Intussusception of the Cecal Appendix Secondary to Endometriosis: Case Report

The intussusception of the appendix is the invagination of the appendix into the cecum, accompanied by changes in peristalsis. 1 This condition is considered a rare finding, with an incidence of 0.01%. In the clinical assessment, the main symptoms presented by the patients are abdominal pain, vomiting, and blood in the rectum. However, their presenta- tion varies. Thus, while some people have acute symptoms similar to those of appendicitis, other patients have

► appendix ► intussusception ► adults ► endometriosis

Introduction Appendicular intussusception is the invagination of the appendix into the cecum. Endometriosis is the presence of endometrial tissue outside the uterine cavity, and it has a variable clinical pict ure, presenting as acute appendicitis or intestinal obstruction due to intussusception. The aim of the present paper is to report a case of cecal appendix intussusception secondary to endometriosis, since this is an extremely rare condition and there are few studies on the subject in the literature. Case Report We herein report the case of a 37-year-old female patient with deep endometriosis and abdominal pain in the righ t iliac fossa associated with menstruation. There was an intraluminal formation in the cecum, in the appendicular ostium. Magnetic resonance imaging showed foci compatible with ectopic endometrium in the uterus, rectum, and sigmoid colon. The cecal appendix was enlarged. Resection of the terminal ileum and cecum was performed, and the surgical specimen led to the diagnosis of appendicular intussusception and endometriosis of the cecal appendix.

In adults, the most common etiologies of appendicular intussusception are endometriosis, mucocele, carcinoid tumors, and adenocarcinomas. In patients with endometriosis, involvement of the cecal appendix is infrequent. The de finitive diagno- sis is established by analyzing the surgical specimen, and imaging tests play a limited role in ruling out malignancies. Laparoscopic cecectomy is usually chosen, preserving the ileocecal valve. Hormone suppression therapy can prevent the recurrence of intestinal endometriosis.

Appendicular intussusception, although an infrequent pathology, is an occurrence that requires surgical treatment and, in patients with endometriosis, it is important to include this hypothesis in the differential diagnosis. received August 13, 2024 accepted after revision November 25, 2024 DOI https://doi.org/ 10.1055/s-0045-1802596. ISSN 2237-9363. © 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution 4.0 International License, permitting copying and reproduction so long as the original work is given appropriate credit (https://creativecommons.org/licenses/by/4.0/). Thieme Revinter Publicações Ltda., Rua Rego Freitas, 175, loja 1, República, São Paulo, SP, CEP 01220-010, Brazil THIEME Case Report 1 Article published online: 2025-03-20 intermittent symptoms, which can persist for weeks or months. The most common cause of appendix intussuscep- tion in adult patients is endometriosis, which accounts for approximately 33% of the cases. 2 Endometriosis can be de fined as the presence of endome- trial glands and stroma outside the uterine cavity. This condition affects around 10% of women who menstruate, and it is present in approximately 70% of the cases of chronic pelvic pain and in 50% of the cases of infertility. 3 The clinical assessment of endometriosis is variable, and many individu- als are asymptomatic. Most of the symptomatic cases tend to present moderate to severe pelvic pain. Endometriosis in the appendix can result in an asymptomatic condition, but it can also present as acute appendicitis, intestinal obstruction due to intussusception, lower gastrointestinal bleeding, or intes- tinal perforation. 3 Given that intussusception of the appendix due to endo- metriosis is an extremely rare finding, there is a scarcity of studies on the subject in the literature, and there is a need for more publications on the subject.2 We herein report a case of a patient with intussusception of the cecal appendix secondary to endometriosis. Case Report A 37-year-old, White, single, female patient, diagnosed with deep endometriosis 3 years before, consulted with a colo- proctologist complaining of recurrent abdominal pain in the right iliac fossa associated with her menstrual period for 2 years, with no change in her bowel habits, bleeding or constitutional symptoms. The physical examination revealed pain on palpation of the right iliac fossa, with no signs of peritonitis. The patient had undergone a colonoscopy two years before, when the symptoms began, in which a tubular adenomatous polyp with low-grade dysplasia was identi fied in the sigmoid, with no other endoscopic findings. The patient returned for a review, presenting partial relief of the symptoms after starting the treatment for endometri- osis with hormone blockade, but continued to present discomfort in her right iliac fossa, with the same character- istics as those at the start of the investigation. A new colonoscopy was recommended to assess deep endometri- osis and as a follow-up after resection of the adenomatous polyp. Upon further examination, the endoscope was intro- duced up to the terminal ileum, showing an intraluminal formation 4 cm long in the cecum, near the concentration of the tapeworms, apparently in the region of the appendicular ostium, with a slightly enanthematous mucosa, but with the architecture of the crypts preserved on biopsy ( ►Fig. 1 ). A 5- mm sessile polyp was also identi fied in the sigmoid colon, which was removed. The material collected was sent for an anatomopathological examination. The sessile sigmoid polyp turned out to be a tubular adenoma with low-grade dyspla- sia, and the biopsy of the cecal lesion identi fied tissue corresponding to the cecal appendix. The next step in the investigation involved a magnetic resonance imaging (MRI) scan to evaluate the colonoscopic findings, which showed hyperintense foci, compatible with ectopic endometrium in the uterine junctional zone, with other foci involving part of the uterus and ligaments, the anterior wall of the rectum, and the sigmoid colon, with parietal thickening and vegetation, possibly related to colon- ic endometriosis ( ►Fig. 2 ). The cecal appendix had diffusely thickened walls and increased volume (2.0 cm in diameter), which may correspond to a case of mucocele, and its base projected into the lumen of the cecum. The main diagnostic hypothesis was of a pathological appendix with suspected intussusception, and the patient was referred for surgery. A right laparoscopic ileocolectomy was performed, with resection of 15 cm of the terminal ileum and cecum ( ►Fig. 3 ) and primary ileocolic anastomosis. The anatomopathological results of the surgical specimen led to the diagnosis of intussusception of the cecal appendix with a marked chronic in flammatory process and associated endo- metriosis of said appendix. The resection margins were viable, with four mesocolic and mesenteric lymph nodes showing reactive lymphoid hyperplasia and sinusoidal con- gestion. The patient progressed satisfactorily and was dis- charged from the hospital on the fifth postoperative day, without any complications. At the 60-day review, she showed a signi ficant improvement in her right iliac fossa pain.

