DISCUSSION The giant cell tumor is an aggressive rare histological variant, which represents 0.1 to 0.4% of lung tumors. Is characterized by giant, anaplastic and pleomorphic cells, which form chains or cords infiltrating the stroma; in our case we observed lymphocyte emperipolesis by malignant giant cells and profuse vascular invasion. Immunohistochemistry showed TTF1 and Napsin A, confirming their lung origin, also strong expression of cytokeratin CKAE1/AE3, CK7, EMA and Vimentin. Finally the proliferation