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

ABSTRACT 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.

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.

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.

Somatic USP8 mutations are frequent events in corticotroph tumor progression causing Nelson's tumor.

OBJECTIVE: Somatic mutations in the ubiquitin-specific protease 8 (USP8) gene are frequent in corticotroph tumors causing Cushing's disease (CD). Corticotroph tumor progression, the so-called Nelson's syndrome (NS), is a potentially life-threatening complication of bilateral adrenalectomy in patients with refractory CD that is caused by the development of an ACTH-secreting tumor of the pituitary gland. Whether USP8 alterations are also present in progressive Nelson's tumors has not been studied in detail so far. DESIGN AND METHODS: Retrospective, multicenter study involving tumors from 33 patients with progressive corticotroph tumors (29 females) and screening for somatic mutations on the mutational hotspot of the USP8 gene in the exon 14 with Sanger sequencing. RESULTS: Fifteen out of 33 tumors (45%) presented with a mutation in the exon 14 of USP8, with c.2159C>A (p.Pro720Gln) being the most frequent (9/33), followed by c.2155_2157delTCC (p.Ser718del, 4/33) and c.2152T>C (p.Ser718Pro, 2/33). This prevalence is similar to that previously reported for CD. Mutations were found exclusively in females. Other variables, such as age at diagnosis with NS, body mass index, hyperpigmentation, visual field defects, adenoma size or mortality, did not significantly differ between patients with wild-type and mutant tumors. Patients with USP8 mutant tumors exhibited higher levels of plasma ACTH after surgery (median: 640 vs 112 pg/mL, P = 0.03). No differences were observed in ACTH normalization (<50 pg/mL) and tumor control after surgery for Nelson's tumor. CONCLUSION: Somatic mutations in USP8 are common in Nelson's tumors, indicating that they do not drive the corticotroph tumor progression that leads to NS, and may be associated with a less favorable biochemical outcome after surgery for Nelson's tumor.

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.

Sustained improvements in plasma ACTH and clinical status in a patient with Nelson's syndrome treated with pasireotide LAR, a multireceptor somatostatin analog.

CONTEXT: Nelson's syndrome refers to aggressive pituitary corticotroph adenoma growth after bilateral adrenalectomy for treatment of Cushing's disease (CD). Pasireotide, a novel somatostatin analog, has been effective in treating CD. Here, the first case report of a patient with Nelson's syndrome treated with pasireotide is presented. CASE PRESENTATION: A 55-year-old female was diagnosed with CD in 1973 at age 15 years and underwent bilateral adrenalectomy 1 year later. She subsequently developed Nelson's syndrome and underwent multiple surgeries and radiotherapy for adenoma growth. After presentation with ocular pain, third cranial nerve palsy, and a finding of suprasellar tumor enlargement with hemorrhage, she began pasireotide long-acting release 60 mg/28 days im. At baseline, fasting plasma ACTH was 42 710 pg/mL (normal, 5-27 pg/mL), and fasting plasma glucose was 98 mg/dL. After 1 month, ACTH declined to 4272 pg/mL, and it has remained stable over 19 months of follow-up. Hyperpigmentation progressively improved. Magnetic resonance imaging scans show reduction in the suprasellar component. Fasting plasma glucose increased to 124 mg/dL, and the patient underwent diabetes management. EVIDENCE ACQUISITION AND SYNTHESIS: In this clinical case seminar, the current understanding of the treatment of Nelson's syndrome and the use of pasireotide in CD are summarized. CONCLUSION: A case of Nelson's syndrome with clinically significant and dramatic biochemical and clinical responses to pasireotide administration is reported. Hyperglycemia was noted after pasireotide administration. Pasireotide may represent a useful tool in the medical management of Nelson's syndrome. Further study of the potential benefits and risks of pasireotide in this population is necessary.

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.

Ovarian adrenal rest tumor in a congenital adrenal hyperplasia patient with adrenocorticotropin hypersecretion following adrenalectomy.