Intussusception of the cecal appendix is a rare, dif ficult-to- diagnose condition with an incidence of 0.01%. 1,2 It is more prevalent in the adult population (76%), with a predomi- nance in females (70%), and it is more commonly associated with cases of endometriosis, appendicular mucocele, Crohn ’s disease, adenoma, and adenocarcinoma. 2,4 The clinical picture of appendicular intussusception is variable, ranging from asymptomatic to nonspeci fic acute and chronic symptoms, or those that can mimic acute appendicitis.5 Chaar et al. 2 have reported that nonspeci fic chronic symptoms are more common, occurring in 63% of the Fig. 1 Lesion identi fied in the cecum during colonoscopy: 4-cm long intraluminal formation, apparently in the region of the appendicular ostium, with slightly enanthematous mucosa. J Coloproctol Vol. 45 No. 1/2025 © 2025. The Author(s). Cecal Appendix Intussusception Secondary to Endometriosis Giongo et al.2 cases, with abdominal pain (78%), vomiting and melena (26%), and hematochezia (28%) standing out. According to Costa et al., 5 the etiology of appendicular intussusception may be related to anatomical factors, such as a large proximal appendicular lumen, hyperperistalsis, a fully mobile appendix or a thin mesoappendix. Among the factors that trigger intussusception are foreign bodies, feca- liths, polyps, adenocarcinomas, carcinoid tumors, parasites, endometriosis, and lymphoid hyperplasia. 1,2,5 In adults, en- dometriosis is the most common etiology, responsible for 33% of the cases, while approximately 7% of the cases are caused by carcinoid tumors, and 6%, by adenocarcinomas. 2 It is estimated that endometriosis affects around 10% of women of reproductive age, causing involvement of the intestinal tract in 3.8 to 37% of the patients. 1,6 Most of these cases develop the disease in the rectum and rectosigmoid junction, with involvement of the cecal appendix being rare, occurring in approximately 3% of cases. 1,7 Endometrial tissue in the intestine most often affects the serous and muscular layers, causing adhesions and hyperplasia of the smooth muscle; the mass formed is propelled by peristalsis and, if it affects the cecal appendix, it can cause its intussusception in the cecum, as in the case herein presented. 2,8 The suspicion of endometriosis as the etiology of intesti- nal intussusception arises mainly due to a previous diagnosis of the disease or a clinical history of complaints such as dysmenorrhea, dyspareunia, chronic pelvic pain, and dyski- nesia. 6 Based on this hypothesis, a targeted investigation into differential diagnoses is essential. The diagnosis of cecal appendix intussusception is an arduous task, and the condition is often confused with neo- plasms.2,5 In addition, most cases are only identi fied during surgery (57%), while preoperative diagnosis (32%) is less frequent. 2 Chaar et al. 2 have reported that preoperative diagnosis after the 2000s with more improved imaging tests has resulted in increased sensitivity. Initially, ultrasound (US), computed tomography (CT) of the abdomen, radiography with barium enema and endo- scopic studies can be performed. 5,9 During colonoscopy, the lesion is usually observed as a polypoid mass covered by normal mucosa and a central depression in the ori fice.5 Computed tomography is more accurate than US, although both tests help in the diagnosis. 3 Magnetic resonance imag- ing has been used 10 for better preoperative assessment and differentiation from mucoceles, showing hyperintense foci compatible with ectopic endometrium, suggestive of colonic endometriosis. However, imaging tests and endoscopic biopsies play a limited role in ruling out malignancies, and the suspicion of endometriosis is not well assessed in colonoscopy biopsies, since most endometrial implants are located in the outer layers of the intestinal wall. 8 In these cases, endoscopic biopsy often shows normal mucosa, as in the case herein described. Therefore, the de finitive diagnosis, in most cases, is established by surgical approach and complete analysis of the specimen. 2 In general, laparoscopic cecectomy is chosen, with pres- ervation of the ileocecal valve, but it may also be necessary to perform ileocecectomy or right hemicolectomy if there is an Fig. 3 Surgical specimen with resection of the terminal ileum and cecum and intussusception of a pathological appendix. The segments of the small and large intestines measure 6.5 cm and 4.5 cm in length respectively and have a grayish-violaceous serosa with congested vessels, in which you can see an area of mesoretraction. At the opening, close to the ileocecal valve, an area of protrusion lesion can be seen in the lumen of the cecum, in which the cecal appendix can be identi fied, measuring approximately 4.5 cm in length and 1.5 cm in maximum diameter, with a shiny gray serosa and mucosa with preserved folding. Fig. 2 Total abdomen magnetic resonance imaging scan in a T2-weighted fast-spin echo (T2 FSE) sequence. ( A) Coronal section with hyposignal in the cecal appendix (blue arrow). ( B) Axial section with hyposignal in the cecal appendix (green arrows). J Coloproctol Vol. 45 No. 1/2025 © 2025. The Author(s). Cecal Appendix Intussusception Secondary to Endometriosis Giongo et al. 3 association with ileocecal or ileoileal intussusception. Lapa- roscopy also enables the assessment of the peritoneal cavity in search of other foci of endometriosis. 9 In addition to surgery, the treatment after the de finitive diagnosis of endometriosis etiology may involve hormone suppression therapy, which presents bene fits mainly in preventing recurrences of intestinal endometriosis. In these cases, the first line of treatment is low dose progesterones or combined oral contraceptives, both of which present few side effects and are inexpensive. Follow-up with a gynecolo- gist and coloproctologist is essential. 6

