Primary Liver Tumours
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
Secondary Liver Tumours
- from a variety of origins
Pancreatic
Image of haemorrhage and pancreatic carcinoma in a cat from Cornell Veterinary Medicine
- In older dogs, more common in Airedale terriers, rare in cats, other species too
- Tend to arise centrally in the gland
- Highly invasive and infiltrative
- Metastases to the liver, visceral serosa, abdominal lymph nodes, spleen, adrenals etc.
- Similar to malignant ovarian tumours - implant on the peritoneum
Gross appearance
- Usually spherical nodules with adhesions to nearby structures
- Single or multiple, variable size
- Greyish or yellow fibrous tissue - firm on cutting
- May show internal necrosis and haemorrhage
- Some tumours may contain cysts wih mucinous content
- Adhesions may occur
Microscopic appearance
- May be well differentiated with normal acini and ducts
- Or diffuse sheet of undifferentiated cells
Endocrine Pancreatic
- Larger than adenomas
- Multilobular
- Invasive into parenchyma and surrounding tissue
- Metastasis into lymph nodes, liver mesentery, omentum
- Few mitotic figures