Complete small intestinal obstruction due to band formation in low-grade appendiceal mucinous neoplasm: A rare case report and literature review.

Introduction: Intestinal obstruction due to external compression is a rare condition, and those caused by appendiceal neoplasms like low-grade appendiceal mucinous neoplasms are extremely rare.

Presentation Of Case: A 67-year-old post-menopausal female, with no history of prior abdominal surgery, presented to the emergency room with constipation for 2 days, and peri-umbilical pain and non-projectile bilious vomiting for 19 h. There was mild abdominal distension and diffuse tenderness. After ultrasonography and Computed Tomography (CT) of the abdomen and pelvis, a provisional diagnosis of complete small bowel obstruction secondary to perforated mucinous neoplasm of the appendix was made. An emergency exploratory laparotomy was performed followed by ileo-cecal resection and ileocolic anastomosis. Intraoperative findings revealed bands extending from the appendix to the ileum forming a closed loop with gangrenous spots in the distal ileum and ascitic fluid with mucin. Later, histopathological examination findings were consistent with low-grade appendiceal mucinous neoplasm (LAMN).

Discussion: We reviewed three cases of intestinal obstruction, caused by compression from a LAMN, including the presented case. Preoperative diagnosis of the cause of small intestinal obstruction on CT is sometimes challenging. Hence, in patients with intestinal obstruction with a transition point in the right lower quadrant of the abdomen on CT, a high index of suspicion for an appendiceal etiology is required.

Conclusion: LAMN with an associated band should be considered as one of the differential diagnoses in the patient presenting with symptoms of complete small intestinal obstruction without prior abdominal surgery.