Examples of canine K19 negative hepatocellular tumours. Immunohistochemical staining of K19 with a negative tumour field (left) and positive reactive ductular proliferation at the periphery of the tumour (arrow) is shown in (A). HE staining, trabeculae of well-differentiated hepatocytes with a uniform appearance are shown in (B). Absence of immunohistochemical staining for Glypican-3 is shown in (C). Positive immunohistochemical staining for HepPar-1 is shown in (D).