Long term results of radical hypophysectomy for Cushing's disease

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.

Transsphenoidal surgery for Cushing's disease: a review of success rates, remission predictors, management of failed surgery, and Nelson's Syndrome

Cushing's disease is a serious endocrinopathy that, if left untreated, is associated with significant morbidity and mortality rates. After diagnostic confirmation of Cushing's disease has been made, transsphenoidal adenomectomy is the treatment of choice. When a transsphenoidal adenomectomy is performed at experienced transsphenoidal surgery centers, long-term remission rates average 80% overall, surgical morbidity is low, and the mortality rate is typically less than 1%. In patients with well-defined noninvasive microadenomas, the long-term remission rate averages 90%. For patients in whom primary surgery fails, treatment options such as bilateral adrenalectomy, stereotactic radiotherapy or radiosurgery, total hypophysectomy, or adrenolytic medical therapy need to be carefully considered, ideally in a multidisciplinary setting. The management of Nelson's Syndrome often requires both transsphenoidal surgery and radio-therapy to gain disease control.

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.

A study of patients with Nelson's syndrome

OBJECTIVE

The prevalence of Nelson's syndrome has varied greatly, at least in part because of the variability of the diagnostic criteria employed by different authors. We define Nelson's syndrome as the presence of an enlarging pituitary tumour associated with elevated fasting plasma ACTH levels and hyperpigmentation in patients with Cushing's disease after bilateral adrenalectomy. We have compared patients with Cushing's disease who developed Nelson's syndrome after bilateral adrenalectomy with those who did not. Our objective was to find differences between the two groups which might predict the development of Nelson's syndrome.

PATIENTS AND METHODS

We have reviewed the records of 30 patients with Cushing's disease after adrenalectomy, and divided them into two groups; I: 14 who developed Nelson's syndrome and II, 16 who did not. The two groups of patients were compared in their clinical, laboratory and imaging data as well as in the therapeutic procedures that preceded the adrenalectomy.

RESULTS

The comparison between the two groups of patients demonstrated a highly significant difference in relation to the development of cutaneous hyperpigmentation (100% in group I and 19% in group II) and neuro-ophthalmological symptoms (21% in group I and 0% in group II) after adrenalectomy. There were no significant differences in laboratory data before adrenalectomy. After adrenalectomy, plasma ACTH levels increased significantly in the patients of both groups, but to much higher levels in those who developed Nelson's syndrome. Plasma ACTH concentrations above 154 pmol/l occurred only in the subjects with Nelson's syndrome. Before adrenalectomy, a pituitary tumour was more frequent in the patients who developed Nelson's syndrome (55% vs. 33% at transsphenoidal pituitary exploration). Pituitary surgery and irradiation were undertaken before adrenalectomy in approximately equal numbers of patients in each group.

DISCUSSION

The prevalence of Nelson's syndrome was 47% in our series of 30 patients with Cushing's disease after bilateral adrenalectomy. No clinical or laboratory data before adrenalectomy predicted the development of the syndrome. The value of prophylactic pituitary irradiation could not be evaluated from our clinical material. However, after adrenalectomy, the presence of hyperpigmentation and ACTH levels above 154 pmol/l had positive predictive value for the development of Nelson's syndrome. In this situation magnetic resonance imaging (MRI) of the pituitary is mandatory and, if no tumour is detected, MRI should be repeated at intervals.

Transsphenoidal adenomectomy in Cushing's disease via a lateral rhinotomy approach

BACKGROUND

Cushing's disease may be treated by surgical pituitary adenomectomy. We present a surgical approach to the pituitary gland that increases the possibilities of a selective adenomectomy, and compare our results with those of other studies.

METHODS

A retrospective study of patients with Cushing's disease undergoing transsphenoidal selective adenomectomy via a lateral rhinotomy at Sahlgrenska University Hospital from 1984-93 is presented. Thirty-one patients (26 women, five men; mean age: 44 years, range: 13-75 years) with Cushing's disease were followed for a median time of 4.5 years after operation (range: 1-10 years). Preoperative and postoperative urinary and serum cortisol, and circadian rhythm of serum cortisol were measured. We also measured serum TSH, T4, PRL, FSH, LH, and testosterone as well as urine and plasma osmolality.

RESULTS

Our remission rate was 77% and the recurrence rate 3%. Hormonal insufficiency was rare. Hypothyroidism and hypogonadism were present in 3% of the patients, and diabetes insipidus occurred in 6% of the patients.

CONCLUSION

Selective adenomectomy with its good opportunities for cure and improvement should be regarded as the treatment of choice for Cushing's disease. Using the lateral rhinotomy approach to the sphenoidal cavity results in good accessibility to the sella turcica and its pituitary adenomas, a low frequency of postoperative pituitary insufficiency, and a high remission rate.

