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[Incidence and clinical manifestation of ACTH-producing pituitary adenoma after bilateral adrenalectomy for Cushing's syndrome (Nelson syndrome)].

29 out of 39 patients bilaterally adrenalectomized for pituitary-dependent Cushing's syndrome between 1958 and 1979 have been followed up at regular intervals. ACTH-producing pituitary adenomas were detected and removed in 9 of them up to 1981. In 4 additional patients an enlarged sella turcica was already found at the time they had Cushing's syndrome, and therefore they were first treated by pituitary surgery or radiotherapy. In the adrenalectomized patients hyperpigmentation was the major clinical symptoms of the adenoma. Only in three instances did extrasellar growth of the adenoma cause ophthalmoplegia or narrowing of the visual fields. The existence of intrasellar ACTH-producing microadenomas in 5 additional patients seems highly probable in view of hyperpigmentation, excessively elevated plasma ACTH concentrations and radiological evidence of sella deformations. These observations indicate that in patients adrenalectomized for pituitary-dependent Cushing's syndrome ACTH-producing adenomas are more common than previously assumed. Moreover, according to recent reports, ACTH-producing microadenomas are frequently found in pituitary-dependent Cushing's syndrome and are assumed by many clinical endocrinologists to be the primary cause of this disease. Therefore, bilateral adrenalectomy is no longer the undisputed therapy of first choice and it is necessary in each individual case to consider carefully whether an attempt to remove selectively an ACTH-producing pituitary adenoma by microsurgery might not be preferable.

ACTH Syndrome, Ectopic↗

[Case of Nelson syndrome].

A clinical description of Nelson syndrome developing in a woman of 44 is presented. Histologically the tumour of the hypophysis was an adenoma of mixed structure, electron microscopically it was found to consist of corticotropocytes in various stages of the secretory cycle. Adenoma of the hypophysis was diagnosed 4 years after bilateral adrenalectomy.

Adult↗

[A comparison of the value of magnetic resonance tomography and computed tomography in Nelson syndrome patients].

The hypophyses of 13 patients with Nelson syndrome following bilateral adrenalectomy were examined by MRI and CT. Diffuse enlargement of the hypophysis was demonstrated in 8 patients by CT and in 9 by MRI. Compared with CT, MRI provides better demonstration of tumour development, such as abnormal convexity of the cranial margin of the hypophysis (MRI 4/13, CT 1/13), displacement of the infundibulum (MRI 4/13, CT 0/13) or optic chiasm (MRI 2/13, CT 0/13). MRI also provides diagnostically important differentiation between scar tissue and recurrence of tumour following hypophysectomy (MRI 1/3, CT 0/3) and more accurate demonstration of infiltration of the cavernous sinus (MRI 4/13, CT 2/13). CT is superior only in showing the floor of the sella. MRI is the method of choice for imaging in cases of Nelson syndrome.

Adrenalectomy↗

Early diagnosis of Nelson's syndrome.

Nelson's syndrome is a specific form of Cushing's disease treated by bilateral adrenalectomy, presenting with a deep hyperpigmentation caused by a pituitary adenoma (corticotropinoma). These ACTH-secreting tumors are frequently aggressive, so early diagnosis is of prime importance. We have studied 33 patients with Nelson's syndrome, 28 women and 5 men, aged 14-56 yr at the time of adrenalectomy and 16-58 yr at the time of Nelson's syndrome diagnosis (observed for 5-32 yr). Methods of examination included simultaneous adrenocorticotropic hormone (ACTH) and cortisol measurements during routine hydrocortisone replacement therapy, computed tomography (CT), pituitary magnetic resonance imaging (MRI), and visual field examination. The results obtained in a group of six patients diagnosed in the last 3 yr were compared with those obtained in a group of 27 patients examined before 1992. High plasma ACTH levels accompanied by normal serum cortisol concentration were characteristic for a late stage of the disease. Absolute temporal scotomas were an early finding. MRI, especially with the gadolinium enhancement, was superior to CT in demonstrating pituitary microadenomas in Nelson's syndrome. Thus, MRI diagnosis allowed for an early neurosurgical treatment of the patients with Nelson's tumors.

Adenoma↗

Activation of virilizing adrenal rest tissues by excessive ACTH production. An unusual presentation of Nelson's syndrome.

Nelson's syndrome occurs in 10 to 35 percent of patients treated for Cushing's disease by bilateral adrenalectomy and features an ACTH-producing pituitary tumor and hyperpigmentation. Cortisol-producing testicular tumors activated by markedly elevated ACTH levels have been described in male patients with Nelson's syndrome. We now describe a female patient with Nelson's syndrome who presented with virilization. Abdominal exploration revealed adrenal rest tumors in the paraovarian tissues and adrenal beds. Iodocholesterol scanning gave negative results. This case illustrates the need for follow-up study of patients with bilateral adrenalectomy for Cushing's disease and describes some of the unusual features these patients may present.

Adrenal Cortex Hormones↗

Cortisol secretion in Nelson syndrome: Persistence after "total" adrenalectomy for Cushing syndrome.

In two patients who were severely pigmented (Nelson syndrome) following bilateral adrenalectomy for Cushing syndrome, symptoms of hyper-cortisolism developed while they were receiving only physiologic steroid replacement. Cortical assays proved that endogenous cortisol production had not been obliterated. Even after total adrenalectomy, steroid measurement should be performed to guard against adrenocortical excess.

17-Hydroxycorticosteroids↗

[A fatal course of Nelson syndrome].