OBJECTIVE: Ovarian adrenal rest tumors (OARTs) are rare in contrast to testicular adrenal rest tumors. We report a case of OART in a patient with congenital adrenal hyperplasia who developed Nelson's syndrome after bilateral adrenalectomy. METHODS: We describe the clinical, imaging, and laboratory findings of the patient and review the relevant literature regarding OART and the possible interaction between ACTH and brown adipose tissue. RESULTS: An 18-year-old female with congenital adrenal hyperplasia, who had undergone bilateral adrenalectomy at the age of 10 years, presented with severe hyperpigmentation and hirsutism. Rectal ultrasonography showed a mass in the right ovary. (18)F-fluorodeoxyglucose PET/CT revealed intense uptake both in this mass and in brown adipose tissue located in typical supradiaphragmatic sites. Laparoscopic removal of the ovarian mass confirmed the diagnosis of OART. A systematic review revealed 9 documented cases of OART. As in our case, all presented with elevated ACTH levels. CONCLUSIONS: Common to all documented cases of OART are sustained high ACTH levels that activate the adrenal anlagen tissue in the ovaries.

No effect of the PPAR-gamma agonist rosiglitazone on ACTH or cortisol secretion in Nelson's syndrome and Cushing's disease in vitro and in vivo.

OBJECTIVE: Surgical tumor resection remains the primary treatment strategy in ACTH-secreting pituitary adenomas, i.e. Cushing's disease (CD) and Nelson's syndrome (NS). However, an effective long-term pharmacological regime is not available in patients with persistent ACTH-hypersecretion. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-gamma) is abundantly expressed in most pituitary adenomas. First encouraging data reported that the PPAR-gamma ligand rosiglitazone antagonizes ACTH hypersecretion and exerts also antiproliferative effects in pituitary cell lines. Herein, we studied the potential therapeutical effects of rosiglitazone in patients with ACTH-secreting pituitary adenomas in vitro and in vivo. MATERIALS AND METHODS: Seven patients with persistent ACTH-hypersecretion (3 with NS, 4 with persistent CD) were treated 5 months with rosiglitazone (4 - 16 mg/day). In vitro assays were performed in primary cell cultures obtained from eight additional patients with ACTH-secreting pituitary adenomas applying 80 microM rosiglitazone repeatedly over a time period of 14 days. RESULTS: Our long-term clinical trial with the PPAR-gamma activator rosiglitazone showed no amelioration of clinical symptoms nor an inhibiting effect on ACTH-secretion in vivo. In vitro, rosiglitazone treatment led to a statistically significant decrease of ACTH levels in 2 out of 8 primary cell cultures after 14 days compared to untreated controls. CONCLUSION: In contrast to the initially promising laboratory data gathered in pituitary cell line experiments and nude mice models, our experimental data obtained in primary human ACTH-expressing pituitary adenoma cell cultures as well as our clinical experience with a long-term rosiglitazone trial in approved antidiabetic doses support the recently reported disappointing reports on acute or short-term medical treatment of ACTH-hypersecretion with PPAR-gamma activators.

Gamma knife stereotactic radiosurgery of Nelson syndrome.

OBJECTIVE: Gamma knife radiosurgery (GKR) can be used as primary or adjuvant therapy for the treatment of an ACTH-producing pituitary tumor after bilateral adrenalectomy, called Nelson syndrome (NS). We have examined the effect of GKR on tumor growth and ACTH-hypersecretion, and characterized the adverse events of this treatment in patients with NS. DESIGN: Cross-sectional follow-up study. First, retrospective data pre- and post-GKR were collected. Patients then underwent a predefined survey including radiological, endocrinological, ophthalmological, and neurosurgical evaluation. SUBJECTS: Ten patients treated with GKR for NS after previous bilateral adrenalectomy. The mean follow-up was 7 years. No patient was lost to follow-up. RESULTS: Tumor growth was stopped in all patients. The ACTH levels declined in eight patients, and normalized in one patient. There was a significant drop in ACTH levels, with a half-time of 2.8 years. No patient developed visual field defects or any other cranial nerve dysfunction as a result of treatment. Four patients started hormone substitution therapy during the follow-up period. The substitution therapy of three pituitary axes present at GKR treatment could be stopped during the same period. One patient developed a glioblastoma in the left parieto-occipital region 14 years after GKR, far from the field of treatment. As the radiation level was below 1Gy to this area, it is unlikely that the GKR treatment itself induced the malignant tumor. CONCLUSION: In patients with NS, GKR is an effective adjuvant treatment, carrying relatively few adverse effects. Although the risk of developing a secondary neoplasia after GKR is present, it is probably extremely low.

