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

Outcomes of therapy for Cushing's disease due to adrenocorticotropin-secreting pituitary macroadenomas

We reviewed our experience with 21 patients who had Cushing's disease due to ACTH-secreting macroadenomas to clarify the natural history of this disease. All patients had typical clinical and biochemical features of ACTH-dependent hypercortisolism. Their mean maximal tumor diameter was 1.6 +/- 0.1 cm, and the range was 1.0-2.7 cm. Six patients had cavernous sinus invasion, three had invasion of the floor of their sella, and nine had suprasellar extension. The observed remission rate was significantly lower in macroadenoma patients than in microadenoma patients (67% vs. 91%; chi 2 = 5.7; P < 0.02). Cavernous sinus invasion (odds ratio, 35; 95% confidence interval, 2.6-475; P < 0.008) and presence of a maximum tumor diameter 2.0 cm or more (odds ratio, 12.9; 95% confidence interval, 1.4-124; P < 0.02) emerged as the only predictors of residual disease after surgery. The observed recurrence rate was significantly higher in macroadenoma patients than in microadenoma patients (36% vs. 12%; chi 2 = 4.2; P < 0.05). Macroadenoma patients tended to suffer from recurrences earlier than did microadenoma patients (16 vs. 49 months). Stepwise multiple logistic regression did not identify any predictors of disease recurrence in macroadenoma patients. Eight macroadenoma patients underwent a total of nine repeat surgical procedures, but none of these resulted in clinical remissions. Only four of seven (57%) patients followed for a sufficient period of time achieved normal urinary free cortisol levels after conventional radiotherapy. Three (75%) of these four patients had re-recurrent hypercortisolism after brief periods of eucortisolism. Pharmacological agents and adrenalectomy were effective in the management of hypercortisolism in patients with residual and recurrent disease. Our results indicate that ACTH-secreting macroadenomas are more refractory to conventional treatments than are ACTH-secreting microadenomas.

Blood pressure in children and adolescents with Cushing's syndrome before and after surgical care

Approximately half of children and adolescents with Cushing's syndrome develop hypertension. To examine the role of hypercortisolism in the pathogenesis of hypertension in young patients and to establish its reversibility, we studied 31 hypertensive children and adolescents with Cushing's syndrome (systolic, diastolic, and/or mean blood pressure more than 2 SD U for age and sex) from a total of 63 patients before, and for a period of 1 yr after surgical cure. Preoperatively, 93.5%, 42%, and 45% of these patients presented with an increase of the systolic, diastolic, and mean blood pressure, respectively. The systolic blood pressure remained increased in 30.7%, 15.8%, and 5.5% of patients at 3, 6, and 12 months after surgical cure, respectively. The diastolic and mean blood pressure completely normalized by 3 months after surgical cure. A significant, positive correlation was observed between the systolic blood pressure and the duration of the disease, but no correlation was seen with the 24-h urinary free cortisol values and/or the patients' body mass indices. The lack of correlation between 24-h urinary free cortisol values and blood pressure suggests that hypercortisolism influences blood pressure through multiple pathways. The positive correlation between the systolic blood pressure and the duration of the disease points towards the deleterious effects of prolonged hypercortisolism and the significance of early diagnosis and treatment. The fact that the blood pressure normalized within a year from the correction of hypercortisolism suggests that, as a rule, young patients with hypercortisolism do not develop essential hypertension.

Transsphenoidal surgery for pituitary tumours

OBJECTIVES

Transsphenoidal surgery (TSS) is the preferred method for the excision of pituitary microadenomas in adults. This study was carried out to establish the long term efficacy and safety of TSS in children.

STUDY DESIGN

A 14 year retrospective analysis was carried out on 23 children (16 boys and seven girls), all less than 18 years of age, who had undergone TSS at our centre.

RESULTS

Twenty nine transsphenoidal surgical procedures were carried out. The most common diagnosis was an adrenocorticotrophic hormone (ACTH) secreting adenoma (14 (61%) patients). The median length of follow up was 8.0 years (range 0.3-14.0 years). Eighteen (78%) patients were cured after the first procedure. No death was related to the operation. The most common postoperative complication was diabetes insipidus, which was transient in most patients. Other complications were headaches in two patients and cerebrospinal fluid leaks in two patients. De novo endocrine deficiencies after TSS in children were as follows: three (14%) patients developed panhypopituitarism, eight (73%) developed growth hormone insufficiency, three (14%) developed secondary hypothyroidism, and four (21%) developed gonadotrophin deficiency. Permanent ACTH deficiency occurred in five (24%) patients, though all patients received postoperative glucocorticoid treatment until dynamic pituitary tests were performed three months after TSS.

CONCLUSIONS

TSS in children is a safe and effective treatment for pituitary tumours, provided it is performed by surgeons with considerable experience and expertise. Surgical complications are minimal. Postoperative endocrine deficit is considerable, but is only permanent in a small proportion of patients.

Pituitary corticotroph macrotumors. Diagnosis and treatment

Pituitary corticotroph macrotumors occur in 10% to 50% of dogs with PDH. Clinical signs may be only those of hypercortisolism or may include neurologic signs such as stupor, inappetance, circling, or pacing. Currently, CT and MRI are the only tests that can confirm the presence of a pituitary macrotumor in these patients. Results of endocrine testing are not significantly different from those of dogs with a microtumor. When a macroscopic pituitary tumor is identified in a dog with neurologic signs, or if a larger tumor is found in a dog even in the absence of neurologic signs, radiation therapy is currently the treatment of choice. Unfortunately, success rates with treatment are variable. A better response may be seen if the tumor is smaller and neurologic signs are minimal or absent at the time of treatment.

