CEACAM5 and adenocarcinoma: Histology of the tumor revealed as adenocarcinoma with positive staining of cluster of differentiation 68 (CD68, +), carcinoembryonic antigen (CEA, +), thyroid transcription factor-1 (TTF-1, +), and Napsin A (+), but negative staining of P40 protein (-) and CD5/6 (-) by histochemistry.