Appendiceal intussusception happens when appendix segment is pulled into itself or into the cecum. This condition can mimic various chronic and acute abdominal conditions, with an important entity to be recognized, since it could be mistaken as a cecal mass.
Appendiceal intussusception is a rare condition, with an estimated incidence of 0,01% of patients who received appendectomy 1.
Symptoms of appendiceal intussusception have been divided into four groups:
- asymptomatic patients
- symptoms are similar to acute appendicitis
- symptoms are consistent with intestinal intussusception, abdominal pain and vomiting occur for several days; bowel movements may be normal and less frequently constipation, diarrhea or melaena
- prolonged history of intermittent severe attacks of right lower quadrant abdominal pain. Vomiting and melaena may be present
The diagnosis is rarely made preoperatively because of its variable presentation and unspecific symptoms.
Appendix intussusception can occur without any underlying abnormality. Anatomical variations of the appendix or pathological conditions such as tumours or polyps, endometriosis, parasitism, cystic fibrosis, fecaliths and foreign bodies, have been described as possible causes.
In most cases the radiographic findings are normal. When there are small bowel obstruction associated, orthostatic abdominal radiograph can demonstrate air-fluid levels.
Ultrasonography has played a role especially in children. Longitudinal sonograms may show the inverted appendix protruding into the caecal lumen.
Similar findings to the intestinal intussusception can be seen, which include:
CT is the most commonly used diagnostic modality. CT scan can clearly show an appendix invaginated into the cecal cavity (see case 1).
Appearance of bowel-within-bowel, which identifies the appendix surrounded by the cecum can be found.
On imaging, differential considerations include
- 1. Laalim SA, Toughai I, Benjelloun el B et-al. Appendiceal intussusception to the cecum caused by mucocele of the appendix: Laparoscopic approach. Int J Surg Case Rep. 2012;3 (9): 445-7. doi:10.1016/j.ijscr.2012.04.019 - Free text at pubmed - Pubmed citation
- 2. Langsam LB, Raj PK, Galang CF. Intussusception of the appendix. Dis. Colon Rectum. 1984;27 (6): 387-92. Pubmed citation