Transsphenoidal microsurgical management of Cushing's disease. Report of 100 cases

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.

Long-term outcomes of tissue-based ACTH-antibody assay-guided transsphenoidal resection of pituitary adenomas in Cushing disease

OBJECTIVE Cushing disease is caused by a pituitary micro- or macroadenoma that hypersecretes adrenocorticotropic hormone (ACTH), resulting in hypercortisolemia. For decades, transsphenoidal resection (TSR) has been an efficacious treatment but with certain limitations, namely precise tumor localization and complete excision. The authors evaluated the novel use of a double-antibody sandwich assay for the real-time quantitation of ACTH in resected pituitary specimens with the goals of augmenting pathological diagnosis and ultimately improving long-term patient outcome. METHODS This study involved a retrospective review of records and an analysis of assay values, pathology slides, and MRI studies of patients with Cushing disease who had undergone TSR in the period from 2009 to 2014 and had at least 1 year of follow-up in coordination with an endocrinologist. In the operating room, biopsy specimens from the patients had been analyzed for tissue ACTH concentration. Additional samples were simultaneously sent for frozen-section pathological analysis. The ACTH assay performance was compared against pathology assessments of surgical tumor samples using receiver operating characteristic (ROC) analysis and against pre- and postoperative MRI studies. RESULTS Fourteen patients underwent TSR with guidance by ACTH-antibody assay and pathological assessment of 127 biopsy samples and were followed up for an average of 3 years. The ACTH threshold for discriminating adenomatous from normal tissue was 290,000 pg/mg of tissue, based on jointly maximized sensitivity (95.0%) and specificity (71.3%). Lateralization discordance between preoperative MRI studies and surgical visualization was noted in 3 patients, confirming the impression that MRI alone may not achieve optimal localization. A majority of the patients (85.7%) attained long-term disease remission based on urinary free cortisol levels, plasma cortisol levels, and long-term corticosteroid therapy. Comparisons of patient-months of remission and treatment failure showed that the remission rate in the study sample statistically exceeds the rate in historical controls (71.9%; p = 0.0007, Fisher's exact test). Long-term unexpected hormonal deficiencies were statistically similar between study patients (29%) and those in a meta-analysis (25%; p = 0.7596, Fisher's exact test). CONCLUSIONS These preliminary findings reflect the promising potential of tissue-based ACTH-antibody-guided assay for improving the cure rates of Cushing disease patients undergoing TSR. Further studies with larger sample sizes, further refinements of assay interpretation, and longer-term follow-ups are needed.

Bilateral inferior petrosal sinus sampling

Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing's syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88-100% and 67-100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50-70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres.

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.

Therapy of endocrine disease: outcomes in patients with Cushing's disease undergoing transsphenoidal surgery: systematic review assessing criteria used to define remission and recurrence

OBJECTIVE

A number of factors can influence the reported outcomes of transsphenoidal surgery (TSS) for Cushing's disease - including different remission and recurrence criteria, for which there is no consensus. Therefore, a comparative analysis of the best treatment options and patient management strategies is difficult. In this review, we investigated the clinical outcomes of initial TSS in patients with Cushing's disease based on definitions of and assessments for remission and recurrence.

METHODS

We systematically searched PubMed and identified 44 studies with clear definitions of remission and recurrence. When data were available, additional analyses by time of remission, tumor size, duration of follow-up, surgical experience, year of study publication and adverse events related to surgery were performed.

RESULTS

Data from a total of 6400 patients who received microscopic TSS were extracted and analyzed. A variety of definitions of remission and recurrence of Cushing's disease after initial microscopic TSS was used, giving broad ranges of remission (42.0-96.6%; median, 77.9%) and recurrence (0-47.4%; median, 11.5%). Better remission and recurrence outcomes were achieved for microadenomas vs macroadenomas; however, no correlations were found with other parameters, other than improved safety with longer surgical experience.

CONCLUSIONS

The variety of methodologies used in clinical evaluation of TSS for Cushing's disease strongly support the call for standardization and optimization of studies to inform clinical practice and maximize patient outcomes. Clinically significant rates of failure of initial TSS highlight the need for effective second-line treatments.

Gender-Specific Differences in Clinical Profile and Biochemical Parameters in Patients with Cushing's Disease: A Single Center Experience

Cushing's disease (CD) is remarkably prevalent among females; however, more severe clinical presentation and adverse outcomes have been found in males. The purpose of this study was to investigate the overall clinical profile and biochemical parameters in patients with CD to identify the gender differences. Here we describe our series of CD patients referred to our medical center during 2012-2013. Among 73 cases, females presented a marked preponderance compared to males. Males had significantly higher ACTH, BMI, HbA1c, systolic blood pressure, and hemoglobin than females. For the first time, the incidence of fatty liver and hepatic function was also shown to be elevated in males. Multiple linear regression analysis was performed to further investigate the correlation of risk factors with hypokalemia, HbA1c, and systolic blood pressure. Gender and serum cortisol were associated with hypokalemia. Age, gender, and serum cortisol were significantly associated with HbA1c. Additionally, only gender was significantly associated with systolic blood pressure. Regarding clinical presentation, purple striae seemed to occur more frequently in males than in females. Thus, more severe clinical presentation, biochemical parameters, and complications were found in males than in females. Clinical professionals should pay more attention to the diagnosis and management of males with CD.

Characterization of persistent and recurrent Cushing's disease

A case of possible recurrent Cushing's disease (CD) is presented and data on current definitions of CD remission, persistence, and recurrence are reviewed. While prevailing guidelines recommend the use of serum cortisol in the first post-operative week for defining initial remission and predicting sustained remission, with the use of 24 h urinary free cortisol measurements if serum cortisol values are equivocal, there is debate as to which methods and thresholds best define CD remission and predict successful outcomes. Other methods used to define remission (and hence persistence and recurrence) include restoration of cortisol suppression after dexamethasone and physiologic diurnal cortisol rhythm as measured by midnight salivary free cortisol. However, the number and degree of abnormal test results needed to define recurrence, and the determination of which biochemical test has more significance when there are discrepancies between markers is inconsistent among studies. Further inquiry is warranted to examine if patients in apparent CD remission who have subtle hypothalamic pituitary adrenal (HPA) axis abnormalities represent distinctive remission subtypes versus mild or early recurrence. Additional investigation could also explore the degree to which these HPA axis abnormalities, such as alterations in cortisol circadian rhythm or partial resistance to dexamethasone, are associated with persistence of CD morbidities, including neuropsychiatric impairments, alterations in body composition, and cardiovascular risk.

Long-term remission and recurrence rates in Cushing's disease: predictive factors in a single-centre study

OBJECTIVE

To investigate the early and late outcomes of patients with Cushing's disease (CD) submitted to a neurosurgical procedure as first-line treatment.

