Ectopic Cushing's syndrome from a corticotropin-releasing hormone-secreting medullary thyroid carcinoma: a rare pitfall of inferior petrosal sinus sampling.

Summary: This case report describes a rare presentation of ectopic Cushing's syndrome (CS) due to ectopic corticotropin-releasing hormone (CRH) production from a medullary thyroid carcinoma (MTC). The patient, a 69-year-old man, presented with symptoms of muscle weakness, facial plethora, and easy bruising. An inferior petrosal sinus sampling test (IPSS) demonstrated pituitary adrenocorticotrophic hormone (ACTH) secretion, but a whole-body somatostatin receptor scintigraphy (68Ga-DOTATOC PET/CT) revealed enhanced uptake in the right thyroid lobe which, in addition to a grossly elevated serum calcitonin level, was indicative of an MTC. A 18F-DOPA PET/CT scan supported the diagnosis, and histology confirmed the presence of MTC with perinodal growth and regional lymph node metastasis. On immunohistochemical analysis, the tumor cell stained positively for calcitonin and CRH but negatively for ACTH. Distinctly elevated plasma CRH levels were documented. The patient therefore underwent thyroidectomy and bilateral adrenalectomy. This case shows that CS caused by ectopic CRH secretion may masquerade as CS due to a false positive IPSS test. It also highlights the importance of considering rare causes of CS when diagnostic test results are ambiguous. Learning points: Medullary thyroid carcinoma may secrete CRH and cause ectopic CS. Ectopic CRH secretion entails a rare pitfall of inferior petrosal sinus sampling yielding a false positive test. Plasma CRH measurements can be useful in selected cases.

When to Suspect Hidden Hypercortisolism in Type 2 Diabetes: A Meta-Analysis.

OBJECTIVE: To investigate whether the available literature helps to identify the characteristics of patients with type 2 diabetes (T2D) more frequently associated with hidden hypercortisolism (HidHyCo). METHODS: A meta-analysis was performed using studies that assessed both the prevalence of HidHyCo in patients with T2D and the characteristics of these patients with and without HidHyCo. The DerSimonian and Laird (DSL) and Hartung-Knapp-Sidik-Jonkman (HKSJ) methods were utilized. RESULTS: Among the 18 available studies, 6 provided the necessary data. The association between HidHyCo and advanced T2D (based on the patients' description given in each study in the presence of microvascular/macrovascular complications or insulin treatment plus hypertension or hypertension treated with 2 or more drugs), hypertension, insulin treatment, and dyslipidemia was reported in 5 (2184 patients), 6 (2283 patients), 3 (1440 patients), and 3 (987 patients) studies, respectively. HidHyCo was associated with advanced T2D as assessed by both the DSL (odds ratio [OR], 3.4; 95% confidence interval [95% CI], 2.12-5.67) and HKSJ (OR, 3.60; 95% CI, 2.03-6.41) methods and with the prevalence of hypertension or insulin treatment as assessed by the DSL method (OR, 1.92; 95% CI, 1.05-3.50 and OR, 2.29; 95% CI, 1.07-4.91, respectively) but not as assessed by the HKSJ method. CONCLUSION: Patients with advanced T2D have a higher prevalence of HidHyCo. These data inform about the selection of patients with T2D for HidHyCo screening.

Growth Hormone and Obesity.

Growth hormone (GH) exerts IGF-I dependent protein anabolic and direct lipolytic effects. Obesity reversibly suppresses GH secretion driven by elevated FFA levels, whereas serum IGF-I levels remain normal or elevated due to elevated portal insulin levels. Fasting in lean individuals suppresses hepatic IGF-I production and increases pituitary GH release, but this pattern is less pronounced in obesity. Fasting in obesity is associated with increased sensitivity to the insulin-antagonistic effects of GH. GH treatment in obesity induces a moderate reduction in fat mass and an increase in lean body mass but the therapeutic potential is uncertain.

[Acromegaly and symptoms of the motor apparatus].

In this case report, a 72-year-old woman presented with symptoms attributed to arthritis, and MRI indicated sacroiliitis. However, the patient also experienced enlargement of hands and feet in addition to sweating and snoring, which in combination with coarse facial features suggested acromegaly. This diagnosis was biochemically confirmed, and MRI revealed a pituitary adenoma, which was successfully removed by transsphenoidal surgery. Symptom relief and reduced swelling occurred immediately post-operatively. Acromegaly can masquerade as arthritis or osteoarthritis, which may delay diagnosis.

Impact of growth hormone receptor blockade on substrate metabolism during fasting in healthy subjects.

CONTEXT: Experimental studies in GH-deficient patients and in healthy subjects receiving somatostatin-infusion suggest that GH is an important regulator of substrate metabolism during fasting. These models may not adequately reflect the selective effects of GH, and GH receptor (GHR) blockade offers a new model to define the metabolic role of GH. OBJECTIVE: The aim of this study was to investigate the impact of GHR blockade on substrate metabolism and insulin sensitivity during fasting. DESIGN: We conducted a randomized, placebo-controlled, crossover study in 10 healthy young men. INTERVENTION: After 36 h of fasting with saline or pegvisomant (GHR blockade), the subjects were studied during a 4-h basal period and 2.5-h hyperinsulinemic euglycemic clamp. MAIN OUTCOME: We measured whole-body and forearm glucose, lipid, and protein metabolism, peripheral insulin sensitivity, and acyl and desacyl ghrelin. RESULTS: GHR blockade significantly suppressed circulating free fatty acids (1226 +/- 83 vs. 1074 +/- 65 micromol/liter; P = 0.03) and ketone bodies (3080 +/- 271 vs. 2015 +/- 235 micromol/liter; P