Adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia as a distinct subtype of Cushing's syndrome. Enzyme histochemical and ultrastructural study of four cases with a review of the literature

Prolonged Hypokalemia Following Metyrapone Treatment for Primary Bilateral Macronodular Adrenal Cortical Disease

Surgical treatment is generally the standard therapeutic regimen used for primary bilateral macronodular adrenal cortical disease (PBMACD). However, in cases for which surgery is difficult or in which there is mild cortisol hypersecretion, metyrapone treatment can be selected. Although hypokalemia has been occasionally noted following metyrapone administration for Cushing syndrome associated with an adrenal adenoma, all such cases have been reported to be transient. Hypokalemia induced by metyrapone treatment is thought to occur due to excessive suppression of cortisol secretion, resulting in overproduction of adrenocorticotropic hormone from the pituitary gland, ultimately leading to excessive production of 11-deoxycorticosterone (DOC) in the adrenal cortex. A 52-year-old man diagnosed with PBMACD and started on metyrapone treatment subsequently presented with persistent hypokalemia. Interestingly, following initiation of metyrapone, blood test findings indicated marginal changes in serum cortisol, adrenocorticotropic hormone, and dehydroepiandrosterone sulfate levels, even when DOC levels were already markedly elevated. In addition to the effects of metyrapone, the present findings suggest a unique DOC synthesis regulatory mechanism involved in the pathogenesis of PBMACD.

Morphological Harbingers of ARMC5-Pathogenic Variant-Related Bilateral Macronodular Adrenocortical Disease

Bilateral macronodular adrenocortical disease (BMAD) is a neoplastic disease associated with a high frequency of germline disease. Armadillo repeat containing 5 (ARMC5) pathogenic variants (PVs) have not been widely studied to determine the morphological and immunohistochemical characteristics of BMAD. We carried out a detailed morphologic review of 22 surgical specimens excised from patients with BMAD and compared them with PV of ARMC5 (PV + , n = 14) and those without (PV - , n = 8), and further comparing them with a control group of adrenals excised from patients with renal cancer (n = 11). No patients presented with a genetic syndrome related to BMAD. Overt Cushing's syndrome was present in 12/22 patients, 10 PV + and 2 PV - (p = 0.074). We also evaluated the expression of Ki-67, BCL-2, BAX, p53, CYP11B1, and ARMC5 protein. The pseudo-glandular and trabecular architectural patterns were strongly associated with the PV + group (both p < 0.001), as well as capsular extrusion (p < 0.001). There was no predictive value in the distinction of ARMC5 variants in Hsiao subtyping. ARMC5 diffuse cytoplasmic staining was observed in all 11 control samples. The ARMC5 expression was significantly lower in BMAD than in the control group (p < 0.001). In all the specimens, expression of BCL-2 was identified only in the medulla, and expression of BAX was observed in adrenocortical cells. CYP11B1 diffuse immunoexpression was identified in all the specimens of BMAD and in the fasciculata zone in the control group. The mitotic count and Ki-67 proliferation index was very low in all three groups (controls, PV + , and PV - BMAD). None of the specimens stained positive for the p53 protein. Although our series is limited, the presence of pseudo-glandular and/or trabecular patterns and capsular extrusion indicated the presence of pathogenic variants of ARMC5 in BMAD. The gland enlargement does not seem to be related to the increase of mitotic count or a higher proliferation index (Ki-67).

Impact of Morphology in the Genotype and Phenotype Correlation of Bilateral Macronodular Adrenocortical Disease (BMAD): A Series of Clinicopathologically Well-Characterized 35 Cases

Bilateral macronodular adrenocortical disease (BMAD) is characterized by the development of adrenal macronodules resulting in a pituitary-ACTH independent Cushing's syndrome. Although there are important similarities observed between the rare microscopic descriptions of this disease, the small series published are not representative of the molecular and genetic heterogenicity recently described in BMAD. We analyzed the pathological features in a series of BMAD and determined if there is correlation between these criteria and the characteristics of the patients. Two pathologists reviewed the slides of 35 patients who underwent surgery for suspicion of BMAD in our center between 1998 and 2021. An unsupervised multiple factor analysis based on microscopic characteristics divided the cases into 4 subtypes according to the architecture of the macronodules (containing or not round fibrous septa) and the proportion of the different cell types: clear, eosinophilic compact, and oncocytic cells. The correlation study with genetic revealed subtype 1 and subtype 2 are associated with the presence of ARMC5 and KDM1A pathogenic variants, respectively. By immunohistochemistry, all cell types expressed CYP11B1 and HSD3B1. HSD3B2 staining was predominantly expressed by clear cells whereas CYP17A1 staining was predominant on compact eosinophilic cells. This partial expression of steroidogenic enzymes may explain the low efficiency of cortisol production in BMAD. In subtype 1, trabeculae of eosinophilic cylindrical cells expressed DAB2 but not CYP11B2. In subtype 2, KDM1A expression was weaker in nodule cells than in normal adrenal cells; alpha inhibin expression was strong in compact cells. This first microscopic description of a series of 35 BMAD reveals the existence of 4 histopathological subtypes, 2 of which are strongly correlated with the presence of known germline genetic alterations. This classification emphasizes that BMAD has heterogeneous pathological characteristics that correlate with some genetic alterations identified in patients.

Primary macronodular adrenal hyperplasia (PMAH) can be generated by a new ARMC5 germline variant (c.52C>T (p.Gln18X))

Primary macronodular adrenal hyperplasia (PMAH) is a rare cause of Cushing syndrome (CS). In many cases of the PMAH family, variant in ARMC5, a putative tumor suppressor gene, are thought to induce the disease. The purpose of this study was to report a large Chinese family, in which a new germline heterozygous variant of ARMC5 (c.52C>T (p.Gln18X)) was found. A 64-year-old female patient (proband) was admitted to the hospital due to bilateral adrenal masses. In order to clarify the nature and function of adrenal masses, the proband completed several relevant screening tests of the adrenal function. After an ectopic receptor screening test and genetic testing, a new ARMC5 gene variant was found that might had led to the occurrence of PMAH. Because of its characteristic of autosomal dominant inheritance, the proband's relatives were recommended to conduct the genetic test. We collected the family members' genetic information, in which have 27 individuals, the proband tested the whole exon sequence, and 12 participants tested the Sanger sequence. Finally, 7 individuals were found have the same germline variant of ARMC5 as the proband. Subsequent computer analysis predicted that the variant significantly impaired protein function and resulted in inactivation of ARMC5. We found a new germline ARMC5 variant (c.52C>T (p.Gln18X)), which may induced PMAH. ARMC5 sequencing can improve the identification of clinical forms of PMAH and allow early diagnosis of the disease.

ARMC5 Alterations in Primary Macronodular Adrenal Hyperplasia (PMAH) and the Clinical State of Variant Carriers

Context

Primary macronodular adrenal hyperplasia (PMAH) is a rare type of Cushing or subclinical Cushing syndrome and is associated with bilateral multinodular formation. ARMC5 is one of the responsible genes for PMAH.

Objectives

This study was performed to identify the genotype-phenotype correlation of ARMC5 in a cohort of Japanese patients.

Patients and Methods

Fourteen patients with clinically diagnosed PMAH and family members of selected patients were studied for ARMC5 gene alteration and clinical phenotype. The associated nonadrenal tumor tissues were also studied.