Recurrence of Cushing’s Disease 10 Years after Transsphenoidal Adenomectomy: Report of a Case

OBJECTIVE

To report a case of recurrent Cushing's disease after an apparent cure and long-term surveillance.

METHODS

We describe in detail the follow-up course of a woman who underwent transsphenoidal resection of a corticotropin-secreting pituitary microadenoma in 1981.

RESULTS

For 2 years postoperatively, the patient exhibited adrenocortical insufficiency. In 1983, the pituitary-adrenal axis was normal. She remained eucorticoid until May 1992, when features of Cushing's syndrome redeveloped. Plasma and urine cortisol and plasma corticotropin levels were once again increased in conjunction with a loss of diurnal variation and abnormal responses to dexamethasone suppression. A magnetic resonance imaging scan of the pituitary gland was consistent with a small lesion on the left side, and petrosal sinus sampling after ovine corticotropin-releasing hormone stimulation was consistent with increased activity on the right side.

CONCLUSION

This 10-year interval between apparent cure and recurrence appears to be the longest thus far reported for a patient with Cushing's disease. These observations reinforce the impression that permanent cure of this disorder is uncertain and indicate the need for indefinite follow-up.

Cushing's disease due to a giant pituitary adenoma in early infancy: CT and MRI features

We report the case of a 12-month-old girl presenting with diabetes insipidus and Cushing s disease. Brain magnetic resonance imaging (MRI) demonstrated a large tumour arising from the sella turcica, extending up to the foramen of Monro and invading the cavernous sinuses. Surgery was performed to remove the suprasellar part of the tumour, and histology revealed an adrenocorticotrophin (ACTH) secreting pituitary adenoma. This entity is very rare in this age group and the MRI features have not previously been described.

Failure of Partial Hypophysectomy as Definitive Treatment in Cushing's Disease Owing to Nodular Corticotrope Hyperplasia: Report of Four Cases

Nodular corticotrope hyperplasia is a rare pathology causing Cushing's syndrome owing to a primary pituitary disease or ectopic CRH production. In this study, we evaluated the laboratory and pathological findings and results of transsphenoidal pituitary surgery in four patients with Cushing's disease. Dynamic tests of pituitary-adrenal function (dexamethasone suppression, metyrapone, CRH, and DDAVP tests) were done before and after transsphenoidal pituitary surgery. Plasma and total urinary cortisol, serum 11-deoxycortisol, and plasma ACTH were determined by RIA. Hormonal dynamic tests and radiologic studies were compatible with a pituitary ACTH source. The transsphenoidal surgery revealed the presence of corticotrope hyperplasia confirmed by immunoperoxidase stain and a preserved reticulum framework in the removed pituitary tissue of these four patients. The pituitary surgery led to a short period of improvement in two of the patients (1 and 4), a 3-yr remission in one patient (patient 2), and no improvement in one (patient 3). We conclude that although our patients appear to have inadequate suppression with high-dose dexamethasone, there is no way to diagnose this pathology presurgically, and that total hypophysectomy, bilateral adrenalectomy, and irradiation are the only alternatives for definitive treatment. A CRH-secreting ectopic tumor could not be found in our patients either before or after surgery in the follow-up period.

Corticotropin-releasing hormone test: improvement of the diagnostic accuracy of simultaneous and bilateral inferior petrosal sinus sampling in patients with Cushing syndrome

Twenty-six consecutive patients with ACTH-dependent Cushing syndrome were subjected to simultaneous, bilateral inferior petrosal sinus sampling for ACTH assay before and after ACTH-releasing hormone (CRH) stimulation. The baseline ACTH inferior petrosal sinus/periphery (IPS/P) ratio was > or = 2 in 12 of 26 patients (46%), whereas the CRH-stimulated IPS/P ratio was > or = 3 in 19 of 26 patients (73%). A pituitary adenoma, ACTH-secreting at immunostaining, was surgically proved in all of the 19 patients who had an ACTH IPS/P ratio > or = 2 basally or > or = 3 after the CRH test but also in three other patients who did not have such ratios. The value of the basal IPS/P ratio and the complete lack of ACTH increase after CRH led to the diagnosis of an ectopic ACTH syndrome in four patients: a bronchial carcinoid was found in three patients, and the site of the tumor was still unknown in the other. In conclusion, the CRH test improved the diagnostic accuracy of inferior petrosal sinus sampling from 61.5% (12 pituitary, 4 ectopic) to 92.0% (19 pituitary, 4 ectopic). Thus it should be performed during the diagnostic process.

Cushing's disease: pituitary imaging

Fourteen patients with adrenocorticotropic hormone (ACTH)-dependent hypercortisolism underwent pituitary scanning with computed axial tomography (CT) and magnetic resonance imaging (MRI). Computed tomography revealed pituitary macroadenomas in two patients, pituitary hyperplasia in one and a suspicion of pituitary microadenoma in one. Thirteen patients underwent MRI. One with a macroadenoma diagnosed on CT did not undergo MRI. The MRI revealed a pituitary macroadenoma in one, microadenoma in three and hyperplasia in two cases. Magnetic resonance imaging following gadolinium diethylene triamine penta acetic acid (gd-DTPA) enhancement revealed four more pituitary microadenomas. All patients who had pituitary adenomas (micro and macro) and hyperplasia underwent trans-sphenoidal pituitary surgery. One of the two patients, who had an enlarged pituitary on imaging but no demonstrable adenoma, was found to have a microadenoma at surgery. Patients with ACTH-dependent hypercortisolism should undergo MRI of the pituitary gland to identify/localize corticotroph pituitary adenomas. The study should include gd-DTPA enhancement in cases where the scan is normal.

