Gamma knife radiosurgery in patients with Nelson's syndrome

PURPOSE

Nelson's syndrome (NS) is a long-term complication of bilateral adrenalectomy in patients with Cushing's disease. The best therapeutic strategy in NS has not been well defined. Gamma knife radiosurgery (GKRS) is very effective to stop the growth of the pituitary adenoma, which is the main goal of the treatment of patients with NS. We report the largest series of patients with NS treated by GKRS at a single center.

METHODS

The study was an observational, retrospective analysis of 28 consecutive patients with NS treated by GKRS in our department between 1995 and 2019. All patients had a growing ACTH-secreting pituitary adenoma. The main outcome of the study was to assess by the Kaplan-Meier method the risk of tumor progression after GKRS.

RESULTS

The median follow-up after GKRS treatment was 98 months (IQR 61-155 months, range 7-250 months). Two patients (7.1%) had a recurrence of disease during follow-up. The 10-year progression-free survival was 91.7% (95% CI 80.5-100%). No patient had deterioration of visual function or oculomotor function after GKRS. New onset of hypogonadism and hypothyroidism occurred in 18.8% and 14.3% of the patients at risk.

CONCLUSION

Our study confirms that GKRS may stop the tumor growth in the majority of patients with NS, even though very aggressive adenomas may ultimately escape this treatment. Safety of GKRS was good in our experience, but due attention must be paid to planning the distribution of radiation to critical structures, especially in patients previously treated by radiation.

Corticotroph tumor progression after bilateral adrenalectomy (Nelson's syndrome): systematic review and expert consensus recommendations

BACKGROUND

Corticotroph tumor progression (CTP) leading to Nelson's syndrome (NS) is a severe and difficult-to-treat complication subsequent to bilateral adrenalectomy (BADX) for Cushing's disease. Its characteristics are not well described, and consensus recommendations for diagnosis and treatment are missing.

METHODS

A systematic literature search was performed focusing on clinical studies and case series (≥5 patients). Definition, cumulative incidence, treatment and long-term outcomes of CTP/NS after BADX were analyzed using descriptive statistics. The results were presented and discussed at an interdisciplinary consensus workshop attended by international pituitary experts in Munich on October 28, 2018.

RESULTS

Data covered definition and cumulative incidence (34 studies, 1275 patients), surgical outcome (12 studies, 187 patients), outcome of radiation therapy (21 studies, 273 patients), and medical therapy (15 studies, 72 patients).

CONCLUSIONS

We endorse the definition of CTP-BADX/NS as radiological progression or new detection of a pituitary tumor on thin-section MRI. We recommend surveillance by MRI after 3 months and every 12 months for the first 3 years after BADX. Subsequently, we suggest clinical evaluation every 12 months and MRI at increasing intervals every 2-4 years (depending on ACTH and clinical parameters). We recommend pituitary surgery as first-line therapy in patients with CTP-BADX/NS. Surgery should be performed before extrasellar expansion of the tumor to obtain complete and long-term remission. Conventional radiotherapy or stereotactic radiosurgery should be utilized as second-line treatment for remnant tumor tissue showing extrasellar extension.

A 52-year-old male with visual changes

A 52 year-old male with a history of Cushing's Disease at age 18 and bilateral adrenalectomy at age 23 presented with visual changes. An MRI scan showed a pituitary macroadenoma (Nelson's syndrome). Other than the development of diabetes mellitus at age 32, his disease was stable until presentation. Serum studies show markedly elevated ACTH levels, but he had no hyperpigmentation. The tumor was removed by endoscopic surgery. Microscopic examination showed a pituitary adenoma with strong immunostaining for ACTH. In addition, the tumor cells showed Crooke's hyaline change and stained strongly for cytokeratin (Crooke's Cell Adenoma). Normal pituitary was not present. Crooke's cell adenomas are extremely rare and have not been previously reported in Nelson's Syndrome.

Pregnancy does not accelerate corticotroph tumor progression in Nelson's syndrome

CONTEXT

Pituitary surgery is the first line of treatment for Cushing's disease; when surgery fails, bilateral adrenalectomy may be proposed, particularly for women with a desire for pregnancy. Little is known about the impact of pregnancy on corticotroph tumor progression after bilateral adrenalectomy.

OBJECTIVE

The aim was to evaluate the impact of pregnancy on corticotroph tumor progression after bilateral adrenalectomy in Cushing's disease and to assess maternal and pregnancy outcomes.