Results

Of fourteen patients with PMAH, 10 had pathogenic or likely pathogenic variants of ARMC5. We found two variants. Five unrelated patients had identical variants (p.R619*). In two patients, the variant was found in offspring with the asymptomatic or presymptomatic state. Six of ten patients who tested positive for the ARMC5 pathogenic or likely pathogenic variant carried nonadrenal tumors; however, no loss of heterozygosity (LOH) or second hit of the ARMC5 gene was evident. The ARMC5 variant–positive group showed a significantly higher basal cortisol level. Furthermore, age-dependent cortisol hypersecretion was seen in the ARMC5 variant–positive group.

Conclusions

ARMC5 pathogenic variants are common (71%) in Japanese patients with PMAH. p.R619* might be a hot spot in Japanese patients with PMAH. Asymptomatic or presymptomatic pathogenic variant carriers were found among the family members of the patients. Although 50% of ARMC5 variant carriers had nonadrenal neoplastic lesions, no LOH or second hit of ARMC5 in the tumor tissues was evident. The ARMC5 variant–positive mutant group showed a higher basal cortisol level than the negative group.

Whole-genome sequencing revealed armadillo repeat containing 5 (ARMC5) mutation in a Chinese family with ACTH-independent macronodular adrenal hyperplasia

Primary macronodular adrenal hyperplasia (PMAH), also known in the past as bilateral macronodular adrenalhyperplasia or adrenocorticotropin (ACTH)-independent macronodular adrenal hyperplasia, is a rare type of Cushing's syndrome (CS) and is associated with bilateralenlargement of the adrenal glands. It accounts for <1% of all endogenous cases of CS. In order toidentify the pathogenic mutations in the causative gene of (AIMAH pedigrees, Whole-genome sequencing of three patients in family I was used to retrieve candidate causative genes. Meanwhile, the causative gene was identified by Sanger sequencing from the two pedigrees. Sequencing of ARMC5 exons of three patients was carried out to identify somatic mutations. Moreover, haploid clone of one tumor DNA sample was conducted. ARMC5 was the causative gene of two pedigrees confirmed by whole-genome sequencing (WGA) and Sanger sequencing. The variant sites of the two families were c.C943T (p.R315W) and c.C1960T (p.R654X), respectively. Autosomal dominant inheritance of AIMAH was confirmed by genotypes of one family member. Several somatic mutations were discovered in tumor DNA samples. In addition, haploid clone of tumor DNA was confirmed by germline mutation and somaticmutation, which suggested the pathogenic mechanism of "two-hit-model." ARMC5 was the causative gene of AIMAH pedigrees. This AIMAH in this study presented autosomal dominant inheritance, fitting to Mendelian inheritance law. However, the pathogenic mode of this disease showed as compound heterozygote.

ARMC5 Mutations in a Large Cohort of Primary Macronodular Adrenal Hyperplasia: Clinical and Functional Consequences

CONTEXT

Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of primary adrenal Cushing's syndrome (CS). ARMC5 germline mutations have been identified recently in PBMAH.

OBJECTIVE

To determine the prevalence of ARMC5 mutations and analyze genotype-phenotype correlation in a large cohort of unrelated PBMAH patients with subclinical or clinical CS.

PATIENTS AND METHODS

ARMC5 was sequenced in 98 unrelated PBMAH index cases. PBMAH was identified by bilateral adrenal nodular enlargement on computed tomography scan. The effect on apoptosis of ARMC5 missense mutants was tested in H295R and HeLa cells. Clinical and hormonal data were collected including midnight and urinary free cortisol levels, ACTH, androgens, renin/aldosterone ratio, cortisol after overnight dexamethasone suppression test, cortisol and 17-hydroxyprogesterone after ACTH 1-24 stimulation and illegitimate receptor responses. Computed tomography and histological reports were analyzed.

RESULTS

ARMC5-damaging mutations were identified in 24 patients (26%). The missense mutants and the p.F700del deletion were unable to induce apoptosis in both H295R and HeLa cell lines, unlike the wild-type gene. ARMC5-mutated patients showed an overt CS more frequently, compared to wild-type patients: lower ACTH, higher midnight plasma cortisol, urinary free cortisol, and cortisol after dexamethasone suppression test (P = .003, .019, .006, and <.001, respectively). Adrenals of patients with mutations were bigger and had a higher number of nodules (P = .001 and <.001, respectively).

CONCLUSIONS

ARMC5 germline mutations are common in PBMAH. Index cases of mutation carriers show a more severe hypercortisolism and larger adrenals. ARMC5 genotyping may help to identify clinical forms of PBMAH better and may also allow earlier diagnosis of this disease.

ARMC5 mutations are common in familial bilateral macronodular adrenal hyperplasia

CONTEXT

Bilateral macronodular adrenal hyperplasia (BMAH) is a rare form of adrenal Cushing's syndrome. Familial cases have been reported, but at the time we conducted this study, the genetic basis of BMAH was unknown. Recently, germline variants of armadillo repeat containing 5 (ARMC5) in patients with isolated BMAH and somatic, second-hit mutations in tumor nodules, were identified.

OBJECTIVE

Our objective was to identify the genetic basis of familial BMAH.

DESIGN

We performed whole exome capture and sequencing of 2 affected individuals from each of 4 BMAH families (BMAH-01, BMAH-02, BMAH-03, and BMAH-05). Based on clinical evaluation, there were 7, 3, 3, and 4 affected individuals in these families, respectively. Sanger sequencing of ARMC5 was performed in 1 other BMAH kindred, BMAH-06.

RESULTS

Exome sequencing identified novel variants Chr16:g.31477540, c.2139delT, p.(Thr715Leufs*1) (BMAH-02) and Chr16:g.31473811, c.943C→T, p.(Arg315Trp) (BMAH-03) in ARMC5 (GRch37/hg19), validated by Sanger sequencing. BMAH-01 had a recently reported mutation Chr16:g.31476121, c.1777C→T, p.(Arg593Trp). Sanger sequencing of ARMC5 in BMAH-06 identified a previously reported mutation, Chr16:g. 31473688; c.799C→T, p.(Arg267*). The genetic basis of BMAH in BMAH-05 was not identified.

CONCLUSIONS

Our studies have detected ARMC5 mutations in 4 of 5 BMAH families tested, confirming that these mutations are a frequent cause of BMAH. Two of the 4 families had novel mutations, indicating allelic heterogeneity. Preclinical evaluation did not predict mutation status. The ARMC5-negative family had unusual prominent hyperaldosteronism. Further studies are needed to determine the penetrance of BMAH in ARMC5 mutation-positive relatives of affected patients, the practical utility of genetic screening and genotype-phenotype correlations.

The role of unilateral adrenalectomy in corticotropin-independent bilateral adrenocortical hyperplasias

BACKGROUND

The objective of the present study was twofold: to demonstrate our experience with unilateral adrenalectomy in the treatment of adrenocorticotropic hormone (ACTH)-independent Cushing syndrome (CS) caused by bilateral adrenocortical hyperplasias, and to evaluate the long-term results as evidenced by the main laboratory and clinical findings.

METHODS

From February 2000 to August 2009, unilateral adrenalectomy was performed on 27 patients with ACTH-independent CS and bilateral adrenocortical hyperplasias, including 14 patients with ACTH-independent macronodular adrenal hyperplasia (AIMAH) and 13 patients with primary pigmented nodular adrenocortical disease (PPNAD). Signs and symptoms of CS, endocrine examinations, and radiographic imaging were evaluated preoperatively and postoperatively.