Preoperative diagnostic evaluation of children with Cushing's syndrome

Recent advances in biochemical and imaging studies have improved the diagnostic accuracy of Cushing's syndrome. To better define roles for these studies in children, the authors reviewed their experience with this rare group of patients. Fifteen children, aged 11 weeks to 17 years, were treated for noniatrogenic Cushing's syndrome over a 33-year period. All children presented with signs of hypercortisolism. Nineteen different diagnostic tests were used, reflecting changes in how these patients are evaluated. Pathological diagnoses were adrenal cortical carcinoma (3), primary adrenocortical nodular dysplasia (PAND) (2), and pituitary adenoma (10). Children with adrenal cortical carcinoma presented with an adrenal mass and at a younger age (mean, 22.3 months). Key diagnostic features of patients with PAND were a low plasma adrenocorticotrophin hormone (ACTH) and no suppression with high-dose dexamethasone. Children with a pituitary cause of Cushing's syndrome presented at an older age (mean, 15.7 years) and were diagnosed using a combination of high-dose dexamethasone testing, simultaneous inferior petrosal sinus sampling, and/or ovine corticotrophin-releasing hormone stimulation test. A strategy for the diagnosis of Cushing's syndrome in children is presented.

The value of inferior petrosal sinus sampling in diagnosis and treatment of Cushing's disease

OBJECTIVE

While microsurgical selective adenomectomy is the best method available at present for the treatment of Cushing's disease, its success depends to a large degree on precise preoperative intrapituitary microadenoma localization. This study compares the results of intrapituitary adenoma localization obtained with inferior petrosal sampling, computerized tomography and magnetic resonance imaging with the adenoma localization as found at surgery.

DESIGN

The results of inferior petrosal sampling for intrapituitary localization of ACTH-producing pituitary adenomas were compared in a retrospective study with the results of computerized tomography, magnetic resonance imaging, surgical and pathological findings. Special attention was paid to the intersinus ACTH relation.

PATIENTS

Thirty-eight patients (33 women and 5 men) of 11-68 years of age suffering from pituitary-dependent Cushing's disease were studied. Patients with ectopic ACTH-secreting tumours and recurrent pituitary adenomas were excluded.

MEASUREMENTS

Blood samples were obtained simultaneously from both inferior petrosal sinuses and a peripheral vein before and 5, 10, 15 and 20 minutes after stimulation with 60 micrograms/m2 human corticotrophin-releasing hormone (hCRH).

RESULTS

Of the adenomas in our series, 42% had a diameter of 3 mm or less. Only 6 of 20 adenomas examined by computerized tomography and 11 of 29 examined by magnetic resonance imaging were identified correctly. Inferior petrosal sinus sampling produced significantly better results, particularly when combined with a stimulation test with hCRH: for 29 of 38 adenomas examined, the location was predicted correctly with these techniques. Analysis of the intersinus adrenocorticotrophin concentration ratio showed that the best right-central-left discrimination was obtained with values of 1.3 and 1.4.

CONCLUSIONS

We conclude that inferior petrosal sinus ACTH sampling after hCRH stimulation is the best method available for the intrapituitary localization of microadenomas causing Cushing's disease provided that the appropriate technique of blood sampling is used meticulously.

Morbidity and mortality in Cushing's disease: an epidemiological approach

OBJECTIVE

Although Cushing's disease is a well documented clinical entity, there is no epidemiological information about it. The present study tries to obtain this information.

DESIGN AND PATIENTS

Forty-nine patients affected by Cushing's disease living in Vizcaya (Spain) between 1975 and 1992 were considered for an epidemiological study.

RESULTS

The prevalence of known cases at the end of 1992 was 39.1 per million inhabitants. The average incidence of newly diagnosed cases was 2.4 cases per million people per year. Cushing's disease was more frequent in women (n = 46) than in men (n = 3), with a ratio of 15:1. Diabetes mellitus and hypertension were observed in 38.7 and 55.1% of patients, respectively. Remission of Cushing's disease was achieved in 36 out of 41 patients (87.5%). In general, the mortality was higher than that expected for the control population (standardized mortality ratio, SMR 3.8, 95% confidence interval, CI 2.5-17.9, P < 0.03). Concerning the cause of death, the SMR of vascular disease was 5 (95% CI 3.4-48.6, P < 0.05). Higher age, persistence of hypertension and abnormalities of glucose metabolism after treatment, were independent predictors of mortality (multivariate analyses, P < 0.01).

CONCLUSIONS

Prevalence of Cushing's disease was 39.1 cases/million inhabitants and average incidence was 2.4 cases/million per year. Mortality was elevated, due to vascular disease, associated with higher age, persistence of hypertension and impaired glucose metabolism.