DESIGN

We conducted a retrospective cohort study.

SETTING

Patients who became pregnant after bilateral adrenalectomy were followed in a single center.

PATIENTS

Twenty pregnancies from 11 patients with Cushing's disease were treated by bilateral adrenalectomy and no pituitary irradiation.

MEASUREMENTS

Corticotroph tumor progression was assessed by serial pituitary magnetic resonance imaging and plasma ACTH measurements before, during, and after pregnancy. Comparisons were performed using paired Wilcoxon rank tests. Data on maternal and neonatal outcomes were recorded by correspondence from patients and obstetricians.

RESULTS

Corticotroph tumor progression occurred in eight of 17 pregnancies, and ACTH increased in eight of 10 pregnancies. However, rates of increase during or after pregnancy were not faster than those observed before pregnancy. Maternal complications occurred in four pregnancies from two patients, including gestational hypertension in three and gestational diabetes mellitus in three. Among these four pregnancies, three had a favorable outcome, and one led to an in utero death after eclampsia, due to loss to follow-up. No other maternal or fetal complications were reported.

CONCLUSION

Pregnancy does not accelerate corticotroph tumor progression after bilateral adrenalectomy. Pregnancy is manageable, provided the patients can be followed closely.

[Nelson syndrome: a rare cause of generalized hyperpigmentation of the skin]

Nelson syndrome is a rare cause of generalized mucocutaneous hyperpigmentation. Its clinical manifestations are due to excessive secretion of adrenocorticotropic hormone from a pituitary adenoma, which develops after bilateral therapeutic adrenalectomy. As this operation has fallen into disuse, Nelson syndrome is now extremely rare and difficult to recognize. We present a very severe case of generalized hyperpigmentation due to Nelson syndrome in a 37-year-old woman.

Gamma knife stereotactic radiosurgery of Nelson syndrome

OBJECTIVE

Gamma knife radiosurgery (GKR) can be used as primary or adjuvant therapy for the treatment of an ACTH-producing pituitary tumor after bilateral adrenalectomy, called Nelson syndrome (NS). We have examined the effect of GKR on tumor growth and ACTH-hypersecretion, and characterized the adverse events of this treatment in patients with NS.

DESIGN

Cross-sectional follow-up study. First, retrospective data pre- and post-GKR were collected. Patients then underwent a predefined survey including radiological, endocrinological, ophthalmological, and neurosurgical evaluation.

SUBJECTS

Ten patients treated with GKR for NS after previous bilateral adrenalectomy. The mean follow-up was 7 years. No patient was lost to follow-up.

RESULTS

Tumor growth was stopped in all patients. The ACTH levels declined in eight patients, and normalized in one patient. There was a significant drop in ACTH levels, with a half-time of 2.8 years. No patient developed visual field defects or any other cranial nerve dysfunction as a result of treatment. Four patients started hormone substitution therapy during the follow-up period. The substitution therapy of three pituitary axes present at GKR treatment could be stopped during the same period. One patient developed a glioblastoma in the left parieto-occipital region 14 years after GKR, far from the field of treatment. As the radiation level was below 1Gy to this area, it is unlikely that the GKR treatment itself induced the malignant tumor.

CONCLUSION

In patients with NS, GKR is an effective adjuvant treatment, carrying relatively few adverse effects. Although the risk of developing a secondary neoplasia after GKR is present, it is probably extremely low.

Treatment of Nelson's syndrome with temozolomide

A 64-year-old woman was previously treated for Cushing's disease with trans-sphenoidal surgery, external beam radiotherapy and bilateral adrenalectomy. Progression of an aggressive corticotroph adenoma was evident 3 years post-adrenalectomy; involvement of the clivus was treated with surgery and gamma knife radiosurgery. Tumour spread through the skull base, occiput and left ear with persistent facial pain and left ear discharge; progression continued despite second gamma knife treatment. ACTH levels peaked at 2472 and 2265 pmol/l pre- and post-hydrocortisone respectively. Treatment with temozolomide resulted in a significant improvement in symptoms, a reduction of plasma ACTH to 389 pmol/l and regression of tumour on magnetic resonance imaging scan after four cycles of treatment. We propose that temozolomide is an effective and well-tolerated therapeutic tool for the treatment of Nelson's syndrome and a useful addition to the range of therapies available to treat this condition.

