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The present study included patients with confirmed diagnosis of ACTH-dependent hypercorticism admitted to the Department of Neuroendocrinology and Osteopathies, Endocrinological Research Centre, between 2008 and 2012. Selective blood sampling from the inferior petrosal sinuses was performed with the stimulation by decompressin administered intravenously at a dose of 8 mcg. The normalized ACTH/prolactin ratio was calculated by dividing the maximum ACTH gradient following decompressin stimulation by the ipsilateral prolactin gradient. The cut off values were calculated from the operating characteristic curves as follows: 1.5 for the prolactin gradient (sensitivity 92.5%, specificity 100%) and 1.18 for the normalized ACTH/prolactin ratio (sensitivity 85.9%; 95% CI 76.8-93.4, specificity 100%; 95% CI 60.9-100). In the study cohort (n=70), the normalized ACTH/prolactin ratio proved to be a more specific but less sensitive parameter than the routine analysis of the ACTH gradient (sensitivity 98.4%, specificity 83.3%). Areas under the operating characteristic curves were on the whole identical. However, comparison of the diagnostic value of selective blood sampling from the inferior petrosal sinuses in combination of the determination of the prolactin gradient and normalized ACTH/prolactin ratio with the results obtained in the patients in whom the catheter position was not controlled (n=47) revealed the advantages of the former approach in terms of both the number of unverified causes of hypercorticism (1 versus 6) and the area under the operating characteristic curves 0.964 (95% CI 0.897-1.032) among 70 patients and 0.910 (95% CI 0.821-0.998) among the first 47 patients (included in the analysis confined to the confirmed cases). It is concluded that the determination of the prolactin gradient and calculation of the normalized ACTH/prolactin ratio allow to increase the diagnostic value of selective blood sampling from the inferior petrosal sinuses under decompressin stimulation. This inference is especially true of doubtful cases.

Aims: this study evaluates the most common associations of symptoms and complications in patients with Cushing’s syndrome (CS) in order to choose a potential population to be screened for CS and estimates the diagnostic accuracy of first line screening tests (cortisol, ACTH) to differentiate ACTH-ectopic CS from Cushing’s disease. Materials and Methods: The clinical data of 259 patients with proven CS during 2001–2011 was analyzed. The clinical presentations of 197 patients (159 Cushing’s disease, 28 ACTH-ectopic CS and 10 cases of benign cortisol-secreting adrenal adenoma) were compared according to the cause of hypercortisolism. ROC-analysis was performed to estimate the diagnostic accuracy of the first line tests (cortisol, ACTH) to suggest ACTH-ectopic CS. A threshold for the test with the highest area under the curves was chosen based on the maximum sum of the sensitivity and specificity. Results: The most frequent complaints were related to fatigue, muscle weakness, weight gain and changes in appearance (facial plethora and fullness, striae). Among the complications of CS the most frequent were being overweight or obese (71%), hypertension (63%), dislipoproteinemia (41%), low traumatic fractures (43%) and steroid-induced diabetes (31%). In women, 16% were older than 50, in those who were younger amenorrhea was registered in 43%. The patients with ACTH-ectopic CS had higher rate of low traumatic fractures (p=0.04), increased serum late-night cortisol, 24 hours urinary free cortisol, morning and evening ACTH and lower levels of potassium (p0.01 for all parameters). Plasma late-night ACTH measurements showed the highest AUC (0,811 (95% CI 0,712–0,909)) to differentiate ACTH-ectopic CS from Cushing’s disease. A cut off value of 108.9 pg/ml for late-night ACTH yielded a sensitivity of 60,7% and a specificity of 79%. Conclusions: patients with a coexistence of obesity, muscle weakness, fatigue, some components of metabolic syndrome and especially low traumatic fractures should be screened for CS. High plasma late night ACTH values in patients with proven CS value suggest ACTH-ectopic syndrome.

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Incidentalomas are the most common neoplasms in the hypothalamic-pituitary region. Diagnostics, treatment strategy, and indications for the surgical intervention on the patients with these tumours pose a serious challenge for a wide circle of specialists. The diagnostic problems arise from the absence of the specific clinical signs and symptoms as well as the reliable biochemical markers of the disease. The modern laboratory methods do not allow to reveal the pathological hormonal secretion during the diagnostic study, predisposition of the neoplasm to the invasive and infiltrative growth, and signs of its «aggressiveness». This considerably complicates the choice of the optimal surgical strategy and the evaluation of the long-term results of the treatment. Bearing in mind the importance of the problem under consideration, the working group was set up for the development of federal recommendations on the treatment of pituitary incidentalomas based on the principles of evidence-based medicine. The experience accumulated by the domestic and international experts was summarized in the federal clinical guidelines on pituitary incidentalomas containing the available information about these neoplasms.