DESIGN

In this single-centre retrospective case notes study, 131 patients with CD with a minimum follow-up period of 6 years (124 operated by transsphenoidal surgery (TSS) and seven by the transcranial approach) were studied. Apparent immediate cure: post-operative 0900 h serum cortisol level <50 nmol/l; remission: cortisol insufficiency or restoration of 'normal' cortisol levels with resolution of clinical features; and recurrence: dexamethasone resistance and relapse of hypercortisolaemic features.

RESULTS

In patients operated by TSS, remission of hypercortisolaemia was found in 72.8% of 103 microadenomas and 42.9% of 21 macroadenomas, with recurrence rates 22.7 and 33.3% respectively with a 15-year mean follow-up (range, 6-29 years). Of 27 patients with microadenomas operated after 1991, with positive imaging and pathology, 93% obtained remission with 12% recurrence. In multivariate analysis, the time needed to achieve recovery of hypothalamo-pituitaryadrenal axis was the only significant predictor of recurrence; all patients who recurred showed recovery within 3 years from surgery: 31.3% of patients had total hypophysectomy with no recurrence; 42% of patients with selective adenomectomy and 26.5% with hemi-hypophysectomy showed recurrence rates of 31 and 13% respectively (χ(2)=6.275, P=0.03). Strict remission criteria were not superior in terms of the probability of recurrence compared with post-operative normocortisolaemia.

CONCLUSIONS

Lifelong follow-up for patients with CD appears essential, particularly for patients who have shown rapid recovery of their axis. The strict criteria previously used for 'apparent cure' do not appear to necessarily predict a lower recurrence rate.

Clinical factors involved in the recurrence of pituitary adenomas after surgical remission: a structured review and meta-analysis

To study the currently available data of recurrence rates of functioning and nonfunctioning pituitary adenomas following surgical cure and to analyze associated predisposing factors, which are not well established. A systematic literature search was conducted using Medline, Embase, Web of Science and the Cochran Library for studies reporting data on recurrence of pituitary adenoma after surgery, in nonfunctioning adenoma (NF), prolactinoma (PRL) acromegaly (ACRO) and Cushing's disease (CUSH). Of 557 initially retrieved potential relevant studies 143 were selected. Recurrence in NFA was defined as reappearance of tumor on MRI or CT. Increase of hormone levels above normal limits as set by the authors after initial remission was used to indicate recurrence in the functioning tumor types. Remission percentage was lowest in NFA compared with other tumor types (P < 0.001). Surgery-related hypopituitarism was more frequent in CUSH than in the other tumors (P < 0.001). Recurrence, expressed as percentage of the cured population or as ratio of recurrence and total patient years of follow-up was highest in PRL (P < 0.001). The remission percentage did not improve over 3 decades of publications, but there was a modest decrease in recurrence rate (P = 0.04). Recurrences peaked between 1 and 5 years after surgery. Most of the studies with a sufficient number of recurrences did not apply multivariate statistics, and mentioned at best associated factors. Age, gender, tumor size and invasion were generally unrelated to recurrence. For functioning adenomas a low postoperative hormone concentration was a prognostically favorable factor. In NFA no specific factor predicted recurrence. Recurrence rate differs between pituitary adenomas, being highest in patients with prolactinoma, with the highest incidence of recurrence between 1 and 5 years after surgery in all adenomas. Patients with NFA have a lower chance of remission than patients with functioning adenomas. The postoperative basal hormone level is the most important predictor for recurrence in functioning adenomas, while in NFA no single convincing factor could be identified.

Cushing's disease: results of treatment and factors affecting outcome

OBJECTIVE

To analyze the therapeutic results of intervention and the factors affecting the outcome of patients with Cushing's disease (CD) cared for at the All Indian Institute of Medical Science (AIIMS), New Delhi.

DESIGN

Patients with Cushing's disease treated at a teritiary care centre from January 2000 to December 2009 were prospectively studied.

RESULTS

Ninety-seven patients received treatment for CD during this period. Mean duration of follow-up was 3.4 ± 2.2 (mean ± SD) years. Eighty-one patients (83.5%) underwent transsphenoidal surgery (TSS) as the primary treatment modality. Fifty-four patients (66.7%) went into remission after initial TSS; ten (18.5%) of them relapsed after a mean follow-up period of 2.9 ± 2.1 (mean ± SD) years. Histopathologic examination of resected tissue showed corticotroph adenoma in 48 of the 54 (88.9%) who went into remission and 17 of the 27 (63.0%) who did not go into remission after the initial TSS. Sixteen patients with severe hypercortisolism underwent bilateral adrenalectomy (BA) as a life-saving measure which was followed by pituitary surgery 6 to 12 months later. Five patients including one with a large macroadenoma required three or more procedures to achieve eucortisolism.

CONCLUSION

Fifty-four out of 81 (66.7%) of our patients with CD had remission following initial TSS, ten of whom relapsed later on. Sixteen patients unerwent BA as a life-saving procedure. Factors affecting outcome were, age, gender, low dose dexamethasone suppression test cortisol value and histologic confirmation of corticotroph adenoma.

Endoscopic endonasal transsphenoidal surgery for functional pituitary adenomas

Object

The purpose of this study was to analyze preoperative predictors of endocrinological remission following endonasal endoscopic resection of therapy-resistant prolactin-, growth hormone (GH)–, and adrenocorticotropic hormone (ACTH)–secreting pituitary adenomas and to establish benchmarks for cure by using the most recent consensus criteria.

Methods

The authors reviewed a prospective database of 86 consecutive functional pituitary adenomas that were resected by a purely endoscopic endonasal transsphenoidal technique. Extent of resection was evaluated on postoperative contrast-enhanced MR imaging. Endocrinological remission was defined according to the most recent consensus criteria.

Results

The majority of functional adenomas (62.8%) were classified as macroadenomas (> 1 cm in maximum diameter), and 20.9% of lesions had invaded the cavernous sinus (CS) at the time of surgery. A gross-total resection was achieved in 75.6% of all patients. The rate of endocrinological remission differed between various types of functional adenomas. Cure rates were 92.3% (microadenomas) and 57.1% (macroadenomas) for prolactinomas, 75% (microadenomas) and 40% (macroadenomas) for GH-secreting tumors, and 54.5% (microadenomas) and 71.4% (macroadenomas) for ACTH-secreting tumors. Lower rates of cure occurred in GH-secreting macroadenomas due to a high rate of CS invasion, and in ACTH-secreting adenomas due to a high rate of lesions that were not visible on preoperative MR imaging. Whereas univariate analysis showed that macroadenoma, suprasellar, cavernous extension, or extent of resection correlated with cure, on multivariate analysis, only extent of resection and suprasellar extension predicted cure. One patient developed postoperative meningitis that was complicated by hydrocephalus requiring a ventriculoperitoneal shunt. Two patients developed postoperative panhypopituitarism, and 2 patients suffered from CSF leaks, which were treated with lumbar CSF diversion.