RESULTS

At a median follow-up of 69 months (range: 23-120 months) for AIMAH and 47 months (range: 16-113 months) for PPNAD, 25 patients were cured by unilateral adrenalectomy. Serum cortisol level, daily urinary free cortisol (UFC), and plasma ACTH regained the normal range in both AIMAH and PPNAD patients at monthly follow-up visits; the circadian serum cortisol rhythm returned to normal, and a normal responsiveness to overnight low-dose dexamethasone administration (LDDST) became obvious. Both systolic and diastolic blood pressure (BP) levels were significantly reduced: 85 % of patients recovered normal BP levels, and the remaining patients need antihypertensive drugs, but at a reduced dose. No surgery-related morbidity occurred, and there was no sign of further enlargement of the residual adrenal gland after successful unilateral adrenalectomy. One patient with PPNAD and another patient with AIMAH with similar weights and sizes of the bilateral adrenals needed contralateral adrenalectomy.

CONCLUSIONS

Unilateral adrenalectomy may be the suitable treatment for selected patients with AIMAH and PPNAD. It can achieve long-term remission of CS and improve glycemic control and BP values.

Adrenal cortical adenoma: the fourth component of the Carney triad and an association with subclinical Cushing syndrome

The Carney triad is the combination of gastric stromal sarcoma, pulmonary chondroma, and extra-adrenal paraganglioma. Herein, we describe the clinical, imaging, pathologic, and follow-up findings from 14 patients for a fourth component of the syndrome, adrenal adenoma. The adrenal neoplasm was asymptomatic and usually a late finding. Results of adrenocortical function tests were normal. Computed tomography revealed low-density adrenal masses that were consistent with adenomas. Bilateral lesions were present in 4 patients. In 13 of the 14 patients who underwent surgery, resected adrenal glands and biopsy specimens featured 1 or more circumscribed, yellow tumors, up to 3.5 cm in diameter, composed of well-differentiated polygonal cells with clear vacuolated cytoplasm and a smaller component of eosinophilic cells. The extratumoral cortex had combinations of normal histologic features, discrete clear cell micronodules, zonal clear cell hypertrophy, and marked atrophy. The lesion in the 14th patient was different, grossly and microscopically resembling the usual sporadic cortisol-secreting adenoma. After the tumor was excised, the patient required glucocorticoid support. None of the tumors recurred or metastasized. Fourteen additional patients had unilateral or bilateral adrenal tumors consistent with adenomas detected by imaging studies.

Adrenal Incidentalomas with Supraphysiologic Response to ACTH Stimulus: A Case Report

We present the diagnostic approach of a patient with adrenal incidentalomas. A 72-year-old African American male had a CT scan of the abdomen showing right and left adrenal masses measuring 5 × 3.5 cm and 3.7 × 2.9 cm, respectively. The patient had negative hormonal workup. The radiologist insisted that the CT findings are consistent with adrenal hyperplasia, and therefore he underwent ACTH stimulation to rule out late-onset congenital adrenal hyperplasia (CAH). The stimulation test revealed that 17-hydroxyprogesterone and 11-deoxycortisol increased to levels high enough to confirm CAH, but cortisol had exaggerated response as well, thus making the diagnosis of CAH unlikely where metabolism is shifted to precursors. Subsequently, the patient underwent screening for Cushing's syndrome (CS) with a dexamethasone suppression test. Patient failed the suppresion test, raising the issue for subclinical CS (SCS), likely due to ACTH-independent macronodular adrenal hyperplasia. Our patient had been diagnosed with MGUS and so far there are only 3 case reports of extramedullary plasmacytoma arising from the adrenals. One was bilateral and one had functional abnormalities. Our differential diagnosis includes subclinical CS with aberrant receptors versus a functioning extramedullary plasmacytoma.

Long-term efficacy of trilostane for Cushing's syndrome due to adrenocorticotropin-independent bilateral macronodular adrenocortical hyperplasia

A 66-year-old man with Cushing's syndrome due to adrenocorticotropin-independent bilateral macronodular adrenocortical hyperplasia (AIMAH) was treated for 7 years with trilostane, a 3β-hydroxysteroid dehydrogenase inhibitor. Administration of trilostane reduced the serum cortisol level to around the upper limit of normal for 7 years, and symptoms of excessive glucocorticoid production (such as moon face and obesity) were gradually improved. On the other hand, the size of both adrenal glands gradually increased despite treatment with trilostane. Though trilostane therapy could not prevent adrenal growth, it did suppress cortisol secretion over the long term, so it might be a reasonable option for AIMAH in addition to adrenalectomy.

ACTH-independent macronodular adrenal hyperplasia

Adrenocorticotropic hormone- (ACTH-)independent macronodular adrenal hyperplasia (AIMAH) is an infrequent cause of Cushing's syndrome (CS). AIMAH presents as incidental radiological finding or with subclinical or overt CS, occasionally with secretion of mineralocorticoids or sex steroids. The pathophysiology of this entity is heterogeneous. The aberrant adrenal expression and function of one or several G-protein-coupled receptors can lead to cell proliferation and abnormal regulation of steroidogenesis. In several familial cases of AIMAH, specific aberrant hormone receptors are functional in the adrenal of affected members. Additional somatic genetic events related to cell cycle regulation, adhesion and transcription factors occur in addition in the various nodules over time. Other mechanisms, such as Gsp or ACTH receptor mutations and paracrine adrenal hormonal secretion, have been rarely identified in other cases of AIMAH. The identification of aberrant receptors can offer a specific pharmacological approach to prevent progression and control abnormal steroidogenesis; alternatively, unilateral or bilateral adrenalectomy becomes the treatment of choice.

Lesions of the adrenal cortex

CONTEXT

In surgical pathology practice adrenal cortical tumors are rare. However, in autopsy series adrenal cortical nodules are found frequently. These are now being identified more commonly in life when the abdomen is scanned for other disease. It is important to differentiate between benign and malignant lesions as adrenal cortical carcinoma is an aggressive tumor. Molecular genetic investigations are providing new information on both pathogenesis of adrenal tumors and basic adrenal development and physiology.

OBJECTIVE

To provide an overview of current knowledge on adrenal cortical development and structure that informs our understanding of genetic diseases of the adrenal cortex and adrenal cortical tumors.

DATA SOURCES

Literature review using PubMed via the Endnote bibliography tool.

CONCLUSIONS

The understanding of basic developmental and physiologic processes permits a better understanding of diseases of the adrenal cortex. The information coming from investigation of the molecular pathology of adrenal cortical tumors is beginning to provide additional tests for the assessment of malignant potential in diagnosis but the mainstay remains traditional histologic analysis.

How the new tools to analyze the human genome are opening new perspectives: the use of gene expression in investigations of the adrenal cortex

With the promise of state-of-the-art molecular technologies and the tools provided by the human genome project, a number of investigators are trying to identify molecular targets of adrenocortical tumorigenesis. One path in this endeavor was the identification by positional cloning of genes that are mutated in rare adrenocortical tumors. The subject of this article is an update of the results of experiments in the second path that was followed by us and others: that of using genome-wide expression analysis of adrenocortical cells in normal and various disease states. Transcriptomic analysis is a rapidly evolving technology; this article summarizes some data on the adrenal cortex and points out how these new technologies can be used in the identification of important genes and molecular pathways in both normal and diseased adrenal cortex.