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.

"Silent"corticotropinoma.

OBJECTIVES: The aim of the study was to evaluate the ACTH-immunopositive pituitary adenomas, especially those without manifestation of Cushing's disease MATERIAL AND METHODS: 148 pituitary adenomas removed surgically in years 1994--2007 were studied. The paraffin sections were immunostained with antibodies against the pituitary hormones. In 79 adenomas the immunostaining with anti-ACTH antibody was performed Additionally, 23 tumors were also immunostained with anti-Ki-67 (MIB-1) antibody. Visualization of reactions was done by means of streptavidin-biotin-peroxidase technique with use of 3,3'-diaminobenzidine as chromogen. RESULTS: ACTH immunopositivity was found in 34 cases (23%). Fourteen ACTH-immunopositive tumors manifested themselves as Cushing's disease (including 1 case of Nelson's syndrome). In the remaining 20 cases in spite of the positive immunostaining for ACTH of the tumor cells, no features of hypercortisolism were observed (in several cases even hypocortisolism was found). Thus, those tumors represented so-called "silent" corticotropinomas. Over one third (37%) of "clinically" nonfunctioning pituitary adenomas, when immunostained with anti-ACTH antibody, showed ACTH immunopositivity. Three adenomas in patients with Cushing's disease (21.4%) and 7 "silent" corticotropinomas (35%) were recurrent tumors. In contrast, the recurrence rate in the group of ACTH-immunonegative clinically nonfunctioning pituitary adenomas was 14.7%. The "silent" corticotropinomas exhibited a tendency towards the higher expression of a proliferation marker, Ki-67 antigen as compared to the "active" corticotropinomas. CONCLUSIONS: (i) "Silent" corticotropinomas are rather frequent. (ii) This adenoma type should be considered as aggressive. (iii) It is hypothetized that--like in Nelson's syndrome--the lack of hypercortisolism or even presence of hypocortisolism favorizes the exaggerated growth of tumoral corticotrophs.

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.

The PPAR-gamma activator rosiglitazone fails to lower plasma ACTH levels in patients with Nelson's syndrome.

BACKGROUND: Peroxisomal proliferator-activated receptors (PPAR)- gamma are expressed abundantly in ACTH-secreting pituitary tumours. The PPAR-gamma activator rosiglitazone has been shown to suppress ACTH secretion in human adrenocorticotroph tumour cells in vitro, and prevent and reduce adrenocorticotroph tumour development in mouse models in vivo. OBJECTIVE: To evaluate the effect of rosiglitazone in patients with persistently elevated plasma ACTH levels postbilateral adrenalectomy for Cushing's disease. PATIENTS: Seven patients were treated with rosiglitazone 8 mg orally per day for 12 weeks. MEASUREMENTS: Plasma ACTH was measured at two hourly intervals from 09:00 h to 17:00 h before and after 6 and 12 weeks of treatment. RESULTS: Plasma ACTH at 09:00 hours immediately before the usual morning hydrocortisone dose was 2599.0 +/- 899.7 ng/l (mean +/- SEM) basally and 1547.6 +/- 515.7 ng/l after 12 weeks of rosiglitazone, whereas levels at 17:00 h were 1433.4 +/- 506.2 ng/l (mean +/- SEM) basally and 1122.3 +/- 460.9 ng/l at 12 weeks (all nonsignificant). CONCLUSION: This study showed no effect of rosiglitazone treatment at maximum approved doses in lowering plasma ACTH levels in patients post bilateral adrenalectomy for Cushing's disease.

ACTH responses to somatostatin, valproic acid and dexamethasone in Nelson's syndrome.