Conclusions

This paper reports benchmarks for endocrinological cure as well as complications in a large series of purely endoscopic pituitary surgeries by using the most recent consensus criteria. The advantages of extended endonasal approaches are most profound in tumors with suprasellar extension and CS invasion.

An unusual presentation of pediatric Cushing disease: recurrent corticotropinoma of the posterior pituitary lobe

Cushing's syndrome (CS) is rare in childhood and adolescence and its diagnosis and work up are often challenging. We report the case of a 15-year-old girl with a recurrent corticotrophin (ACTH)-secreting adenoma, located in the posterior lobe of the pituitary gland. At the age of 11, she presented with classic CS symptoms; biochemical investigation was compatible with ACTH-dependent Cushing disease, although pituitary gland imaging did not show any tumor. Following transsphenoidal surgery (TSS), histopathological analysis identified an ACTH-secreting pituitary microadenoma arising from the posterior gland. The patient went into remission but 4 years later she presented with recurrent CS; this time, pituitary gland imaging showed a microadenoma located in the posterior lobe, which was resected after TSS. Posterior lobe pituitary adenomas are very rare and often hard to diagnose and treat; this is the first case of such a tumor causing recurrent Cushing's disease in a child.

Peri-operative management of Cushing's disease

Management of patients with ACTH producing pituitary adenoma remains to be challenging. Removal of the pituitary adenoma through transsphenoidal surgery is the main stay of treatment. Complete resection of the adenoma is followed by the development of ACTH deficiency since the normal corticotrophs are suppressed by the pre-existing hypercortisolemia. The concern for ACTH deficiency has led many centers to advocate the use glucocorticoids before, during and after surgery. We provide evidence that such coverage with glucocorticoids is unnecessary until clinical or biochemical documentation of need is established. Given that patients are closely monitored, they are immediately treated with glucocorticoids once they exhibit any clinical and/or biochemical evidence of adrenal insufficiency. Defining remission in the immediate postoperative period has been rather difficult despite using different biochemical markers. Serum cortisol continues to be the best determinant of disease activity after surgical adenomectomy. However it needs to be interpreted with caution as a biochemical marker of remission in patients given glucocorticoids during and after surgery. Other biochemical markers are also used in the peri-operative period to determine the possibility of remission. These include the dexamethasone suppression test, CRH stimulation without dexamethasone, urinary free cortisol measurements, desmopressin stimulation test, the determination of salivary cortisol and / or plasma ACTH concentrations. Each test has its own advantages and limitations. The simplest and most informative approach is to measure serum cortisol levels repeatedly after surgery without the administration of exogenous glucocorticoids. Low serum cortisol levels (less than 2 μg/dL) in the peri-operative period are highly indicative of surgical success and a high likelihood for clinical remission. Higher serum cortisol levels require careful interpretation and further planning and discussions between the patient and the management team.

Surgical management of pediatric Cushing's disease: an analysis of 15 consecutive cases at a specialized neurosurgical center

OBJECTIVE: The aim of this study was to review the results of surgery for pediatric patients with Cushing's disease who were less than 18 years old and underwent transsphenoidal surgery in a specialized center during a 25-year period. SUBJECTS AND METHODS: Retrospective study, in which the medical records, histology and pituitary imaging of 15 consecutive pediatric patients with Cushing's disease (mean age: 13 years) were evaluated by the same team of endocrinologists and a neurosurgeon from 1982 to 2006. Patients were considered cured when there was clinical adrenal insufficiency and serum cortisol levels were below 1. 8 µg/dL or 50 nmol/L after one, two, three, or seven days following surgery; they therefore required cortisone replacement therapy. Follow-up was for a median time of 11.5 years (range: 2 to 25 years). RESULTS: Clinical and biochemical cure was achieved in 9/15 patients (60%) exclusively after transsphenoidal surgery. Hypopituitarism was observed in four patients; growth hormone deficiency, in two; permanent diabetes insipidus, in one case. CONCLUSIONS: Cushing's disease is rare in children and adolescents. Transsphenoidal surgery is an effective and safe treatment in most of these patients. Plasma cortisol level < 1. 8 µg/dL following surgery is the treatment goal and is a good predictive factor for long-term cure of Cushing's disease.

Somatostatin and somatostatin receptors in Cushing's disease

Cushing's disease is caused by an ACTH secreting pituitary adenoma. Surgery is the treatment of choice and cure rates between 60 and 90% are reported. For patients in which surgery fails, effective medical treatment options are needed. Somatostatin (SS) receptors (sst) are expressed on normal and tumoral corticotroph cells. However, the role of somatostatin and in particular the current clinically available sst(2)-preferring SS analogs in the regulation of normal ACTH secretion, as well as in lowering ACTH and cortisol hypersecretion in patients with Cushing's disease, has been shown to be limited. Recent studies have provided renewed insights into the expression of sst subtypes, as well as into the functional role of SS-analogs in the regulation of ACTH secretion by corticotroph tumors. Sst(2) and sst(5) seem the predominantly expressed sst in corticotroph adenoma cells and targeting both these receptors with a new generation of multiligand SS analogs showed promising effects in terms of lowering ACTH release and urinary free cortisol (UFC) levels in patients with Cushing's disease. In this review an overview of the current insights into the role of SS and sst in the regulation of normal and pathological ACTH secretion is provided.

Late recurrences of Cushing's disease after initial successful transsphenoidal surgery

CONTEXT

Few studies have systematically analyzed the long-term recurrence rates of Cushing's disease after initial successful transsphenoidal surgery.

SETTING

This was a retrospective review of patients treated at the University of Virginia Medical Center.

PATIENTS

A total of 215 subjects with Cushing's disease who underwent initial transsphenoidal surgery for resection of a presumed pituitary microadenoma from 1992-2006 were included.

MAIN OUTCOME MEASURES

Remission and recurrence rates of Cushing's disease were examined. Recurrence was defined as an elevated 24-h urine free cortisol with clinical symptoms consistent with Cushing's disease.

RESULTS

Of the 215 patients who underwent transsphenoidal surgery for Cushing's disease, surgical remission was achieved in 184 (85.6%). The mean length of follow-up was 45 months. Actuarial recurrence rates of Cushing's disease after initially successful transsphenoidal surgery at 1, 2, 3, and 5 yr were 0.5, 6.7, 10.8, and 25.5%, respectively. Among the 184 patients who achieved remission, 32 (17.4%) patients followed for more than 6 months ultimately had a recurrence of Cushing's disease. The median time to recurrence was 39 months. Immediate postoperative hypocortisolemia (serum cortisol < or = 2 microg/dl within 72-h surgery) was achieved in 97 (45.1%) patients. Patients who had postoperative serum cortisol of more than 2 microg/dl were 2.5 times more likely to have a recurrence than patients who had serum cortisol less than or equal to 2 microg/dl (odds ratio = 2.5; 95% confidence interval 1.12-5.52; P = 0.022).