Early repeat surgery for persistent Cushing's disease

The potential efficacy of early repeat transsphenoidal surgery for persistent Cushing's disease has not previously been examined. On 222 patients with no prior pituitary treatment and a preoperative diagnosis of Cushing's disease, 29 (13%) remained hypercortisolemic after an initial transsphenoidal pituitary exploration. Seventeen of these 29 patients underwent further surgery 7 to 46 days after the initial transsphenoidal approach in order to completely excise suspected residual tumor. Patients were followed for 4 to 84 months (mean +/- standard deviation, 34 +/- 25 months) to document sustained remission or recurrence of Cushing's disease (a urine free cortisol level > 90 micrograms/day was considered evidence of recurrence). Of the 17 patients with repeat surgery, 12 (71%) had resolution of hypercortisolism (morning plasma cortisol level < 5 micrograms/dl); however, in three of these 12, hypercortisolism recurred 5, 12, and 24 months later. In 14 patients a lesion that appeared to be a tumor was identified during the initial procedure or on histological examination. Of these, 12 had immediate resolution of hypercortisolism and nine are still in remission. Three patients, in whom no adenoma could be identified during the initial surgery or an examination of the partial hypophysectomy specimen from the initial surgery, had persistent Cushing's syndrome after the second operation. Seven (41%) of the 17 patients developed hypopituitarism requiring treatment with thyroid hormone, gonadal steroid, or vasopressin replacement. The low incidence of identification of an adenoma on computerized tomography or magnetic resonance images (three of 17 patients), the failure to find a corticotrophic adenoma during the initial surgery (10 of 17 patients), and the failure of these 17 patients to respond to the initial transsphenoidal surgery suggest that they may comprise a subset of patients who are more difficult to treat successfully with surgery than most patients with Cushing's disease. Despite that, early reoperation induced immediate remission of hypercortisolism in 71% of cases, but did so at the expense of a high risk of hypopituitarism. However, since the alternative treatments (such as radiation therapy, long-term drug therapy, or bilateral adrenalectomy) also have potential adverse effects, early reoperation deserves consideration for the management of persistent Cushing's disease, especially when an adrenocorticotrophic hormone-secreting adenoma was partially excised during the first surgery.

Bilateral adrenalectomy: low mortality and morbidity in Cushing's disease

OBJECTIVE

We assessed the current role of bilateral adrenalectomy in the overall management strategy of hypercortisolism.

DESIGN

Retrospective review of case notes.

PATIENTS

Twenty-six patients (20F/6M); mean age 46 years (range 15-70 years), median duration of follow-up 5.25 years (0.6-19.1 years) who had undergone bilateral adrenalectomy at the Royal Victoria Hospital since 1972. Eighteen had had prior transsphenoidal surgery which did not control the hypercortisolism.

MEASUREMENTS

Morbidity, mortality, incidence of Nelson's syndrome.

RESULTS

Surgery was performed through bilateral postero-lateral incisions (20 patients) or a long epigastric incision (six patients). The mean combined weight of the adrenals at surgery was 11.2 g. Twenty patients received subcutaneous heparin and 18 antibiotic prophylaxis peri and post-operatively. There was no operative mortality. Minor complications included one post-operative wound infection and a small pneumothorax requiring drainage. Major complications occurred in two other patients, both with pre-existing invasive pituitary tumours and considered at high risk because of age and general debility. One patient had a massive pulmonary embolus and the other a subphrenic abscess post-operatively. This latter patient, the only mortality, died from an unrelated cause three years post-operatively. Six patients have subsequently undergone pituitary surgery and three have received external pituitary irradiation therapy for expanding tumours.

CONCLUSIONS

Bilateral adrenalectomy, in experienced hands, is a relatively safe and useful management option in patients with hypercortisolism. Growth of a pituitary adenoma post-operatively is now the most worrying complication.

The radiological investigation of occult ectopic ACTH-dependent Cushing's syndrome

The radiological features of 14 patients with Cushing's syndrome due to 'occult' ectopic ACTH syndrome have been reviewed. In 11 of the 14 patients (79%), the ACTH-producing tumour was located in the thorax. Bronchial carcinoid tumours (eight patients) were the single most common source of 'occult' ectopic ACTH production with thymic carcinoid tumours (two patients) and mediastinal metastases from a medullary carcinoma of the thyroid gland (one patient) accounting for the other intrathoracic tumours. The tumours were usually small with five of the eight bronchial carcinoid tumours measuring between 4 and 10 mm in diameter. Since it remains difficult to distinguish between pituitary-dependent Cushing's disease and 'occult' ectopic ACTH-dependent Cushing's syndrome both clinically and biochemically, the role of radiology remains vital.

High prolactin levels in patients with Cushing's disease without pathological evidence of pituitary adenoma

OBJECTIVE

This study was designed to compare the clinical and biochemical features of patients with Cushing's disease without pathological evidence of pituitary adenoma (n = 11) to those in whom a pituitary ACTH adenoma was documented (n = 11).

DESIGN

The clinical and biochemical features of 11 patients with Cushing's disease without pathological evidence of pituitary adenomas were compared to 11 subjects with ACTH-secreting adenomas. The patients underwent transsphenoidal microsurgery between 1979 and 1989. During surgery, when an adenoma was not visualized, a partial hypophysectomy of the central mucoid wedge was performed.

MEASUREMENTS

Cushing's disease was established by the clinical features of hypercortisolism and the high levels of 24-hour free urinary cortisol with no suppression in response to low, but with suppression in response to high, doses of dexamethasone. Basal and post TRH-GnRH plasma prolactin, FSH and LH levels were assessed in each patient before transsphenoidal microsurgery.

