Cortisol-secreting Adenomas Research Articles

Adrenal Incidentalomas: Diagnostic Evaluation and Long-Term Follow-up

To evaluate the cause and the clinical and laboratory features of adrenal incidentalomas (AI) in 52 patients and to assess the evolution of nonsurgically treated lesions during long-term follow-up. We retrospectively analyzed the medical records of 52 patients with AI undergoing routine follow-up in 2 Brazilian endocrine centers. In our study group, nonfunctioning adenomas were the most frequent cause of AI (42%), followed by cortisol-secreting adenomas (15%), metastatic disease (10%), pheochromocytomas (8%), myelolipomas (6%), cysts (6%), carcinomas (4%), lymphomas (4%), tuberculosis (4%), and aldosteronoma (2%). Only 13 lesions (25%) were functioning (8 cortisol-secreting adenomas, 4 pheochromocytomas, and 1 aldosteronoma). Carcinomas were the largest adrenal masses (mean diameter, 11.7 +/- 1.3 cm). With the exception of 1 pheochromocytoma, 1 cyst, and 1 myelolipoma, all AI larger than 6 cm were carcinomas. During follow-up of 21 patients with nonsurgically treated AI for 6 to 36 months (mean, 24.8 +/- 8.9), no patient had tumor reduction or disappearance. After 12 months of follow-up, however, a 45-year-old woman had adrenal mass enlargement from 3.2 cm to 4.4 cm; the excised lesion proved to be an adenoma. Moreover, evidence of cortisol hypersecretion developed after 24 months of follow-up in a 30-year-old man with a 3.5-cm adenoma in the left adrenal gland. Our findings demonstrate that most AI are nonfunctioning benign lesions and emphasize the need for long-term follow-up of patients with conservatively managed lesions, in light of the potential for evolution to hormonal hypersecretion or tumor growth.

Adrenal Incidentalomas: Diagnostic Evaluation and Long-Term Follow-Up

ObjectiveTo evaluate the cause and the clinical and laboratory features of adrenal incidentalomas (AI) in 52 patients and to assess the evolution of nonsurgically treated lesions during long-term follow-up. MethodsWe retrospectively analyzed the medical records of 52 patients with AI undergoing routine followup in 2 Brazilian endocrine centers. ResultsIn our study group, nonfunctioning adenomas were the most frequent cause of AI (42%), followed by cortisol-secreting adenomas (15%), metastatic disease (10%), pheochromocytomas (8%), myelolipomas (6%), cysts (6%), carcinomas (4%), lymphomas (4%), tuberculosis (4%), and aldosteronoma (2%). Only 13 lesions (25%) were functioning (8 cortisol-secreting adenomas, 4 pheochromocytomas, and 1 aldosteronoma). Carcinomas were the largest adrenal masses (mean diameter, 11.7 ± 1.3 cm). With the exception of 1 pheochromocytoma, 1 cyst, and 1 myelolipoma, all AI larger than 6 cm were carcinomas. During follow-up of 21 patients with nonsurgically treated AI for 6 to 36 months (mean, 24.8 ± 8.9), no patient had tumor reduction or disappearance. After 12 months of follow-up, however, a 45-year-old woman had adrenal mass enlargement from 3.2 cm to 4.4 cm; the excised lesion proved to be an adenoma. Moreover, evidence of cortisol hypersecretion developed after 24 months of follow-up in a 30-year-old man with a 3.5-cm adenoma in the left adrenal gland. ConclusionOur findings demonstrate that most AI are nonfunctioning benign lesions and emphasize the need for long-term follow-up of patients with conservatively managed lesions, in light of the potential for evolution to hormonal hypersecretion or tumor growth. (Endocr Pract. 2008;14:269-278)

Androgen- and cortisol-secreting adrenocortical adenoma may also be “subdinical”

Androgen- and cortisol-secreting adrenocortical adenoma may also be “subdinical”

Differential Expression of Ghrelin and its Receptor (GHS-R1a) in Various Adrenal Tumors and Normal Adrenal Gland

