Fig. 4

(a,b,c) Low power view and high power view demonstrated that stromal round cells in the left side transformed to the malignant tumor (black arrow), round cells in the transition area (yellow arrow) had dysplasia (h&e). (d, b, f) Low power view and high power view demonstrated that Ki-67 proliferation index was significantly increased in the malignant area (black arrow). (g) Thyroid transcription factor-1 (TTF-1) was positive in stromal round cells. (h) Pancytokeratin was negative in stromal round cells. (i) E-cadherin was negative in stromal round cells