Intermittent Hypercortisolism: A Disorder Strikingly Prevalent After Hypophysial Surgical Procedures

OBJECTIVE

To determine the frequency of intermittent hypercortisolism in a consecutive series of patients with Cushing's disease who underwent hypophysial surgical treatment.

METHODS

Thirty-three patients with hypercortisolism of central origin underwent follow-up at approximately annual intervals for prolonged periods after a transsphenoidal pituitary surgical procedure. Clinical evaluation was done, and urinary steroid measurements, as well as dexamethasone suppression tests in some patients, were performed.

RESULTS

Frequently normal but intermittently increased urinary 17-hydroxycorticosteroid or cortisol excretion (or both) was found in six patients postoperatively, associated with intermittently severe hypertension, headaches, and weakness in only one patient. In a seventh patient, intermittently excessive cortisol excretion was clearly evident preoperatively.

CONCLUSION

Because corticoid excretion was variable preoperatively in three of the seven study patients, we conclude that intermittent hypercortisolism is commoner than previous evidence has shown, constitutes an extremely difficult diagnostic problem, and did not result from but failed to be cured by pituitary surgical treatment in 6 of 33 patients (18%). The findings emphasize the need for regular follow-up for several years in all patients with Cushing's syndrome who have undergone a hypophysial surgical procedure. Variable consistency of follow-up might partly explain the wide discrepancies between reports of 80 to 90% and 40 to 60% cure rates after a single hypophysial adenomectomy.

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.

Treatment of Cushing's disease by transsphenoidal, pituitary microsurgery: prognosis factors and long-term follow-up

Transsphenoidal pituitary microsurgery is considered as the best treatment of Cushing's disease. However, some recent studies reported disappointing results, leading their authors to suggest the possibility of returning to a first line adrenalectomy treatment. The aim of this study was to evaluate long-term results of transsphenoidal surgery in Cushing's disease, with special interest in factors that could affect the surgical outcome on the one hand and particular attention to surgical endocrine effects on the other. Fifty consecutive patients (34 females, 16 males, mean age 29.64 +/- 1.52 yr) were studied. The median post-operative follow-up was 71.5 months (range 25-219). Clinical, biological, surgical and pathological data between the success and failure groups were compared. Criteria of cure were: normal urinary free cortisol excretion, circadian cortisol rhythm and low dose dexamethasone test. Recovery of corticotroph and somatotroph functions were followed using the insulin test. Particular attention is given to clinical evolution in evaluating other pituitary functions. T4 or FT4, prolactin, E2 in women, testosterone in men, were measured. TRH and LHRH tests were not systematically performed. Only two parameters differed significantly between the cured and failure groups: the size of the adenomas was smaller and the pathological confirmation of the adenoma more frequent in the cured group. One patient had permanent corticotropic failure while two other had impaired response to hypoglycemia with normal cortisol basal levels. No acquired hypothyroidism nor hypogonadism were observed except in a patient who underwent two operations and radiotherapy. Recovery of GH function was slow. Definitive short stature was observed in all the patients whose disease began before the age of 16. Two patients had permanent diabetes insipidus. In conclusion, the most favorable prognosis in transsphenoidal surgery for Cushing's disease is observed in case of microadenoma confirmed by pathological examination. With this treatment, we obtained satisfactory results in Cushing's disease with minimal complications and no necessity of life-long endocrine substitutive therapy.

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.

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.

Endocrine function in patients with Cushing's disease before and after treatment

OBJECTIVE

To estimate the value of some commonly used tests in diagnosing Cushing's disease and to assess the outcome after treatment.

DESIGN

Follow-up of a consecutive group of patients for 4.1 to 109.6 months, median 34.4.

PATIENTS

Forty-six patients assumed to have ACTH dependent hypercorticism (of 50 patients with Cushing's syndrome) were included. Forty-five underwent transsphenoidal neurosurgery. Ten were treated preoperatively with radiotherapy.

MEASUREMENTS

Pituitary, adrenal, thyroid and gonadal function, radiology and pituitary histology were evaluated.

RESULTS

One main finding was a significant correlation between the urinary excretion of cortisol before and during administration of dexamethasone. Thus patients with modestly elevated urinary cortisol excretion had an apparently normal suppression. The urinary cortisol values during the dexamethasone test were significantly related to the peak plasma cortisol concentrations at the 30-minute ACTH tests. Computed tomography failed to identify an adenoma in 10 of the 19 patients who were histologically proved to harbour a corticotroph adenoma. At 6 months after radiotherapy, clinical and biochemical improvement was noted in none. Cure was achieved in 36 after neurosurgery. Eventually, adrenalectomy was needed in eight patients. Sixteen patients developed persisting adrenal insufficiency after neurosurgery so that the total number of patients on permanent steroid substitution was 24. Post-operative thyroid and gonadal insufficiency (in men and women of fertile age) was found in 36 and 49%, respectively.