OBJECTIVE: Pituitary tumours occurring in patients bilaterally adrenalectomized because of Cushing's disease (Nelson's syndrome) are frequently invasive and a complete their resection is not possible in most of them. Administration of the drugs decreasing ACTH secretion could be helpful in such unresectable tumours. We tried to evaluate the influence of somatostatin and valproic acid, compared to dexamethasone, in short-term studies, on plasma ACTH levels in Nelson's syndrome (NS). MATERIAL AND METHODS: Basal ACTH levels were determined within 18 h after last dose of hydrocortisone and next, 1 and 2 hours following oral administration of 20 mg of hydrocortisone. Somatostatin was injected s.c. in two patients with NS while sodium valproate and dexamethasone were administered orally for three days in three patients with NS (two with an invasive pituitary tumour and one with a localized, intrasellar adenoma). The blood for ACTH and cortisol determination was drawn before the tests (two hours after 20 mg of hydrocortisone ingestion) as well as 1 and 2 hours following somatostatin injection and after 3 days of valproic acid or dexamethasone administration. RESULTS: High plasma ACTH levels were found before the tests. Somatostatin lowered ACTH levels in both patients, more effectively in the patient with non-invasive pituitary adenoma. Valproic acid decreased moderately ACTH concentration in two patients, while following dexamethasone administration a fall in ACTH levels was observed in all three patients, the most evident in the patient with a non-invasive Nelson's adenoma. CONCLUSION: Somatostatin seemed to be more effective in its inhibitory action on ACTH secretion than valproic acid, thus its administration in invasive cases of NS could be tried as a supplementary method to neurosurgery. The response to dexamethasone administration indicates that a feed-back regulation, although impaired, exists in these cases.

Rosiglitazone for prevention or adjuvant treatment of Nelson's syndrome after bilateral adrenalectomy.

OBJECTIVE: To investigate the effect of Rosiglitazone in three patients treated with bilateral adrenalectomy followed by hyperpigmentation and hypersecretion of ACTH. PATIENTS AND METHODS: One patient had increasing ACTH after previous transsphenoidal surgery for Nelson's syndrome, and two patients without pituitary adenomas had recurrence of Cushing's disease after primary and repeated transsphenoidal surgery with need for bilateral adrenalectomy. The patients developed hyperpigmentation and increasing ACTH at nadir 2-4 h after morning hydrocortisone dose. ACTH during Rosiglitazone therapy (4 mg/day for 4 weeks and then 8 mg/day) was measured at regular intervals 24 h after the latest dose of hydrocortisone. RESULTS: In two patients there was a decrease in ACTH by 40% after 5 months. The first of these patients showed an escape with increasing ACTH to the initial value after 11 months. In the third patient no effect was observed. Tumour development or progression on magnetic resonance imaging was not observed. CONCLUSION: Rosiglitazone might represent an adjuvant therapy in patients with ACTH hypersecretion. Larger long-term studies are needed.

Profound amplification of secretory-burst mass and anomalous regularity of ACTH secretory process in patients with Nelson's syndrome compared with Cushing's disease.

OBJECTIVE: As described originally, Nelson's syndrome is characterized by grossly elevated ACTH concentrations, a sellar mass and skin hyperpigmentation emerging in the course of Cushing's disease after bilateral adrenalectomy. No detailed studies have defined whether the mechanisms directing ACTH secretion differ in Nelson's syndrome and untreated Cushing's disease. PATIENTS AND METHODS: To address this pathophysiological issue, we studied nine patients fulfilling the criteria of Nelson's syndrome receiving glucocorticoid and mineralocorticoid replacement; nine patients with untreated pituitary-dependent Cushing's disease and nine gender- and age-matched controls. ACTH release was appraised by monitoring plasma ACTH concentrations in blood samples collected every 10 min for 24 h. ACTH secretion rates and endogenous decay were quantified by multiparameter deconvolution analysis. The orderliness of the ACTH release process was delineated by the approximate entropy (ApEn) statistic. Diurnal variation in ACTH secretion was appraised by cosinor analysis. RESULTS: Basal ACTH secretion was increased sixfold and pulsatile secretion ninefold in patients with Nelson's syndrome compared with Cushing's disease (P

A study of patients with Nelson's syndrome.

