Adenoma

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Oral Papilloma Neoplasia in Dog (Courtesy of Alun Williams (RVC))
  • Adenomas are unusual but may develop in oropharyngeal salivary tissue.

Intestinal adenoma

Adenoma of brunners glands (duodenum) (Courtesy of Bristol BioMed Image Archive)
  • An adenoma is a growth of glandular origin.
  • Intestinal adenomas are found in both the small and large intestines.
  • Intestinal adenomas usually grow into the lumen.
  • These growths are bengin and polyp-like.


Tumours of the Perianal Area

Hepatoid Gland Tumours (Perianal Adenomas)

Perianal gland- normal (Courtesy of Bristol BioMed Image Archive)

* Affect the dog.

  • Arise from the solid, modified sebaceous circumanal glands.
  • Common in ageing entire males.
    Perianal gland- adenoma (Courtesy of Bristol BioMed Image Archive)
  • Lesions range from hyperplasia to true adenomas (benign).
    • These low grade lesions are under hormonal control.
      • Castration/ administation of oestrogens or anti-androgens causes reduction in size.
        Perianal adenoma- gross appearance (Courtesy of Bristol BioMed Image Archive)
  • Occasionally hepatoid carcinomas (malignant) arise in affected males
    • Outwith hormonal control.
  • Hepatoid gland tumours occur rarely in bitches.
    • Are commonly malignant.
  • Hepatoid glands are also found at the tail head, prepuce and occasionally other skin sites.
    • Hepatoid tumours can also arise in these areas.

Hepatocytic

  • seen mostly in sheep and cattle

Gross

  • a single, pale, soft, often large nodule
  • well demarcated from adjacent tissue, often with a noticeable capsule

Microscopically

  • normal hepatocytic appearance
  • no portal tracts within the mass
  • a capsule surrounds the growth

Cholangiocellular - bile duct

  • very rare
  • reported in dogs and cats

Pancreatic

Image of multifocal pancreatic adenoma in a dog from Cornell Veterinary Medicine

  • Very rare
  • May be difficult to distinguish from nodular hyperplasia
  • Single and larger nodules than normal pancreas