Comparison of Thirty Trace Elements Contents in Thyroid Tissue Adjacent to Thyroid Malignant and Benign Nodules

Background: Thyroid nodules (TN) are the most common endocrine disorder worldwide. Etiology and pathogenesis of thyroid benign and malignant
nodules (TBN and TMN, respectively) are still not enough understood. The present study was performed to clarify the role of some trace elements
(TEs) in the origination and development of TN.

Methods: Contents of TEs such as silver (Ag), aluminum (Al), boron (B),, beryllium (Be), bismuth (Bi), cadmium (Cd), cerium (Ce), cobalt (Co),
chromium (Cr), cesium (Cs), iron (Fe), gallium (Ga), mercury (Hg), lanthanum (La), lithium (Li), manganese (Mn), molybdenum (Mo), neodymium
(Nd), nickel (Ni), lead (Pb), praseodymium (Pr), rubidium (Rb), antimony (Sb), scandium (Sc), selenium (Se), tin (Sn), thallium (Tl), uranium (U),
yttrium (Y), and zinc (Zn) were prospectively evaluated in thyroid tissue adjacent to TBN (79 patients) and to TMN (41 patients). Measurements were
performed using a combination of non-destructive instrumental neutron activation analysis and destructive method such as inductively coupled plasma
mass spectrometry. Results of the study were additionally compared with previously obtained data for the same TEs in “normal” thyroid tissue.

Results: It was found that in thyroid tissue adjacent to TMN the mass fractions of Hg, Rb, and Se are 1.61, 1.82 and 1.60 times, respectively, higher
those in thyroid tissue adjacent to TBN. The common characteristics of thyroid tissue adjacent to TBN and TMN were elevated levels of Ag, Al, Co, Hg,
Mo, Ni, Rb, Sb, and U, which overdrew those in “normal” thyroid approximately in 34, 2.1, 1.8, 32, 1.95, 5.2, 1.9, 1.9 and 3.6 times, respectively, as well as
reduced levels of Cs and Sc, which were 38% and 78%, respectively, lover “normal” levels of these elements, and similar contents of all other TEs studied.

Conclusions: Role of TEs in etiology and pathogenesis TBN and TMN is similar and exessive accumulation of Ag, Al, Co, Hg, Mo, Ni, Rb, Sb, and
U in thyroid tissue may be involved in the TN origination and development.