Immunocytochemistry and Immunohistochemistry on Liquid-Based Preparations of Thyroid FNA

Immunocytohistochemistry/immunohistochemistry (ICC/IHC) has become an indispensable tool in the practice of surgical pathology and cytology. In our daily clinical practice, most specimens from thyroid fine needle aspiration (FNA) and liquid-based preparations (LBP) are diagnosed without the routine use of immunostain, but IHC can be used judiciously on the corresponding cell block in certain situations to confirm or rule out a diagnosis. Scraping of thick Diff-Quik (DQ)–stained smears into the CytoLyt/CytoRich Red (collection media for ThinPrep [TP] and SurePath [SP] respectively) at the time of rapid on-site evaluation (ROSE) to prepare the cell block can further enhance the yield, and multiple immunostains can be performed on the cell block if needed.