Tumor cells were cultured at 37 C in 5% CO2. of the adrenals revealed nonpigmented micronodular cortical hyperplasia associated with relative atrophy of internodular cortex. No genomic and/or somatic adrenal mutations of thePRKAR1A,PDE8B, andPDE11Agenes were detected. 17-Hydroxylase and 21-hydroxylase immunoreactivities as well as CYP11B1 mRNA were detected NCGC00244536 in adrenal and adenoma tissues. ACTH and dexamethasone activated cortisol secretion from adenoma cells. The stimulatory action of dexamethasone was mediated by a nongenomic effect involving the protein kinase A pathway. Conclusion:This case suggests that unknown molecular defects can favor both micronodular adrenal hyperplasia and ectopic adrenocortical adenoma associated with Cushings syndrome. The unusual association of adrenal micronodular hyperplasia and ectopic adrenocortical adenoma as a cause of ACTH-independent Cushings syndrome is discussed. Main adrenal cortisol hypersecretion is HSPB1 responsible for 1520% of all cases of Cushings syndrome. In 1015% of cases, Cushings syndrome is due to bilateral adrenal lesions that include micronodular and macronodular adrenal hyperplasias and, more rarely, bilateral adenomas or carcinomas (1,2). Micronodular adrenal hyperplasias are defined by the presence of multiple cortical micronodules,i.e. measuring less than 1 cm in diameter. They are themselves divided into two subtypes depending on the presence of internodular atrophy and nodular pigment. Main pigmented nodular adrenocortical disease (PPNAD) is usually characterized by multiple pigmented micronodules usually surrounded by internodular cortical atrophy. PPNAD may be isolated or may occur as part of the Carney complex that also includes spotty skin pigmentation, myxomas, and endocrine neoplasms (3). Most patients with PPNAD, especially when the disease is usually a component of Carney complex, have germline-inactivating mutations of thePRKAR1A[protein kinase A (PKA) regulatory subunit type 1] gene. Mutations of the phosphodiesterase (PDE)11AandPDE8Bgenes have also been described in patients with PPNAD or nonpigmented variants of the disease (4,5). All these genetic events lead to constitutive activation of the cAMP/PKA pathway that secondarily favors glucocorticoid hypersecretion and adrenocortical hyperplasia (2,3). It has been shown that patients with PPNAD exhibit a paradoxical increase in cortisol secretion in response to Liddles test;i.e. administration of dexamethasone at doses of 2 mg/d for 2 d followed by 8 mg/d for 2 d (6). This abnormal cortisol response is now used as a biological criterion for the diagnosis of the disease (7). An increase in urinary free cortisol excretion on the second day of high-dose dexamethasone administration higher than 50% of the basal level supports the diagnosis of PPNAD (6). In the present study, we statement a case of ACTH-independent Cushings syndrome associated with a paradoxical increase in urinary cortisol level in response to dexamethasone. The patient NCGC00244536 was found to have bilateral nonpigmented micronodular adrenocortical hyperplasia and ectopic,i.e. pararenal, adrenocortical adenoma. No germinal mutations of thePRKAR1A,PDE8B, andPDE11Agenes were detected. Similarly, molecular studies NCGC00244536 showed no somatic mutations of these three genes in adrenal gland and ectopic adenoma tissues. Immunohistochemical and quantitative PCR studies revealed the presence of 17-hydroxylase and 21-hydroxylase immunoreactivities and the expression of CYP11B1 mRNA in adrenal and adenoma tissues. Finally,in vitrostudies showed the occurrence of a paradoxical stimulatory effect of dexamethasone on cortisol production from cultured adenoma cells. == Patient and Methods == == Patient == A 35-yr-old woman was referred to our department of endocrinology for overt Cushings syndrome,i.e. presenting with faciotruncal obesity, facial erythrosis, easy bruising, striae, hypertension, and amenorrhea. Plasma cortisol concentrations were 264 g/liter [730 nmol/liter; NCGC00244536 normal: 91308 g/liter (250850 nmol/liter)] in the morning and 241 g/liter (666 nmol/liter) at midnight. Urinary cortisol concentrations, measured on two impartial samples, were 793 g/d [2190 nmol/d; normal: 2080 g/d (55220 nmol/d)] and 821 g/d (2266 nmol/d), respectively. The morning plasma ACTH concentration was undetectable [<5 pg/ml (1.1 pmol/liter); normal: 1080 pg/ml (2.217.6 pmol/liter)]. During the Liddles test, urinary cortisol increased from 821 to 1024 g/d (2825 nmol/liter). Administration of cosyntropin (250 g iv) induced a substantial increase in plasma cortisol levels from 253 g/liter (698 nmol/liter) to 458 g/liter.