[Diagnostic value of bilateral inferior petrosal sinus sampling in various modifications and methods of radiation and radionuclide imaging in the diagnosis and differential diagnosis of ACTH-dependent endogenous hypercortisolism].

AIM: To analyze the diagnostic performance of bilateral inferior petrosal sinus sampling (BIPSS) with desmopressin as a stimulation agent and prolactin measurements to control catheter position with or without the ACTH/prolactin normalized ratio calculation in the differential diagnosis of ACTH-dependent endogenous hypercortisolism, and the diagnostics performance of ectopic ACTH-syndrome (EAS) visualization. MATERIALS AND METHODS: A single-center diagnostic study with a retrospective analysis of the data was carried out. The study included patients with ACTH-dependent endogenous hypercorticism with no visualization of pituitary adenoma on MRI or adenoma sizes less than 6 mm. All patients underwent BIPSS with and without calculation of the ACTH/prolactin normalized ratio. Visualization of an EAS included pituitary MRI (to exclude EAS), whole-body CT scan with contrast, and somatostatin receptor scintigraphy with 99mTc-Tectrotide and CT (99mTc-Tectrotide SPECT). The final verification was based on immunohistochemical confirmation of the tumor or stable remission of Cushing's disease (CD) after surgical treatment. Statistical data processing was carried out by using IBM SPSS Statistics 23. Confidence intervals were calculated using the JavaStat online calculator. RESULTS: 230 BIPSS were performed in 228 patients (166 women, 62 men), of which 178 patients were verified as CD and 50 cases were EAS of various localization. The effectiveness of catheterization of petrosal sinuses was 96.9%. The sensitivity of BIPSS without ACTH/prolactin ratio calculation (n=70) was 95.9% (95% CI 86.3-98.9), specificity was 92% (95% CI 75.0-97.8), for the BIPSS with additional determination of ACTH/prolactin-normalized ratio (n=51) - 97.3% (95% CI 86.2-99.5) and 93.8% (95% CI 71.7-98.9), respectively. The use of the MRI method for this sample of patients had a sensitivity of 60.2% (95% CI 52.6-67.5), specificity of 59.2% (95% CI 44.2-73.0), the total body CT with contrast has a sensitivity of 74% (95% CI 59.7-85.4), specificity of 100% (95% CI 97.95-100). The diagnostic accuracy for 99mTc-Tectrotide SPECT in NET visualization has a sensitivity of 73.3% (95% CI 44.9-92.2), specificity of 100% (95% CI 95.3-100). CONCLUSION: BIPSS with desmopressin stimulation and prolactin measurements to control catheter position, as well as the additional calculation of the ACTH/prolactin-normalized ratio, is an optimal method for the differential diagnosis of EAS. Patients who are identified an EAS on BIPSS may be further referred for 99mTc-Tectrotide SPECT and CT for tumor visualization.

[Clinical features, diagnostics and treatment of FGF23 secreting tumors: series of 40 clinical cases].

INTRODUCTION: Tumor-induced osteomalacia is an acquired rare disease manifested by hypophosphatemic osteomalacia due to excessive secretion of fibroblast growth factor 23 (FGF23). FGF 23 is a non-classical hormone secreted by bone tissue (osteocytes) and regulates phosphorus metabolism.The aim of this work is to present clinical experience in the diagnosis, treatment and rehabilitation of patients with tumor-induced osteomalacia. MATERIALS AND METHODS: 40 patients with clinically-confirmed tumor-induced osteomalacia were included in the study, 34 of whom had the tumor localized, 27 underwent surgical treatment and 21 achieved stable remission. RESULTS: The median age was 48 [41; 63] years, 43% were men, the time left from the the onset of the disease was 8 [4; 10] years. Biochemical findings were hypophosphatemia 0.47 [0.4; 0.53] mmol/l, a decrease in the tubular reabsorption phosphate 62 [52; 67]%, and an increase in alkaline phosphatase of 183 [112; 294] units/l. At the time of diagnosis, 100% had multiple pathological fractures, only 10% could move independently, and 77.5% classified the pain as unbearable (8-10 points according to the 10-point pain syndrome scale ). Among the methods used to detect tumors, the most sensitive were scintigraphy with tectrotide with SPECT/CT 71.4% (20/28) and MRI 90% (18/20). In 35% of cases, the tumor was localized in soft tissues and in 65% in bone tissue; The tumor was most often detected in the lower extremities, followed by the head in frequency of localization. 18 patients currently have no remission and they receive conservative treatment (phosphorus and alfacalcidol n=15 and burosumab n=3). In case of achieving remission (n=21), regression of clinical symptoms and restoration of bone and muscle mass was observed. Extensive excision of the tumor without prior biopsy resulted in the best percentage of remission - 87%. CONCLUSION: Tumor-induced osteomalacia is characterized by severe damage to bone and muscle tissue with the development of multiple fractures, muscle weakness and severe pain syndrome. In laboratory diagnostics, attention should be paid to hypophosphatemia, a decrease in the tubular reabsorption phosphate index and increased alkaline phosphatase. The use of functional diagnostic methods with a labeled somatostatin analogue to the subtype 2 receptor and MRI with contrast enhancement are the most accurate methods of topical diagnostics. In case of localization of the tumor, a wide excision without a preliminary biopsy is recommended.