RESULTS

Similar results were observed in patients with and without ACTH-secreting adenomas regarding cure rate, and free urinary cortisol levels both basal and after 2 days of dexamethasone, 8 mg daily. After surgery, plasma cortisol levels in cured patients were lower in subjects with ACTH-secreting adenomas than in those without pituitary tumours (P < 0.05). Areas under the curve of PRL (P < 0.002) and LH (P < 0.04) were significantly higher in patients without pituitary adenoma after TRH-GnRH administration. Compared to controls, the peak prolactin level after TRH-GnRH administration was higher in patients without pituitary adenoma (P < 0.005) and lower in those with ACTH adenoma (P < 0.005). Furthermore, a peak prolactin level equal to or greater than 1410 mU/l during the TRH-GnRH test was found in 11/11 patients without ACTH adenoma and 3/11 patients in the other group (P < 0.001), while the CT-scan findings were suggestive of pituitary adenoma in six patients of each group.

CONCLUSION

This study suggests that patients with Cushing's disease without pituitary adenomas can be distinguished from those with ACTH-secreting adenomas by their high prolactin levels after TRH-GnRH administration.

Investigation of Cushing's syndrome by inferior petrosal sinus sampling

Bilateral simultaneous inferior petrosal sinus sampling, in combination with CRH stimulation, is now able to confirm the diagnosis of pituitary-dependent Cushing's disease with near certainty. In expert hands, the procedure is straightforward and safe. As well as confirming the differential diagnosis, the test may aid surgical success, especially if no adenoma is apparent at transsphenoidal exploration. In this article, we review the technique and its interpretation and consider which patients should undergo the procedure.

Cutaneous markers of internal malignancy. II. Paraneoplastic dermatoses and environmental carcinogens

A variety of cutaneous disorders may reflect the presence of an internal disease. The ability to recognize those that may indicate an underlying malignancy is of particular importance. In part I of this series malignant involvement of the skin, either direct or metastatic, and the genodermatoses with malignant potential were reviewed. In this portion, we describe the paraneoplastic dermatoses as well as the cutaneous effects of some environmental carcinogens associated with internal malignancy. In addition, several uncommon and controversial associations between benign dermatoses and internal malignant disease will be discussed.

Transsphenoidal resection in Cushing's disease: undetectable serum cortisol as the definition of successful treatment

OBJECTIVE

We tested the hypothesis that in Cushing's disease, ACTH secretion from the normal pituitary surrounding an ACTH-secreting adenoma is inhibited and hence removal of the entire adenoma should result in an undetectable serum cortisol in the immediate post-operative period.

DESIGN

A retrospective study of patients undergoing transsphenoidal selective adenomectomy, hemi-hypophysectomy or total hypophysectomy for Cushing's disease at St Bartholomew's Hospital between 1985 and 1990.

PATIENTS

Forty-eight consecutive patients (33 women, mean age 43, range 7-69 years) undergoing transsphenoidal hypophysectomy for Cushing's disease. Ten patients who underwent a second operation were re-evaluated; the patients were followed for a median time of 40 months after operation (range 15-70).

MEASUREMENTS

Post-operatively, serum cortisol was measured daily at 0900 h. Serum TSH, T4, prolactin, LH, FSH, testosterone or oestradiol plus plasma and urine osmolality were measured.

RESULTS

After initial surgery, post-operative serum cortisol was undetectable (< 50 nmol/l) in 20 out of 48 patients (42%) and < 300 nmol/l in 32 out of 48 patients (67%). Re-exploration of the pituitary fossa in 10 patients found undetectable cortisol levels in 25 (52%) and levels < 300 nmol/l in 39 (81%) patients. Cushing's syndrome has not recurred, clinically or biochemically, in any patient in whom the post-operative cortisol was < 50 nmol/l. Post-operatively, hypothyroidism was present in 40% of patients and hypogonadism in 53% of men and 30% of premenopausal women. Diabetes insipidus, persisting for at least six months, occurred in 46% of patients.

CONCLUSIONS

Cushing's disease has not recurred in any patient with an undetectable serum cortisol (< 50 nmol/l) post-operatively. Serum cortisol should be regarded as a tumour marker in Cushing's disease and the aim of transsphenoidal hypophysectomy for Cushing's disease should be to render the immediate post-operative serum cortisol undetectable.

Assessment of endocrine function after transsphenoidal surgery for Cushing's disease

OBJECTIVE

We assessed the endocrine outcome after transsphenoidal surgery for Cushing's disease.

DESIGN

Five-year (mean) follow-up (range 1 month-12 years) of patients undergoing transsphenoidal surgery for Cushing's disease between 1977 and 1990; review of case notes, current clinical and biochemical assessment including 24-hour urinary free cortisol.

SETTING

Northern Ireland.

SUBJECTS

Forty-one patients (33F: 8M); mean age at diagnosis 39.1 years (9-72 years).

MAIN OUTCOME MEASURES

Measurements of early post-operative 0800 h serum cortisol and 24-hour urinary free cortisol at least 24 hours after withdrawal of oral hydrocortisone therapy. This was followed by low dose dexamethasone testing. Current 24-hour urinary free cortisol measurements. Retrospective definition of cure.

