Fig. 2

Histopathologic comparisons of the triple lung cancers. a-c The first tumor of adenocarcinoma at the right upper lobe. a Pleomorphic neoplastic cells with an acinar pattern (hematoxylin and eosin stain, ×200). b Immunoreactivity for TTF-1(×200). c Negative for P40(×200). d-f The second tumor of squamous cell carcinoma at the right lower lobe. d Polygonal cells with a solid pattern and no keratinization (hematoxylin and eosin stain, ×200). e No immunoreactivity for TTF-1(×200). f Strong staining of P40 at tumor cells(×200). g-i The third tumor of small cell carcinoma at the left lower lobe. g Small cells with scant cytoplasm and lack of nucleoli with a high mitotic activity (hematoxylin and eosin stain, ×200). h Positive neuroendocrine markers of CD56(×200). i Positive neuroendocrine marker of synaptophysin(×200). Equipment used to obtain images: Olympus BX53 microscope/Olympus objective lens WHN10X/22 UIS2, Olympus DP72 cameras and acquisition software: Olympus CellSens Standard 1.6 software. TTF-1, thyroid transcription factor-1