Easy Endotracheal Intubation of a Patient Suffering from Both Cushing's and Nelson's Syndromes Predicted by the Upper Lip Bite Test Despite a Mallampati Class 4 Airway

A 31-yr-old woman with concurrent Cushing's and Nelson's syndromes was scheduled for transsphenoidal hypophysectomy. The patient had generalized edema, morbid obesity, and a history of sleep apnea. Her Mallampati assessment was Class 4, suggesting very difficult intubation, but the upper lip bite test predicted easy intubation. After rapid sequence induction, there was a Class 1 view on laryngoscopy, and intubation was accomplished easily.

Pituitary corticotroph hyperplasia preceding adenoma in a patient with Nelson's syndrome

We report the case of a 42-year-old woman with Cushing's disease and Nelson's syndrome. When she was 17 years old, transsphenoidal surgery was performed. A detailed morphologic study demonstrated nodular hyperplasia of corticotroph cells but no adenoma. Following a long-lasting remission (14 years), Cushing's disease recurred. After an unsuccessful second transsphenoidal surgery, Cushing's disease persisted and both adrenals were removed (at the age of 34). Subsequently the patient developed Nelson's syndrome. The pituitary tumor proved to be a corticotroph adenoma; it was removed by the transsphenoidal approach (at the age of 42). Although in most patients Cushing's disease is due to an ACTH-secreting pituitary corticotroph adenoma which precedes the manifestation of Nelson's syndrome, our case indicates not only that corticotroph hyperplasia may cause Cushing's disease but that it may exist before the development of Nelson's syndrome after the removal of both adrenals. Our study supports the view that protracted stimulation of corticotrophs resulting from the elimination of the negative inhibitory feedback effect by corticosteroids plays a role in adenoma initiation.

[Pituitary gland imaging in Cushing's disease]

Specific MR techniques are required for optimal detection of adenocorticotropic hormone secreting adenomas responsible for Cushing's disease. Adequate MR sequences, high resolution coronal T1 and T2 - weighted images, dynamic MR imaging, post-gadolinium delayed images, dose of gadolinium adjusted for each sequence can routinely demonstrate pituitary adenomas less than 3 mm in Cushing's disease.

Immunocytochemical accumulation of p53 in corticotroph adenomas: relationship with heat shock proteins and apoptosis

The pathogenesis of corticotroph adenomas is unknown. In a recent study accumulation of p53 protein was detected by immunohistochemistry in a substantial proportion of pituitary corticotroph adenomas, and it has been suggested that it may be causally related to their development. However, other immunohistochemical studies have not confirmed the high incidence of p53 accumulation in this tumor type. Therefore, in the present study, p53 protein accumulation was re-examined in a series of 31 cases of corticotroph adenomas, using different sets of well validated anti-p53 antibodies. Furthermore, in view of the known association of p53 protein with apoptosis, and the known property of p53 to form complexes with heat shock proteins (HSPs), the relationship of p53 accumulation in corticotroph adenomas with apoptosis and HSP-70 was also investigated. Tumor samples from 31 patients with Cushing's disease or Nelson's syndrome were studied. Accumulation of p53 protein was tested by the standard ABC method using two different sets of clone Pab1801 and DO-7 monoclonal antibodies, applied after incubation of sections in a microwave oven. Using the DO-7 antibody, nuclear accumulation of p53 protein was detected in a total of 15 cases, with cytoplasmic staining observed in only 3 tumors. In contrast, using the Pab1801 antibody nuclear staining was observed in only 5 adenomas, with 11 adenomas demonstrating focal cytoplasmic immunoreactivity. Parallel sections of all corticotroph tumors demonstrating cytoplasmic accumulation of p53 protein were tested for the immunohistochemical presence of heat shock protein HSP-70. A striking similar distribution pattern of these two proteins was observed. Apoptosis, identified by the in situ end labeling technique, was detected in a total of 15 out of 28 corticotroph adenomas tested. Calculation of the apoptotic labeling index (ALI) by image analysis showed a significantly lower ALI in those corticotroph adenomas demonstrating nuclear p53 accumulation compared to those with no nuclear p53 immunostaining (p < 0.05). There was no significant difference in the ALI between cytoplasmic p53 positive and negative tumors. It is concluded that depending on the antibody used there is a significant variation of p53 protein detection in corticotroph adenomas. Overall, a significant proportion of corticotroph adenomas studied expressed the p53 protein, which depending on the antibody used, was located either in the nucleus and/or the cytoplasm of tumorous corticotroph cells. Cytoplasmic accumulation of p53, as shown by our colocalization studies with HSP-70, may be due to p53/HSP-70 complex formation. Although such a complex-mediated cytoplasmic exclusion of p53 has no significant effect on apoptosis, nuclear accumulation of p53 protein is associated with a significantly lower apoptotic index indicating a failure of p53 protein to exert its apoptotic action in at least a subset of this tumor type.

