Fig. 2.

Immunohistochemical analysis. (2A) Strong nuclear positivity for TTF-1 (original magnification ×400). (2B) Diffuse cytoplasmic reactivity for cytokeratin 8/18 (original magnification ×400). (2C) Many of the neoplastic cells show membranous-pattern positivity for CD56 (original magnification ×200). (2D) Focal cytoplasmic positivity for synaptophysin (original magnification ×400).