A diagnostic approach to adrenal cortical lesions

The adrenal gland is not a common specimen in surgical pathology practice as, until recently, adrenal tumors were recognized in life only if associated with hypersecretion of hormones or evidence of malignancy. However, adrenal nodules are not uncommon at autopsy, and the number of these found in life is now increasing as they are identified when the abdomen is scanned for the investigation of other diseases using computed tomography or magnetic resonance imaging. It is therefore becoming increasingly important for the surgical pathologist to be aware of the range of pathology in the gland and to understand how to approach the specimens. This short review will deal with lesions of the adrenal cortex.

Cushing's syndrome secondary to ACTH-Independent macronodular adrenal hyperplasia

ACTH-Independent macronodular adrenal hyperplasia (AIMAH) is a rare cause of endogenous Cushing's syndrome (CS), in which clinical features usually become apparent only after several decades of life. This form of adrenal hyperplasia typically produces excess cortisol with overt or subclinical CS, but concurrent secretion of mineralocorticoids or sexual steroids can also occur. The diagnosis is suspected by bilateral adrenal nodules larger than 1 cm on incidental imaging studies or following the demonstration of ACTH-independent hormonal hypersecretion. The pathophysiology of this entity is heterogeneous and has been intensely explored in recent years. Several G-protein coupled receptors aberrantly expressed in the adrenal cortex have been implicated in the regulation of steroidogenesis and in the initial cell proliferation in AIMAH. Several familial cases of AIMAH have been recently described with the same pattern of aberrant hormone receptors in all affected members of the family. It is probable that additional somatic genetic events related to cell cycle regulation, adhesion and transcription factors occur in addition over time in the various nodules; other mechanisms, as Gsp or ACTH receptor mutations and paracrine adrenal hormonal secretion have been rarely identified as the molecular mechanism in some cases. When systematically screened, most patients with AIMAH exhibit an in vivo aberrant cortisol response to one or various ligands suggesting the presence of aberrant adrenal receptors. The identification of these receptors creates the possibility of a specific pharmacological treatment isolated or associated with adrenalectomy.

Familial adrenocorticotropin-independent macronodular adrenal hyperplasia with aberrant serotonin and vasopressin adrenal receptors

ACTH-independent macronodular adrenocortical hyperplasia (AIMAH) is rare and generally presents as a sporadic disease. We describe a familial case of AIMAH with in vivo and in vitro demonstration of aberrant 5-HT4 and vasopressin adrenal receptors. Two sisters presented with clinical and biological features of mild Cushing's syndrome with bilateral macronodular adrenal enlargement on computerized tomography (CT)-scan evaluation. In vivo pharmacological tests showed a significant increase in plasma cortisol after terlipressin and metoclopramide administration. Unilateral adrenalectomy was performed in one of these patients. Reverse transcriptase-PCR analysis of the hyperplastic tissue revealed expression of 5-HT4 receptor isoforms (a), (b), (c), (i), and (n), and of vasopressin receptors, V1 and V2. Their father and brother were overweight, had easy bruisability and presented with biological features of subclinical Cushing's syndrome. CT scan showed moderate adrenal enlargement. In vivo pharmacological screening tests for the detection of adrenal aberrant receptors in the brother were negative. Finally, three out of the two sisters' children were evaluated. They had neither clinical nor biological features of Cushing's syndrome. Their adrenal glands were normal on CT-scan evaluation. In vivo evaluation for the detection of aberrant adrenocortical receptors performed in one of these subjects was negative. In conclusion, this study shows that (i) familial AIMAH could be an autosomal dominantly inherited disorder; (ii) aberrant 5-HT4 serotonin and vasopressin receptors can be expressed in familial AIMAH; and (iii) phenotypic expression of familial AIMAH could be varied in a same family and more pronounced in female than in male patients.

Simultaneous Bilateral Laparoscopic Adrenalectomy for Adrenocorticotropic Hormone-Independent Macronodular Adrenal Hyerplasia: Report of a Case

Cushing's syndrome caused by adrenocorticotropic hormone (ACTH)-independent macronodular adrenal hyperplasia (AIMAH) is an extremely rare disease, which shows bilateral macronodular adrenal hypertrophy and autonomous cortisol production. We herein report a case of AIMAH treated successfully by minimally invasive simultaneous bilateral laparoscopic adrenalectomy. A 73-year-old woman with hypertension, diabetes mellitus, and osteoporosis was referred to our hospital because of an incidentally found huge bilateral adrenal mass. An abdominal computed tomography scan showed large bilateral adrenal glands with multiple nodules. A diagnosis of AIMAH was made and a simultaneous bilateral laparoscopic adrenalectomy was thus performed. The total operation time was 310 min and blood loss was 70 g. Both glands were hypertrophic (right 5 x 3 cm, 48.5 g and left 4 x 2 cm, 39.2 g) and consisted of multiple golden yellow macronodules. The postoperative course was uneventful. A simultaneous bilateral adrenalectomy for AIMAH performed by an experienced surgical team is therefore considered to be a safe and minimally invasive procedure.

A case of adrenocorticotropin-independent bilateral adrenal macronodular hyperplasia (AIMAH) with primary hyperparathyroidism (PHPT)

We report a rare case of ACTH-independent macronodular adrenal hyperplasia (AIMAH) with primary hyperparathyroidism (PHPT). A 57-year-old woman was admitted to our hospital for further examination of secondary hypertension and bilateral adrenal macrotumors. Midnight serum cortisol elevation with undetectable plasma ACTH, increased 24-hour urinary free cortisol excretion, and loss of the normal circadian rhythm in cortisol secretion established the diagnosis of Cushing's syndrome. Total resection of the enlarged left adrenal gland was performed with subsequent steroid replacement. Her general condition improved but serum calcium level increased 3 weeks after surgery. PHPT was diagnosed on the basis of endocrinological examination, although imaging studies failed to detect parathyroid lesion. In summary, we believe this to be the first report of a case of AIMAH with PHPT.

Expression of ACTH receptor pathway genes in glucose-dependent insulinotrophic peptide (GIP)-dependent Cushing's syndrome

OBJECTIVE

The molecular mechanisms responsible for glucose-dependent insulinotrophic peptide receptor or gastric inhibitory polypeptide receptor (GIPR) ectopic expression and function in GIP-dependent Cushing's syndrome (CS) are still unknown. GIPR presumably acts, like the ACTH receptor (ACTHR), through the Gs protein/cyclic AMP/protein kinase A (PKA) pathway to stimulate steroidogenesis. We studied the expression of several genes involved in this pathway in the adrenal tissues of patients with GIP-dependent CS.

DESIGN AND METHODS

RNA was extracted from adrenal tissues from nine patients with GIP-dependent CS [seven ACTH-independent bilateral macronodular adrenal hyperplasia (AIMAH), two adenomas], two control whole adult adrenals, two fasciculata cell-enriched preparations from normal adrenals, seven patients with Cushing's disease (CD) and two normal pancreas. Multiplex reverse transcriptase polymerase chain reaction (RT-PCR) evaluated the expression of GIPR, ACTHR, SF-1, Nur77, DAX-1, CYP11A, 3beta-HSD, CYP21, CREB and CREM genes.

RESULTS

GIPR mRNA was overexpressed in all GIP-dependent cases. In normal adrenals and in the adrenal tissues from patients with CD, minimal amounts of GIPR mRNA were detected. ACTHR mRNA expression was observed in all GIP-dependent adrenal tissues. The expression of steroidogenic enzymes and some specific and ubiquitous transcription factors (TFs) involved in the ACTHR cascade was significantly reduced.

