+ 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

+ Ultrasonography

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

+ Endoscopy

  • 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


+ Surgery

  • 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

+ Chemotherapy

  • 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

+ Prognosis

  • 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