CONCLUSIONS

A quarter of the patients with Cushing's disease who achieve surgical remission after transsphenoidal surgery, recur with long-term follow-up. This finding emphasizes the need for continued biochemical and clinical follow-up to ensure remission after surgery.

Treatment options for Cushing disease after unsuccessful transsphenoidal surgery

Cushing disease is considered an aggressive pituitary endocrinopathy because of the devastating effects from untreated hypercortisolemia. Although they are histologically benign, these adrenocorticotropic hormone (ACTH)-secreting pituitary tumors are associated with significant morbidity and premature death. Currently, transsphenoidal surgery is the primary treatment of Cushing disease associated with an ACTH-secreting pituitary tumor, resulting in remission rates ranging from about 50 to 90%. Some patients, however, will not achieve sustained remission after transsphenoidal surgery and can exhibit persistent or recurrent Cushing disease that requires multimodal treatment to achieve remission. In these patients, options for treatment include repeat transsphenoidal resection, radiation therapy (including conventional fractionated radiation therapy and stereotactic radiosurgery), and medical therapy. Despite undergoing multiple treatment modalities, some patients may ultimately require bilateral adrenalectomy for definitive treatment to eliminate hypercortisolemia associated with Cushing disease. In this article, the authors review the treatment options for patients who have persistent or recurrent Cushing disease after unsuccessful transsphenoidal surgery. The indications, current results reported in the literature, and complications of each treatment modality are discussed.

Criteria of cure and remission in Cushing's disease: an update

We review the clinical and biochemical criteria used for evaluation of the transsphenoidal pituitary surgery results in the treatment of Cushing's disease (CD). Firstly, we discuss the pathophysiology of the hypothalamic-pituitary-adrenal axis in normal subjects and patients with CD. Considering the series published in the last 25 years, we observed a significant variation in the remission or cure criteria, including the choice of biochemical tests, timing, threshold values to define remission, and the interference of glucocorticoid replacement or previous treatment. In this context we emphasize serum cortisol levels obtained early (from hours to 12 days) in the postoperative period without any glucocorticoid replacement or treatment. Our experience demonstrates that: (i) early cortisol < 5 to 7 µg/dl, (ii) a period of glucocorticoid dependence > 6 mo, (iii) absence of response of cortisol/ACTH to CRH or DDAVP, (iv) return of dexamethasone suppression, and circadian rhythm of cortisol are appropriate indices of remission of CD. In patients with undetectable cortisol levels early after surgery, recurrence seems to be low. Finally, although certain biochemical patterns are more suggestive of remission or surgical failure, none has been proven to be completely accurate, with recurrence observed in approximately 10 to 15% of the patients in long-term follow-up. We recommended that patients with CD should have long-term monitoring of the CRH-ACTH-cortisol axis and associated co-morbidities, especially hypopituitarism, diabetes mellitus, hypertension, cardiovascular disturbances, and osteoporosis.

Unusual causes of Cushing's syndrome

Although in the majority of the patients with Cushing's syndrome (CS), hypercortisolism is due to ACTH hypersecretion by a pituitary tumour or to ectopic ACTH secretion from an extrapituitary neoplastic lesion or to autonomous cortisol secretion by an adrenal tumour, in occasional patients a much rarer entity may be the cause of the syndrome. Herein, we attempted to summarise and categorise these unusual causes according to their presumed aetiology. To this end, we performed a comprehensive computer-based search for unusual or rare causes of CS. The following unusual forms of CS were identified: (i) ACTH hyperesecretion due to ectopic corticotroph adenomas in the parasellar region or the neurohypophysis, or as part of double adenomas, or gangliocytomas; (ii) ACTH hypersecretion due to ectopic CRH or CRH-like peptide secretion by various neoplasms; (iii) ACTH-independent cortisol hypersecretion from ectopic or bilateral adrenal adenomas; (iv) glucocorticoid hypersensitivity; (v) iatrogenic, due to megestrol administration or to ritonavir and fluticasone co-administration. Such unusual presentations of CS illustrate why Cushing's syndrome represents one of the most puzzling endocrine syndromes.

Radiotherapy of pituitary adenomas: state of the art

Pituitary adenomas represent approximately 12% of intracranial tumors. They are defined as tumors that are functional or nonfunctional and invasive or noninvasive. Therapeutic strategies rely on surgery, medical treatment, and radiotherapy depending on histology. Neither the role of external radiotherapy nor the technique to be used are firmly established. Nonfunctioning adenomas must be operated on to relieve the compression. Prolactin-secreting adenomas are first treated with dopamine agonists, and GH-secreting adenomas are first treated by surgery if excising the complete tumor is possible; otherwise medical treatment is started. The first-line treatment of ACTH-secreting adenomas is surgery; however, in many cases, insufficient control of either secretion or tumoral volume leads to consideration of irradiation. Complications of conventional radiotherapy are well known and fractionated stereotactic radiotherapy appears to be as safe as radiosurgery. The volume to irradiate is still difficult to define, and this parameter can influence the technique chosen for treatment. Because the indications of radiotherapy are still debated, irradiation of pituitary adenomas must be decided by the complete team of endocrinologists, neurosurgeons, radiologists and radiotherapists.

Prognostic factors for outcome after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism

Object

The aim of this study was to determine prognostic factors for outcome after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism (PDH).

Methods

One veterinary neurosurgeon performed transsphenoidal hypophysectomies in 181 dogs with PDH over a 12-year period. Survival analysis was performed with the Kaplan–Meier method. Prognostic factors were analyzed with the univariate Cox proportional hazard analysis followed by stepwise multivariate analysis. The log-rank test was used to assess disease-free fractions in three groups categorized according to early postoperative urinary corticoid/creatinine (C/C) ratios.

Results

Multivariate analysis revealed that old age, large pituitary size, and high preoperative concentrations of plasma adrenocorticotropic hormone were associated with an increased risk of PDH-related death. In addition, large pituitary size, thick sphenoid bone, high C/C ratio, and high concentration of plasma α-melanocyte–stimulating hormone (α-MSH) before surgery were associated with an increased risk of disease recurrence in the dogs that went into remission after hypophysectomy. Disease-free fractions were significantly higher in dogs with postoperative urinary C/C ratios in the lower normal range (< 5 × 10−6) than in dogs with postoperative C/C ratios in the upper normal range (5–10 × 10−6).