CONCLUSIONS

Our results indicate that the expression of ACTHR and other genes located downstream in the ACTHR cascade, including steroidogenic enzymes genes and some transcription factors, are relatively suppressed in GIP-dependent CS. Although the expression of aberrant receptors plays an important role in steroidogenesis and initiation of cell proliferation, additional genetic events might occur, altering the activity of the ACTHR pathway.

Clinical and Subclinical ACTH-Independent Macronodular Adrenal Hyperplasia and Aberrant Hormone Receptors

ACTH-independent macronodular adrenal hyperplasia (AIMAH) is a very rare cause of endogenous Cushing's syndrome (CS). In this review, the clinical characteristics, the pathophysiology, and the management of AIMAH are described. AIMAH typically presents with overt CS, but subclinical oversecretion of cortisol has been increasingly described. The diagnosis is suspected by adrenal nodular enlargement on conventional imaging following the demonstration of ACTH-independent hypercortisolism. Final diagnosis is established by histological examination of the adrenal tissue. Bilateral adrenalectomy is the treatment of choice but unilateral adrenalectomy has been proposed in selected cases. In patients with subclinical CS, the decision to treat should be individualized. The pathophysiology of this condition has begun to be elucidated in recent years. Diverse aberrant membrane-bound receptors expressed in a non-mutated form in the adrenal gland have been found to be implicated in the regulation of steroidogenesis in AIMAH. When systematically screened, most patients with AIMAH and CS or subclinical CS exhibit an in vivo aberrant cortisol response to one or various ligands suggesting the presence of aberrant adrenal receptors. A protocol designed to screen patients for the presence of these aberrant receptors should be undertaken in all patients with AIMAH. The identification of these receptors provides the potential for novel pharmacological therapies by suppressing the endogenous ligands or blocking the receptor with specific antagonists.

Bilateral adrenal Cushing's syndrome: macronodular adrenal hyperplasia and primary pigmented nodular adrenocortical disease

Corticotropin (ACTH)-independent bilateral macronodular adrenal hyperplasia (AIMAH) and primary pigmented nodular adrenocortical disease (PPNAD) are responsible for approximately 10% of adrenal Cushing's syndrome. AIMAH also can be present as subclinical bilateral incidentalomas in sporadic or familial forms. Diverse aberrant hormone receptors have been found to be implicated in the regulation of steroidogenesis and pathophysiology of AIMAH. PPNAD can be found alone or in the context of Carney complex, a multiple endocrine neoplasia syndrome. Additionally, it can be secondary to mutations of type 1 alpha-regulatory subunit of cAMP-dependent protein kinase A (PRKARIA). Strategies for the investigation and treatment of AIMAH and PPNAD are discussed.

Histopathological diagnosis and prognostic factors in adrenocortical carcinoma

A great majority of adrenocortical tumors are benign, and many adrenocortical carcinomas (ACC) are obviously malignant at presentation. The histopathological diagnosis of ACC is occasionally difficult, particularly with stage I and stage II disease. The prognosis of ACC is generally poor. Surgery is the major treatment, with chemotherapy and radiotherapy being applicable to only restricted patients. The Weiss criteria are useful in diagnosing the common adult type of ACC. Histopathological prognostic factors of ACC have not been fully established because of the rarity of the disease. In this article, we first describe the current histopathological diagnostic and prognostic factors of ACC, highlighting the special types of ACC to which Weiss's criteria are not fully applicable. These special type tumors include pediatric adrenocortical tumors, oncocytomas, and aldosterone-producing tumors of pure zona glomerulosa type. Then we present three cases with unusual small adrenocortical tumors. One patient had an unequivocal ACC showing metastatic disease. One had a histologically defined ACC with no metastasis or macroscopic invasion. The third was a pediatric patient with a tumor showing a nodule-in-nodule pattern with insulin-like growth factor II expression.

Cushing's syndrome due to a large adrenocortical adenoma with histological features simulating ACTH-independent macronodular adrenocortical hyperplasia

A 53-year-old woman presented with Cushing's syndrome resulting from an adrenocortical adenoma, 6.5 cm in diameter and 75 g in weight, which is larger than usual. Endocrinological data of this patient showed adrenocorticotropin (ACTH)-independent hypercortisolemia. A computed tomography scan of the adrenal glands revealed a single large and well-encapsulated tumor with an irregularly shaped area of calcification and loss of parenchyma on the left adrenal. The right adrenal gland was atrophic. Laparoscopic removal of the left adrenal tumor was performed. The tumor was lobulated and clearly encapsulated, and the non-neoplastic area of the left adrenal was atrophic without any nodularity. The histological analysis confirmed the diagnosis of adrenal adenoma. In addition, this adenoma displayed histopathological features in common with ACTH-independent macronodular adrenocortical hyperplasia (AIMAH), including clear cell predominance, a pattern of small compact cell nests in clear cell areas, and very long cord-like arrangement of small compact cells. In AIMAH, adrenals are extremely enlarged and are more massive than in any other subtype of Cushing's syndrome. The fact that the present adrenocortical adenoma was larger than those typical adenomas of Cushing's syndrome may reflect an AIMAH-type cellular composition of clear cell predominance and small compact cell nests.

Clinical and molecular genetic studies of bilateral adrenal hyperplasias

ACTH-independent, cortisol-producing hyperplasia is caused by 2 distinct disorders, primary pigmented nodular adrenocortical disease (PPNAD) and ACTH-independent macronodular adrenal hyperplasia (AIMAH). We will review recent findings on the clinical and molecular aspects of PPNAD and AIMAH. Inactivating mutations of PRKAR1A on 17q22-24, which codes for the type 1A regulatory subunit of protein kinase A, have been found in a subgroup of patients with PPNAD with and without Carney complex. AIMAH is a rare condition in which cortisol secretion may be mediated by non-ACTH circulating hormones such as gastric inhibiting polypeptide (leading to food-dependent Cushing's syndrome), vasopressin, catecholamines, luteinizing hormone, serotonin, angiotensin-II or leptin. The primary etiology of AIMAH remains unclear. Recently, we studied the expression profile of AIMAH by genomic cDNA microarray analysis. Several candidate genes were identified, suggesting pathways that affect the cell cycle, adhesion and transcription as possible mediators of adrenocortical hyperplasia.

Hiperplasia adrenal macronodular independente de ACTH (AIMAH): aspectos clínicos e moleculares

A AIMAH é caracterizada pela presença de macronódulos em ambas as adrenais, na ausência da estimulação do ACTH. Habitualmente, as manifestações clínicas aparecem somente após várias décadas de vida, provavelmente em função da baixa atividade esteroidogênica do tecido hiperplásico. Entretanto, em indivíduos assintomáticos cuja AIMAH foi descoberta acidentalmente, o eixo HHA já se encontra alterado. Estudos têm demonstrado que, na maioria dos casos de AIMAH, a secreção de cortisol é regulada de modo "aberrante" por hormônios como o GIP, AVP, catecolaminas, LH/hCG e serotonina, através de seus respectivos receptores, ectópicos ou eutópicos, porém aberrantemente acoplados à esteroidogênese. Os mecanismos moleculares responsáveis pela expressão ectópica dos receptores hormonais e/ou de seu acoplamento anormal à esteroidogênese adrenal ainda são pouco conhecidos. Embora a expressão aberrante destes receptores hormonais possa desempenhar um papel importante na iniciação da proliferação celular aumentada, bem como na esteroidogênese, é provável que eventos genéticos adicionais ocorram, envolvendo a regulação do ciclo celular, adesão e transcrição. Mutações no gene GNAS1 não associadas à síndrome de McCune-Albright podem ser encontradas em raros casos de AIMAH. Em alguns casos, a presença de receptor hormonal aberrante abre novas possibilidades de tratamento farmacológico específico do hipercortisolismo, seja isolado ou associado à adrenalectomia unilateral.

