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==Description==

==Description==

Intestinal adenocarcinomas are a reasonably common malignant neoplasm of dogs and cats arising from the epithelial lining of the gastrointesinal tract. The tumour may have an annular form and cause stenosis of the intestinal lumen.

Intestinal adenocarcinomas are a reasonably common malignant neoplasm of dogs and cats arising from the epithelial lining of the gastrointesinal tract. As yet, no causative organism or chemical agent has been identified for intestinal adenocarcinomas. The appearance of intestinal adenocarcinomas vary from pedunculated to annular forms, and there may be some association between the shape and behaviour of the tumour. By the time of diagnosis, intestinal adenocarcinomas have often metastasised via the lymphatic and vascular routes, most commonly to the mesenteric lymph nodes. Other sites of metastasis include the liver, kidneys, peritoneal cavity, omentum and lungs. Intestinal adenocarcinomas display aggressive local growth and invasion, and tumours frequently recur after resection.

* No organism or chemical agent has been identified that will induce spontaneous intestinal [[Adenocarcinoma|adenocarcinoma]].

* The gross appearance of colorectal [[Adenocarcinoma|adenocarcinomas]] vary from pedunculated, particularly in the distal rectum, cobblestone, in particularly the middle rectum, and annular, also usually in the middle recutum, and may also have associations with tumour behaviour and prognosis.

* In cats, [[Adenocarcinoma|adenocarcinomas]] have been reported to have been found in the ileum and ileocaecal region. Another study reports the jejunum to be the most common site.

* Metastasis occurs via lymphatic and vascular routes. For small intestinal [[Adenocarcinoma|adenocarcinomas]] the most frequent sites of metastasis are the mesenteric lymph nodes. Other sites include the liver, kidneys, peritoneal cavity, omentum and lungs. Metastatic spread is commonly encountered at time of diagnosis.

* Large intestinal [[Adenocarcinoma|adenocarcinomas]] often metastasise to the deep inguinal lymph nodes. The liver is less frequently affected. These tumours also undergo aggressive local growth and local recurrence after resection frequently occurs.

==Signalment==

==Signalment==