TTF1 and neoplasm: Tumor cells are arranged in clusters or monolayer sheets but show less nuclear irregular contours or molding or crowding; nuclear atypia is more evident in the isolated elements Figure 3 (A and B) These cellular elements showed positivity for two specific markers of thyroid origin, nuclear TTF‐1, and cytoplasmic Tg on immunocytochemical analysis Figure 4(A–C).18