A Unique Presentation of a Rectosigmoid Intussusception in a 59-Year-Old Female: A Case Report.

Adult intussusception is an uncommon condition that normally presents with nonspecific GI symptoms. It is typically associated with some form of a pathological lead point, especially malignancy in colonic cases. This report discusses the case of a 59-year-old female who presented with abdominal distention and constipation with on-and-off rectal bleeding for two days prior to ED admission. Imaging with computed tomography (CT) revealed findings compatible with a distal intussusception of the sigmoid colon/rectum. Emergent surgical intervention confirmed the diagnosis via a laparoscopic left-sided colectomy that required splenic flexure mobilization. Primary anastomosis was deferred due to heavy stool burden, and a Hartmann procedure was performed. Histopathological examination revealed a 3.0 × 2.5 × 2.2 cm well-differentiated adenocarcinoma infiltrating the muscularis propria. The resection specimen was staged as pT2N0Mx, with negative surgical margins. This is a case of an unusual, self-resolving adult rectosigmoid intussusception with an obstructing malignant lead point. The patient's history and clinical presentation of intermittent abdominal pain, rectal bleeding, and constipation necessitate the need for imaging. CT, coupled with colonoscopy, provides the best chance for definitive diagnosis and guidance for possible treatment. Surgical intervention remains the first-line treatment for obstructing malignant lead points. Adult rectosigmoid intussusception is a rare condition; its intermittent presentation and nonspecific symptoms make diagnosis difficult. Only by maintaining a high level of suspicion and applying appropriate imaging modalities can a definitive diagnosis be established. The Hartmann procedure is one of several surgical options for rectosigmoid intussusception with a malignant lead point.