Intussusception is a rare occurrence that is dif ficult to diagnose in the adult population, and it involves the colon less often than the small intestine. Despite the rarity of the clinical picture, the case herein reported, of a female patient with cecal appendix intussusception due to endometriosis, who underwent surgical treatment with good postoperative evolution, demonstrates the need to include this hypothesis in the differential diagnosis of patients with similar symp- toms of recurrent abdominal pain in the right iliac fossa related to the menstrual period. Authors’ Contributions Sofia Marasca Giongo was responsible for analyzing and interpreting all data, as well as contributing to the design of the study. Gabriela Pinho Fillmann was involved in the analysis and interpretation of data, as well as in writing the manuscript. Marcelo Garcia Toneto and Lúcio Sarubbi Fillmann supervised the manuscript and conducted the final review. Alessandro Batista Soares, Mariana Tanus Stefani, Marina Tonin and Ana Laura Avila Caumo contrib- uted by analyzing and interpreting the data and assisting in writing the manuscript. Irina Maria Ayala Lopez ana- lyzed the images used in the article. Funding The author(s) received no financial support for the research. Conflict of Interests The authors have no con flict of interests to declare.

1 L o p e zM P J ,C h a nV ,M e l e n d r e sM F ,L u t a n c oR .A p p e n d i c e a li n t u s s u s - ception from endometriosis. BMJ Case Rep 2021;14(06):e241592 2 Chaar CI, Wexelman B, Zuckerman K, Longo W. Intussusception of the appendix: comprehensive review of the literature. Am J Surg 2009;198(01):122–128 3 Yoon J, Lee YS, Chang HS, Park CS. Endometriosis of the appendix. Ann Surg Treat Res 2014;87(03):144 –147 4 Trefois C, Coche E. Appendiceal Intussusception Secondary to Endometriosis: A Rare Etiology of Right Lower Quadrant Abdom- inal Pain. J Belg Soc Radiol 2022;106(01):34 5 Costa M, Bento A, Batista H, Oliveira F. Endometriosis-induced intussusception of the caecal appendix. BMJ Case Rep 2014;2014: bcr2013200098 6 Nezhat C, Li A, Falik R, et al. Bowel endometriosis: diagnosis and management. Am J Obstet Gynecol 2018;218(06):549 –562 7 Gustofson RL, Kim N, Liu S, Stratton P. Endometriosis and the appendix: a case series and comprehensive review of the litera- ture. Fertil Steril 2006;86(02):298 –303 8 Paolini M, Berkey SE, Liang J, Nabi E, Bello BL. Intussusception of the Appendix Secondary to Endometriosis. ACS Case Rev Surg 2023;4(01):25–30 9 Mehmood S, Phair A, Sahely S, et al. Appendiceal intussusception caused by endometriosis. Lancet 2012;380(9848):1202 10 Tsuda M, Yamashita Y, Azuma S, et al. Mucocele of the appendix due to endometriosis: a rare case report. World J Gastroenterol 2013;19(30):5021–5024 J Coloproctol Vol. 45 No. 1/2025 © 2025. The Author(s). Cecal Appendix Intussusception Secondary to Endometriosis Giongo et al.4