Cytomorphology and immunocytochemistry of columnar cell variant of papillary thyroid carcinoma

Columnar cell variant of papillary thyroid carcinoma (PTC) can be challenging and elusive in making a definitive diagnosis from the cytologic specimen due to lack of classical nuclear features of PTC. This case illustrates the use of an immunocytochemical panel to confirm the diagnosis in the setting of convincing cytomorphology and clinical history.