Ectopic ACTH syndrome: our experience with 25 cases.

OBJECTIVE: Ectopic ACTH syndrome (EAS) occurs in about 5-10% of all patients with ACTH-dependent hypercortisolism with most of them caused by intrathoracic neoplasms. It may be associated with overt malignancies or with occult and indolent tumors. We assessed the accuracy of dynamic tests, inferior petrosal sinus sampling (IPSS) using desmopressin, and imaging in the work-up diagnosis of EAS. DESIGN AND SUBJECTS: Tumor markers, imaging, and outcome data from 25 patients (13F/12M) aged 18-72 years. High dexamethasone suppression test (HDDST), desmopressin test, GHRP-6 test, corticotropin-releasing hormone (CRH) test, IPSS, computed tomography (CT), magnetic resonance imaging (MRI), and (111)In-pentetreotide scintigraphy were revised. RESULTS: In 5 out of 20 patients HDDST was positive. In 13 patients who underwent desmopressin test, ACTH- and cortisol-positive responses were seen in six and five patients respectively. GHRP-6 test was positive in two out of three cases. Two patients underwent CRH test with negative response. In the seven patients submitted to IPSS using desmopressin in six of them, none had ACTH gradients. CT was positive in 15 out of 21 patients and MRI in 8 out of 17 cases. (111)In-pentetreotide scintigraphy was positive in three out of five patients. Fourteen patients had intrathoracic tumors, five had pheochromocytomas, three had pancreatic tumors, one had a glomic tumor, and had three occult tumors. Six out of 11 patients with metastasis died and 3 others without metastasis died. CONCLUSIONS: IPSS with desmopressin was helpful for differential diagnosis. Patients initially harboring occult carcinoids may also exhibit severe hypercortisolism and those harboring tymic carcinoids had poor prognoses when compared with bronchial carcinoids and pheocromocytomas.

Deletion mapping of chromosome 17 in benign and malignant adrenocortical tumors associated with the Arg337His mutation of the p53 tumor suppressor protein.

The human p53 tumor suppressor gene is located at the short arm of chromosome 17. A germinative mutation (Arg337His) in the tetramerization domain of p53 has been frequently identified in Brazilian children with sporadic adrenocortical tumors. Loss of heterozygosity at this region was demonstrated in the majority of the cases. In the present study, we performed deletion mapping of chromosome 17 in 30 adrenocortical tumors from 29 Brazilian patients (15 children and 14 adults). One boy had bilateral adrenocortical tumor. Sixteen patients had the germinative Arg337His mutation. Loss of heterozygosity analysis using six polymorphic microsatellite markers disclosed loss of the entire chromosome 17 in 18 tumors (10 adenomas and eight carcinomas) from 17 patients. The Arg337His mutation was present in 13 of them. Chromosomal instability involving chromosomes 2, 9, and 11 was also found in 47, 47, and 70% of the 17 patients who exhibited chromosome 17 losses, respectively. The concomitant loss of chromosomes 2, 9, 11, and 17 was evidenced exclusively in malignant tumors. Therefore, chromosomal instability involving three or more chromosomes may contribute to define the malignant adrenocortical lesions. In conclusion, we demonstrated a high frequency of biallelic inactivation of p53 derived from two distinct events, the germinative Arg337His mutation and the acquired loss of the entire chromosome 17. In addition, the isolated loss of the entire chromosome 17 did not correlate with aggressive tumor behavior in these patients with adrenocortical tumors.

The role of desmopressin in bilateral and simultaneous inferior petrosal sinus sampling for differential diagnosis of ACTH-dependent Cushing's syndrome.

OBJECTIVE: Bilateral inferior petrosal sinus sampling (BIPSS) with corticotrophin-releasing hormone (CRH) stimulation is currently the gold standard test for the differential diagnosis of ACTH-dependent Cushing's syndrome. Reports on the use of desmopressin in this approach are limited. The aim of this study was to evaluate the use of desmopressin during BIPSS in a cohort of patients with ACTH-dependent Cushing's syndrome. DESIGN: A retrospective case-record study. PATIENTS: Fifty-six patients with confirmed ACTH-dependent Cushing's syndrome underwent BIPSS with desmopressin stimulation when presenting negative pituitary tumour imaging. MEASUREMENTS: Central to peripheral (CEN:PER) ACTH gradient, lateralization of the ACTH source and surgical tumour confirmation were evaluated. RESULTS: A CEN:PER ACTH gradient was found in 40 patients under basal conditions (CEN:PER >or= 2) and in 47 patients after desmopressin stimulation (CEN:PER >or= 3). Ectopic ACTH-producing tumours (three lung carcinoid tumour, one thymus carcinoid tumour and one thymus hyperplasia) were confirmed in five out of nine patients without the CEN:PER ACTH gradient, and four cases were false negative for Cushing's disease. Lateralization (IPS:IPS >or= 1.4) was observed in 80.8% of patients under basal conditions (38/47) and in 97.8% after desmopressin (46/47), and it was surgically confirmed in 78.7%. There were no false-positive cases. Sensitivity and specificity were 92.1% and 100%, respectively. CONCLUSIONS: Desmopressin improves the differential diagnosis of ACTH-dependent Cushing's syndrome by amplifying the CEN:PER and IPS:IPS ACTH gradients, and is therefore a useful ACTH secretagogue in BIPSS.