Bilateral adrenalectomy for Cushing's syndrome: a comparison between laparoscopy and open surgery

We report our experience with bilateral adrenalectomy for treatment of Cushing's syndrome and we compare the outcome of laparoscopy with open surgery in terms of effectiveness and safety. A series of 23 patients underwent bilateral adrenalectomy for treatment of Cushing's syndrome [Cushing's disease in 16, ectopic ACTH syndrome in 2, and ACTH-independent macronodular adrenal hyperplasia (AIMAH) in 5 cases]. From 1993 to 1996, all patients were treated using an open approach (Group A), while from 1997 all patients were treated using a transperitoneal laparoscopic approach (Group B). The comparison between the 2 groups was performed considering patients characteristics, operative times, blood losses, intraoperative and post-operative complications, analgesic consumption, post-operative hospital stay and recovery. Open surgery was performed in 10 patients and laparoscopy in 13 patients. No significant difference was recorded between the two groups as to patients' characteristics and complications. Mean operative time was significantly increased in Group B, while post-operative hospital stay was significantly longer in Group A. Laparoscopic bilateral adrenalectomy can be safely and effectively employed to treat Cushing's syndrome. However, long operatives times may represent a limitation especially in high risk patients.

Vasopressin responsiveness of subclinical Cushing's syndrome due to ACTH-independent macronodular adrenocortical hyperplasia

OBJECTIVE

Vasopressin (AVP) is reported to be an important factor for regulating cortisol secretion in patients with Cushing's syndrome due to ACTH-independent macronodular adrenocortical hyperplasia (AIMAH). Recently, there have been several case reports of subclinical Cushing's syndrome due to AIMAH, in which the pathophysiological role of AVP has been unknown. The aim was to conduct an extensive investigation of AVP in the autonomous secretion of cortisol in subclinical Cushing's syndrome due to AIMAH.

PATIENTS AND MEASUREMENTS

Five cases of AIMAH with subclinical Cushing's syndrome underwent prospective study including physical examination, imaging (MRI, CT and 131I-adosterol scintigraphy) and endocrinological evaluation that comprised basal plasma cortisol levels and urinary excretions of steroid metabolites, a dexamethasone suppression test and an AVP stimulation test. In case 1, left adrenalectomy was performed and the pathological diagnosis of AIMAH was established. An in vitro experiment using the cultured AIMAH adrenal cells was conducted to investigate cortisol secretion and expression of the V1-AVP receptor, mRNA by RT-PCR.

RESULTS

All five cases were discovered incidentally to have bilateral adrenal nodules. Imaging by MRI and CT revealed large multinodular lesions in both adrenal glands, which showed positive uptake on 131I-adosterol scintigraphy. Although the basal values of plasma cortisol and urinary excretions of steroid metabolites were within normal limits, autonomous secretion of cortisol was assumed to occur because of lack of suppression during dexamethasone suppression. The five patients had no overt signs of Cushing's syndrome, and they were therefore diagnosed with subclinical Cushing's syndrome due to AIMAH. In all five patients, AVP stimulated cortisol secretion in vivo, whereas desmopressin acetate failed to affect cortisol secretion. In case 1, AVP stimulated cortisol secretion from cultured AIMAH adrenal cells, but this secretion had no relationship with cAMP production. In addition, over-expression of V1-AVP receptor mRNA in AIMAH tissue was determined by RT-PCR.

CONCLUSION

Patients with subclinical Cushing's syndrome due to AIMAH commonly exhibit cortisol responsiveness to AVP, and this is probably mediated through activation of overexpressed V1-AVP receptors.

Adrenocorticotropin-independent macronodular adrenal hyperplasia treated by simultaneous bilateral laparoscopic adrenalectomy

A 61-year-old woman was admitted to our hospital with hypertension and diabetes mellitus, and was found to have Cushing's syndrome. Radiological and endocrinological findings suggested adrenocorticotropic hormone-independent macronodular adrenal hyperplasia. Simultaneous bilateral laparoscopic adrenalectomy was performed, minimizing the number of trocar sites and operation time. Success was attributed to the careful selection of trocar sites to permit safe dissection.

Laparoscopic bilateral adrenalectomy for Cushing's syndrome due to ACTH-independent macronodular adrenocortical hyperplasia

We performed simultaneous bilateral laparoscopic total adrenalectomy in two patients with Cushing's syndrome due to ACTH-independent macronodular adrenocortical hyperplasia (AIMAH). Preoperative serum cortisol in the patients was 29.5 and 53.2 microg/dl, respectively. The clinical symptoms of the latter patient were advanced, and respiration was labored with orthopnea. Laparoscopic adrenalectomies were performed transabdominally in the sequential lateral decubitus positions with extension of the lateral abdominal wall of the affected side. Three 12-mm and three 5-mm trocars were positioned, and two trocar sites in the midline were used on both sides. The flexible fiberscope was inserted through the umbilical port. The adrenal glands were large, fragile, and multinodular. The maximal diameters of the removed glands were 7.8 and 8.7 cm, respectively. In both patients, the adrenal glands were successfully removed without fragmentation. The operation times were 505 and 320 min, and the estimated blood loss was 150 and 5 ml, respectively. Neither intraoperative nor postoperative complications occurred, although the latter patient required muscle training before ambulation on postoperative day 42. The procedures resulted in marked clinical improvements. Compliance with the substitutive therapy remained excellent, and the patients expressed a very high degree of satisfaction with the laparoscopic adrenal surgery. The procedures of bilateral laparoscopic adrenalectomy were successful, and provided increased experience with the laparoscopic techniques.

[Macronodular adrenal hyperplasia: a case report]

This case report describes a 53-year old man with Cushing's syndrome due to Adrenocorticotropic Hormone (ACTH) independent bilateral adrenocortical macronodular hyperplasia (AIMAH). His plasma cortisol showed no diurnal rhythm and was unsuppressable by high-dose dexamethasone. Plasma ACTH was undetectable and did not respond to corticotrophin-releasing hormone. The aetiology of this rare disease remains uncertain. The treatment is based on bilateral adrenalectomy.