Ghrelin is a newly characterized, widely distributed peptide thought to be involved in the regulation of appetite. Significant effects on the release of growth hormone (GH) and ACTH have been demonstrated. This study compares the expression of ghrelin and its receptor (GHS-R) in various adrenal tumors and normal adrenal gland. Normal adrenal tissue was obtained after autopsy. Tissue was obtained from 13 pheochromocytomas (PHEOs), 15 cortisol-secreting adenomas (CPAs), 12 aldosterone-secreting adenomas (APAs), and 16 nonfunctional adenomas (NFAs) following laparoscopic surgery. Expression of ghrelin and GHS-R1a was investigated on RNA levels by using real-time reverse transcription polymerase chain reaction (RT-PCR) and on protein levels by using immunohistochemistry. In the seven normal adrenal glands analyzed, ghrelin mRNA levels were 12-fold lower than in stomach. Ghrelin protein expression was confirmed by immunohistochemistry. In all adrenal tumors, relevant levels of ghrelin mRNA were observed, with significantly lower expression in PHEOs and APAs than in normal adrenal gland. Ghrelin protein was detected in 0% of PHEOs, 55% of APAs, 87% of CPAs, and 54% of NFAs. GHS-R1a mRNA expression was detectable in normal adrenal gland, but the receptor protein was absent. In adrenal tumors, detectable levels of receptor mRNA were found in 38% of PHEOs, 13% of CPAs, and 25% of NFAs. GHS-R1a protein was absent in the majority of adrenal tumors. Expression of ghrelin in normal adrenal gland and adrenal tumors may indicate some unknown physiological function. The pathophysiological relevance of ghrelin expression in adrenal tumors remains to be investigated.

Surgery for Cushing’s Syndrome: An Historical Review and Recent Ten‐year Experience

Cushing's syndrome (CS), due to multiple etiologies, is a disorder associated with the ravages of cortisol excess. The purpose of this review article is to provide a historical synopsis of surgery for CS, review a recent 10-year period of operative management at a tertiary care facility, and to outline a practical approach to diagnosis and management. From 1996 to 2005, 298 patients underwent 322 operative procedures for CS at Mayo Clinic, Rochester, Minnesota. A retrospective chart review was carried out. Data was gathered regarding demographics, preoperative assessment, procedures performed, and outcomes. Data are presented as counts and percentages. Five-year survival rates were calculated where applicable by the Kaplan-Meier method. Statistical analysis was carried out with SAS, version 9 (SAS Institute, Inc., Cary, NC). Two-hundred thirty-one patients (78%) had ACTH-dependent CS and 67 patients (22%) had ACTH-independent CS. One-hundred ninety-six patients (66%) had pituitary-dependent CS and 35 patients (12%) had ectopic ACTH syndrome. Fifty-four patients (18%) had cortisol-secreting adenomas, 10 patients (3%) had cortisol-producing adrenocortical carcinomas, and 1% had other causes. Cure rates for first time pituitary operations (transsphenoidal, sublabial, and endonasal) were 80% and 55% for reoperations. Most benign adrenal processes could be managed laparoscopically. Five-year survival rates (all causes) were 90%, 51%, and 23% for adrenocortical adenomas, ectopic ACTH syndrome, and adrenocortical carcinomas, respectively. Surgery for CS is highly successful for pituitary-dependent CS and most ACTH-independent adrenal causes. Bilateral total adrenalectomy can also provide effective palliation from the ravages of hypercortisolism in patients with ectopic ACTH syndrome and for those who have failed transsphenoidal surgery. Unfortunately, to date, adrenocortical carcinomas are rarely cured. Future successes with this disease will likely depend on a better understanding of tumor biology, more effective adjuvant therapies and earlier detection. Clearly, IPSS, advances in cross-sectional imaging, along with developments in transsphenoidal and laparoscopic surgery, have had the greatest impact on today's management of the complex patient with CS.