Progression of a Nelson's adenoma to pituitary carcinoma; a case report and review of the literature

A 25-year-old woman developed Nelson's syndrome, 3 years after successful bilateral adrenalectomy for Cushing's disease. Despite pituitary surgery and radiotherapy the tumour showed invasive growth, leading to visual disturbance, paresis of the oculomotor nerve and, 34 years after adrenalectomy, to death by widespread purulent leptomeningitis. Autopsy revealed a large adenohypophyseal carcinoma with a metastasis attached to the dura, both tumours showing immunocytochemical staining for ACTH and TSH. We review the literature on metastatic adenohypophyseal carcinoma in Cushing's disease and Nelson's syndrome and discuss the role of proliferation markers as indicators of malignant progression.

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.

Carcinomas of the pituitary: definition and review of the literature

Pituitary carcinomas are defined by their disconnected mode of extension, i.e. by the existence of intra- or extra-cerebral metastases. Since an invasive growth in the sella and its neighboring regions can also be noted in many pituitary adenomas, this invasion cannot be counted as a criterion for malignancy. Almost all pituitary carcinomas stem from previously operated or irradiated invasive adenomas. Like adenomas, they are classified with regard to the presumable cell of origin and the hormone which was produced contingently. Together with 67 pituitary carcinomas already published, three own cases are subject to a critical, summarizing judgement.

Long-term treatment of Nelson's syndrome by octreotide: a case report

Medical management of Nelson's syndrome by drugs such as bromocriptine, sodium and magnesium valproate has provided disappointing or, at least, controversial results. We report here on the results of long-term (2 yr) treatment with the somatostatin analogue octreotide (300 micrograms daily sc) in one patient affected by Nelson's syndrome occurring after bilateral adrenalectomy for Cushing's syndrome. During treatment, skin hyperpigmentation and serum ACTH levels decreased dramatically and a slight (about 10%) reduction in tumor size, as assessed by computerized tomography, was also observed. These results suggest that octreotide may be useful for the medical management of Nelson's syndrome.

Demonstration of pro-opiomelanocortin mRNA in pituitary adenomas and para-adenomatous gland in Cushing's disease and Nelson's syndrome

Pro-opiomelanocortin (POMC) mRNA was demonstrated in pituitary adenomas from 16 patients with Cushing's disease and 10 with Nelson's syndrome. The intensity of signal was significantly greater in Nelson's syndrome than in Cushing's disease and there was a trend towards a greater proportion of positive cells. This probably reflects inhibition of POMC gene expression by the high circulating levels of cortisol in Cushing's disease. In the para-adenomatous gland, the intensity of signal was variable in cells showing Crooke's hyaline change, ranging from negative to strongly positive, in keeping with the functional heterogeneity of corticotrophs. In one case, junctional corticotrophs were present and these were more intensely stained than anterior lobe corticotrophs in the same gland. This supports the concept that these cells are subject to different regulatory influences from corticotrophs in the anterior lobe. Whether this is related to differences in embryological origins or to local factors is at present unclear.

The effects of Gamma Knife surgery of pituitary adenomas on tumor growth and endocrinopathies

Fifteen patients were treated in the Gamma Knife Unit and followed for 18 months or longer. Four patients had Cushing's disease, 4 had acromegaly, 3 had Nelson's syndrome and 3 had prolactinomas. One patient had no endocrinopathy. One of the patients with acromegaly and 2 of those with prolactinomas had been operated prior to Gamma Knife treatment. Radiological tumor localization was not an insuperable problem in this series. The effect of Gamma Knife treatment on the anterior pituitary neoplasia, as such, was consistently successful. All the tumors which received 10 Gy or more to the edge showed either a reduction in volume or at least cessation of growth. On the other hand, the effect of the treatment was less consistent in respect to the endocrinopathies. These results are discussed in respect of dose and tumor size. It is suggested that the role of the Gamma Knife in the treatment of pituitary adenomas requires further clarification, based on prospective studies.