Laparoscopic adrenalectomy for incidentaloma and bilateral adrenal disease

Adrenalectomy is ideally suited to minimally invasive surgery based on the characteristics of adrenal tumours, which are usually small and benign. The aim of this study was to verify that laparoscopic adrenalectomy is minimally invasive and to assess the indication of laparoscopic adrenalectomy for incidentaloma. From October 1995 through August 2002, 133 patients underwent adrenal surgery at the Department of Surgery II, Nagoya University School of Medicine. Of these, 111 underwent laparoscopic adrenalectomy. All laparoscopic adrenalectomies were performed using the transabdominal lateral approach. In 50 of 133 patients, the adrenal tumours were incidentally discovered. There were 27 non-functioning adrenal tumours and six of seven preclinical Cushing's test syndrome cases incidentally discovered. Six of 27 non-functioning adrenal tumour patients underwent open adrenalectomy because of large tumour size or malignancy. Based on the present criteria for laparoscopic adrenalectomy, 15 of 133 patients were retrospectively considered to have required open adrenalectomy. The average size of a non-functioning adrenal tumour was 5.8 cm in diameter, which was equal to the average size of a phaeochromocytoma. A simultaneous bilateral laparoscopic adrenalectomy was performed in a patient in poor condition with advanced Cushing's syndrome due to adrenocorticotrophic hormone-independent macronodular adrenocortical hyperplasia (AIMAH). The adrenal glands were successfully removed without fragmentation in this patient, and the postoperative course was uneventful, thanks to the minimally invasive surgery. The laparoscopic technique assures less morbidity and faster recovery, and appears to be equally effective in eradicating functioning and non-functioning adrenal masses. The benefits of the laparoscopic approach to adrenalectomy should not result in a more aggressive attitude toward the excision of clinically silent, benign-appearing adrenal incidentalomas.

Adrenal cortical diseases: international case conference

Six pathologists from Japan and the United Kingdom evaluated four different cases of adrenocortical disorders independently. These adrenocortical disorders included an adrenal tumor in a 45-yr-old female without any endocrine abnormalities, bilateral adrenocortical lesions in a 55-yr-old female with Cushing syndrome, an adrenocortical mass in a 44-yr-old man with hypertension, and an adrenocortical lesion in a 62-yr-old female with chronic hypertension for 30 yr. In this article, we provide a clinical summary, macroscopic and histologic findings, and histologic diagnosis of these four adrenocortical cases.

Simultaneous bilateral laparoscopic adrenalectomy in ACTH-independent macronodular adrenal hyperplasia

Laparoscopic surgery for urological conditions has now become popular worldwide. The case is reported of a 56-year-old woman who underwent simultaneous bilateral laparoscopic adrenalectomy for adrenocorticotropic hormone-independent macronodular adrenocortical hyperplasia (AIMAH), followed by autotransplantation of resected adrenal gland fragments. Simultaneous laparoscopic adrenalectomies seem feasible for a patient with AIMAH because of its minimally invasive nature. However, autotransplantation of adrenal fragments failed in this patient with AIMAH.

Adrenocorticotropin-independent macronodular adrenal hyperplasia: an uncommon cause of primary adrenal hypercortisolism

PURPOSE

To describe the imaging findings in the adrenal glands of 12 patients with adrenocorticotropin (ACTH)-independent macronodular adrenocortical hyperplasia (AIMAH).

MATERIALS AND METHODS

Computed tomographic (CT) and magnetic resonance (MR) imaging findings in the adrenal glands were reviewed retrospectively in 12 patients (three men, nine women) with ACTH-independent Cushing syndrome and with bilateral nonpigmented multinodular adrenal hyperplasia. The results of pituitary MR imaging, adrenal scintigraphy, and petrosal sampling were available in nine, five, and six patients, respectively. Eleven patients underwent bilateral and one patient underwent unilateral adrenalectomy.

RESULTS

Eleven patients had enlarged multinodular adrenal glands: Nodules were 0.1-5.5 cm. The combined weight of both adrenal specimens for the 11 bilateral adrenalectomy specimens was 28-297 g, with a mean weight of 122 g. Glands were hypointense compared with the liver on T1-weighted images and were hyperintense on T2-weighted images. Pituitary MR imaging findings were negative in nine of nine patients. Iodomethylnorcholesterol scintigraphy showed bilateral uptake in four of five patients. Petrosal sinus sampling revealed no petrosal-to-peripheral ACTH gradients before corticotropin-releasing hormone (CRH) stimulation in six of six patients, but three patients had gradients after CRH stimulation. After undergoing bilateral or unilateral adrenalectomy, all patients were cured.

CONCLUSION

AIMAH is a rare cause of ACTH-independent Cushing syndrome, with characteristic CT findings of massively enlarged multinodular adrenal glands. Bilateral adrenalectomy is indicated on the basis of clinical and CT findings.

Surgical management of Cushing's syndrome

Patients with Cushing's syndrome (137 total) who underwent adrenalectomy from 1957 through 1999 were reviewed for survival and complications. Of the 137 patients, 83 had adrenocortical adenoma, 30 Cushing's disease, seven primary pigmented nodular adrenocortical disease (PPNAD), eight adrenocorticotropin (ACTH)-independent macronodular hyperplasia, five adrenocortical carcinoma, and four ectopic ACTH syndromes. Seventy-eight patients with adrenocortical adenoma are alive, and their survival rate was equal to the age-matched control population, when patients who died of postoperative complications were excluded. Of the patients with Cushing's disease, 20 are alive, and ten of 16 patients (63%) who were followed and evaluated, had skin pigmentation. Four of 16 patients (25%) developed Nelson's syndrome. Five PPNAD patients and six with ACTH-independent macronodular hyperplasia are alive. All five adrenocortical carcinoma patients and four with ectopic ACTH syndrome died within two years after operation. The prognosis for patients with adrenocortical adenoma after unilateral adrenalectomy is excellent, though it is important to avoid operative complications. The rapid disappearance of signs and symptoms of glucocorticoid excess after total adrenalectomy is assured, and the prognosis is satisfactory under careful glucocorticoid replacement, making total adrenalectomy an alternative treatment for Cushing's disease.

Subclinical Cushing syndrome due to adrenocorticotropic hormone-independent macronodular adrenocortical hyperplasia: changes in plasma cortisol levels during long-term follow-up

A 63-year-old man with bilateral adrenal tumors was treated for hypertension and diabetes mellitus. Endocrinologic examination during follow-up revealed the production of cortisol to be independent of the regulation of the hypothalamo-pituitary-adrenal axis. Therefore, he was diagnosed as having subclinical Cushing syndrome, and these tumors were removed. Adrenocorticotropic hormone-independent macronodular adrenal hyperplasia (AIMAH) was endocrinologically and histopathologically diagnosed. This is the first report demonstrating that endocrinologic changes of AIMAH can be observed during long-term follow-up.

Food-dependent Cushing's syndrome: possible involvement of leptin in cortisol hypersecretion

Stimulation ofcortisol secretion by food intake has been implicated in the pathogenesis of some cases of ACTH-independent Cushing's syndrome, via an aberrant response of the adrenal glands to gastric inhibitory polypeptide (GIP). We report here a novel case of food-dependent Cushing's syndrome in a patient with bilateral macronodular adrenal hyperplasia. In this patient we were able to confirm a paradoxical stimulation of cortisol secretion by GIP in vivo as well as in vitro on dispersed tumor adrenal cells obtained at surgery. In addition to GIP, in vitro stimulation of these cultured tumor adrenal cells with leptin, the secreted product of the adipocyte, induced cortisol secretion. By comparison, no such stimulation was observed in vitro in adrenal cells obtained from another patient with bilateral macronodular adrenal hyperplasia and Cushing's syndrome that did not depend on food intake, in tumor cells obtained from a solitary cortisol-secreting adrenal adenoma, and in normal human adrenocortical cells. These results demonstrate that as in previously described cases of food-dependent Cushing's syndrome, GIP stimulated cortisol secretion from the adrenals of the patient reported here. Therefore, they indicate that such a paradoxical response probably represents the hallmark of this rare condition. In addition, they suggest that leptin, which normally inhibits stimulated cortisol secretion in humans, participated in cortisol hypersecretion in this case. Further studies in other cases of food-dependent Cushing's syndrome, however, will be necessary to better ascertain the pathophysiological significance of this finding.