CONCLUSIONS

The diagnostic value of measuring the cortisol excretion during dexamethasone administration appears doubtful. The outcome after neurosurgical treatment for Cushing's disease is not entirely satisfactory. Further studies are needed to decide whether adrenalectomy as the first line of therapy should be considered relevant in some patients with Cushing's disease.

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.

Long-term follow-up of low-dose external pituitary irradiation for Cushing's disease

Twenty-four patients (three male) with Cushing's disease, aged between 11 and 67 years, were treated with low-dose external pituitary irradiation (20 Gy in eight fractions over 10-12 days) and followed for between 13 and 171 months (median 93 months). Eleven patients (46%) went into remission 4-36 months after irradiation, but five subsequently relapsed. Two of these received no further active treatment, one underwent successful pituitary surgery, one underwent a second course of low-dose external irradiation (as yet unsuccessful) and one has been treated with metyrapone for a total of 75 months. One of the 13 patients who did not respond received a further course of low-dose pituitary irradiation with prompt remission and two have received metyrapone for 41 months and 15 years without ill effect. One patient died from cerebrovascular disease. The remaining nine patients underwent bilateral adrenalectomy (one after unsuccessful pituitary surgery) with rapid resolution of hypercortisolism. Five of these patients have developed hyperpigmentation and elevated ACTH levels (range 505-1150 ng/l). A pituitary microadenoma has been demonstrated on CT scan in three and successfully removed by microadenomectomy. In the present series, the low incidence of radiation-induced hypopituitarism and absence of other complications attributable to radiotherapy suggest that low-dose pituitary irradiation may be a useful treatment option in selected patients. However, long-term follow-up has demonstrated a high relapse rate and failure to prevent Nelson's syndrome in adrenalectomized patients, indicating that it should not be used as primary treatment in preference to selective adenomectomy.

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.

Adrenal autotransplantation with attached blood vessels for treatment of Cushing's disease

A case of Cushing's disease was treated successfully by staged total adrenalectomy, left adrenal autotransplantation with the attached blood vessels and pituitary irradiation. In the first stage the left adrenal gland was removed with its attached blood vessels intact, and adrenal autotransplantation then was performed. An end-to-end anastomosis was made between the adrenal central vein and the right inferior epigastric artery. The anastomosis between the right saphenous vein and the adrenal middle artery was accomplished by intussuscepting the artery into the vein followed by suturing. The second stage operation was total right adrenalectomy. Steroid replacement therapy was stopped 7 days postoperatively and all laboratory studies were normal. Two months after total right adrenalectomy the patient had a sensation of facial fullness. Plasma cortisol and 24-hour urinary 17-hydroxycorticosteroid levels were elevated. Part of the graft was excised with the patient under local anesthesia. The symptoms disappeared and the laboratory studies returned to normal. Pituitary irradiation was administered as supplementary treatment of Cushing's disease. This method for the treatment of Cushing's disease has proved feasible. The inguinal region is the optimal site for adrenal autotransplantation.

The management of pituitary tumours and post-operative visual deterioration

The indications and results of transsphenoidal surgery for pituitary adenomas are analysed. The advantages and disadvantages of Bromocriptine and radiotherapy are considered. Transsphenoidal surgery does not damage pre-existing pituitary function. It produces excellent results in micro and mesoadenomas, curing about 70-80% of patients irrespective whether the tumour produces ACTH, prolactin or growth hormone. Moreover there is a very small relapse rate. Macroadenomas of non-functioning type are also well treated by transphenoidal surgery, with a small recurrence rate as judged by CT scan follow-up. But macroadenomas secreting prolactin or growth hormone are less effectively treated by transsphenoidal surgery, only about 40% being cured. Invasive macro prolactinomas are not helped by surgery and should be treated with Bromocriptine and radiotherapy. Radiotherapy should be used sparingly and has inevitable complications. Post-operative delayed visual deterioration is caused either by recurrent tumour or radiotherapy. There is no good evidence to support the secondary empty sella syndrome as a cause of such delayed visual deterioration.

