Veterinary Society of
Surgical Oncology

General Considerations

  • ADC and LSA are the most common large intestinal tumors in cats
  • other large intestinal tumors include MCT, HSA, and neuroendocrine carcinoma
  • intestinal HSA metastatic to regional lymph nodes and carcinomatosis has been reported
  • ileocolic junction most common site for large intestinal tumors

Clinical Signs

  • hematochezia, vomiting, and weight loss


Physical Examination

  • cachexia is common
  • abdominal mass is frequently palpable via either abdomen and rectal palpation
  • other findings include dehydration and abdominal pain


  • circumferential transmural thickening with loss of normal intestinal layering reported in 5 cats with intestinal ADC


  • endoscopy is recommended prior to definitive treatment
  • biopsy samples should be interpreted histologically as cytologic misdiagnosis is common with intestinal ADC being misdiagnosed as either septic inflammation or LSA
  • biopsy samples are often small and superficial resulting in false-negative diagnosis if lesion is either submucosal or associated with surface ulceration and necrosis

Exploratory Celiotomy

  • definitive diagnosis with exploratory celiotomy and biopsy
  • feline large intestinal ADC more commonly associated with mucosal ulceration and bowel thickening than annular stenosis
  • leiomyoma and sarcoma are usually large solitary masses growing through the intestinal serosa



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


  • multiagent protocols recommended for LSA as either adjuvant therapy or sole treatment for diffuse disease
  • chemotherapy is also recommended for cats with intestinal plasmacytoma and MCT
  • no effective chemotherapy for ADC


  • MST for cats with colonic tumors is significantly better with:
  • surgical resection compared to conservative management (198 days v 22 days)
  • MCT compared to LSA (199 days v 97 days)
  • no metastasis in cats with ADC (49 days v 259 days)
  • however, some cats with metastatic disease had prolonged survival time


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