The Clinical Conundrum of Corticotropin‐independent Autonomous Cortisol Secretion in Patients with Bilateral Adrenal Masses

Management of patients with bilateral adrenal masses and corticotropin (ACTH)-independent Cushing syndrome (CS) or subclinical CS is problematic. We report our experience with adrenal venous sampling (AVS) in the evaluation of 10 patients with bilateral masses who had ACTH-independent CS or subclinical CS. Ten patients (9 women, 1 man, mean age 56.4 years) with bilateral adrenal masses and ACTH-independent CS (n=3) or subclinical CS (n=7) underwent AVS. Autonomous cortisol secretion was documented in all cases with suppressed serum ACTH concentrations and lack of cortisol suppression with dexamethasone administration. Adrenal venous sampling was performed on the second day of dexamethasone administration. Cortisol and epinephrine levels were measured from each adrenal vein (AV) and from a peripheral vein (PV). Mean (+/-SD) maximal diameter of the adrenal masses on computed tomography was 3.3+/-1.3 cm (range: 1.2-6.0 cm). Successful catheterization was confirmed with AV:PV epinephrine gradients. A cortisol AV:PV gradient>6.5 was consistent with a cortisol-secreting adenoma in 11 adrenal glands; 5 patients had clinically important bilateral autonomous cortisol hypersecretion, 3 had bilateral cortisol-secreting adenomas, and 2 had ACTH-independent macronodular adrenal hyperplasia. Adrenal venous sampling-guided adrenalectomy was completed in all 10 patients-2 patients had total bilateral adrenalectomy and 2 others had subtotal bilateral adrenalectomy. During a mean follow-up of 36.1 months (range: 0.7-123 months), CS or clinically important cortisol secretory autonomy did not recur. Adrenal venous sampling contributed to the localization of autonomous hypercortisolism in the setting of ACTH-independent CS or subclinical CS in patients with bilateral adrenal masses.

Immunohistochemical localization of somatostatin receptor subtypes in benign and malignant adrenal tumours

Somatostatin mediates its action through five receptor subtypes (sst1-5) that are widely distributed in various endocrine tissues and tumours. Because of the inhibitory effects of somatostatin, long-acting analogues have been synthesized. In contrast to their well-established use in neuroendocrine and pituitary tumours, little is known about their potential use in adrenal tumours. We examined somatostatin receptor protein expression in adrenal tumours of various aetiologies. Immunostaining was performed with specific polyclonal antibodies for sst1-5. Seven benign and eight malignant pheochromocytomas (PHEOs), eight aldosterone-secreting adenomas (APAs), nine cortisol-secreting adenomas (CPAs), seven nonfunctioning adrenal tumours (NFAs) and 25 adrenal carcinomas (CAs) as well as eight normal adrenal glands were investigated. Staining pattern, distribution and subcellular localization of the somatostatin receptor subtypes were evaluated. In the majority of normal cortices the expression of sst1-5 was limited to the reticular zone. The medulla was predominantly positive for sst3. Most cortical adenomas were positive for all five subtypes. However, in the majority of these tumours, less than 30% of cells were positively stained. A high expression of sst4 was found in CPAs but only very few cortical carcinomas exhibited sst immunostaining. All benign PHEOs were positive for sst3. The majority presented with more than 60% of tumour cells stained. By contrast, only six out of eight malignant PHEOs were positive for sst3. Somatostatin receptor subtypes are expressed in PHEOs as well as in tumours of the adrenal cortex with tumour-specific distribution patterns. This may offer new diagnostic and therapeutic possibilities.

Different expression of protein kinase A (PKA) regulatory subunits in cortisol-secreting adrenocortical tumors: Relationship with cell proliferation

The four regulatory subunits (R1A, R1B, R2A, R2B) of protein kinase A (PKA) are differentially expressed in several cancer cell lines and exert distinct roles in growth control. Mutations of the R1A gene have been found in patients with Carney complex and in a minority of sporadic primary pigmented nodular adrenocortical disease (PPNAD). The aim of this study was to evaluate the expression of PKA regulatory subunits in non-PPNAD adrenocortical tumors causing ACTH-independent Cushing's syndrome and to test the impact of differential expression of these subunits on cell growth. Immunohistochemistry demonstrated a defective expression of R2B in all cortisol-secreting adenomas ( n = 16) compared with the normal counterpart, while both R1A and R2A were expressed at high levels in the same tissues. Conversely, carcinomas ( n = 5) showed high levels of all subunits. Sequencing of R1A and R2B genes revealed a wild type sequence in all tissues. The effect of R1/R2 ratio on proliferation was assessed in mouse adrenocortical Y-1 cells. The R2-selective cAMP analogue 8-Cl-cAMP dose-dependently inhibited Y-1 cell proliferation and induced apoptosis, while the R1-selective cAMP analogue 8-HA-cAMP stimulated cell proliferation. Finally, R2B gene silencing induced up-regulation of R1A protein, associated with an increase in cell proliferation. In conclusion, we propose that a high R1/R2 ratio favors the proliferation of well differentiated and hormone producing adrenocortical cells, while unbalanced expression of these subunits is not required for malignant transformation.