In vivo and in vitro effects of AVP and V1a receptor antagonist on Cushing's syndrome due to ACTH-independent bilateral macronodular adrenocortical hyperplasia

We examined the possibility that AVP and V1a receptors were involved in regulating cortisol production in a 49 year old man with ACTH-independent bilateral macronodular adrenocortical hyperplasia (AIMAH), and investigated the effects of a V1a receptor antagonist. An i.v. injection of a small dose (0.1 or 0.3 U) of AVP, insulin-induced hypoglycaemia, upright posture tests, and oral administration of a V1a receptor antagonist (OPC-21268; 300 mg), and its repeated administration at a dose of 600 mg/day for 8 days were performed. An in vitro study of dispersed cells obtained from resected AIMAH tissue was also conducted. Plasma ACTH, AVP and cortisol levels and 24-h urinary free cortisol excretion were measured in the in vivo studies and cortisol concentrations in incubation media in the in vitro study. Injection of small doses of AVP stimulated cortisol secretion without any elevation of plasma ACTH. Insulin-induced hypoglycaemia caused a rise in plasma AVP followed by an increase in plasma cortisol. Although plasma cortisol levels were not affected by single or repeated administrations of OPC-21268, 24-h urinary free cortisol excretion was significantly decreased by the repeated treatment. In the in vitro study, more cortisol was stimulated by AVP from adrenal cells of the AIMAH tissue than from those of a normal adrenal gland, and this secretion was completely suppressed by OPC-21268. These results suggested that hypersensitivity to AVP may have contributed to overproduction of cortisol in this case of ACTH-independent bilateral macronodular adrenocortical hyperplasia, and may have contributed to its pathogenesis.

Differential diagnosis and management of Cushing's syndrome

The diagnosis of endogenous Cushing's syndrome requires demonstration of an increased cortisol secretion rate, best achieved by urinary free cortisol excretion determinations. In borderline or confusing cases, loss of diurnal cortisol rhythmicity, a combined dexamethasone/corticotropin releasing hormone (CRH) test, or close monitoring of the patient for a few months will be helpful in ruling out pseudo-Cushing's. Primary adrenal Cushing's syndrome can be ruled out on the basis of a normal or elevated basal and/or CRH-stimulated plasma adrenocorticotropin (ACTH) and a negative adrenal computed tomography. ACTH-dependent Cushing's syndrome can then be differentiated on the basis of a CRH test and imaging procedures. A discrete pituitary lesion on magnetic resonance imaging and a standard CRH test with results consistent with such a lesion are sufficient to proceed to transsphenoidal surgery. If no discrete pituitary lesion is present, or if the CRH test is equivocal, bilateral simultaneous inferior petrosal sinus sampling with CRH administration is necessary to distinguish between a pituitary and an ectopic source. Surgery is the treatment of choice for all types of Cushing's syndrome. In the few cases in which transsphenoidal surgery fails or the disease recurs, repeat transsphenoidal surgery, or radiation therapy in association with mitotane treatment, is a reasonable alternative. Bilateral adrenalectomy effectively cures hypercortisolism if resection of the ACTH-secreting tumor is unsuccessful and radiation/medical therapy fails.

Autonomous nodular hyperplasia of the adrenal cortex: tertiary hypercortisolism?

Two cases of Cushing's syndrome are reported in which apparently autonomous adrenal adenomata were associated with the presence of pituitary tumours. In one case the patient was apparently cured by unilateral adrenalectomy, although she was noted to have radiological evidence of an intrasellar tumour; serum cortisol was not suppressed by dexamethasone and ACTH was undetectable. Serum ACTH in the second case was initially 31 ng/l but became undetectable during the course of investigation. Transsphenoidal removal of a corticotroph adenoma did not affect serum cortisol and she proceeded to unilateral adrenalectomy. The pathogenesis of autonomous macronodular hyperplasia is discussed, as well as the options for management.

Proliferating cell nuclear antigen in ACTH-independent bilateral macronodular adrenal hyperplasia

ACTH-independent bilateral macronodular adrenal hyperplasia (AIMAH) has been recently described as a rare cause of Cushing's syndrome and it is an unusual process of unknown etiology. This report describes a case of a 59-year-old man with AIMAH. The proliferating cell nuclear antigen (PCNA) has been implicated in the process of cell proliferation and is detectable throughout most of the cell cycle. This report also describes the expression of PCNA in AIMAH by immunohistochemical staining. Most of the positive expression was seen in the greater part of the epithelial cells of the cortical lesion, but not in the interstitial cells. These data suggest that some effective factor, specific for adrenal cortical cell growth, might be produced in AIMAH.

Advances in the diagnosis and treatment of Cushing's syndrome

Excess endogenous glucocorticoid production, whether ACTH-dependent or ACTH-independent, results in the classic clinical and biochemical picture of Cushing's syndrome. The diagnosis requires demonstration of an increased cortisol secretion rate, best achieved using determination of urinary free cortisol as an index. In mild cases, distinction from the hypercortisolism of pseudo-Cushing states may prove difficult. If the physician is in doubt, a dexamethasone/CRH test should be performed. Primary adrenal Cushing's syndrome can be diagnosed on the basis of undetectable plasma ACTH and the results of adrenal imaging procedures. ACTH-dependent Cushing's syndrome can be differentiated using an oCRH test and imaging procedures. In the presence of a discrete pituitary lesion on imaging, a standard oCRH test with results consistent with such a lesion is sufficient to proceed to transsphenoidal surgery. In the absence of such a lesion or if the oCRH test is equivocal, simultaneous BIPSS with oCRH administration should be performed to distinguish between a pituitary or ectopic source. Surgical ablation is the treatment of choice for all types of Cushing's syndrome. In the 5% of cases with Cushing's disease in whom transsphenoidal surgery fails and in the 5% of cases in whom the disease recurs, repeat transsphenoidal surgery or radiation therapy in association with mitotane treatment are reasonable alternatives. Bilateral adrenalectomy effectively cures hypercortisolism if resection of the ACTH-secreting tumour is unsuccessful and radiation/medical therapy fails.

Adrenocorticotropic hormone-independent bilateral macronodular adrenocortical hyperplasia associated with Cushing's syndrome

A case of adrenocorticotropic hormone independent bilateral adrenocortical macronodular hyperplasia (AIMAH) is reported. A 59 year old male was admitted to hospital because of hypertension. Subsequently, hypercortisolism, low plasma adrenocorticotropic hormone (ACTH), loss of diurnal rhythm of ACTH, lack of suppression with high dose dexamethasone were found and bilateral adrenal enlargement was detected by abdominal computerized tomography and adrenal scintigraphy. Bilateral total adrenalectomy was performed under a diagnosis of bilateral adrenal hyperplasia associated with Cushing's syndrome. Both adrenal glands were enlarged in size and weight. Bulging nodules were found at the cut section. Microscopically, a variegated histologic pattern including trabecular, adenoid and zona glomerulosa-like (ZG-like) structures was revealed in the nodules. Immunohistochemical examination disclosed positive staining of cytochrome P-450 17 alpha, negative of 3 beta-HSD in the ZG-like structure. Ultrastructurally, the cells composing the ZG-like structure were similar to those of the ZG in normal adrenal cortex. The authors agree that AIMAH is one of the entities causing Cushing's syndrome, and advise pathologists to keep this disorder in mind when they examine the adrenals in Cushing's syndrome.