Coexisting corticotroph and lactotroph adenomas: case report with reference to the relationship of corticotropin and prolactin excess

A 57-year-old obese woman with hypertension, diabetes mellitus, osteoporosis, and a 40-year history of secondary amenorrhea was diagnosed with corticotropin-dependent Cushing's syndrome. Dynamic endocrine testing and radiological evaluation did not reveal definitively the source of the excess corticotropin. Bilateral adrenalectomy was performed with resolution of the signs and symptoms of hypercortisolism. Four years later, the patient was noted to have rising serum corticotropin levels and an enlarging pituitary mass; hyperprolactinemia also was documented. A diagnosis of Nelson-Salassa syndrome was made, and she underwent a transsphenoidal adenomectomy. A histological examination of the specimen revealed two distinct, albeit contiguous, adenomas: a corticotroph adenoma and a lactotroph adenoma. Postoperatively, the serum prolactin and corticotropin levels decreased significantly. Although the stalk section effect resulting from compression by a pituitary adenoma can raise serum prolactin levels, a concurrent lactotroph adenoma should be considered in patients with nonfunctional or functional pituitary adenomas of other types associated with significantly elevated prolactin levels. The mechanisms underlying simultaneous adrenocorticotropic hormone and prolactin excess are discussed.

Electron microscopical morphometry of well-differentiated and undifferentiated ACTH secreting adenomas in Cushing's disease and Nelson's syndrome

Adrenocorticotrophic hormone (ACTH)-secreting adenomas of patients with Cushing's disease (undifferentiated and well-differentiated ACTH-cell adenomas) were studied ultrastructurally and analysed morphometrically by a computer-supported quantitative image-analysing system. They were compared with identically prepared ACTH tumours (undifferentiated and well-differentiated ACTH-cell adenomas) of pituitaries from bilateral adrenalectomised patients with Nelson's syndrome. The aim of our study was to look for significant differences in ultrastructure and to evaluate these findings statistically regarding adenoma types and clinical syndromes. Clinical syndromes aside, more secretory granules and larger-sized prosecretory granules were measured in the well-differentiated ACTH-cell adenomas. The undifferentiated adenomas showed a greater content of nucleoli and prosecretory granules. Within the adenoma types, comparison of well-differentiated ACTH-cell adenomas showed that the clinical group of Cushing's disease contained larger areas of cytofilaments, whereas the clinical group of Nelson's syndrome had a larger tumour size and more lysosomes. Comparing the undifferentiated adenomas of both clinical groups the adenomas in Cushing's disease contained larger nuclei and more lysosomes, whereas the adenomas in Nelson's syndrome were larger in tumour size and contained larger prosecretory granules. Comparison of well-differentiated and undifferentiated adenomas in Cushing's disease showed more secretory granules and bigger prosecretory granules in well-differentiated adenomas whereas in undifferentiated adenomas the total area of the nuclei is larger, the nucleoli increase in number and size and the lysosomes are more frequent. Comparison of well-differentiated and undifferentiated adenomas in Nelson's syndrome demonstrated more lysosomes in well-differentiated adenomas and a larger total area of the nuclei in undifferentiated adenomas. The differences between the well-differentiated adenomas (mainly more secretory granules and larger prosecretory granules) and undifferentiated adenomas (mainly more and larger nuclei and nucleoli and more prosecretory granules) prove the clear separability between the adenoma types, not demonstrated in the literature up to now. The significant differences between adenomas in Cushing's disease (mainly more cytofilaments) and Nelson's syndrome (mainly more ribosomes and larger prosecretory granules) may be interpreted as different cell reactions due to the hypercortisolism present in Cushing's disease and lacking in Nelson's syndrome following adrenalectomy. Despite the fact that both clinical syndromes are based on the same adenoma types, indistinguishable by light microscopy, significant morphometrical findings in ultrastructure allow a clear discrimination of both clinical types.

[Immunoelectron microscopical study on human pituitary corticotrophic adenomas]

5 cases of pituitary adenomas associated with Cushing's disease or Nelson's syndrome were studied with electron microscopy and immunoelectron microscopy by using protein A--gold complex. Diversified ultrastructure was displayed in these tumors, among which 4 revealed presence of ACTH positive secretory granules. These granules were round or polyhedric in shape, varied in number, size and electronic density. Bundles of microfilaments could be seen in the tumor cells frequently, which were of the highest diagnostic value. There was no significant difference found in ultrastructure and immunocytochemical reaction of adenomas in Cushing's disease and Nelson's syndrome.