RESULTS

Twenty-seven patients were either cured or improved by surgery, 14 were considered definite failures. Of 19 patients cured, eight had unmeasurable early post-operative 0800 h serum cortisol levels while of 15 tested, 13 had complete suppression with dexamethasone and two suppressed normally but to still measurable levels (39 and 60 nmol/l respectively). Seventeen patients in total have subsequently had bilateral adrenalectomy of whom two have developed Nelson's syndrome. Seven of the 41 patients were shown to have definite cyclical cortisol secretion first diagnosed post-operatively in three patients. Hormone deficiency included TSH (5), LH/FSH (1), cortisol (1) and ADH (temporary in 7, permanent in 1). In all, seven patients had some type of permanent hormonal deficiency post-operatively.

CONCLUSIONS

Transsphenoidal surgery offers a worthwhile cure rate without the necessity of life-long endocrine therapy. Post-operative endocrine assessment must be rigorous so that early further management can be planned in the significant percentage of patients in whom cure is not achieved. Early complete suppression on low dose dexamethasone testing is very suggestive of cure but repeated and long-term monitoring of 24-hour urinary free cortisol is advisable.

Failure of total hypophysectomy to remove intrasellar microadenoma in cushing's disease

The pathological findings are described of a female patient with persistent Cushing's disease after two unsuccessful transsphenoidal operations: a left transsphenoidal hemihypophysectomy followed by a total hypophysectomy 1 month later. The patient was finally cured by bilateral adrenalectomy but suddenly died of heart failure 4 months later. Postmortem examination did not show invasive ACTH-secreting tissue in the pituitary region or an ectopic ACTH-secreting tumor, as initially presumed. Instead, a very small corticotroph adenoma was located immediately under the diaphragm sellae at the left side. The reasons for surgical failure in Cushing's disease are discussed. As in our patient, a missed small intrasellar adenoma must not be excluded when "total" hypophysectomy fails to cure Cushing's disease.

Pituitary histology in Cushing's disease

OBJECTIVE

We assessed pituitary histology in patients with Cushing's disease.

DESIGN

Systematic histological assessment of pituitary tissue removed at surgery.

PATIENTS

Thirty-six consecutive patients cured from Cushing's disease by transsphenoidal neurosurgery.

MEASUREMENTS

Microscopical examination of all available tissue removed at operation.

RESULTS

After selective removal of tissue supposed to represent an adenoma in 25 patients this could be histologically verified in 18. In the 11 patients who had undergone a total hypophysectomy an adenoma could be demonstrated in three patients only, despite a systematic search of the entire pituitary gland. Only in 21 of the 36 cured patients (58%) could an adenoma be verified.

CONCLUSIONS

Combining the present results with previous reports there is strong reason to believe that in some patients with Cushing's disease no histological lesion in the pituitary is verifiable.

Hypothalamic abnormalities in patients with pituitary-dependent Cushing's syndrome

OBJECTIVE

We aimed to investigate the pattern of 24-hour ACTH and cortisol secretion in pituitary-dependent Cushing's syndrome and to evaluate the pituitary and hypothalamic contributions to the disease.

PATIENTS

Five women with Cushing's disease (mean age 35 +/- 5 (SEM) years) and five normal female controls (mean age 25 +/- 2 years) were studied.

DESIGN AND MEASUREMENTS

Plasma ACTH and cortisol levels were measured every 15 minutes for 24 hours using established IRMA and RIA respectively. ACTH and cortisol mean and trough levels, pulse number and amplitude were calculated using established computer software, programmed to identify ACTH and cortisol peaks.

RESULTS

Patients with Cushing's disease had a twofold increase in 24-hour mean cortisol levels and a threefold increase in 24-hour mean ACTH levels (Cushing's 5.9 +/- 1.0, controls 1.9 +/- 0.2 pmol/l, P less than 0.01). This was predominantly mediated by an increase in ACTH pulse amplitude. However, 24-hour ACTH pulse number was also increased (Cushing's 15.2 +/- 2.6, controls 10.6 +/- 1.7, P less than 0.05) due to an increase in pulse number between 1800 and 2400 h. ACTH trough levels were also higher in patients with Cushing's disease (Cushing's 5.3 +/- 1.3, controls 2.3 +/- 0.2 pmol/l, P less than 0.05).

CONCLUSIONS

Twenty-four-hour mean plasma cortisol and ACTH levels are elevated two to three-fold in patients with Cushing's disease. The increase in ACTH pulse amplitude suggests a pituitary abnormality in patients with Cushing's disease. However, the increased ACTH pulse frequency together with elevated trough levels is interpreted as indicating coexisting hypothalamic stimulation (or loss of inhibition).

Neurosurgeons and ideas before their time

As a complementary inquiry to previous studies on citation analysis in neurosurgery, a group of ideas before their time has been arbitrarily selected by the author from 3792 first-authored papers written between 1897 and 1980 by 50 of the first American neurosurgeons. There were eight neurosurgeons who proposed 12 original theories or procedures whose importance was not recognized at the time of publication. Although the value of these ideas was not initially judged to be significant, these concepts became a part of the intellectual consensus of neurosurgery or related disciplines after varying periods of time. Technical constraints constituted the most important reason for delayed recognition of these innovative and creative ideas. Other factors were an unsuitable medium of communication, fixed scientific attitudes, prestige of previous authors, incomplete literature review by later authors, and a failure to verify observations by other investigators. The question is raised as to whether these factors might continue to affect present and future clinical investigation and laboratory research in neurosurgery.

