Figure 1: Cytologic features observed in classic PTC: (a) Atypical bare nuclei (Pap stain ×200), (b) Histocytic giant cells (Pap stain ×200), (c) Swirling sheets (Pap stain ×400), (d) Chewing gum colloid, (Pap stain ×200), (e) Oval enlarged nuclei, with overlapping and intranuclear grooves (Pap stain ×400), (f) Cell clusters with anatomical edges (Pap stain ×200)