Histopathological findings in metastatic Sinonasal undifferentiated carcinoma (SNUC). Hematoxylin-Eosin (H&E) staining of liver tissue shows complete replacement of normal liver parenchyma by neoplastic high grade cells with extensive necrosis (A: x40). The atypical cells show irregular nuclear borders, vesicular chromatin and prominent nucleoli, with abundant atypical mitoses (arrow) and apoptosis (circle) (B: x600). Immunohistochemical stain for p16 (CINtec) is positive (nuclear and cytoplasmic staining) in the areas with viable tumor (C: x20).