Recurrent Cushing's disease with low adrenal androgen production

A 33 year old woman presented with recurrent Cushing's disease 4 years after complete remission induced by pituitary surgery. On relapse she exhibited the unusual pattern of elevated indices of cortisol secretion with markedly suppressed serum DHEA-S; urinary 17-ketosteroid excretion was also below the normal range. Biochemical testing was otherwise consistent with ACTH-mediated hypercortisolism, and adrenal histopathology showed bilateral hyperplasia with no evidence of tumor. This case illustrates that serum DHEA-S is not an infallible guide to the differential diagnosis of Cushing's syndrome, and it supports the existence of a pituitary-secreted adrenal androgen stimulating factor that is distinct from ACTH.

Complications of the transsphenoidal approach to sellar lesions

Transsphenoidal surgery is currently performed extensively for lesions of the sella turcica. The mortality and morbidity of this surgical approach are minimal, and the results satisfactory overall. Only a few studies have addressed the complications of this approach. The authors present a retrospective study of 200 transsphenoidal procedures in 196 patients over an eleven year period. There was one death due to meningitis. Major morbidity consisted of intraventricular hemorrhage in three patients, false aneurysm of the internal carotid artery in one patient and thalamic infarction in another patient. Minor morbidity details are presented. The pathogenesis of the most serious of these complications along with possible preventive measures are discussed.

Transnasal microsurgery of Cushing's disease 1990. Overview including personal experiences with 256 patients

The current concepts of differential diagnosis and therapy of Cushing's disease are reviewed. Our own results in a recent series of 103 patients are compared with patients treated by transsphenoidal microsurgery until 1986. In 97% as compared to 91% of prior series a discrete adenoma was found and selective adenomectomy led to remission in about 90%. The endocrine tests alone proved to be highly reliable to discriminate pituitary-dependent Cushing's disease from other forms of Cushing's syndrome. All our 3 patients without pituitary adenoma had some atypical endocrine tests. From these findings and results of other published series invasive investigations as inferior petrosal venous sampling may be reserved for equivocal cases. Magnetic resonance imaging now reveals two thirds of the micro-adenomas and provides the surgeon with excellent anatomical pictures. Rapid intraoperative measurement of peripituitary venous ACTH gradients may help to identify occult adenomas. In spite of different modes of therapy as pharmacological suppression of the adrenals and more sophisticated forms of radiotherapy, transsphenoidal microadenomectomy in experienced hands remains the most effective and the only immediately definite treatment of Cushing's disease.

The Cushing syndromes

The 10 years since this journal's last review of CS have seen extraordinary advances in our understanding of many aspects of its causes, diagnosis, and treatment. The spectrum of what are now called the Cushing syndromes has expanded considerably to include CD, multiple sources of ectopic ACTH secretion, and an apparent autoimmune cause. Improved assays of ACTH and the availability of CRF have provided new insight into the physiology and pathophysiology of the HPA axis and new tools for diagnosis of CS, especially in combination with selective catheterization and sampling. New imaging technology has improved our visualization of pituitary adenomas and has provided powerful methods for identifying tumors ectopically secreting ACTH and primary adrenal tumors. Finally, the refinement of transsphenoidal surgery and its success in treating CD have provided a safe and effective therapy for this disease. For those occasional patients who require medical therapy, drugs are available that decrease steroid biosynthesis. We now have a much better understanding of a fascinating disease process and are able to diagnose and treat it more correctly. One is impatient to see which new pieces of this puzzle will fall into place over the next ten years.

An overview of bilateral synchronous inferior petrosal sinus sampling (BSIPSS) in the pre-operative assessment of Cushing's disease

This study examines the role of bilateral synchronous inferior petrosal sinus sampling (BSIPSS) in resolving two major issues in the pre-operative assessment of Cushing's disease, namely proof of pituitary dependent disease and accurate lateralisation of tumour within the pituitary. BSIPSS was technically successful in 16 of 20 patients. The central to peripheral ACTH gradients, supporting the diagnosis of pituitary dependent disease, was greater than 2.0 (2.0-27.2) in all patients with histologically proven ACTH-secreting pituitary tumours and in those who remained in remission following pituitary surgery. In addition, BSIPSS accurately localised the site of the tumour within the pituitary in 13 of the 16 technically satisfactory studies and thus contributed to the outcome of surgical treatment. In contrast CT scan demonstrated a definite tumour in only two patients.

Transsphenoidal surgery for Cushing's disease: does what is removed determine the endocrine outcome?

Fifty-seven patients with pituitary-dependent Cushing's syndrome and eight with Nelson's syndrome underwent transsphenoidal pituitary exploration, with removal of macroscopically abnormal tissue in 64 patients and detailed histology of this in 63. The cure rate by stringent criteria 1 month later was 48 (83%) of the 58 with assessable data, who were followed for 225 patient-years. Two patients relapsed later, a rate of one per 112 patient-years of follow-up. In 27% of patients, the macroscopically abnormal tissue removed was histologically indistinguishable from normal pituitary gland but the cure rate was 82%, and a quarter of the patients in this group assessable for recovery of normal ACTH function gained it. Another 53% of biopsies showed corticotroph adenomas, and the cure rate in these was 89% though rather more (69%) recovered normal ACTH function. The remaining 20% of biopsies were consistent with corticotroph hyperplasia. The cure rate varied little whether the lesion was diffuse or localized, whether or not it was in the invasion zone/interlobar cleft, whether or not there was pituitary enlargement, or whether the surgery was radical or selective. Six patients, of whom three are cured, showed surgical or radiological evidence of invasion outside the pituitary fossa. The data are consistent with the idea that pituitary adenoma is merely the end stage of some other process in the corticotrophs, and cure often follows removal of a lesion other than adenoma. Of patients who were permanently cured, 47% regained normal ACTH function within 3 years of operation (none later), 53% remaining ACTH-deficient at 3 years or more. Of all patients 48% acquired gonadotrophin deficiency, 28% have TSH deficiency and 25% permanent diabetes insipidus. All these pituitary function deficits were more common after radical surgery and in patients with normal histology, The literature contains so little objective data on these functions that we cannot say whether the endocrine damage in our patients is exceptional or not.

