Rectal prolapse is usually of benign etiology. Rarely, sigmoido-rectal intussusception results from a malignant lead-point. We report the case of a patient with a partially obstructing sigmoid cancer causing a full thickness rectal prolapse requiring surgical intervention. An 82-year-old woman presented with 1 week of rectal bleeding, fecal incontinence, and weight loss. Computed tomography identified sigmoido-rectal intussusception. Colonoscopic biopsy revealed high-grade dysplasia. Magnetic resonance imaging demonstrated a 6-cm mass forming the lead point of the intussusceptum with epiploic appendages seen within the rectal lumen. She underwent laparoscopic low anterior resection with final pathology consistent with T2N0 adenocarcinoma, and recovered well. Among adult patients with rectal prolapse, suspicion for underlying malignancy should prompt a thorough investigation to inform the decision for resection, which may be safely performed by minimally invasive techniques.