[Pathogenic TSHR variants in children with thyroid dysgenesis].

BACKGROUND: Loss-of-function mutations in the TSH receptor gene (TSHR) (NP_000360.2) are the potential causes of thyroid dysgenesis in patients with congenital hypothyroidism. Heterozygous variants of the TSHR gene lead to partial resistance to TSH, homozygous and compound heterozygous variants have been shown to cause CH due to thyroid hypoplasia or TSH resistance. Recently more and more articles in this field have appeared in the international literature sources, while local publications are limited. The studies are necessary to understand the etiology, pathogenesis of the disease, to improve the management of these patients. AIM: To assess the frequency of incidence of pathogenic variants of the TSHR gene in children with CH due to thyroid dysgenesis. To study inheritance and phenotypic patterns of CH in families. MATERIALS AND METHODS: In this single-center interventional one-stage non-comparative study a group of CH patients was examined. The patients underwent neck ultrasound and radionuclide imaging. The examination was performed 14 days after hormone replacement therapy suspension or prior to its initiation. The structure of thyroid dysgenesis was estimated, genetic testing for mutations in the TSHR gene was performed using the NGS method. RESULTS: The study included 95 children with primary CH (75 girls; 20 boys). The patients' median age at the time of examination was 6.2 years [4.5; 8.9], the median level of neonatal TSH was 157.5 mU/l [60.9; 257.2]. Ectopic thyroid was found in 52% of children, aplasia in 36%, hypoplasia and hemiagenesis in 10% and 2%, respectively. In 5.4% of cases (in 5 out of 95 patients), different variants of the TSH gene were detected. Two children had heterozygous p.R450H and p.D487N variants in TSHR gene, two patients was homozygous for the p.S49Afs * 9 variant, one child had compound heterozygous variants (p.A485D and p.R450H). According to ultrasound imaging, all patients had thyroid hypoplasia of varying severity. Three children underwent thyroid scintigraphy, which revealed decreased 99mТc pertechnetate uptake (0.3-0.9%). CONCLUSION: In our study, the incidence of different variants in the TSHR gene in children with CH was 5.3%. Our analysis uncovered two previously undescribed variants. Genetic testing may be able to help with making the diagnosis, patient's management, and genetic counseling.

[Ectopic thyroid gland: clinical features and diagnostics in children].