Frequent mutations of β‐catenin gene in sporadic secreting adrenocortical adenomas*

Molecular alterations remain largely unknown in most sporadic adrenocortical tumours and hyperplasias. In our previous work, we demonstrated the differential expression of several Wnt/beta-catenin signalling-related genes implicated in ACTH-independent macronodular adrenal hyperplasias (AIMAH). To better understand the role of Wnt/beta-catenin signalling in adrenocortical tumours, we performed mutational analysis of the beta-catenin gene. We studied 53 human adrenocortical samples (33 adenomas, 4 carcinomas, 13 AIMAH, 3 ACTH-dependent adrenal hyperplasias) and the human adrenocortical cancer cell line NCI-H295R. All samples were screened for somatic mutations in exons 3 and 5 of the beta-catenin gene. Eleven and six samples were analysed for beta-catenin protein expression by Western blotting and immunohistochemistry, respectively. No mutations were detected in adrenocortical carcinomas, AIMAH and ACTH-dependent hyperplasias. Genetic alterations were found in 5 (15%) out of 33 adenomas: three cortisol-secreting adenomas, one aldosterone-secreting adenoma and one nonfunctional adenoma. Two-point mutations occurred at serine residues of codons 37 and 45 (S37C and S45F). The remaining three tumours contained deletions of 6, 55 and 271 bp. H295R cells carry an activating S45P mutation. Western blot analysis of samples with 55- and 271-bp deletions showed an additional shorter and more intense band representing an accumulation of the mutated form of beta-catenin protein. In addition, cytoplasmic and/or nuclear accumulation of beta-catenin was observed in mutated adenomas by immunohistochemistry. Activating mutations of exon 3 of the beta-catenin gene are frequent in adrenocortical adenomas, and further characterization of the Wnt/beta-catenin signalling pathway should lead to a better understanding of adrenal tumourigenesis.

Benign cortisol‐secreting adrenocortical adenomas produce small amounts of androgens

Serum androgen levels are below normal in patients with benign cortisol-secreting adrenocortical adenomas, owing to ACTH suppression. Associated androgen secretion is usually considered as indicative of malignancy. The objective of the study was to analyse the androgen-producing ability of cortisol-secreting adrenocortical adenomas. Retrospective data collection in a single referral hospital centre. Dehydroepiandrosterone sulfate (DHEAS), Delta4androstenedione and testosterone concentrations were measured before and after adrenalectomy and then at 6-month intervals in 20 women (eight cortisol-secreting adrenocortical adenomas, six subclinical cortisol-secreting adrenocortical adenomas, and six nonfunctional adenomas). Before adrenalectomy, serum androgen concentrations were measurable in all women with clinically apparent and subclinical cortisol-secreting adrenocortical adenomas. DHEAS levels were either at the lower end of the normal range or below normal, but were always clearly detectable. Postoperatively, during adrenocortical insufficiency, DHEAS, Delta4androstenedione and testosterone concentrations fell to near the detection limit in all patients with cortisol-secreting adrenocortical adenomas (P = 0.008 for each marker) and showed a similar tendency to fall in all patients with subclinical cortisol-secreting adrenocortical adenomas. Pre- and post-treatment androgen concentrations did not differ in patients with nonfunctional adenomas. Immunohistochemical analysis confirmed CYP17, HSD3B2, SULT2A1 and CYB5 expression by all cortisol-producing tumours. The intensity of CYP17 and SULT2A1 expression was stronger in cortisol-secreting adenomas than in their adjacent normal adrenal tissue. Both clinically apparent and subclinical cortisol-secreting adrenocortical adenomas appear to show moderate autonomous androgen production. Thus, weak androgen secretion in patients with adrenocortical tumours should not necessarily be considered as a sign of malignancy.

