Veterinary Society of
Surgical Oncology

GENERAL CONSIDERATIONS

Biologic Behaviour

  • signalment: purebred male dogs of miniature breeds
  • clinical signs: anorexia, lethargy, vomiting, and diarrhea
  • hematology: anemia, hypoproteinemia, and mastocytemia are common
  • GI ulceration is a common finding
  • 100% metastatic rate with metastatic sites including regional lymph nodes (common), liver, spleen, heart, and lungs

CLINICAL FEATURES

Clinical Signs

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

Diagnosis

Physical Examination

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

Laboratory Tests

  • anemia and leukocytosis are common in dogs with non-lymphoid intestinal tumors

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

  • intestinal mass identified in 57% of dogs with non-lymphoid intestinal tumors
  • contrast radiographs: mural lesions include luminal filling defect, intestinal wall thickening, mucosal ulceration, abnormal positioning of intestinal loops, and constricting annular lesions

Ultrasonography

  • 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

TREATMENT

Surgery

  • 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

Chemotherapy

  • chemotherapy is recommended for intestinal MCT

Prognosis

  • MST 16 days with 100% tumor-related mortality within 2 months of diagnosis
  • 100% metastatic rate

SMALL INTESTINAL MAST CELL TUMOR

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