Conclusions

The results of this study indicate that pituitary size, sphenoid bone thickness, plasma α-MSH concentration, and preoperative level of urinary cortisol excretion are predictors of long-term remission after transsphenoidal hypophysectomy for PDH in dogs. Urinary C/C ratios measured 6 to 10 weeks after surgery can be used as a guide for predicting the risk of tumor recurrence.

Surgical management of pediatric Cushing's disease

BACKGROUND

Cushing's disease may have a direct effect on growth pattern, pubertal maturation, and long-term survival in pediatric patients.

METHODS

Dexamethasone suppression test was done in 10 children (median age, 15 years) and showed variable suppressibility, with microadenoma seen in 5, macroadenoma in 3, and normal gland in 2 patients. Inferior petrosal sinus sampling (IPPS) was also carried out and confirmed pituitary adenoma as source of ACTH in 2 patients. We adopted sublabial transsphenoidal (n = 9) or pterional transsylvian route (n = 1) in macroadenoma with conchal sphenoid sinus. Serum cortisol level <50 nmol/L was taken as the criteria for biochemical remission.

RESULTS

Clinical remission was achieved in 7 of 10 operated patients. In 2 patients where clinical remission was achieved, postoperative BSC could not be done. Postoperative BSC was less than 50 nmol/L in 2 (25%) of 8 patients and remained elevated in 6. Remission was achieved in both patients with postoperative BSC less than 50 nmol/L and in 3 of 6 with elevated levels. Three patients had neither clinical nor biochemical remission: 2 underwent bilateral adrenalectomy and 1 received radiotherapy. Postoperative CSF leak seen even in microadenomas associated with arachnoidal prolapse. Among 7 patients who initially remitted (median follow-up of 82 months; range, 24-120 months), recurrence of disease occurred in 3 (42.8%) patients after a median interval of 5 years.

CONCLUSIONS

In children with CD, endocrinal manifestations are more frequent than visual symptoms. Transsphenoidal route is the preferred approach, but a nonpneumatised sphenoid sinus may be present. Sellar arachnoidal prolapse may cause postoperative CSF leak even in microadenomas. Surgery is the first line of treatment, but constant monitoring is mandatory to pick up the relapsed cases.

Preclinical and clinical experiences with the role of somatostatin receptors in the treatment of pituitary adenomas

The patho-physiological role of somatostatin receptor subtypes (sst) in neuro endocrine diseases has gained enhanced scientific interest in the past few years. The development of novel somatotropin-release inhibiting factor analogs, both sst-specific and universal ligands, seem promising as a tool to further increase fundamental insights in sst function. Eventually, this research should result in novel medical therapeutic opportunities in patients suffering from neuro-endocrine diseases. In the present review, the functional role of sst in all types of pituitary adenomas, based on recent preclinical and clinical studies, is being discussed.

[Nelson's Syndrome: a case report]

The aim of this article is to present and discuss several aspects of the pathogenesis, the clinical, hormonal, and imaging diagnosis, and the treatment of Nelson's syndrome, based on a typical patient's report, in whom several therapeutic approaches were shown to be ineffective.

Surgical remission of pituitary adenomas confined to the neurohypophysis in Cushing's disease

CONTEXT

Partial or total removal of the pituitary cures 60-80% of patients with Cushing's disease (CD) in whom an adenoma cannot be identified at surgery. Many patients who fail complete or partial hypophysectomy are cured by sellar and parasellar irradiation.

DESIGN/PATIENTS

As part of a series of prospective studies of CD, we identified 12 patients (34.5 +/- 19.9 yr; 11 females; four children) with tumors located completely within the neurohypophysis among 730 patients undergoing surgery for CD.

SETTING

The study was conducted at a tertiary referral center at a clinical research hospital.

RESULTS

All 12 patients had clinical and biochemically defined CD. Tumor was visible at surgery in 11 patients; all 12 tumors were positive for ACTH by immunohistochemistry. Two tumors were excised at repeat surgery because of persistent hypercortisolism within 14 d of negative exploration of the adenohypophysis. There were no long-term complications. At follow-up of 71.9 +/- 34.2 months (range, 30-138 months), all patients are in remission of CD. Adult patients have had significant improvement in weight and body mass indices, with restoration of normal menses in all women. In the four pediatric patients, height, weight, and body mass indices have been restored toward normal by surgical remission of CD. Hypopituitarism or long-term neurohypophysial dysfunction has not occurred.

CONCLUSION

We report a new subset of patients with CD, ACTH-secreting adenomas that arise wholly within the posterior lobe of the pituitary gland. In cases of CD in which an adenoma is not identified in the adenohypophysis and in patients with persistent hypercortisolism after complete or partial excision of the anterior lobe, tumor within the neurohypophysis should be considered; selective adenomectomy of a neurohypophyseal, ACTH-secreting tumor can produce long-term remission.

Pituitary surgery and postoperative management in Cushing's disease

Transsphenoidal pituitary surgery is the therapy for most Cushing's disease patients. This article describes the surgical technique, efficacy, perioperative management, and complications associated with this procedure. Numerous biochemical tests of cortisol status have been studied for the evaluation of the postoperative patient. Factors that predict postoperative remission and future relapse of Cushing's disease are addressed. Secondary interventions for persistent or recurrent disease include repeat transsphenoidal resection, pituitary radiation, medical therapy, and bilateral adrenalectomy

Molecular pathology shows p16 methylation in nonadenomatous pituitaries from patients with Cushing's disease

PURPOSE

The majority of cases of Cushing's disease are due to the presence of a corticotroph microadenoma. Less frequently no adenoma is found and histology shows either corticotroph hyperplasia, or apparently normal pituitary. In this study we have used molecular pathology to determine whether the tissue labeled histologically as "normal" is indeed abnormal.

EXPERIMENTAL DESIGN

Tissue from 31 corticotroph adenomas and 16 nonadenomatous pituitaries were subject to methylation-sensitive PCR to determine the methylation status of the p16 gene CpG island. The proportion of methylated versus unmethylated CpG island was determined using combined bisulphite restriction analysis. Methylation status was correlated with immunohistochemical detection of p16.

RESULTS

Seventeen of 31 adenomas (54.8%), 4 of 6 cases of corticotroph hyperplasia, and 7 of 10 apparently normal pituitaries showed p16 methylation. Ten of 14 (71%; P = 0.01) adenomas and 2 of 3 cases of corticotroph hyperplasia, which were methylated, failed to express p16 protein. However, only 2 of 7 apparently normal pituitaries that were methylated failed to express p16 protein. Quantitative analysis of methylation using combined bisulphite restriction analysis showed only unmethylated CpG islands in postmortem normal pituitaries; however, in adenomas 80-90% of the cells within a specimen were methylated. The reverse was true for corticotroph hyperplasia and apparently normal pituitaries where only 10-20% of the cells were methylated. Thus, the decreased proportion of cells that were methylated, particularly in those cases of apparently normal pituitary, is the most likely explanation for the lack of association between this change and loss of cognate protein in these cases.