Laparoscopic Partial Adrenalectomy for Bilateral Cortisol-secreting Adenomas

Bilateral cortisol-secreting adenomas are a rare cause of Cushing's syndrome. We report a case of a 35-year-old woman who presented with ACTH-independent Cushing's syndrome and bilateral adrenal adenomas. Adrenal venous sampling confirmed both adenomas to be hyper-secreting cortisol. She underwent bilateral laparoscopic adrenalectomy; total right and partial left adrenalectomies. At 2-year follow-up, she is maintained on low-dose fludrocortisone and hydrocortisone, and without recurrence of hypercorticolism. Laparoscopic partial adrenalectomy is a feasible option for this rare condition; however, long-term follow-up is needed to determine her total independence from steroid usage.

Metabolic syndrome in patients with adrenocortical adenoma

To investigate the prevalence and characteristics of metabolic syndrome (MS) in patients of adrenocortical adenoma. MS-related indexes, including waist circumference (WC), blood pressure, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), fasting plasma glucose, plasma and urinary aldosterone, plasma potassium, basic and upright plasma renin activity (PRA), plasma and urinary cortisol, and plasma ACTH, were examined among 61 patients of aldosterone producing adenoma (APA, Group 1), 23 patients of cortisol-secreting adenoma (CSA, Group 2), 24 patients of nonfunctional adrenal adenoma (NAA, Group 3), and 26 healthy controls (Group 4). As defined by the National Cholesterol Education Program Adult Treatment Panel III criteria, the prevalence rates of MS were 27.9%, 39.1%, 16.7%, and 11.5% in Groups 1, 3, 3, and 4. The abdominal obesity rate was 26.2% in Group 1 and 9.1% in Group 2, both significantly higher than those of Group 3 and 4 (20.8% and 15.4% respectively). The prevalence rates of hypertension and systolic blood pressure were the highest in Group 1, followed by Group 2, 3, and 4 t. The diastolic blood pressure in patients of Group 1 was also higher than those of the other three groups. The prevalence rates of hypertriglyceride were 24.6%, 52.2%, 21.7%, and 23.1% in Group 2 1 approximately 4. The prevalence rates of low HDL-C was 32.8%, 47.8%, 30.4%, and 26.9% respectively. The prevalence rates of hyperglycemia were 13.1%, 26.1%, 8.7%, and 7.7% respectively. Patients with adrenocortical adenoma have a significantly high prevalence of metabolic syndrome, especially the patients of CSA and NAA.

Diagnostic Value of Biochemical Parameters in the Differential Diagnosis of an Adrenal Mass

In patients with an adrenal mass, hormonally active tumors including pheochromocytomas as well as aldosterone- and cortisol-secreting adenomas need to be considered. Several studies have demonstrated that metanephrines, which are the metabolites of catecholamines, are reliable parameters for the diagnosis of pheochromocytoma. In patients with an adrenal mass, we found plasma metanephrines, measured by a newly available radioimmunoassay, to be highly sensitive and specific for pheochromocytomas, with a better accuracy than any other biochemical parameter. The plasma aldosterone concentration (PAC) to plasma renin activity (PRA) ratio is an established screening tool for primary hyperaldosteronism. However, determination of active renin concentration (ARC) in contrast to PRA may offer advantages in regard to processing and standardization. We found a PAC to ARC ratio of >62 in patients with PAC levels>200 ng/L to be a reliable screening method for primary hyperaldosteronism in patients with adrenal masses. The screening for hypercortisolism relies on excess urinary cortisol secretion, loss of the physiological feedback during dexamethasone challenge, and loss of the circadian rhythm. Because urinary-free cortisol may not identify subclinical Cushing's syndrome, in which hypercortisolism is still mild, the 1-mg dexamethasone suppression test has been recommended in all patients with incidentally detected masses. Alternatively, late-night cortisol levels in saliva have been found to have a high sensitivity and specificity for the diagnosis of Cushing's syndrome. In summary, in patients with an adrenal mass, hormonally active adrenal tumors can be excluded with high certainty using a few highly reliable biochemical parameters.

