Appendiceal Endometriosis

Although appendiceal endometriosis is rare, appendix is the second most common site of intestinal endometriosis. Clinical diagnosis is difficult and histopathology is the only way to establish the diagnosis. CASE REPORT A 31-year-old woman nulliparous presented with recurrent cyclic right-sided pelvic pain for two years duration which was worse during defecation and urination. Her cycles were regular, no history of hematuria or hematochezia. She was previously investigated by a urologist and a gastroenterologist with negative findings. Abdominal and pelvic imaging including computerized tomography scan was within normal limits. At laparoscopy, we found endometriotic implants in the posterior cul de sac. The appendix was stretched and adhered to the anterior abdominal wall [Figure 1]. Excision of the endometriosis and appendectomy led to the resolution of her pain symptoms. Histopathological examination revealed endometriosis of the cul de sac and the appendix [Figure 2].

Intestinal endometriosis is usually asymptomatic and found incidentally during surgery for other conditions.[] Although appendiceal endometriosis (AE) is rare, appendix is the second most common site of intestinal endometriosis.[] Clinical diagnosis is difficult and histopathology is the only way to establish the diagnosis. The incidence of endometriosis of the appendix varies from 0.8% to 20%.[] Collins reported that the rate of AE was 0.05% in 50 000 cases of appendectomy.[] There are no pathognomonic criteria to establish an accurate preoperative diagnosis of appendiceal endometriosis.[] AE is usually asymptomatic but may present with acute or chronic abdominal pain. Acute appendicitis as a manifestation of AE is extremely rare.[] Massive lower intestinal bleeding[] or intestinal intussusceptions' secondary to AE has been described.[] In pregnancy, inflammatory changes associated with appendiceal endometriosis tend to be more prominent, and rare complications such as perforation and gangrenous inflammation can occur.[] Another rare finding is the association between appendiceal endometriosis and obstructive mucocele. The mucous distension can cause secondary obstruction of the appendix.[] The natural history of AE is unclear, but endometriosis-related adhesions could cause obstruction and lead to acute or intermittent appendicitis. Small superficial endometriotic implants on the serosa under hormonal influence proliferate and infiltrate the appendix. Cyclic hemorrhage from these implants can lead to partial or complete obstruction of the lumen resulting in acute inflammation of the appendix. Chronic inflammation causes fibrosis, stricture formation, and adhesion to the neighboring pelvic structures. There is no specific radiologic test to diagnose AE. Laparoscopy provides detailed evaluation of the appendix but gross inspection of appendix alone is not enough to rule out AE. In fact, 38% of grossly normal appearing appendix has histological evidence of endometriosis.[] Mittal et al. studied 16 cases of AE, 6 of them presented as acute appendicitis and 2 others had a ruptured appendix. Histopathological examinations revealed that the body of the appendix is involved in 56% of the cases and the tip of the appendix is involved in another 44%. The base of the appendix was involved in one case only.[] Endometriosis of the appendix usually involves the serosa or serosa and muscularis propria; the mucosa remains intact.[] Another study reported that among 31 cases of AE, 13 (40%) involve the muscularis layer and 18 (60%) involve the serosa and muscularis layers.[] Mital et al. found that among 16 AE specimens, muscular and seromuscular involvement occurred in two third of patients, while serosal involvement only in one third of the patients. In all patients, glands and stroma typical of endometriosis were found.[] Rarely, the mucosa is involved by endometriosis where the patients may present with melena or rectal bleeding.[] The appendix may be involved and contributes to pelvic pain in women with endometriosis. Harris et al. studied 65 women with symptomatic endometriosis and right low abdominal quadrant pain pain; 52 (80%) underwent appendectomy as a part of surgery and abnormal looking appendix. Of these 52 excised appendices, 12 (31%) had histologically confirmed AE.[] Berker et al. studied 231 patients who underwent appendectomy during laparoscopic treatment of endometriosis and chronic pelvic pain. One hundred and fifteen patients (22.1%) were found to have concomitant appendiceal pathology.[] Routine performance of appendectomy in patients with chronic pelvic pain was evaluated in several studies.[] In one study, 106 patients underwent routine appendectomy during laparoscopic treatment of ovarian endometriosis. Gross abnormality was found in 3.3% of cases, and microscopic examination revealed endometriosis in 13.2% of cases.[] Agarwala and Liu reported a routine appendectomy as the only procedure associated with improvement in 91% of women with pelvic pain. In their study, 48 of 317 appendices had visible pathology. AE was encountered in 14 cases (4.4%).[] It appears that patients with abnormal looking appendix are likely to have AE compared to those with normal looking appendix. Clinically, AE should be differentiated from catamenial appendicitis, where the patient experiences cycle-dependent symptoms such as right lower quadrant pain and anorexia, mimicking acute appendicitis. This condition is associated with histopathological finding of increased numbers of mast cells in the appendiceal muscularis. In those with pelvic endometriosis, it is speculated that cyclic production of peritoneal fluid prostaglandins or other vasoactive compounds by endometriotic lesions leads to appendiceal ischemia or reperfusion injury. Symptoms always resolve following appendectomy.[] The appendix may harbor endometriosis and could be a cause of chronic pelvic pain. When performing surgeries in a patient with chronic pelvic pain, surgeons should be aware of the possible contribution of AE to the pelvic pain in patients with endometriosis. The appendix should be examined thoroughly during endometriosis-related operations. Appendectomy should be performed if the appendix looks abnormal. Source of Support Nil, Conflicts of interest None declared.

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