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.

Pituitary pathology in Cushing's disease

Pituitaries of 137 cases with Cushing's disease were microscopically and immunohistologically studied. Many alterations and parameters (sex, age, anamnesis, cortisol plasma levels, tumor size, invasiveness, localization, differentiation of adenomas, immunohistological hormone content, capillarity, recurrences, peritumorous ACTH cell hyperplasia, and Crooke's cells) were analyzed and compared. Whereas most parameters were not correlated, we found some important statistically significant correlations: Undifferentiated adenomas are more frequently invasive than differentiated ones. Invasive adenomas recur more frequently than non-invasive adenomas. Extremely laterally localized adenomas are more often invasive. Larger adenomas are more frequently invasive than micro-adenomas. ACTH cell hyperplasia are more often demonstrable in specimens from total hypophysectomies (confined to our earlier series) than from partial hypophysectomies and adenomectomies. Recurrences of adenomas are more frequent in pituitaries with periadenomous ACTH cell hyperplasia. Very rarely ACTH cell hyperplasia are the only source of ACTH hyperfunction. The more Crooke's cells are demonstrable, the longer the post-operative replacement dose of Cortisol is required. Adenomas in Cushing's disease and adenomas in Nelson's syndrome differ significantly in the following points: Adenomas in Nelson's syndrome are larger and contain more plurinuclear cells. In the ultrastructure, adenomas in Cushing's disease show more cytofilaments. Paraadenomous Crooke's cells are lacking in Nelson's syndrome.

Human corticotroph cell adenomas

Sixty-one pituitary corticotroph adenomas from 47 patients with Cushing's disease, 10 with Nelson's syndrome, and four eucorticoid patients were studied by light microscopy, immunoperoxidase, and electron microscopy. Seventy nine percent of all tumors and 70% of Nelson's cases were microadenomas, sometimes minute. A contiguity between the posterior lobe and the adenoma was seen in ten cases. Spontaneous infarction of the tumor with remission of Cushing's syndrome occurred in one case. Light microscopy revealed that the adenoma cells were basophilic and contained PAS-positive granules also staining with Herlant tetrachrome and lead-hematoxylin. The granules stained positively with antiserum to adrenocorticotrophic hormone (ACTH), beta-lipotropic hormones (beta-LPH) and beta-endorphin. The most characteristic ultrastructural finding was the presence of perinuclear bundles of microfilaments found in all our cases. Oncocytic changes were seen in three tumors. Four silent corticotroph adenomas, two of them originally microadenomas that had enlarged to enclosed adenomas while being treated with bromocriptine for hyperprolactinemia and one a large diffuse invasive tumor, did not differ in their microscopic, immunocytological, or ultrastructural features.

Long-term culture of human corticotropin-secreting adenomas on extracellular matrix and evaluation of serum-free conditions. Morphological aspects

Tissues from 12 human corticotropin-secreting adenomas, obtained during transsphenoidal surgery for Cushing's disease (CD, ten cases) or Nelson's syndrome (NS, two cases), were mechanically dispersed. The resulting single cells and cell aggregates were plated on extracellular matrix derived from bovine corneal endothelia. CD and NS cells showed distinct morphological differences initially, CD cells being much more spherical than the flattened NS cells. By 10 days at the latest after plating, however, CD and NS cells were indistinguishable morphologically. Cultured cells from both entities responded with rounding to cortisol (hydrocortisone, 10(-6) M) within 4-6 h. Synthetic ovine corticotropin-releasing factor (10(-8) M) produced flattening and extension of cytoplasmic processes after as early as 2 h.

The evaluation of sodium valproate in the treatment of Nelson's syndrome

It has previously been reported that sodium valproate (Epilim) lowers plasma ACTH levels in Nelson's syndrome. This report describes further experience with its use. Ten patients with Nelson's syndrome were treated with sodium valproate (600-1200 mg/day) for 5-32 weeks. Plasma ACTH was measured by cytochemical methods and RIA. Initial treatment for 5-12 weeks significantly (P less than 0.005) lowered plasma ACTH from a pretreatment mean of 2460 +/- 1870 ng/liter to 480 +/- 330 ng/liter, and the ACTH circadian rhythm was restored in two patients. On discontinuing treatment, plasma ACTH levels remained suppressed for 3 weeks and rose to pretreatment values in 5-12 weeks. Two patients' plasma ACTH levels failed to show a second response to treatment, while a third patient had a favorable second response to treatment over 32 weeks. In six patients, skin pigmentation lightened with treatment, and in one patient, a reduction in size of a pituitary microadenoma, demonstrated radiographically, occurred with treatment. gamma-Aminobutyric acid and sodium valproate were shown to be ineffective in inhibiting ACTH secretion from cultured pituitary tumor cells from a patient with Nelson's syndrome. The results show that sodium valproate is effective in some cases of Nelson's syndrome. We suggest that it reduces the hypersecretion of ACTH by enhancing gamma-aminobutyric acid function in the hypothalamus, thereby inhibiting the release of corticotropin-releasing factor.