Differential Expression of the Human Somatostatin Receptor Subtypes sst1 to sst5 in Various Adrenal Tumors and Normal Adrenal Gland

Somatostatin (SRIF) is a widely distributed peptide with growth-inhibiting effects in various tumors. So far, five distinct human SRIF receptor subtypes (sst1-sst5) have been identified. We investigated expression of the five ssts in various adrenal tumors and in normal adrenal gland. Tissue was obtained from ten pheochromocytomas (PHEOs), nine cortisol-secreting adenomas (CPAs), eleven aldosterone secreting adenomas (APAs) and eight non-functional adenomas (NFAs) after retroperitoneoscopic surgery, and used for RNA extraction. Adrenal tissue surrounding the tumor was available for analysis in twenty-seven cases. Receptor expression was studied by RT-PCR using sst-specific primers and subsequently confirmed by Southern blotting. Expression of all five receptor subtypes was observed in RNA obtained from normal adrenal gland. Furthermore, each receptor subtype was expressed in more than 50 % of all tumors analyzed. No sst5 expression was found in PHEOs, while sst1 was present in nearly all of these tumors. Only a few of the CPAs expressed subtypes sst1 and sst4. Expression of all five subtypes was distributed equally in APAs. No sst4 was found in any of the NFAs. Differential expression of ssts in various adrenal tumors may point to new aspects in the pathogenesis of these adenomas. Furthermore, the presence of specific ssts could expand the diagnostic and therapeutic strategies during management. New subtype specific analogues of SRIF may be used in the future depending on the type of adrenal tumor and receptor subtype expressed.

Expression of urocortin 3/stresscopin in human adrenal glands and adrenal tumors

Urocortin 3 (Ucn 3)/stresscopin (SCP) is a novel peptide of the corticotropin-releasing factor (CRF) family and is a specific ligand for the CRF type 2 receptor. In the present study, we studied expression of Ucn3/SCP in the normal adrenal and adrenal tumors by radioimmunoassay and reverse transcriptase-polymerase chain reaction (RT-PCR). High concentrations of immunoreactive (IR)-Ucn3 were present in the normal portions of adrenal glands (4.2 ± 0.51 pmol/g wet weight, mean ± S.E.M., n = 14), and the levels were higher than those in the brain. IR-Ucn3 was also detected in the tumor tissues of aldosterone-secreting adenomas (6.2 ± 0.6 pmol/g wet weight, n = 10), cortisol-secreting adenomas (5.0 ± 1.2 pmol/g wet weight, n = 4), and pheochromocytomas (1.9 ± 0.4 pmol/g wet weight, n = 7). Reverse phase high performance liquid chromatography showed that IR-Ucn3 in normal portions of adrenal glands and aldosterone-secreting adenomas was eluted mainly in the positions of Ucn3 and SCP with several minor peaks eluting earlier. The RT-PCR showed expression of Ucn3 mRNA in normal portions of adrenal gland (positive ratio; 4/4), aldosterone-secreting adenomas (3/4), cortisol-secreting adenomas (1/3) and pheochromocytomas (6/7). These findings indicate that Ucn3 is produced in normal adrenal and adrenal tumors (both adrenocortical tumors and pheochromocytomas), and suggest that Ucn3 acts as an autocrine or paracrine regulator in normal adrenal and adrenal tumors.

The Sp transcription factors are involved in the cellular expression of the human glucose-dependent insulinotropic polypeptide receptor gene and overexpressed in adrenals of patients with Cushing’s syndrome

The best characterized effect of glucose-dependent insulinotropic polypeptide (GIP) is its stimulatory effect on insulin secretion by pancreatic beta-cells. Recently, it was demonstrated that some cases of primary adrenal Cushing's syndrome were secondary to the ectopic expression of non-mutated GIP receptor (GIP-R) in bilateral adrenal hyperplasias or unilateral adrenal adenomas, resulting in food-dependent steroidogenesis. Using a human multiple-expression tissue array, GIP-R was found to be expressed in a large number of human adult and fetal tissues, but not in the adrenal gland. The analysis of the promoter region of human (h) GIP-R gene revealed six consensus sequences important in regulating the reporter gene activity and capable of binding to Sp1 and Sp3 transcription factors. Data obtained by gene array and semi-quantitative RT-PCR showed an increase in the expression of Sp3 and CRSP9 (co-regulator of Sp1 transcription factor, subunit 9) in the adrenal adenomas or bilateral macronodular hyperplasias of patients with GIP-dependent Cushing's syndrome; they were, however, also increased in some patients with non-GIP-dependent cortisol-secreting adenomas or with ACTH-dependent Cushing's disease. This study represents the first step in our understanding of the mechanisms involved in the regulation of the expression of the hGIP-R gene.

