Figure 1.

Spindle cell carcinoma. 1a: Spindle cell lesion with myxoid stroma (HE ×200). 1b: Mild to moderate atypia in tumor cells with rare mitoses (HE ×400). 1c: Vimentin immunoperoxidase – strong expression in tumor cells (×400). 1d: Pan-cytokeratin AE1/3 immunoperoxidase (×400). 1e: smooth muscle actin immunoperoxidase (×400). 1f: Proliferation (Ki67) up to 80% (immunoperoxidase ×200).