TTF1 and neoplasm: A bronchoscopic biopsy of the lung tumor revealed an autochthonous CEA-, CK7-, calcitonin- and TTF1-positive neoplasm comprised of medium to large-sized cells with large nuclei, granular karyoplasm, clearly recognizable nucleoli, broad cytoplasm, solid and trabecular growth pattern, as well as focal necrosis (Fig. 2).