A Comparative Study of Fine Needle Aspiration Cytology (FNAC) and Immunocyto-chemistry in Preoperative diagnosis of Solitary Thyroid nodules

Preoperative Diagnosis of solitary thyroid nodules

Abstract

Introduction: Solitary thyroid nodule is a common entity encountered in day to day clinical practice. The importance of evaluation of a thyroid nodule is the need to exclude malignancy, but the optimum diagnostic strategy is still a matter of debate. Aims and objectives: The present study was undertaken to evaluate the utility of fine needle aspiration cytology (FNAC) and immunocytochemistry in the preoperative diagnosis of solitary thyroid nodules. Methods and Material: This was a cross sectional study carried out in the Department of Endocrinology, Gauhati Medical College and Hospital, Assam, India from January 2012 to November 2013. The study enrolled 48 patients above 18 years of age with solitary thyroid nodules. Galectin-3 was used as the immunocytochemical marker of interest and was examined in all FNA biopsied specimens. Results: FNAC has both high sensitivity as well as specificity for diagnosis of solitary thyroid nodules (100% and 90% respectively); on the other hand immunocytochemistry has a high specificity but low sensitivity (100% and 66.67% respectively). Particularly in nodules with indeterminate cytology, expression of galectin-3 has been found to have a positive predictive value of 100%. Conclusion: FNAC remains the gold standard for preoperative evaluation of solitary thyroid nodule. However, in those nodules where FNAC cannot arrive at a definite diagnosis, use of a molecular marker in the form of galectin-3 is promising. Galectin-3 expression can be used as a reliable pre-surgical molecular marker to aid in diagnosis of indeterminate nodules.