Cell Block Preparation for Fine Needle Aspiration Cytology of Thyroid; Cost Effective Method in a Resource Poor Setting

Abstract

Over the past thirty years thyroid tumor incidence has triplicated and it is currently 7% of a given population. However, interestingly the thyroid cancer incidence is quite low and is approximately 5-10% of the thyroid tumor patients. Expeditious diagnosis of the thyroid nodules at the pre surgery stage is important to determine the tumor prognosis. A Widely used diagnostic approach is the direct observation of the fine needle aspiration specimens. However, using only this method many reported cases of unnecessary surgeries and re-operative incidents due to false diagnosis at the preoperative stage have been observed. Poor cellularity, loss of tissue architecture, poor cytomorphologic features in fine needle aspiration smears leads to incorrect diagnosis. Cell block technique is a better diagnostic approach at the pre-operative stage to overcome the pitfalls in direct smears as it concentrates the cells and preserve tissue architecture. Further, multiple sections with same cellularity can be prepared from a single cell block allowing the use for more advanced techniques like immunohistochemistry and molecular diagnosis. Cell block technique strengthen the diagnosis of tumors by fine needle aspiration specimens. Combined use of cell block technique with fine needle aspiration can reach to a sensitivity of about 95-100% suggesting that every FNAC specimen should be subjected to cell block preparation whenever possible.