BACKGROUND: The frequency of ectopia of thyroid gland among all types of dysgenesis varies from 30 to 70%, its most common localization is the root of the tongue. Otorhinolaryngologists, oncologists, pediatricians can take lingual ectopia for hypertrophy of the lingual tonsil or fibroma of the tongue root, which leads to unreasonable surgical treatment. Thyroid scintigraphy plays a key role in the diagnosis of ectopia. AIM: To assess the etiological structure of congenital hypothyroidism (CH) and demonstrate the clinical course in patients with ectopic thyroid tissue in the root of the tongue. MATERIALS AND METHODS: A group of patients with CH was examined. All patients underwent neck ultrasound and radionuclide imaging. The examination was carried out against the background of the abolition of hormone replacement therapy for 14 days or before its initiation. Patients with ectopia in the root of the tongue underwent videofibrolaryngoscopy. Some patients underwent a genetic study with using genes panel of a panel of candidate genes responsible for the development of CH using the NGS method. The molecular genetic study was conducted to some patients, next-generation sequencing with the genes panel. RESULTS: The study included 73 patients with primary CH aged from 2 weeks to 17.3 years: 69 children were diagnosed based on the results of neonatal screening, 4 children with thyroid ectopia were first examined older than 6 years. The median age of patients at the time of the examination was 6.9 years [4.8; 10.0]. By data of ultrasound aplasia was diagnosed in 47.9% of patients, one child had hemiagenesis and ectopic thyroid tissue of various localization was detected in 26.0% of  children. In 24.7% of children thyroid tissue was found in a typical location. Scintigraphy confirmed thyroid aplasia in 65.7% of children. Examination revealed various variants of ectopically located thyroid tissue in 31 children (42.4%): thyroid ectopia in the root of the tongue in 25 children (80.6%), ectopia in the sublingual region in 5 children (16.2%), double ectopia was detected in 1 child. The median level of TSH in newborns with ectopic thyroid gland was 124 IU/ml and was significantly lower than in children with aplasia - 219 IU/ml, p<0.05. On the other side the level of TG in children with ectopia was significantly higher than in children with aplasia - 37.12 ng/ml versus 0.82 ng/ml, p><0.05. CONCLUSION: Combination of two methods is the best diagnostic approach to determine the etiology of CH - ultrasound and scintigraphy studies compensates deficiencies of each other. Our study demonstrates the importance of scintigraphy in children with CH and patients with the formation of the root of the tongue and the anterior surface of the neck in order to avoid unnecessary removal of the thyroid gland. In case of confirmation of thyroid ectopia in the root of the tongue and in the absence of symptoms of obstruction or bleeding, it is recommended to refer the patient to an endocrinologist for conservative treatment. ><0.05. On the other side the level of TG in children with ectopia was significantly higher than in children with aplasia - 37.12 ng/ml versus 0.82 ng/ml, p< 0.05. CONCLUSION: Combination of two methods is the best diagnostic approach to determine the etiology of CH - ultrasound and scintigraphy studies compensates deficiencies of each other. Our study demonstrates the importance of scintigraphy in children with CH and patients with the formation of the root of the tongue and the anterior surface of the neck in order to avoid unnecessary removal of the thyroid gland. In case of confirmation of thyroid ectopia in the root of the tongue and in the absence of symptoms of obstruction or bleeding, it is recommended to refer the patient to an endocrinologist for conservative treatment.

[The clinical practice guidelines for primary hyperparathyroidism, short version].

Primary hyperparathyroidism (PHPT) is an endocrine disorder of parathyroid glands characterized by excessive secretion of parathyroid hormone (PTH) with an upper normal or elevated blood calcium level. Classical PHPT refers to a symptomatic, multi-system disorder, wich can lead to a significant decrease in the quality of life, disability of patients, and even an increased risk of premature death. Hypercalcemia and the catabolic effect of PTH on various cells are considered as the main pathogenetic mechanisms of the PHPT associated complications. In the last two decades, there has been an increase in the incidence of PHPT, mainly due to the mild forms of the disease, primarily due to the routine calcium screening in North America, Western Europe and, Asia. High prevalence of the disease, as well as the variety of clinical manifestations, cause the attention of different specialists - physicians, rheumatologists, urologists, nephrologists, cardiologists and other doctors. This review cover the main issues of Russian guidelines for the management of PHPT, approved in 2020, including laboratory and instrumental methods, differential diagnosis, surgical and conservative approach, short-term and long-term follow-up. This guidelines also include the recommendations for special groups of patients with hereditary forms of PHPT, parathyroid carcinoma, PHPT during pregnancy.

[Clinical practice guidelines for acute and chronic thyroiditis (excluding autoimmune thyroiditis)].