Pituitary gland

This review summarizes current knowledge on pathology of proliferative lesions of the human pituitary. The morphologic classification of pituitary adenomas--based on histology, immunohistochemistry and electron microscopy--has now been firmly established. It has been conclusively proven that all presently recognized adenohypophysial cell types give rise to adenoma and all known pituitary hormones may be secreted in excess. Evidence is accumulating that hyperplasia of various adenohypophysial cell types can lead to hypersecretory syndromes similar to those associated with the corresponding adenomas. Owing to the rarity of studies on pituitary hyperplasia, the condition is still incompletely defined. The difficulties regarding morphologic diagnosis of pituitary hyperplasia are discussed. Despite major advances in the field of pituitary pathology, several problems concerning structure-function relationship, as well as pathogenesis of proliferative lesions are still unresolved. There is strong circumstantial evidence suggesting that the cytological mapping of the pituitary is incomplete and there are still cell types waiting to be discovered.

Treating Cushing's disease

Images

The definition of true recurrence of pituitary-dependent Cushing's syndrome after transsphenoidal operation

Two patients are described with pituitary-dependent Cushing's syndrome who had successful transsphenoidal selective removal of basophil microadenomas. After a period of adrenal insufficiency the clinical signs and the cortisol secretion rate became normal after 12-18 months, together with the return of a normal feedback response to glucocorticoids (dexamethasone suppression), a normal diurnal rhythm of plasma cortisol, and a normal response to stress (increase of plasma cortisol to insulin-induced hypoglycaemia). However, pituitary-dependent Cushing's syndrome recurred 38 and 56 months after operation. This was preceded by gradual changes of the results of the dexamethasone tests, disappearance of the diurnal rhythm of cortisol, and of the responses of plasma cortisol to hypoglycaemia. 'True recurrence' should be defined as the return of the clinical and biochemical characteristics of Cushing's syndrome after a successful transsphenoidal operation, with a normal hypothalamic-pituitary-adrenal axis as evidenced by a normal response to dexamethasone, a normal diurnal rhythm of cortisol and a normal increase of plasma cortisol with insulin-induced hypoglycaemia.

Diagnosis, treatment and postoperative results of Cushing's disease

One hundred patients with Cushing's disease were operated on in Nagoya University Hospital between January 1977 and January 1984. Pituitary adenomas were found and resected in 93 cases and complete clinical remissions were observed in 89 treated by operation alone and in two additional cases by operation followed with radiotherapy. The clinical features, pre-operative endocrine data, radiological findings including high resolution CT with coronal and sagittal reconstructions, data of selective venous sampling, operative findings, tumour pathology, postoperative clinical course, postoperative endocrine results and follow-up findings are presented and discussed.

Long-term follow up of trans-sphenoidal hypophysectomy for Cushing's disease

Fourteen patients with Cushing's disease treated by trans-sphenoidal hypophysectomy between 1962 and 1975 were reviewed in 1983. Complete ablation had been attempted. There were no surgical deaths and one episode of bacterial meningitis. Two patients required a second operation for a cerebrospinal fluid leak. There have been three late deaths from unrelated causes. All patients had a biochemical remission of their Cushing's disease postoperatively and no relapse has been recorded. Most patients need some hormone replacement but residual pituitary function and sella radiography have remained stable. This treatment seems satisfactory and the evidence implies a pituitary aetiology of the syndrome.

Transsphenoidal microsurgery for Cushing's disease

Nineteen patients thought to have Cushing's disease were treated by transsphenoidal microsurgery; the type of operation performed depended upon the findings in the individual patient. Seventeen patients remitted. Failures occurred in a patient with an invasive macroadenoma and in a patient who was subsequently found to have a thymic carcinoid tumour secreting ACTH. One patient who remitted suffered a recurrence during pregnancy, 30 months after operation. The ten patients (Group I) who had a selective removal of a microadenoma or a limited resection of the gland were often GH deficient, but seven regained cortisol reserve and all ten regained normal pituitary-thyroid and pituitary-gonadal responses. By contrast abnormalities of pituitary function were common in nine patients who had a radical or total hypophysectomy. We conclude that transsphenoidal microsurgery is the best treatment for Cushing's disease and that, when feasible, a selective microadenomectomy is the most appropriate operation.

Treatment of Cushing's disease with low dose radiation therapy

Nineteen patients with Cushing's disease were treated with low dose external pituitary irradiation (20 Gy (2000 rad) in eight fractions over 10 days). While awaiting the effects of pituitary irradiation all patients were treated with metyrapone. Seven patients had a complete remission of their disease within six to 12 months of irradiation. They did not require any further treatment and were followed up for a mean of three and a half (range one to eight) years. Another patient had a complete remission after a second course of pituitary irradiation. A further two patients showed a significant biochemical improvement after irradiation, although they were not rendered eucorticoid. There were no complications after this dose of irradiation. These results compare favourably with those reported after pituitary irradiation at conventional doses (40-50 Gy (4000-5000 rad) over four or five weeks) but were not associated with any complications. It is therefore recommended that low dose external pituitary irradiation be used as definitive first line treatment for Cushing's disease.