Pituitary adenomas: immunohistology and ultrastructural analysis of 118 tumors

An analysis is presented of the immunohistological and ultrastructural features in a series of 118 surgically removed pituitary adenomas all of which were studied immunohistologically using antisera to growth hormone (GH), prolactin (PRL) ACTH, beta FSH, beta LH and beta TSH, and 75 of which were studied ultrastructurally. Results were analysed according to the mode of presentation of patients. Forty-one (35%) of the tumours were from patients with acromegaly or gigantism, ten (9%) from patients with Cushing's syndrome or Nelson's syndrome, 19 (16%) from patients with clinical features associated with hyperprolactinaemia and 48 (40%) from patients with space occupying lesions which appeared clinically to be overtly endocrinologically functionless. By light microscopy, using the immunoperoxidase (PAP) technique, immunoreactive GH was demonstrated in all the tumours from patients with acromegaly or gigantism, immunoreactive ACTH in all tumours from patients with Cushing's syndrome or Nelson's syndrome and immunoreactive PRL in 95% of tumours associated with effects of hyperprolactinaemia. Forty-five percent of the tumours from acromegalic patients contained some PRL-positive cells as well as GH-positive cells. Among the tumours which appeared clinically to be endocrinologically functionless were three tumours (from males) uniformly stained for immunoreactive PRL. Of the remainder, 60% were negative for immunoreactive hormones and 40% contained small numbers of cells which were positive for a variety of immunoreactive hormones. ACTH-cell and PRL-cell tumours had ultrastructural features as described in previous studies. Fifty percent of GH-cell tumours examined at the EM level contained fibrous bodies, while in the remainder these structures were not identified. Tumours with fibrous bodies were more likely to contain PRL as well as GH with immunoperoxidase. All tumours that were endocrinologically functionless and which were examined at the EM level contained secretory granules. Oncocytic change was common in these tumours. No ultrastructural differences were observed between those which contained immunoreactive hormones by light microscopy and those which did not.

Massive hyperplasia of testicular adrenal rests in a patient with Nelson's syndrome

The case of a 23-year-old man with Nelson's syndrome is presented. He had undergone bilateral adrenalectomy at age 15 years for Cushing's syndrome. Postoperatively, his cushingoid features resolved; however, 13 months later, he became hyperpigmented and showed radiographic evidence of sellar enlargement and midline expansion of the sellar floor. In 1972, he received radiation therapy to the pituitary gland. He underwent transsphenoidal hypophysectomy in 1974 and 1975 for recurrent pituitary adenoma, and recurrent Cushing's syndrome developed concomitantly with bilateral firm testicular masses in 1978. External scanning with NP-59 localized steroid production to the testes, and bilateral orchiectomy was performed. Immunohistochemical studies of the pituitary tumor confirmed the presence of adrenocorticotropic hormone, and morphologic and ultrastructural examinations of the testes supported the adrenal nature of the testicular tumors.

Evaluation of surgically treated Nelson's syndrome

In 17 primary transnasal operations on Nelson tumours long-term results are assessed measuring ACTH plasma levels and performing regular neuroradiological controls. In small intrasellar adenomas only one recurrent ACTH elevation near to pretreatment levels without symptoms from tumour growth was observed after 10 years. ACTH normalization was rarely achieved in large tumours, but only in one patient was a relapse visible in CT scan after three years. Thus selective tumour removal seems to be advisable at an early stage when sellar enlargement occurs. Interpretation of ACTH plasma levels has to include completeness of adrenalectomy, cystic tumour necrosis, and corticoid replacement which reduces ACTH levels. Elevation of ACTH plasma levels over 5,000 pg/ml has been regularly accompanied by extrasellar tumour extension. In large adenomas with definitely elevated ACTH levels, additional radiation therapy should be considered.

