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[ENDOCRINOLOGY].

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Adrenocortical Hyperfunction↗

[The results of hypophyseal irradiation with a proton beam in acromegaly patients].

The investigation of 26 acromegalic patients long after irradiation of the pituitary body with a proton beam showed clinical and hormonal improvement in 38% of the patients, clinical improvement without complete growth hormone normalization in 46%, and the absence of any effect in 15%. The latter was mainly a result of partial irradiation of pituitary adenoma. Some patients after proton irradiation demonstrated signs of adenohypophyseal functional insufficiency, more marked in patients with a decreased level of Gy (over 5 ng/ml). A conclusion is that proton beam therapy is effective (provided all criteria for patients' eligibility are observed) and can be used as an independent method for the treatment of acromegalic patients.

Acromegaly↗

The coexistence of pituitary adenomas and meningiomas: three case reports and a review of the literature.

A coexistence of pituitary adenomas and meningiomas is very rare. We have reported on three of our own cases and reviewed the 17 cases reported in the literature. One has to differenciate between the coexistence of a pituitary adenoma and a meningioma without previous irradiation, and the occurrence of a meningioma following the irradiation of a pituitary adenoma. In the cases without irradiation, the adenoma and the meningioma are diagnosed simultaneously. On the other hand meningiomas arising after irradiation of a pituitary tumour are usually diagnosed only after a long latent period. The coexistence of pituitary tumours and meningiomas resulting from hormone dependent growth as well as the induction of growth of meningiomas by irradiation are discussed.

Adenoma↗

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.

Adolescent↗

Hypothalamic-pituitary-testicular system following testicular X-irradiATION.

Testes of adult, male rats were exposed to a total dose of 1500 R of X-irradiation. Testicular weight decreased from day 8 after X-ray treatment. This decrease was, however, preceded by an increment of the testis weight on day 4 following treatment. X-ray treatment of testes was associated with significant increases in serum FSH. Testicular irradiation had, however, no effect on ventral prostate and seminal vesicles weights. Serum testosterone increased only on day 1, 2 and 4 after irradiation, while serum LH levels tended to increase from day 8 post-irradiation. These changes were not significant, however, when compared with non-irradiated controls. At 7, 13 and 20 days following 1500 R of bilateral, testicular X-irradiation, the hypothalamic-pituitary unit was still capable of responding to exogenous gonadotrophin releasing factor. Serum FSH may in male rats by regulated at least partly by circulating steroids of testicular origin and partly by an unknown factor of non-interstitial cell nature.

Animals↗

Hypothalamo-pituitary-adrenal axis integrity after cranial irradiation for childhood posterior fossa tumours.

BACKGROUND: The evolution of anterior pituitary deficits after treatment for pituitary tumours has been largely attributed to local irradiation, but may be influenced as much by tumour mass or surgery. Other than growth hormone (GH) insufficiency, the late endocrinopathies after survival from non-central brain tumours have been little documented. The aim of this study was to investigate the hypothalamic-pituitary-adrenal (HPA) axis in long-term survivors of cranial irradiation for childhood posterior fossa tumours. PROCEDURE: We studied long-term data in patients treated prepubertally for posterior fossa brain tumours and systematically referred by radiation oncologists for growth and pubertal monitoring to the London Centre for Paediatric Endocrinology over the last 25 years. They must have undergone HPA axis assessment twice, first prepubertally at documentation of growth failure, and second at completion of growth and puberty. Data on sixteen patients (12 males, 4 females; median age: 5.7 years, range: 2.5-8.8 years), who had undergone excision surgery with high dose cranial irradiation and/or chemotherapy for childhood posterior fossa tumours, were examined. Patients were followed for a median of 11.0 (range: 6.8-21.4) years after radiotherapy. HPA axis assessment was undertaken with the insulin-induced hypoglycaemia test (ITT). Basal thyroid, cortisol and gonadal function tests were undertaken annually throughout the follow-up period and any deficits replaced. RESULTS: At each ITT, all patients mounted an inadequate GH response. By the end of the follow-up period all patients remained severely GH deficient, two (12.5%) had partial ACTH insufficiency, one (6.3%) had secondary hypothyroidism but none were gonadotropin deficient or hyperprolactinaemic. CONCLUSIONS: Unlike the severe, evolving multiple pituitary deficits after treatment of pituitary or central tumours in adults, these findings in children with posterior fossa tumours suggest that, with the exception of GH, neurotoxicity due to irradiation per se is associated with a low prevalence of anterior pituitary hormone deficiencies, even at a long follow-up. Since the children in this study were selected for assessment on the basis of growth failure, the high prevalence of GH insufficiency at first testing is to be expected; however, the early onset (within 1-3 years of irradiation) and permanence we have identified supports the view that GH is the most sensitive hormone to radiation injury.

Adolescent↗