Cells have nuclei with "salt and pepper" chromatin (dusty appearance with inconspicuous nucleoli).
Crush artifact (smearing of cells) and nuclear molding is common.
High mitotic activity, apoptosis and necrosis common.
Immunohistochemistry: positive for neuroendocrine markers synaptophysin (image D) and chromogranin.
Most patients present with EPE, large tumor, advanced stage, and distant metastasis.
Poor prognosis with mean survival of <1 year after development of SCC component.
No difference in prognosis between pure SCC and those SCC mixed with acinar adenocarcinoma.