+ Biologic Behavior

• Site: distal rectum
• 80% are single lesions and 20% are multiple
• 0%-41% local tumor recurrence rate after surgical resection
• 18% rectal polyps undergo malignant transformation
• Tenesmus, hematochezia, dyschezia, rectal bleeding unassociated with defecation, and polyp prolapse
• Other signs can include vomiting, diarrhea and weight loss

+ Physical Examination

• Abdominal mass is frequently palpable via either abdomen and rectal palpation
• Other findings include dehydration and abdominal pain

+ Laboratory Tests

• Anemia and leukocytosis reported but occur less commonly than small intestinal tumors
• Paraneoplastic leukocytosis reported with adenomatous rectal polyp

+ 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

+ Surgical Techniques

Surgical approaches: rectal eversion

transanal endoscopic resection of benign rectal tumors has been described in 6 dogs

+ Cryosurgery

Cryosurgery of pedunculated stalk can be considered with rectal polyps

+ Chemotherapy

Piroxicam (suppository or oral) for rectal tubulopapillary polyps with significant PR or CR in 88% (7/8)

+ Prognosis

• 0%-41% local tumor recurrence rate after surgical resection or cryosurgery
• 18% rectal polyps undergo malignant transformation
• Survival time > 1 year with few deaths related to polyp
• Survival time for polyps diagnosed as carcinoma in situ 5-24 months