have adverse effects. Stereotactic radiosurgery needs to be evaluated more precisely. The aim of this study was to determine long-term hormonal effects and tolerance of gamma knife (GK) radiosurgery in Cushing's disease.

DESIGN

Forty patients with Cushing's disease treated by GK were prospectively studied over a decade, with a mean follow-up of 54.7 months. Eleven of them were treated with GK as a primary treatment.

METHODS

Radiosurgery was performed at the Department of Functional Neurosurgery of Marseille, France, using the Leksell Gamma Unit B and C models. Median margin dose was 29.5 Gy. Patients were considered in remission if they had normalized 24-h free urinary cortisol and suppression of plasma cortisol after low-dose dexamethasone suppression test.

RESULTS

Seventeen patients (42.5%) were in remission after a mean of 22 months (range 12-48 months). The two groups did not differ in terms of initial hormonal levels. Target volume was significantly higher in uncured than in remission group (909.8 vs 443 mm(3), P = 0.038). We found a significant difference between patients who were on or off anticortisolic drugs at the time of GK (20 vs 48% patients in remission respectively, P = 0.02).

CONCLUSION

With 42% of patients in remission after a median follow-up of 54 months, GK stereotactic radiosurgery, especially as an adjunctive treatment to surgery, may represent an alternative to other therapeutic options in view of their adverse effects.

Monitoring neuropeptide-specific proteases: processing of the proopiomelanocortin peptides adrenocorticotropin and alpha-melanocyte-stimulating hormone in the skin

The neuroendocrine precursor protein proopiomelanocortin (POMC) and its derived neuropeptides are involved in a number of important regulatory processes in the central nervous system as well as in peripheral tissues. Despite its important role in controlling the local activation of melanocortin (MC) receptors, the extracellular proteolytic processing of POMC peptides has received little attention. The mechanisms relevant for controlling the bioavailability of adrenocorticotropin and melanocyte-stimulating hormones for the corresponding MC receptors in the skin by specific peptidases such as neprilysin (neutral endopeptidase; NEP) or angiotensin-converting enzyme (ACE) have been addressed in a number of recent investigations. This review summarizes the current body of knowledge concerning the qualitative and quantitative POMC peptide processing with respect to the action and specificity of NEP and ACE and discusses relevant recent analytical methodologies.

Cushing's syndrome

Cushing's syndrome results from lengthy and inappropriate exposure to excessive glucocorticoids. Untreated, it has significant morbidity and mortality. The syndrome remains a challenge to diagnose and manage. Here, we review the current understanding of pathogenesis, clinical features, diagnostic, and differential diagnostic approaches. We provide diagnostic algorithms and recommendations for management.