Multiple cellular forms of corticotrophs in surgically removed pituitary adenomas and periadenomatous tissue in Cushing's disease

Transsphenoidally removed samples of pituitary adenomas from 14 patients with Cushing's disease and 5 patients with Nelson's syndrome always contained groups of uniform small ACTH-cells. Antibodies against the pro-opiocortin precursor fragments beta-endorphin, ACTH, and 16k-peptide recognized material in typical adenoma cells. A subpopulation of these cells, varying in number from sample to sample, specifically exhibited alpha-melanotropin immunoreactivity. Most periadenomatous samples showed signs of severe degeneration. Typical Crooke cells only occurred in samples from patients with Cushing's syndrome, but, with this exception, no clear differences between pituitaries of patients with Cushing's and Nelson's syndromes could be discerned. Two other forms of ACTH-immunoreactive cells were observed: rare, single, highly immunoreactive cells, with characteristics of both normal and Crooke cells, and numerous syncytial groups of cells in an advanced state of disintegration, presumably the remnants of hyperplastic follicles. The four different corticotrophs are characterized according to their fine structure and immunoreactivity in this study.

[Nelson's syndrome. A case report (author's transl)]

Two cases of Nelson syndrome with typical clinical and laboratory features are presented. Both had radiological evidence of pituitary tumor; in one case it was evident on the plain film while in the other one it was better appreciated by means of tomography. It is important in the post-surgery follow-up of patients who underwent bilateral adrenectomy for Cushing's disease a periodical evaluation of skin pigmentation, visual field width and sellar morphology for the early detection of a pituitary adenoma.

Adrenocorticotropin and lipotropin secretion by dispersed cell cultures of a human corticotropic adenoma: effect of hypothalamic extract, arginine vasopressin, hydrocortisone, and serotonin

Basal and modulated secretion of ACTH and lipotropin (LPH) by cultures of trypsin-dispersed cells of a biopsy of a human corticotropic adenoma have been examined. ACTH secretion was detectable throughout the period of culture (13 days) but declined steadily from an initial production rate of 238 +/- 124 ng/3 X 10(5) cells/12 h. The time course of secretion showed a slower phase over the first 4 h, with increases up to 12 h. An extract of rat stalk median eminence caused a significant (P less than 0.005) dose-dependent increase in both ACTH and LPH secretion during 30 min. The patterns of response for ACTH and LPH were very similar; both exhibited a decline in the basal release of peptide subsequent to the period of stimulation. The addition of hydrocortisone (0.2 micrograms/ml) did not suppress basal ACTH secretion during 30 min but significantly (P less than 0.05) inhibited stimulation produced by rat stalk median eminence extract. Arginine vasopressin (dose range, 1-9 ng/ml) significantly (P less than 0.025) stimulated both ACTH and LPH secretion during 30 min. The patterns of response were again very similar. Serotonin (dose range, 0.01-10 micrograms/ml) did not affect ACTH secretion during incubations of 30 min to 4 h. The results obtained with the cell cultures of a human corticotropic cell adenoma concur with in vivo findings of incomplete autonomy of secretion, parallel secretion of ACTH and LPH in response to provocative stimuli, and suppression by corticosteroids. The technique has potential for exploring the cellular mechanisms controlling secretion by human corticotropic adenomas as well as the nature of the hormones produced.

Nelson's syndrome: one disease or two?

We present a case of Nelson's syndrome in which the clinical, radiographic, and surgical findings are indicative of a discrete microadenoma rather than of diffuse pituitary hyperplasia. Ultrastructural analysis reveals this to be the first example of a sparsely granulated lesion in Nelson's syndrome and only the second such adrenocorticotropic hormone-secreting tumor reported. Unfortunately, there do not seem to be any firm ultrastructural features that differentiate between hyperplasia and discrete adenoma. Separation of the two entities may be important in delineating the pathogenesis and treatment of Nelson's syndrome; these are discussed.

Conservative removal of small pituitary tumours: is it justified by the pathological findings?

Operation by the trans-sphenoidal route allows removal of small pituitary adenomata with conservation of normal gland. Histological examination of tissue obtained at operation and necropsy in 73 cases showed that surgical methods at present in use are likely to leave tumour behind in the pituitary gland and in the dura mater of the pituitary fossa. The clinical significance of these findings will only become evident after following patients for an extended period, but there appears to be a strong indication for routine postoperative radiotherapy.