CONCLUSIONS

To our knowledge this is the first report that describes an intrinsic molecular change, namely methylation of the p16 gene CpG island, common to all three histological patterns associated with Cushing's disease. Thus, the use of molecular pathology reveals abnormalities undetected by routine pathological investigation. In cases of "apparently" normal pituitaries it is not possible to determine whether the change is associated with adenoma cells "scattered" throughout the gland, albeit few in number, or with the ancestor-clonal origin of these tumor cells.

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

OBJECTIVE

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

DESIGN

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

PATIENTS

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

RESULTS

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

CONCLUSION

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

The role of somatostatin analogs in Cushing's disease

Somatostatin (SRIF) has been proposed to be of therapeutic interest in the medical treatment of Cushing's disease. While in vitro data demonstrate the presence of SRIF-receptor subtype (sst) expression in corticotroph adenomas, the current clinically available SRIF-analog Octreotide, predominantly targeting sst(2), is ineffective in lowering ACTH levels in Cushing's disease and only appears to inhibit the release of ACTH in Nelson's syndrome. In the present review, current knowledge on the physiological role of SRIF in the regulation of ACTH secretion by the anterior pituitary gland, as well as by corticotroph tumor cells is summarized. In addition, the role of glucocorticoids in regulating sst-mediated inhibition of ACTH release by corticotroph adenoma cells is discussed. Recently, it was reported that the novel multiligand SRIF-analog SOM230 might have the potential to be of therapeutic interest for Cushing's disease. On the basis of the potent suppressive effects on ACTH release by SRIF-analogs with high binding affinity to sst(5) and the observation that sst(5) expression and action is relatively resistant to glucocorticoid treatment, including the recent observation that sst(5) is the predominant sst expressed in human corticotroph adenomas, it is hypothesized that sst(5) may be a new therapeutic target for the control of ACTH and cortisol hypersecretion in patients with pituitary dependent Cushing's disease.

Crooke's cell adenoma of the pituitary: an aggressive variant of corticotroph adenoma

Cushing's disease is caused by functional corticotroph adenomas of the pituitary, mostly noninvasive microadenomas. Classic Crooke's cells are nonneoplastic corticotrophs with cytoplasmic accumulation of cytokeratin filaments in response to glucocorticoid excess. Corticotroph adenomas exhibiting Crooke's change are rare and incompletely understood. We intend to define more clearly the clinicopathological features of Crooke's cell adenomas (CCA). Thirty-six CCAs were retrieved from the files of Mayo Clinic and from our (B.W.S., K.K.) consultation files. The number of informative cases varied for different criteria. Clinical follow-up was obtained in 31 cases. The 27 females and 9 males were 18 to 81 years of age (mean 46 years). At presentation, Cushing's disease was evident in 22/34 (65%); 81% were macroadenomas and 72% were invasive. All were initially treated by transsphenoidal resection. Twenty-five patients were followed for more than 1 year (mean 6.7 years). Of these, 15 (60%) developed recurrent tumor, and 6 (24%) had multiple recurrences. Lastly, 3 of these 25 patients (12%) died of tumor: 1 after multiple local recurrences and 2 from pituitary carcinoma. Compared with typical corticotroph adenomas, CCAs are aggressive. Most are functional adenomas occurring in middle-aged women and are invasive macroadenomas prone to recurrence. Morbidity and mortality rates are substantial. CCAs represent a distinct entity that should be separated from corticotroph adenomas without Crooke's hyaline change.

Transsphenoidal microsurgical treatment of Cushing disease: postoperative assessment of surgical efficacy by application of an overnight low-dose dexamethasone suppression test

OBJECT

Transsphenoidal adenomectomy with resection of a defined pituitary adenoma has been the treatment of choice for CD for the last 30 years. Surgical resection, however, may not always result in long-term remission of CD. This is particularly important in light of the high risk of morbidity and mortality in patients in the unsuccessfully treated cushingoid state. As such, it is interesting to identify prognostic factors that may predict the likelihood of long-term remission.

METHODS

The authors review their series of 174 patients who have undergone transsphenoidal procedures for CD over a period of 20 years with minimum follow-up periods of 5 years. Selection of these patients was based on clinical, imaging, and laboratory criteria that included serum cortisol levels, loss of diurnal variation in serum cortisol levels, urinary free cortisol concentration, and results of a dexamethasone suppression test, petrosal sinus sampling, and corticotroph-releasing hormone stimulation tests as indicated. All patients who met the biochemical criteria underwent transsphenoidal microsurgery. The authors found an overall rate of remission of 74% at 5 years postoperatively. Patients in whom morning serum cortisol concentrations were lower than 3 microg/dl (83 nmol/L) on postoperative Day 3, following an overnight dexamethasone suppression test, had a 93% chance of remission at the 5-year follow-up examination. Patients with cortisol concentrations higher than this level uniformly failed to achieve long-term remission.

CONCLUSIONS

Transsphenoidal microsurgery is an effective means of control for patients with adrenocorticotrophic hormone-producing microadenomas. Clinical outcome correlated well with the size of the tumor, as measured on preoperative imaging studies, and with postoperative morning cortisol levels following an overnight dexamethasone suppression test. Postoperative cortisol levels can be used as a useful prognostic indicator of the likelihood of future recurrence following transsphenoidal adenomectomy in CD.

Comparison of endonasal endoscopic surgery and sublabial microsurgery for prolactinomas

BACKGROUND

Endonasal endoscopy is a promising minimally invasive surgery for the treatment of pituitary adenomas; it is also a good alternative to traditional sublabial microsurgery. In this study, we compared endoscopic surgery with microsurgery and evaluated both for their safety and effectiveness. We chose prolactinomas for study because their hormone and symptomatic changes facilitated the comparison.

METHODS

During the past five years, 44 randomized prolactinoma patients underwent pituitary adenomectomy. Group A (22 patients) underwent endonasal endoscopic surgery for prolactinomas. Group B (22 patients) underwent sublabial transsphenoidal microsurgery for prolactinomas.

RESULTS

In groups A and B, patients with prolactinoma exhibited significantly reduced postoperative prolactin levels, return of menstrual cycle, and relief of galactorrhea, (Wilcoxon signed rank test) (p < 0.001). But there were no statistically significant differences in the effectiveness of the procedures used in group A and group B. Visual improvement in cases of macroadenoma was satisfactory in both groups. Hospital stay in group A ranged from 2-5 days, with a mean of 3.2 days. Hospital stay in group B ranged from 4-8 days with a mean of 5.3 days. The hospital stay for group A patients was shorter (2.1 days) than for group B (Student t test, p < 0.05). The operative time was shorter by 1 hour in Group A (mean: 1.7 hours vs. mean: 2.7 hours, p < 0.05). There were fewer complications in group A (4.5%) than in group B (27%), p < 0.05.

