Canis ISSN: 2398-2942

Adenoma / adenocarcinoma

Contributor(s): Malcolm Brearley, William Brewer Jr, Jane Dobson


  • Common tumor type arising from glandular epithelial tissue.
  • Malignant tumors (adenocarcinomas) are much more common than benign tumors (adenomas).
  • Treatment: variable response to chemotherapy and surgery and/or radiation therapy which are the mainstays of treatment.
  • Prognosis: depends on site.



  • Adenocarcinomas occur in the skin (sweat gland, ceruminous gland, anal gland Anal sac adenocarcinoma ), oropharynx, nasal chamber, salivary gland, stomach, intestine, bile duct, gall bladder, mammary gland, larynx, trachea and lung.
  • Locally invasive and, depending on site, metastasize to local and distant sites.
  • Adenomas occur in the skin (sweat gland) oropharynx, intestine, bile duct, mammary gland, kidney and thyroid gland.
  • Non-invasive and do not metastasize.


  • Adenocarcinomas much more common, locally invasive and often metastasize to local and distant sites.
  • Sweat gland adenocarcinomas often occur on head and neck.
  • Ceruminous gland adenocarcinoma in external and middle ear canal.
  • Gastrointestinal tract: adenomas are rare, adenocarcinomas common, majority occur in small intestine Alimentary tract: neoplasia (ileum or jejunum), causing diarrhea and/or vomiting, rarely in the stomach
  • Bile duct adenomas and adenocarcinomas occur with similar frequency and present with cranial abdominal mass/hepatomegaly and signs of vague malaise and jaundice.
  • Mammary gland adenocarcinomas often originate from the caudal two mammary glands. The mass may be ulcerated. Rarely there may be signs of tumor metastasis, eg dyspnea due to pulmonary metastasis.
  • Nasal adenocarcinomas → nasal discharge, obstruction, sneezing.
  • Oropharyngeal adenocarcinoma → dysphagia, salivation.
  • Gastrointestinal metastatic disease is usually abdominal.

Tumor behavior

  • Anal sac adenocarcinomas commonly associated with hypercalcemia Hypercalcemia: overview.
  • Sweat gland and ceruminous gland adenocarcinomas - locally invasive, metastasize to lungs, lymph nodes, liver, digits (rarely).
  • Salivary gland adenocarcinoma - limited studies suggest cure with excision followed by radiation therapy Salivary gland: neoplasia.
  • Mammary gland tumors - 90% are adenocarcinoma and are aggressive. Systemic metastasis Mammary gland: neoplasia can occur to lymph node, pleura, lung, liver, spleen, kidneys.
  • Pulmonary adenocarcinoma - aggressive tumor. Metastatic potential depends on size and histology.
  • Nasal adenocarcinoma - usually locally invasive but with low metastatic potential.
  • Gastrointestinal adenocarcinomas often extend into mesentery. Distant metastasis to lymph nodes, spleen, lungs or kidney common in small intestinal adenocarcinomas, less common in large intestine.


  • Weeks/months.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Ross J T, Scowelli T D, Matthiesen D T & Patnaik A K (1989) Adenocarcinoma of the apocrine gland of the anal sac in the dog - a retrospective study of 31 dogs. Vet Surg 18 (1), 71 VetMedResource.
  • Kosovsky et al (1988) Surgical resection of intestinal adenocarcinoma.