Leiomyoma is a harmless and non-spreading rare tumor in dogs. It arises from smooth muscles (muscles found in internal organs) of the stomach and intestines. While leiomyoma is relatively inoffensive and non-spreading in nature, it can block normal passage of fluids and food through gastrointestinal tract or displace internal organs which can result in secondary complications.
There is no breed or sex predilection but the neoplasm commonly affects middle to old age dogs, usually over six years of age.
Symptoms depend on location of the tumor. If the tumor is present in stomach, it may only be characterized by vomiting, without any abnormal stomach findings. In case of small intestine having this tumor, the dog may suffer from vomiting, weight loss, rumbling stomach and gas (flatulance). In addition, an abdominal mass may be present as well as occasional distended, painful loops of small bowel.
Feeling of incomplete defecation, bright red, bloody stools (hematochezia), protrusion of the rectal wall through the anus (rectal prolapse) and/or palpable mass during rectal examination are signs of Leiomyoma of large intestine and rectum.