CONCLUSIONS

The endoscopic era of pituitary surgery may be coming. Endonasal endoscopic surgery may have the same effectiveness as traditional microsurgery. However, endoscopic surgery may shorten hospital stay and operative time, and lead to fewer complications. It seems to be a good minimally invasive surgical technique for prolactinomas.

Basis of persistent and recurrent Cushing disease: an analysis of findings at repeated pituitary surgery

OBJECT

The goal of this study was to establish the clinical importance of occult dural invasion--invasion of the dura mater or cavernous sinus that is not evident on imaging studies and is not obvious to the surgeon--as the basis of recurrent or persistent tumor and endocrinopathy.

METHODS

The authors retrospectively reviewed the case files of patients who underwent repeated transsphenoidal surgery for resection of an adrenocorticotropic hormone (ACTH)-producing pituitary adenoma. Patient selection required the availability of operative and pathology reports from the initial and repeated transsphenoidal surgeries. Because no determination of the cause of persistent or recurrent disease could be made if the tumor could not be localized during the repeated surgery, a pathology report confirming the presence of tumor from the second surgery was also required. Sixty-eight patients met these criteria. In 43 patients (63%) an ACTH-producing tumor was identified at the initial surgery, in 25 patients (37%) no tumor was found, and in three patients (4%) dural invasion was noted at surgery. In 49 (72%) of the 68 patients there was initial resolution of hypercortisolism and recurrent Cushing disease (CD), whereas in 19 patients (28%) there was persistent CD after the initial surgery. At repeated surgery (44 +/- 35 months after the initial surgery) in all 43 patients in whom tumor had been identified at the initial surgery, the tumor was found at the same site or contiguous to the same site. Dural invasion was noted by the surgeon in only three patients at the original surgery, whereas dural invasion by an ACTH-producing tumor was identified during repeated surgery in 42 (62%) of the 68 patients. In addition, 39 (93%) of the 42 invasive adenomas were located laterally and involved the cavernous sinus. Adenomatous invasion of the dura mater was found in 31 (54%) of the 57 microadenomas and in all 11 macroadenomas at repeated surgery. The presence of tumor was not detected in 28 of the 59 patients studied with magnetic resonance (MR) imaging and in none of these 59 patients was dural invasion evident on MR images.

CONCLUSIONS

Recurrent and persistent CD consistently results from residual tumor. At repeated surgery the residual tumor can be found at or immediately contiguous to the site at which the tumor was found originally. Unappreciated dural invasion with growth of residual tumor within the cavernous sinus dura, which frequently occurs without residual tumor or dural invasion being evident on MR images or to the surgeon during surgery, is the basis of surgical failure in many patients with CD. Occult lateral dural invasion by tumor may also underlie recurrences of other types of pituitary adenomas.

Intraoperative bilateral cavernous sinus sampling for ACTH measurements during transsphenoidal pituitary surgery in patients with Cushing's disease

Intraoperative bilateral cavernous sinus sampling combined with rapid ACTH measurement was performed in a pilot study in seven patients with Cushing's disease during transsphenoidal pituitary surgery before and immediately after removal of the ACTH-producing pituitary microadenoma. Before tumor removal a gradient in ACTH concentrations greater than 1.5:1 toward the side of the tumor was found in six patients whereas ACTH concentrations in the right and left cavernous sinuses were similar in one patient with a midline tumor. Immediately after tumor removal, six of seven patients showed variable decreases in ACTH levels in the ipsilateral and/or contralateral side, whereas in one patient the ACTH levels in cavernous sinuses failed to reflect successful tumor removal. These results indicate that intraoperative bilateral cavernous sinus sampling combined with rapid ACTH measurement may be useful to confirm and lateralize ACTH-producing pituitary microadenomas during surgery, but ACTH levels measured immediately after tumor removal do not always predict surgical cure.

Long-term follow-up results of transsphenoidal surgery for Cushing's disease in a single centre using strict criteria for remission

OBJECTIVE

Transsphenoidal selective adenomectomy (TSA) is widely accepted as the treatment of choice for Cushing's disease but not all patients are cured by this procedure. The success of surgery depends on the skill and experience of the surgeon but the criteria used to define remission are highly variable. We have analysed the outcome following surgery in our centre using the stringent requirement of a postoperative serum cortisol of < 50 nmol/l as our definition of remission and assessed whether changes in surgical policy, including a greater emphasis on selective procedures and the move in recent years to a single surgeon undertaking all pituitary surgery, have improved complication and remission rates.

PATIENTS AND METHODS

The case notes, histology and pituitary imaging of 54 consecutive patients (42 females, mean age 41 years) with pituitary-dependent Cushing's syndrome who had undergone transsphenoidal surgery between January 1980 and November 2000 were reviewed. Follow-up was for a median of 6 years (range 6 months to 21 years).

RESULTS

One patient died within 1 week of surgery (1.9%) and major morbidity occurred in eight patients (15%). Clinical and biochemical remission was achieved in 41 patients (77%) with only two recurrences (5%) to date. Success was related to tumour size with 37 (86%) of 43 intrasellar lesions successfully resected compared with only four (40%) of 10 extrasellar adenomas. Twenty-four (59%) of those in remission developed partial or complete hypopituitarism compared with four (33%) of those not in remission. The extent of surgical exploration predicted the development of hypopituitarism (88% total hypophysectomy, 33% hemihypophysectomy, 14% selective adenomectomy) but not remission (75% total hypophysectomy, 87% hemihypophysectomy, 71% selective adenomectomy). Among complications, an excess of venous thromboembolic disease was noted, with three patients (6%) developing deep venous thrombosis or pulmonary embolism postoperatively. Comparison of the data for individual surgeons revealed an improvement in outcome over time, with 100% remission of microadenomas, 29% hypopituitarism and 12% complications following the move to a single surgeon undertaking all pituitary surgery.

CONCLUSION

Transsphenoidal surgery is a safe and effective treatment for Cushing's disease and our results compare favourably with those from published series, the majority of which comprise relatively small numbers. The presence of an intrasellar lesion and postoperative serum cortisol < 50 nmol/l are good predictors of remission in the long term but historically in our centre this can only be achieved in a significant number of patients at the expense of some degree of hypopituitarism. However, the surgical outcome for Cushing's disease, including a reduced frequency of hypopituitarism, can be improved if patients are operated on by a single pituitary surgeon, using selective adenomectomy as the preferred surgical approach wherever possible.

