deamino-arginine-vasopressin and Neuroendocrine-Tumors

Inferior petrosal sinus sampling (IPSS) is used to diagnose Cushing's disease (CD) when dexamethasone-suppression and CRH tests, and pituitary magnetic resonance imaging (MRI), are negative or give discordant results. However, IPSS is an invasive procedure and its availability is limited.. To test a noninvasive diagnostic strategy associated with 100% positive predictive value (PPV) for CD.. Retrospective study.. Two university hospitals.. A total of 167 patients with CD and 27 patients with ectopic ACTH-syndrome investigated between 2001 and 2016.. Performance of a strategy involving the CRH and desmopressin tests with pituitary MRI followed by thin-slice whole-body computed tomography (CT) scan in patients with inconclusive results.. Using thresholds of a cortisol increase > 17% with an ACTH increase > 37% during the CRH test and a cortisol increase > 18% with an ACTH increase > 33% during the desmopressin test, the combination of both tests gave 73% sensitivity and 98% PPV of CD. The sensitivity and PPV for pituitary MRI were 71% and 99%, respectively. CT scan identified 67% EAS at presentation with no false-positives. The PPV for CD was 100% in patients with positive responses to both tests, with negative pituitary MRI and CT scan. The Negative Predictive Value was 100% in patients with negative responses to both tests, with negative pituitary MRI and positive CT scan. Using this strategy, IPPS could have been avoided in 47% of patients in whom it is currently recommended.. In conjunction with expert radiologic interpretation, the non-invasive algorithm studied significantly reduces the need for IPSS in the investigation of ACTH-dependent Cushing's syndrome.

Topics: ACTH Syndrome, Ectopic; Adolescent; Adrenocorticotropic Hormone; Adult; Aged; Aged, 80 and over; Algorithms; Deamino Arginine Vasopressin; Decision Support Techniques; Diagnosis, Differential; Female; Humans; Hydrocortisone; Magnetic Resonance Imaging; Male; Middle Aged; Neuroendocrine Tumors; Petrosal Sinus Sampling; Pituitary ACTH Hypersecretion; Pituitary Function Tests; Pituitary Gland; Predictive Value of Tests; Retrospective Studies; Tomography, X-Ray Computed; Young Adult

A 32-year-old Chinese woman with rapid weight gain and progressive edema was found to have typical Cushingoid features. Her endocrine data were consistent with a diagnosis of ACTH-dependent Cushing's syndrome. To differentiate ectopic ACTH syndrome (EAS) from Cushing's disease (CD), various dynamic endocrine and imaging tests were performed. Her ACTH response was negative to corticotropin-releasing hormone (CRH) and positive to desmopressin. Magnetic resonance imaging of the pituitary showed no mass lesion. Computed tomography scan of the chest revealed a large mass (21 × 15 mm) in the anterior mediastinum, where positron emission tomography showed accumulation of [(18)F] fluorodeoxyglucose. Selective venous sampling showed marked step-up in ACTH level in the internal thoracic vein but not in the cavernous sinus after CRH stimulation. These data are compatible with the diagnosis of EAS. The resected tumor was pathologically consistent with thymic neuroendocrine tumor (NET) positive for ACTH by immunohistochemistry and abundant V1b receptor gene expression by RT-PCR. Postoperatively, her circulating ACTH/cortisol levels became normalized, and responded to stimulation with CRH but not with desmopressin. Her Cushingoid appearance gradually disappeared, and she was free from recurrence 5 years after surgery. This is a rare case of desmopressin-responsive EAS caused by thymic NET with predominant V1b gene expression, which was successfully localized by imaging modalities combined with selective venous sampling.

Topics: ACTH Syndrome, Ectopic; Adrenocorticotropic Hormone; Adult; Corticotropin-Releasing Hormone; Deamino Arginine Vasopressin; Diagnosis, Differential; Female; Fluorodeoxyglucose F18; Gene Expression; Humans; Hydrocortisone; Neuroendocrine Tumors; Pituitary ACTH Hypersecretion; Positron-Emission Tomography; Receptors, Vasopressin; Thymus Neoplasms; Tomography, X-Ray Computed