An unusually therapy-resistant form of Nelson's syndrome developed in a 23-year-old woman two years after treatment of a pituitary-dependent Cushing's syndrome by bilateral adrenalectomy (1977). Removal of a corticotrophic adenoma by a first transsphenoidal pituitary operation (1979) brought only temporary relief. Two years later, regrowth and apoplexy of the pituitary adenoma led to oculomotor paralysis and had to be treated by a second transsphenoidal operation (1981). A second relapse became manifest two years later. Treatment with bromocriptine relieved the headaches but did not diminish the tumor size. A third pituitary operation (1984) became necessary when neurological signs revealed penetration of the cavernous sinus. The tumor was only partly removed by transsphenoidal surgery. Postoperative deterioration of the patient required emergency craniotomy to check a subarachnoidal hemorrhage and for removal of the remaining tumor. The patient died three days later of pneumococcal meningitis which had developed after the third pituitary operation.

Adrenalectomy↗

Cavernous sinus involvement in recurrent Nelson's syndrome.

Nelson's syndrome is rare and difficult to cure. The tumours in this condition may behave invasively and require multiple interventions. Two patients who had been followed up for nearly 20 years developed signs of cavernous sinus involvement, one with an empty sella. Long term follow-up for such patients is emphasized.

Adult↗

Human adenohypophysis in Nelson syndrome. Ultrastructural and clinical study.

The manifestations that comprise the disease known as Nelson syndrome are pituitary hyperplasia and cutaneous hyperpigmentation, which sometimes follow bilateral adrenalectomy, in patients with hypercortisolism. We present a comprehensive endocrinologic, structural study of a patient in whom the evidence obtained supports the hypotheses that: (a) the primary disorder in this form of hypercortisolism is probably hypothalamic; (b) the hyperplasia of the adenohypophysis, following adrenalectomy, is closely associated with lowered plasma cortisol levels; and (c) the cillular hyperplasia in the adenohypophysis involves primarily the corticotroph, a cell believed to be associated with the secretion of adrenocorticotrophic hormone and melanocyte-stimulating hormone.

17-Ketosteroids↗

Treatment of acromegaly, Cushing disease and Nelson syndrome.

Since 1957 we have treated more than 429 patients who had pituitary neoplasms, most of which were hormone-secreting tumors. Long-term follow-up in the large group of patients treated for acromegaly shows a median survival of better than 16 years, with improvement over time. The short-term follow-up results in patients with Cushing* disease, Nelson syndrome and chromophobe adenoma are very encouraging. To compare these excellent results with those following surgical procedures, a large study of patients followed for a long period after the operations is needed.

Acromegaly↗

Excessive testosterone production in a patient with Nelson syndrome and bilateral testicular tumors.

Bilateral primary testicular tumors are rare and usually consist of either interstitial cells or hypertrophic testicular adrenal remnant tissue. Their differentiation on clinical presentation and histologic examination remains difficult but is essential because of the different therapeutic approaches. We report a rare case of excessive testosterone production by bilateral testicular tumors in a patient with Nelson syndrome (ACTH-secreting pituitary adenoma after bilateral adrenalectomy in patients with Cushing's disease). Increased ACTH stimulation in this patient supports the thesis of pluripotent cells within the testis which can undergo differentiation to cells which are not only morphologically similar to Leydig cells but also have the functional property of these cells. Our clinical findings support the diagnosis of hyperplasia of adrenal remnant or pluripotent cells rather than a true Leydig cell tumor. We emphasize the need for hormonal evaluations which should be assessed in the context of the size of these nodular tumors prior to therapeutic decisions. In cases with elevated serum ACTH and small nodular hyperplasia, we would favor a 'wait-and-see' strategy with appropriate hormonal therapy. In large tumors with clinical signs of hormonal activity, patient noncompliance with steroid replacement regimens or with local symptoms, scrotal exploration and tumor enucleation are indicated.

Adrenalectomy↗

[Effect of aminoglutethimide on ACTH plasma levels in Cushing's disease and Nelson syndrome].

Out of all steroidogenesis inhibitors aminoglutethimide is most frequently used agent for so-called chemical adrenalectomy, especially in oncological cases. The present studies aimed at assessing an effect of the inhibition of cortisol synthesis on plasma ACTH in patients treated with aminoglutethimide. According to the rules of negative feedback, an increase in plasma ACTH should be expected. Aminoglutethimide has been administered to 24 patients with Cushing's disease for 1-6 months. Plasma ACTH did not increase but statistically significantly decreased despite a decrease in blood cortisol. It indicates that aminoglutethimide directly inhibits ACTH secretion. No return of the normal circadian rhythm of cortisol and ACTH release suggests that the drug exerts an effect on ACTH release regulating mechanisms. No definite results were achieved in patients with Nelson syndrome treated with aminoglutethimide for a short period of time. Plasma ACTH levels tend to decrease but no statistical significance was observed in comparison with placebo. It may depend on markedly increased corticotrophin secretion in Nelson tumors.

Adolescent↗

Pituitary Cushing's syndrome and Nelson's syndrome: diagnostic criteria, surgical therapy, and results.

Eight patients with pituitary Cushing's syndrome and 2 with Nelson's syndrome were followed from one to ten years after removal of pituitary adenomas. A detailed assessment of the pituitary-adrenal axis was obtained in all patients when last seen, save the first, who had undergone a complete hypophysectomy ten years previously. Long-term observations have shown sustained endocrine cure in 7 of 8 patients with pituitary Cushing's syndrome. One patient with Nelson's syndrome was also cured. There was no operative morbidity or mortality. There were no instances of diabetes insipidus. The long-term results in this study indicate that patients with pituitary Cushing's syndrome have a better than 90% chance of being cured after transsphenoidal removal of the pituitary (micro) adenomas. Current diagnostic and therapeutic concepts in the management of pituitary Cushing's syndrome are discussed in detail.

Adrenocorticotropic Hormone↗