Acute and chronic thyroid diseases are the most frequently detected disorders being second only to diabetes mellitus.The World Health Organization points out that thyroid diseases' incidence tends to grow every year. The present paper consists of clinical practice guidelines that consider etiology, clinical course, diagnostics and treatment of acute and chronic inflammatory thyroid diseases (except those of autoimmune type).The clinical practice guidelines provide an important working tool for clinicians including specialty physicians and medical experts. Containing structured and concise information on the specific nosology, diagnostic methods and treatment tips these guidelines allow medical specialists to quickly resolve difficulties and choose the most efficient and personalized treatment (following strict principles of evidence-based medicine at the same time).The clinical practice guidelines were drawn up by highly-skilled professional team of specialty physicians approved by the Expert Council of Russian Federation's Health Department. These guidelines contain the most complete and up-to-date information required to diagnose acute and chronic thyroiditis, provide patient care and treatment.The working group publishes the present paper in the professional journal dealing with endocrinology topics to improve healthcare quality and refine treatment of acute and chronic thyroiditis (autoimmune thyroiditis excluded). It is advisable to acquaint as many endocrinology and general (family) medicine specialists as possible with the full text of these clinical guidelines.

[Nodular toxic goiter in children: clinical features, morphological variants].

BACKGROUND: Toxic nodular goiter (TNG) is a rare disease in which the cause of hyperthyroidism is the presence of a node or nodes that autonomously secrete thyroid hormones. With children and adolescents this condition is extremely rare - in 5-7.5% of all cases of nodular goiter. Therapy of toxic nodular goiter is aimed at relieving the symptoms of hyperthyroidism taking into account the malignant potential of the nodular formation. In the available literature, there are no data on the clinical course, comparative results of cytological and histological data in patients with toxic nodular goiter, which debuted in their childhood. AIM: Analysis of the features of the clinical course, comparison of the results of cytological and histological studies of toxic nodular goiter in children and adolescents. MATERIALS AND METHODS: A retrospective, single-center study of 21 patients with single-nodular toxic goiter, hospitalized at the Endocrinology Research Centre in the period from January 2016 to December 2019. RESULTS: The mean age at the time of the survey was 13.9 years. Thirteen patients (65%) had manifest thyrotoxicosis, and seven (35%) had subclinical hyperthyroidism. More than half of children - 57.1% (n = 12) did not receive thyreostatic therapy. The cytological picture in 11 patients (61.1%) corresponded to benign changes (nodular colloid goiter or adenomatous goiter) - Bethesda II, in 4 patients - follicular tumor - Bethesda IV, in 4 children the study was not informative. 19 patients (90.5%) underwent surgical treatment (hemithyroidectomy). According to the results of histological examination, follicular adenoma was found in 44.4% of children with nodular toxic goiter with benign results of TAB (Bethesda II) and was found in 50% with revealing follicular neoplasia (Bethesda IV). CONCLUSION: For the first time in the Russian Federation was carried out a comparative analysis of the characteristics of cytological and histological studies in children with toxic nodular goiter. It is significant that only in 10.5% (n=2) cytological and morphological results were consistent. The choice of radical treatment tactics should take into account the high frequency of mismatches between histological and morphological studies.

[A clinical case of combined differentiated thyroid cancer and primary hyperparathyroidism: the complexity of topical differential diagnosis].

In recent years, the understanding of the epidemiology, symptoms and strategies for managing patients with hyperparathyroidism has changed significantly. The most common cases in clinical practice are of sporadic primary hyperparathyroidism, which today ranks third in prevalence among endocrine diseases (the frequency of occurrence in the adult population is, on average, 12%). In primary hyperparathyroidism, solitary parathyroid adenoma is detected in up to 85% of all cases. The only treatment is radical surgical removal of pathologically altered parathyroid tissue. Early diagnosis and treatment of hyperparathyroidism makes it possible to avoid severe lesions of the skeletal bones and visceral organs. A diagnostically challenging clinical case of a combined onco-endocrine pathology in a 70-year-old patient is presented. The main difficulties in the initial diagnosis were associated with the absence of pathognomonic symptoms of the disease, which was often completely asymptomatic. The most urgent problem appears to be the topical diagnosis of pathologically altered parathyroid glands. Therefore, there is a need to develop an algorithm for the combining and sequential use of existing medical imaging methods.