The complete normalization of the adrenocortical function as the criterion of cure after transsphenoidal surgery for Cushing's disease

Transsphenoidal microsurgery is the standard treatment for patients with Cushing's disease. However, there is general lack of agreement regarding the definition of cure. We studied 58 patients with corrected hypercortisolism after transsphenoidal surgery for Cushing's disease. Plasma and urinary cortisol levels were measured after surgery. After the postsurgical hypocortisolism stage (or periodically in patients without hypocortisolism), urinary free cortisol, plasma cortisol at 0800 h and 2300 h, morning cortisol after 1 mg dexamethasone, and cortisol response to insulin-induced hypoglycemia were performed. Patients were classified in 3 groups: group I, patients with transient hypocortisolism and normal hypothalamus-pituitary-adrenal axis afterwards; group II, patients with transient hypocortisolism and abnormalities in the circadian rhythm or the stress response afterwards; and group III, patients without postoperative hypocortisolism. Thirty-three patients were included in group I, 8 in group II, and 17 in group III. Groups I and II were similar in postsurgical plasma cortisol (46.9 +/- 30.3 vs. 60.7 +/- 38.6 nM) and mean follow-up (69.8 vs. 68.8 months) but were significantly different in their recurrence rate (3.4% vs. 50%, P < 0.001). Patients in group III had normal postsurgical plasma and urinary cortisol but persistent abnormalities in circadian rhythm and stress response. After a mean follow-up of 39.1 months, their recurrence rate was similar to that of group II (64.7% vs. 50%). The complete normalization of the adrenocortical function, which is always preceded by postsurgical hypocortisolism, is associated with a very low recurrence risk and should be considered, in our opinion, the main criterion of surgical cure in Cushing's disease.

Multiple pituitary adenomas in Cushing's disease

OBJECT

Clinically evident multiple pituitary adenomas rarely occur. The authors assess the incidence and clinical relevance of multiple adenomas in Cushing's disease.

METHODS

A prospective clinical database of 660 pituitary surgeries was analyzed to assess the incidence of multiple pituitary adenomas in Cushing's disease. Relevant radiographic scans, medical records, and histopathological reports were reviewed. Thirteen patients with at least two separate histopathologically confirmed pituitary adenomas were identified. Prolactinomas (nine patients) were the most common incidental tumors. Other incidental tumors included secretors of growth hormone ([GH], one patient) and GH and prolactin (two patients), and a null-cell tumor (one patient). In two patients, early repeated surgery was performed because the initial operation failed to correct hypercortisolism, in one instance because the tumor excised at the initial surgery was a prolactinoma, not an adrenocorticotropic hormone-secreting tumor. One patient had three distinct tumors.

CONCLUSIONS

Multiple pituitary adenomas are rare, but may complicate management of patients with pituitary disease.

Ectopic corticotroph adenoma in the cavernous sinus: case report

OBJECTIVE AND IMPORTANCE

Adrenocorticotropin (ACTH)-secreting pituitary adenomas causing Cushing's disease are often difficult to identify because of their variable locations and their small size. This report presents histological evidence of an ectopic ACTH-secreting adenoma located entirely within the cavernous sinus.

CLINICAL PRESENTATION

A 62-year-old woman presented with central obesity, hypertension, and osteoporosis. Endocrinological evaluation suggested the presence of an ACTH-secreting pituitary adenoma; however, imaging studies, including dynamic magnetic resonance imaging, did not reveal any visible lesions in the pituitary gland. Bilateral cavernous sinus sampling demonstrated a large central/peripheral ACTH gradient, with a right/left ACTH gradient. The patient was treated as having pituitary-dependent Cushing's disease, until she died suddenly as a result of acute respiratory failure.

INTERVENTION

In a postmortem histological examination, an ACTH-secreting adenoma was found in the right cavernous sinus, which was completely surrounded by dura mater and had no direct connection with the pituitary gland.

CONCLUSION

Although they are rare, such adenomas located in the cavernous sinus should be recognized as one of the reasons for inaccurate cavernous sinus sampling and the failure of transsphenoidal surgery for patients with ACTH-dependent Cushing's syndrome.

Antisense oligonucleotide-induced inhibition of adrenocorticotropic hormone release from cultured human corticotrophs

OBJECT

Available therapies for Cushing's disease are often inadequate or involve the risk of significant morbidity. Accordingly, the need arises for the development of novel treatments, especially for cases caused by corticotroph hyperplasia, a condition difficult to treat using standard therapies. In this study, the authors investigated the use of phosphorothioate antisense oligonucleotides as a potential treatment for Cushing's disease.

METHODS

Corticotrophs, obtained from a patient with Cushing's disease in whom pathological findings showed multifocal areas of corticotroph adenoma and hyperplasia, were grown in tissue culture. By assessing cell viability and using immunoradiometric assay techniques, it was determined that these cells grew autonomously and secreted adrenocorticotropic hormone (ACTH) in vitro. A fully phosphorothioated antisense oligonucleotide was constructed to be complementary to the first 25 bp of the region coding for ACTH in exon 3 of the proopiomelanocortin precursor. After incubation of the corticotrophs with liposome-coated phosphorothioate antisense oligonucleotides, a greater than 90% decrease in ACTH release was noted on Days 3 and 6, compared with nonsense-treated controls (p < 0.05).

CONCLUSIONS

Antisense oligonucleotides may prove to be a useful adjunct in treating Cushing's disease by targeting one of its fundamental problems, ACTH hypersecretion.

What can predict postoperative "endocrinological cure" in Cushing's disease?

OBJECTIVE

The goal of surgical treatment for Cushing's disease is "endocrinological cure." The purpose of this study was to determine predictors for postoperative endocrinological cure in Cushing's disease.

METHODS

Postoperative endocrinological studies were evaluated in 18 patients with Cushing's disease who underwent transsphenoidal surgery for selective adenomectomy. Serum adrenocorticotropic hormone (ACTH) levels were measured by radioimmunoassay during the first week after surgery. One week after surgery, a test using corticotropin-releasing hormone (CRH) was performed on each patient to check the reserve function of normal ACTH-secreting cells.

RESULTS

In eight patients, postoperative ACTH levels were below the measurable level for 1 week, and ACTH showed no response to the CRH test. In these patients, serum ACTH and cortisol levels were kept in the normal range with a normal diurnal variation during long-term follow-up. These patients can be defined as endocrinologically cured. In seven patients, the ACTH level returned to within normal range on the day after surgery, but ACTH was provoked by the CRH test. Five of these seven patients showed subsequent re-elevation of ACTH above the normal range. ACTH levels were never normalized in the remaining three patients, and medical treatments were unavoidable.

CONCLUSION

The most reliable indicators for predicting endocrinological cure in Cushing's disease are no response of ACTH to the CRH test in the early postoperative stage and an unmeasurably low ACTH level in the week after surgery. Obtaining a normal range of ACTH level postoperatively is insufficient to define endocrinological cure.