CLINICAL FEATURES

Biologic Behaviour

•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

TREATMENT

Surgery

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