Carcinoma

Hepatocytic

• more in dogs and cats

Gross

• can be difficult to distinguish grossly from adenomas
• usually one single large mass and additional smaller masses (intrahepatic metastases)
• may have features of malignancy such as internal necrosis and haemorrhage

Microscopically

• can be very variable appearing as sheets or cords of neoplastic cells
• cells generally smaller with a higher nucleus to cytoplasmic ratio

Cholangiocellular - bile duct

• more common than adenoma
• reported in all species (mostly dogs and cats)

Gross

• usually multiple whitish umbilicated nodules that are present diffusely throughout the liver
  • actually look as though they were secondary tumours
• firm on cut surface
  • due to fibrosis

Microscopically

• distinctly adenocarcinomatous
• ductal and acinar proliferation in abundant fibrous tissue
• sometimes papillary formations