OBJECTIVE: The prevalence of Nelson's syndrome has varied greatly, at least in part because of the variability of the diagnostic criteria employed by different authors. We define Nelson's syndrome as the presence of an enlarging pituitary tumour associated with elevated fasting plasma ACTH levels and hyperpigmentation in patients with Cushing's disease after bilateral adrenalectomy. We have compared patients with Cushing's disease who developed Nelson's syndrome after bilateral adrenalectomy with those who did not. Our objective was to find differences between the two groups which might predict the development of Nelson's syndrome. PATIENTS AND METHODS: We have reviewed the records of 30 patients with Cushing's disease after adrenalectomy, and divided them into two groups; I: 14 who developed Nelson's syndrome and II, 16 who did not. The two groups of patients were compared in their clinical, laboratory and imaging data as well as in the therapeutic procedures that preceded the adrenalectomy. RESULTS: The comparison between the two groups of patients demonstrated a highly significant difference in relation to the development of cutaneous hyperpigmentation (100% in group I and 19% in group II) and neuro-ophthalmological symptoms (21% in group I and 0% in group II) after adrenalectomy. There were no significant differences in laboratory data before adrenalectomy. After adrenalectomy, plasma ACTH levels increased significantly in the patients of both groups, but to much higher levels in those who developed Nelson's syndrome. Plasma ACTH concentrations above 154 pmol/l occurred only in the subjects with Nelson's syndrome. Before adrenalectomy, a pituitary tumour was more frequent in the patients who developed Nelson's syndrome (55% vs. 33% at transsphenoidal pituitary exploration). Pituitary surgery and irradiation were undertaken before adrenalectomy in approximately equal numbers of patients in each group. DISCUSSION: The prevalence of Nelson's syndrome was 47% in our series of 30 patients with Cushing's disease after bilateral adrenalectomy. No clinical or laboratory data before adrenalectomy predicted the development of the syndrome. The value of prophylactic pituitary irradiation could not be evaluated from our clinical material. However, after adrenalectomy, the presence of hyperpigmentation and ACTH levels above 154 pmol/l had positive predictive value for the development of Nelson's syndrome. In this situation magnetic resonance imaging (MRI) of the pituitary is mandatory and, if no tumour is detected, MRI should be repeated at intervals.

Acute effects of bromocriptine, cyproheptadine, and valproic acid on plasma adrenocorticotropin secretion in Nelson's syndrome.

Previous studies have found that bromocriptine, cyproheptadine, and valproic acid can reduce ACTH secretion in Nelson's syndrome, but none of these agents has achieved widespread use due to their failure to normalize ACTH in most patients. The current study was undertaken to determine whether these three agents, which act through different mechanisms, decrease plasma ACTH synergistically when administered together. Six adult female patients (mean age, 41 yr) with Nelson's syndrome were studied. ACTH was measured every 20 min for 8 h, 2 h before and 6 h after each of the following six treatments: placebo, bromocriptine (2.5 mg), cyproheptadine (8 mg), valproic acid (1 g), cyproheptadine plus valproic acid, and the combination of all three drugs. The sequence of treatments was determined randomly, and there was an interval of at least 2 days between each treatment. The hourly ACTH values were averaged, and the percent maximal suppression of plasma ACTH, relative to the baseline values before drug administration, was compared among the six treatments. Basal plasma ACTH levels in the six patients ranged from 40-3324 pmol/L (normal range, 1-8). The percent maximal suppression of ACTH after administration of placebo (6 +/- 11%), cyproheptadine (17 +/- 15%), valproic acid (37 +/- 10%) or the combination of cyproheptadine and valproic acid (19 +/- 14%) did not achieve statistical significance. Bromocriptine, on the other hand, caused a significant decrease in plasma ACTH (52 +/- 8%; P < 0.05), as did the combination of bromocriptine, cyproheptadine, and valproic acid (58 +/- 12%; P < 0.05). However, the combined effect of the three drugs did not significantly exceed the effect of bromocriptine alone. We conclude that at the doses studied, bromocriptine had the greatest acute effect in suppressing ACTH secretion in Nelson's syndrome, and that combined administration with valproic acid and cyproheptadine did not further increase this acute ACTH-suppressive effect.