Biochemical and hormonal composition, cytological examination of thyroid cyst fluid, and comparison according to gender and color of cyst fluid

Background: The aim of this study was to evaluate the biochemical composition and cytological examination of 25 thyroid cyst fluid specimens that were obtained by fine needle aspiration, and to compare results according to gender and color of cyst fluid. We anticipated that measuring biochemical routine parameters in cyst fluid would contribute to the pathophysiology of thyroid nodule formation leading to better clinical outcomes when compared to therapies based only on cytological examination. Methods: We analyzed 23 parameters in serum and cyst fluid samples taken from 25 euthyroid patients. In addition, cytological examination of cyst fluids was performed. Results: We revealed that mean levels of glucose, phosphorus, high-density lipoprotein cholesterol, antibodies to thyroglobulin, and activities of alanine aminotransferase and alkaline phosphatase were lower, and mean levels of uric acid, free triiodothyronine, free thyroxine, and thyroglobulin and activity of lactate dehydrogenase in the cyst fluid of thyroid nodules were higher when compared to their own serum sample levels. Also, there were significant differences according to gender and color of cyst fluid. Conclusions: Biochemical examination of thyroid cyst fluid may be of value for the clinician to evaluate the nature of thyroid nodules. The potential benefits of thyroid cyst fluid examination warrant further investigation in patients with thyroid nodules.