Sigmoid-rectal intussusception in an elderly patient: A case report of an unusual presentation of intestinal obstruction.

Introduction: Sigmoid-rectal intussusception or invagination is an infrequently documented condition in the adult population, with only a handful of cases reported in the medical literature. The underlying pathological mechanism involves impaired peristalsis, often attributed to a malignant tumor.

Case Presentation: A 78-year-old patient, with a history of abdominal pain and lower gastrointestinal bleeding, sought care at our emergency department with evident symptoms indicative of large bowel obstruction. Abdominal examination revealed distension and rectal examination found a mass mimicking an internal rectal prolapse. Subsequently, imaging studies confirmed the diagnosis of sigmoid-rectal intussusception. The patient underwent an emergency open sigmoid resection with Hartman's procedure. The postoperative course was uneventful. Anatomopathological analysis revealed the presence of stage I adenocarcinoma. A restoration of digestive continuity was scheduled six months later. One-year follow-up assessments showed no indications of local recurrence or distant metastasis.

Discussion: Sigmoid rectal intussusception stands as a unique and infrequently reported medical entity. The absence of distinct clinical symptoms often renders diagnosis a challenging task, with confirmation typically relying on radiological findings. In contrast to the non-surgical approaches employed in pediatric cases, intussusception in adults necessitates surgical intervention due to its predominantly malignant underpinnings.

Conclusion: While sigmoid-rectal intussusception is an exceedingly rare occurrence, its manifestation with a multitude of non-specific symptoms can complicate clinical recognition. Nevertheless, it should be duly considered as a potential etiological factor in cases of large bowel obstruction, particularly when suggestive signs are found on rectal examination.