Mutational Analysis of PRKAR1A and Gsα in Sporadic Adrenocortical Tumors

Little is known about the pathogenesis of adrenocortical tumors. The cAMP-dependent pathway is physiologically activated by ACTH in adrenocortical cells and different components of this cascade may be altered in some functioning adrenocortical tumors. Recently, mutations of the gene encoding the PKA type 1 A regulatory subunit (R1 A), PRKAR1A, associated with loss of heterozygosity (LOH) at PRKAR1A locus, have been demonstrated in primary pigmented nodular adrenocortical disease (PPNAD), either isolated or associated with Carney complex. Moreover, activating mutations of the Gs(alpha) gene (the gsp oncogene) have also been found in a small number of adrenocortical cortisol-secreting adenomas. Aim of this study was to investigate the presence of such genetic alterations on a series of 10 ACTH-independent Cushing syndrome due to non-PPNAD adrenocortical adenomas. The coding sequence of PRKAR1A, evaluated by PCR and direct sequencing analysis, revealed the absence of mutations while heterozygosity for at least 1 polymorphism excluded LOH in most tumors. In one single adenoma gsp mutation was detected. In conclusion, we provide additional evidence that the only mutational changes able to activate the cAMP pathway so far identified, i.e. PRKAR1A mutations and gsp oncogene, are a rare event in adrenocortical tumors.

Ten Years of Laparoscopic Adrenalectomy: Lesson Learned from 104 Procedures

The purpose of this study was to evaluate the short- and long-term results of 104 consecutive laparoscopic adrenalectomies performed during a period of 10 years in two specialist centers. One hundred four patients underwent laparoscopic adrenalectomy in two specialist centers in Italy between 1994 and 2003. Indications to laparoscopic adrenalectomy were aldosterone-secreting adenoma (20%), pheochromocytoma (24%), cortisol-secreting adenoma (11.5%), incidentaloma (26.9%), multiple endocrine neoplasia (MEN) type 2A (2.8%), adrenal metastases from lung cancer (3.8%), adrenal cyst (6.7%), and angiomyolipoma (3.8%). Transperitoneal anterior and lateral approaches were adopted in 17 and 84 patients, respectively. Retroperitoneal approach was adopted in three patients. Mean operative time was 108 +/- 39.1 minutes (range, 40-300 minutes). There was no correlation between adrenal tumor diameter and operative time. Mean intraoperative blood loss was 106 mL (range, 40-600 mL). Intraoperative complication rate and conversion rate were 4.8 per cent (5 cases). Laparoscopic adrenalectomy is a safe procedure. After a relatively short learning curve, it can be performed successfully by any surgeon with low operative morbidity and mortality. The size of the adrenal tumor should not be considered a contraindication to this procedure.

Preproorexin and Orexin Receptors Are Expressed in Cortisol-Secreting Adrenocortical Adenomas, and Orexins Stimulate in Vitro Cortisol Secretion and Growth of Tumor Cells

