Diagnostic value of lymph node calcification in thyroid cancer

Abstract

The role of pathological biomineralization (PBM) as a prognostic and diagnostic marker in thyroid cancer is continuously debated among investigators. Detection of pathological biomineralization in the lymph nodes of the neck is an alarming signal for clinicians. Typically, a lymph node with signs of calcification is a symptom of papillary thyroid cancer. The lymph node contains such a form of calcification as psammoma bodies in such cases. Psammoma bodies of relatively large size (more than 200 μm) can be detected by ultrasound. Our study aims to study the crystal-chemical and phase characteristics of calcifications of metastatic lymph nodes in thyroid cancer to develop promising methods of early diagnosis. Materials and methods. Several complex research methods have been conducted for a deeper understanding of the pathological biomineralization of metastatic lymph nodes in thyroid cancer, such as macroscopic examination, ultrasound diagnostics, detection of strict lymph node, histological, histochemical, and electron microscopic (scanning electron microscopy, X-ray diffraction, and transmission electron microscopy). Our study found that the main component of pathological biomineral deposits is calcium phosphate compounds. The Ca / P ratio corresponds to the characteristic features of hydroxyapatite. A significant proportion of β-tricalcium magnesium phosphate was also detected in some cases. The specific plate structure and the known phase and crystal-chemical composition of psammoma bodies can be the point of application of searches for their early detection using the latest diagnostic methods with high resolution. Conclusion. Our study demonstrated the significance of PBM in lymph nodes as a diagnostic symptom of papillary thyroid cancer patients. The presence and extent of PBM in the lymph nodes should be considered a metastasis of papillary thyroid cancer. The study of the structure, physicochemical, phase composition of lymph node calcifications, and visualization features is promising given the possible practical application for early diagnosis of metastases of papillary thyroid cancer.