Medullary thyroid cancer (MTC) is a rare form of cancer derived from parafollicular or C cells. Currently, there is an active search for predictors of the course of MTC and markers that can predict the treatment response. Understanding the biological characteristics of the tumor requires insights from both embryology and genetics. While the genetic aspects of MTC are relatively well-studied, the embryonic origin of C-cells remains a subject of ongoing investigation. The prevailing hypothesis suggests an ectodermal origin, yet recent studies have identified the expression of markers in C-cells that are typical of cells with endodermal lineage. These data deepen the understanding of their biological role and provide reasons for further research. C-cells produce several essential hormones, including calcitonin, and possess a unique ability to synthesize and secrete other peptide hormones. This article focuses on members of the calcitonin family of hormones — calcitonin gene-related peptide, amylin, adrenomedullin, and intermedin — which regulate critical physiological processes. Some of these hormones and their receptors have been identified in malignant tumors and are associated with poorer prognosis. This review analyzes current findings on the origins of C-cells and calcitonin precursors, along with structurally similar peptides, highlighting their importance in the context of clinical oncology.

Papillary Microcarcinoma of the Thyroid Gland (PMTC) is the most common type of malignant thyroid neoplasm, characterized by its small size and generally favorable prognosis. The increased detection rate of PMTC is associated with advancements in high-precision diagnostic methods such as ultrasound and fine-needle aspiration biopsy. Diagnostic approaches include the use of the EU-TIRADS and Bethesda systems for risk assessment, as well as the analysis of molecular markers, such as BRAF gene mutations and promising studies on the role of microRNAs in predicting tumor progression.

Optimal management of patients with PMTC requires an individualized therapeutic approach due to differences in disease progression. This article analyzes current diagnostic and treatment methods for PMTC, including the use of molecular-genetic markers, minimally invasive technologies, and active surveillance strategies, with an emphasis on a personalized approach to prognosis and therapy.

Multiple endocrine neoplasia syndrome type 1 (MEN-1) is an inherited disorder associated with mutations in the MEN1 gene and characterized by the «classic triad»: involvement of the parathyroid gland, pancreatic islet cells and anterior pituitary. The penetrance of primary hyperparathyroidism (PHPT) in MEN-1 reaches 90-100% with age. Primary hyperparathyroidism in MEN-1 is associated with polyglandular lesions, and tumors do not always develop synchronously, leading to a high incidence of disease recurrence after surgery. In MEN-1-associated PHPT, hyperplasia is most common and multiple adenomas are less common. The growth of hyperplastic cells may be diffuse, nodular or diffuse-nodular, which complicates the differential diagnosis between adenoma and diffuse-nodular hyperplasia with the presence of a single dominant nodule. Carcinomas and atypical tumors in MEN-1 are casuistically rare. We present the unique case of a young patient with a germline mutation in the MEN1 gene (c.684dup) and clinically «aggressive» course of PHPT due to atypical parathyroid tumors.

46th Annual Meeting of the European Thyroid Association was held in September 2024 where topical issues of clinical and  scientific thyroidology were discussed. This article provides a brief overview of the event.