Adult sigmoidorectal intussusception related to colonic lipoma: A rare case report with an atypical presentation

INTRODUCTION: Adult intussusception is rare. Lipoma is the second most common benign tumor of the colon and most common to cause colonic intussusception in adults, but rare. PRESENTATION OF CASE: A 35-years-old male presented with a history of intermittent abdominal pain and bright red rectal bleeding, with symptoms waxing and waning for one month. On physical examination, the abdomen was distended with tenderness over the periumbilical, suprapubic, and left lower quadrant regions with guarding. CT demonstrated colo-colonic intussusception of the sigmoid colon with a 2.3 cm × 2.6 cm intra-mural lipoma of the rectosigmoid region. The patient underwent an exploratory laparotomy with partial reduction of the intussusception, sigmoid colon resection and end colostomy. Histopathology confirmed a 2.5 cm sub-mucosal lipoma without evidence of malignancy. DISCUSSION: Sixty–sixty five percent of cases with intussusception of the large bowel in adults are related to a malignant etiology and most cases of sigmoidorectal intussusception reported in the literature are secondary to underlying malignancy. Colo-colic intussusception is the most common type of intussusception in adults. The incidence of lipomas of the large intestine is reported to range from 0.035% to 4.4%. Ninety percent of colonic lipomas are submuscosal and are mostly located in the right hemicolon. Only 25% of patients with colonic lipoma develop symptoms. Colonic lipomas of the rectosigmoid region represent a very rare occurrence and subsequent etiology for sigmoidorectal intussusceptions in adults. CONCLUSION: Colonic lipoma should be considered in the differential diagnosis of adults with intussusception, with reduction and resection leading to excellent results.