Veterinary Society of
Surgical Oncology


Biologic Behaviour

  • intestinal LSA is the most common intestinal tumor
  • majority are multifocal and involve the small intestine


Clinical Signs

  • anorexia, weight loss, intermittent vomiting, and diarrhea
  • severe, persistent vomiting is occasionally observed if proximal small intestinal tumor causes obstruction


Physical Examination

  • palpable abdominal mass and cachexia are common
  • other findings include dehydration and abdominal pain

Laboratory Tests

  • mesenchymal tumors are associated with microcytic hypochromic anemia, hypoproteinemia, and mild leukocytosis

Abdominal Radiographs

  • abdominal mass, obstruction, or persistent irregularity of bowel appearance are identified in 25% of small intestinal tumors and nearly 50% of non-lymphoid intestinal tumors
  • abdominal mass is detected in 60% of canine mesenchymal small intestinal tumors

Contrast Radiography

  • contrast radiographs: mural lesions include luminal filling defect, intestinal wall thickening, mucosal ulceration, abnormal positioning of intestinal loops, and constricting annular lesions


  • intestinal mass identified in 87% (13/15) dogs with non-lymphoid small intestinal tumors
  • loss of wall layering is an excellent predictive factor for differentiating intestinal neoplasia from enteritis in dogs (99% v 12%) with intestinal tumors 50.9-times more likely to have loss of wall layering
  • intestinal tumors also have significant increases intestinal wall thickness (15 mm v 6 mm) and are significantly less likely to have diffuse intestinal involvement (2% v 72%)

Exploratory Celiotomy

  • definitive diagnosis with exploratory celiotomy and biopsy



  • debilitation and hypoproteinemia may complicate treatment
  • exploratory celiotomy with resection and end-to-end anastomosis with 4-8 cm margins and serosal patching
  • mesenteric and regional lymph nodes should be assessed ± aspirated


  • multiagent protocols recommended for LSA as either adjuvant therapy or sole treatment for diffuse disease


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