Orexins A and B are hypothalamic peptides that originate from the proteolytic cleavage of preproorexin and act through two subtypes of receptors, named OX1-R and OX2-R. OX1-R almost exclusively binds orexin-A, whereas OX2-R is nonselective for both orexins. We previously found that orexin-A, via the OX1-R, stimulates cortisol secretion from dispersed human adrenocortical cells. In this study, we demonstrate that six of eight cortisol-secreting adenomas expressed preproorexin mRNA, and seven of 10 adenomas contained measurable amounts of orexin-A but not orexin-B. Normal adrenal cortexes neither expressed preproorexin nor contained orexins. All adenomas expressed OX1-R and OX2-R mRNAs, and real-time PCR showed that the expression of both receptors was up-regulated in adenomas, compared with normal adrenal cortex. Orexin-A concentration-dependently raised basal cortisol secretion from freshly dispersed normal and adenomatous cells, minimal and maximal effective concentrations being 10(-10) and 10(-8) m, and the peptide efficacy (percent increase elicited by 10(-8) m orexin-A) was significantly higher in adenomas than in the normal adrenal cortex. Orexin-B was ineffective, thereby indicating that orexin secretagogue action is mediated by the OX1-R. In contrast, both orexins (10(-8) m) raised the proliferative activity of cultured normal and adenomatous cells, suggesting that this effect is mediated by OX2-R or both receptor subtypes. Collectively, our findings allow us to conclude that the orexin system is overexpressed in cortisol-secreting adenomas and suggest that orexin-A may act as an autocrine-paracrine regulator of the secretory activity and growth of some of these adrenal tumors.

Dopamine receptor expression and function in human normal adrenal gland and adrenal tumors.

Dopamine is known to play a role in the modulation of aldosterone and catecholamine secretion from the adrenal gland, where dopamine receptors (DR), in particular the DR type 2 (D(2)), have been found to be expressed. DR expression has also been demonstrated in some types of benign adrenal tumors. The aims of the current study were to evaluate DR expression and D(2) localization in the normal adrenal gland and in different types of benign and malignant adrenal tumors, as well as to evaluate the in vitro effects of the dopamine agonists bromocriptine and cabergoline on hormone secretion in nontumoral adrenal cells. Adrenal tissues from 25 patients, subjected to adrenal surgery for different diseases, were studied. These included three normal adrenals; five adrenal hyperplasias; four aldosterone-secreting, two cortisol-secreting, and two clinically nonfunctioning adrenal adenomas; two aldosterone-secreting, two cortisol-secreting, and two androgen-secreting adrenal carcinomas; and three pheochromocytomas. In all tissues, DR and D(2) isoform (D(2long) and D(2short)) expression was evaluated by RT-PCR. D(2) localization was also evaluated by immunohistochemistry using a specific polyclonal antibody, whereas D(2)-like receptor expression was evaluated by receptor-ligand binding study, using the radiolabeled D(2) analog (125)I-epidepride. The effects of bromocriptine and cabergoline on baseline and ACTH and/or angiotensin II-stimulated aldosterone, cortisol, and androstenedione secretion were evaluated in cell cultures derived from five different adrenal hyperplasia. At RT-PCR, both D(1)-like and D(2)-like receptors were expressed in all normal and hyperplastic adrenals. D(2) and D(4) were expressed in aldosterone- and cortisol-secreting adenomas, cortisol-secreting carcinomas, and clinically nonfunctioning adenomas, whereas no DR was expressed in aldosterone- and androgen-secreting carcinomas. D(2), D(4), and D(5) were expressed in pheochromocytomas. In all D(2)-positive tissues, both D(2) isoforms were expressed, with the exception of one case of aldosterone-secreting adenoma and the cortisol-secreting carcinomas, in which only the D(2long) isoform was expressed. D(2)-like receptor expression was confirmed at receptor-ligand binding study. At immunohistochemistry, D(2) was mainly localized in the zona glomerulosa and reticularis of the adrenal cortex and, to a lesser extent, in the zona fasciculata and medulla of normal and hyperplastic adrenal tissue. In the positive tumors, D(2) was localized in the tumoral cells. At the in vitro study, a significant inhibition of both baseline and ACTH-stimulated aldosterone secretion was found after high-dose cabergoline, but not bromocriptine, administration; and a significant inhibition of angiotensin-II-stimulated aldosterone secretion was found after both bromocriptine and cabergoline administration in the adrenal hyperplasias. In conclusion, the current study demonstrated that both D(1)-like and D(2)-like receptors are expressed in the normal adrenal gland and in a percentage of adrenal adenomas or carcinomas. Bromocriptine and cabergoline induce only a minor inhibition of the secretion of adrenal hormones in the nontumoral adrenal gland in vitro, not excluding, however, the possible effective use of dopamine agonists in vivo in the treatment of adrenal tumors.