Cushing's disease: results of transsphenoidal microsurgery with emphasis on surgical failures

From 1977 to 1988, 56 patients with a preoperative diagnosis of Cushing's disease were treated by transsphenoidal microsurgical exploration of the pituitary gland. In 42 patients, a discrete tumor was found and a selective adenomectomy was performed. Total hypophysectomy was performed in nine patients. In an attempt to preserve pituitary function, a technique of subtotal hypophysectomy was utilized in the remaining five patients. Regular and adequate follow-up results were obtained in 53 patients. A sustained remission was obtained in 45 of these 53 patients for a remission rate of 84.9%. Eight patients were classified as therapeutic failures. The causes for failure included: 1) invasive tumor; 2) hyperplasia mistaken for an adenoma; 3) a presumed ectopic source of adrenocorticotropic hormone; 4) misdiagnosis; 5) atypical tumor; and 6) recurrence of disease after remission. In cases of therapeutic failure, the original diagnosis of Cushing's disease must be reevaluated and treatment continued until sustained remission is achieved. Necessary measures to help avoid surgical failures and an approach for further diagnostic and therapeutic maneuvers in these cases are discussed.

Comparison of long term results between prolactin secreting adenomas and ACTH secreting adenomas

A series of 100 prolactin secreting pituitary adenomas was reviewed and demonstrated an early cure rate of 85.2% with a cure rate of 89% if prolactin was less than 200 ng/ml. For macroadenomas the cure rate was 50% giving an overall cure rate of 71% for the entire group. When long term (greater than 5 years) followup was obtained a 17% incidence of recurrence was noted for the microadenoma group with a 20% recurrence rate for the macroadenoma group. Secretory dynamic studies were done shortly after surgery and then after a delay. Many showed a return to normal prolactin secretory dynamic suggesting that the underlying hypothalamic regulation is normal in most patients. Abnormal secretory dynamics at 6 weeks post operative testing were not predictive of which patients would relapse as many patients who had abnormal dynamics early did not relapse even during prolonged followup. Conversely a normal response to provocative testing did not preclude late relapse. A similar series of 40 consecutive patients with Cushing's disease was reviewed. Tumor was found in all but three cases. 84% of patients were cured and thus far only one patient (2.5%) has shown late recurrence with this occurring at 6 2/3 years following surgery with normal stimulatory dynamics present for five years. The implication is that hypothalamic regulation is normal in Cushing's disease as well. The differences in recurrence rates may be reflective of the aggressiveness with which one disease is treated, with the acceptance of a higher incidence of hypopituitarism as a consequence of more radical surgery for Cushing's disease.

Repeat transsphenoidal surgery for Cushing's disease

Transsphenoidal resection of adrenocorticotrophic hormone (ACTH)-producing pituitary adenomas has the potential of curing most patients with Cushing's disease. However, transsphenoidal exploration of the pituitary is not always curative, and patients who have remission of hypercortisolism following surgery occasionally develop a recurrence. Whether repeat pituitary surgery should be performed for recurrent or persistent Cushing's disease has not been evaluated previously. To determine the efficacy of transsphenoidal surgery in recurrent or persistent Cushing's disease, we performed transsphenoidal surgery in 31 patients (22 women and nine men) who had previously undergone a transsphenoidal operation and two female patients who had had previous pituitary irradiation only. In 24 (73%) of the 33 patients, remission of hypercortisolism was achieved by surgery. Although preoperative computerized tomography (CT) scanning identified an adenoma in only three of the 33 patients, in 20 patients a discrete adenoma was identified at pituitary exploration. The incidence of hypercortisolism was greatest if an adenoma was identified at surgery and the patient received selective adenomectomy (19, or 95% of 20 patients), if there was evidence at surgery or by preoperative CT scanning that the previous surgical exposure of the pituitary was incomplete (seven, or 78% of nine patients), if an adenoma was seen on preoperative CT scanning (three of three patients), or if the patient had had prior pituitary irradiation without surgery (two of two patients). In contrast, only five (42%) of 12 patients who received subtotal or total hypophysectomy had remission of hypercortisolim. Surgically induced hypopituitarism occurred in six (50%) of these 12 patients, but in only one (5%) of the 20 patients who underwent selective adenomectomy. Three (13%) of the 24 patients who were in remission from hypercortisolims following repeat surgery developed recurrent hypercortisolism 10 to 47 months postoperatively. Repeat transsphenoidal exploration of the pituitary and treatment limited to selective adenomectomy should be considered in patients with hypercortisolism despite previous pituitary treatment. If an adenoma is identified during surgery, the chance of remission of Cushing's disease is high and the risk of hypopituitarism is low; however, if no adenoma can be found and partial or complete hypophysectomy is performed, remission of hypercortisolism is less likely and the risk of hypopituitarism is about 50%.