Colonoscopic Diagnosis of Appendiceal Intussusception: Case Report and Review of the Literature

Abstract

Intussusception of the appendix is an extremely rare condition. Although approximately 200 cases of appendiceal intussusception have been reported in the literature, very few have ever been diagnosed preoperatively. We report a case of appendiceal intussusception secondary to endometriosis in an otherwise healthy female. The case was diagnosed preoperatively by colonoscopy and treated surgically at laparoscopy. We review the literature of appendiceal intussusception and discuss the associated conditions, diagnosis, and a classification scheme for this unusual finding.

INTRODUCTION

Intussusception of the appendix is an extremely rare condition. Although approximately 200 cases of appendiceal intussusception have been reported in the literature, very few have ever been diagnosed preoperatively. We report a case of appendiceal intussusception secondary to endometriosis in an otherwise healthy female and review the literature regarding this rare finding.

CASE REPORT

A 45-year-old female presented as an outpatient complaining of a several year history of rectal bleeding and intermittent right lower quadrant pain. She reported an association of her pain and rectal bleeding with her menstrual periods, and she stated that her symptoms were gradually worsening. An anorectal examination revealed external and internal hemorrhoids as well as a 1.5-cm pedunculated rectal polyp. A full colonoscopy was scheduled.

At colonoscopy, 3 benign rectosigmoid polyps were removed. In the cecum, she had an appendiceal intussusception (Figure 1). A computed tomograhic scan was ordered that did not reveal any evidence of intraabdominal disease. After appropriate counseling, the patient was taken to the operating room for laparoscopy. Intraoperative findings showed an intussuscepted appendix (Figure 2) as well as multiple scattered small peritoneal and mesenteric deposits (Figure 3) consistent with endometriosis. A partial cecectomy was performed including the intussuscepted appendix while preserving the ileocecal valve. Final pathology of the specimen (Figure 4) showed extensive adherent endometriosis along the appendix and mesoappendix. The patient's postoperative course was unremarkable, and 12 months after surgery, she is doing well and is without symptoms.

Figure 1.

Endoscopic view of cecum and intussuscepted appendix.

Figure 2.

Intraoperative laparoscopy with view of patient's right lower quadrant. Only tip of appendix was visualized secondary to intussusception into the cecum (center). Endometrioma is noted at bottom center.

Figure 3.

Small endometriomas were visualized upon perito-neal, mesenteric, and bowel surfaces.

Figure 4.

Resected specimen including intussuscepted appendix and portion of cecum removed via laparoscopy.

DISCUSSION

First reported in a 7-year-old boy in 1858 by McKidd,¹ intussusception of the appendix is an extremely rare entity. It more frequently occurs in males and in the first decade of life.² Approximately 200 cases of appendiceal intussusception have been reported in the surgical literature, but very few have been diagnosed preoperatively as in this case.³ In fact, less than 10 cases have been reported in which a preoperative diagnosis had been made; ultrasound and barium enema were useful in diagnosing many of these,^4–8 whereas diagnosis by colonoscopy has been noted in only a select few.^3,9,10

Although the cause of intussusception is unknown, the postulated mechanism for its occurrence is abnormal peristalsis provoked by local irritation.¹¹ Possible intrinsic causes of intussusception are varied and include foreign body, fecalith, polyp, carcinoid or other neoplasm, mucocele, Crohn's disease, parasites, lymphoid hyperplasia, or endometriosis. The appendix may be completely normal or may harbor a malignancy, endometriosis, or any of the other conditions listed. The appearance of intussusception may mimic that of acute appendicitis or, as in this case, may present as a constellation of vague and non-specific symptoms.

Radiologic studies may be helpful in diagnosis, but they are rarely diagnostic for intussusception, as supported by the majority of cases being diagnosed at laparotomy. A “coiled-spring” or “spiral shell” appearance of the appendix may be seen with abdominal ultrasound or contrast enema.¹² Computed tomography may also be useful in establishing a diagnosis by demonstrating a “target” appearance or concentric rings of intussuscepted appendix and cecum. Absence of filling of the appendix with barium enema is suspicious but neither sensitive nor specific for intussusception.

A classification scheme for appendiceal intussusception was proposed by McSwain¹³ and modified by Langsam et al.⁸ A type I intussusception begins at the appendix tip that intussuscepts (the intussusceptum) into the more proximal appendix (the intussuscipiens). In type 2, the base of the appendix is the intussusceptum that invaginates into the cecum. Type 3 intussusception occurs when the proximal appendix is the intussusceptum and invaginates into the distal portion of the appendix. A type 4 intussusception is a complete appendiceal inversion into the cecum with associated ileocecal intussusception. The case report described here correlates with a type 2 intussusception.

Recognition of appendiceal intussusception is important in avoiding misdiagnosis and misguided attempts at endoscopic removal or inappropriate surgery. An appendiceal intussusception may be mistaken for a polyp or carcinoma, and failure to accurately diagnosis this condition has resulted in patients undergoing colonoscopic polypectomy with resultant perforation and peritonitis.¹⁴ Alternatively, patients have also undergone unnecessary hemicolectomy when the intussuscepted appendix is regarded as a malignancy.^15–17 Although reduction of the intussuscepted appendix may occur via increased cecal luminal pressure from barium enema or colonoscopy, the definitive treatment requires surgical resection. As in this case, preoperative identification by colonoscopy facilitates selection of appropriate surgical management and ultimate treatment of this rare condition.