{"paper_id":"593c8b71-8821-411b-86dd-f0f571ca9944","body_text":"492 Hong Kong Medical Journal    ©2019 Hong Kong Academy of Medicine. CC BY-NC-ND 4.0\nAppendiceal endometriosis: a greater mimicker \nof appendicitis\nDavid H Jeong *, MD, Hyojin Jeon, MD, MPH, Karen Adkins, MD\nDepartment of Surgery, Trinity School of Medicine, Ribishi, Saint Vincent\n* Corresponding author: kb_1991@hotmail.com\nEndometriosis is defined as the presence of \nfunctioning endometrial glandular cells outside \nthe uterine cavity. It is a common cause of pelvic \npain that is worse during the menstruation cycle. \nEndometriosis is extremely difficult to diagnose \nbased on clinical features, because the location of \nthe ectopic endometrial cells could lead to diagnosis \nof other common pathological causes of abdominal \npain specific to that area. Although some female \npatients remain asymptomatic, endometriosis is \nusually associated with dysmenorrhea, chronic \npelvic pain, and infertility and can lead to bowel \nobstruction or abdominal mass.\n1\n Although endometriosis within the uterine \nmuscle wall is commonly seen in about 10% of \nwomen of menstrual age, ectopy of endometrial cells \ninto the appendix is rare. The true prevalence of \nextragenital endometriosis is unclear, owing to the \nlack of studies or cases; the incidence of appendiceal \nendometriosis has been reported to be as low as \n0.054% and as high as 0.8%.\n2 Although endometriosis \nhas been reported in almost any part of the human \nbody, to the best of our knowledge no cases have yet \nreported endometriosis in the spleen.\n3\n Appendiceal endometriosis is diagnosed \npathologically. The presence of glandular tissue, \nendometrial stroma, and haemorrhage are typical \nfindings in patients with endometriosis regardless \nof the location.\n4 There is no correlation between \nthe location of the endometriotic foci and clinical \nsymptoms\n5 and endometriosis is much likely to \nmimic primary inflammatory diseases. In the \npatient described in this case report, ectopic \nendometrial cells mimicked inflammation inside the \nappendiceal cavity and the patient presented with \nclinical symptoms that were consistent with acute \nappendicitis.\n In 2018, we experienced a 34-year-old woman \nwho presented with right lower quadrant abdominal \npain for 1 day. The patient described the localised \npain as crampy and rated the pain severity as “10” on \na scale of 1 to 10. The patient presented with nausea, \nvomiting, headache, constipation, menorrhagia, and \ndizziness. She also reported that she was actively \nmenstruating and that these symptoms typically \noccurred monthly with menstruation, but had been \nHong Kong Med J 2019;25:492–3\nhttps://doi.org/10.12809/hkmj187654\nparticularly severe in that month. The patient has \ntwo children and reported not using any form of \ncontraception. The patient’s medical history included \ninflammatory bowel disease, migraine, chronic lower \nback pain, and asthma. The patient had a Caesarean \nsection delivery in 2000 and left fallopian tube/ovary \nremoval secondary to ruptured ectopic pregnancy \nin 2008. The patient denied use of alcohol, tobacco, \nor illicit drugs. There was no relevant family history \nof gastrointestinal diseases or malignancies and the \npatient was allergic to morphine and azithromycin.\n Physical examination showed mild distension \nof the abdomen and tenderness to palpation on \nboth right and left lower quadrants. No rebounding \ntenderness or guarding was noted. Vital signs \nand laboratory test results were all within normal \nlimits with the exception of slightly elevated white \nblood cell at 11.69 K/mm\n3. Although 5.32 M/mm 3 \nof red blood cell was observed in the urinalysis, \nthe results were considered within normal limits \nsince the patient was actively menstruating at the \ntime of the test. Computed tomography scan of the \npatient’s abdomen and pelvis (Fig 1) showed thick-\nwalled appendix (>7 mm) consistent with acute \nappendicitis.\n The patient was taken to the operation room for \nlaparoscopic appendectomy. When the laparoscope \nwas inserted inside the patient’s abdominal cavity, \nsignificant adhesion of the entire abdominal wall \nwas noted. The appendix was unable to be visualised \neven after lysis of adhesion was attempted using \nelectrocautery. A decision was made to proceed \nto open appendectomy. Further lysis of adhesions \nhad to be done to visualise the appendix, which did \nnot show any gross inflammation. The appendix \nwas excised and sent to pathology lab for further \ninvestigation.\n The appendix did not show any signs of \ninflammation, and the preoperative diagnosis \nof acute appendicitis was changed to possible \nendometriosis or ruptured cyst. However, 3 days \nafter the appendectomy, pathology results showed \ninfiltration of endometrial glands, endometrial \nstroma, and blood into the appendix (Fig 2). On the \nbasis of these findings, appendiceal endometriosis \nwas finally diagnosed. After the appendectomy, the \nCOMMENTARY\n\n#  Appendiceal endometriosis  # \n493\nHong Kong Med J  ⎥   Volume 25 Number 6  ⎥   December 2019  ⎥   www.hkmj.org\npatient reported substantial improvement of the \nright lower quadrant pain.\n Appendiceal endometriosis is rare and its \npreoperative diagnosis based on clinical features \nand/or imaging is extremely difficult. Differential \ndiagnosis in female patients who present with \nacute pain in the right lower quadrant, especially \nthose who are of menstruating age, should include \nappendiceal endometriosis. Laparoscopy is useful \nfor the diagnosis since no gross inflammation is \nobserved in the appendix itself and appendectomy \nrelieves the acute symptoms.\nAuthor contributions\nAll authors contributed to the concept of study, acquisition \nand analysis of data, drafting of the article, and critical revision \nfor important intellectual content. All authors had full access \nto the data, equally contributed to the study, approved the \nfinal version for publication and take responsibility for the \naccuracy and integrity of the content.\nConflicts of interest\nThe authors have no conflicts of interest to disclose.\nFunding/support\nThis research has received no specific grant from any funding \nagency in the public, commercial, or not-for-profit sectors.\nEthics approval\nThe patient was treated in accordance with the Declaration \nof Helsinki. The patient provided informed consent for all \nprocedures.\nReferences \n1. Yantiss RK, Clement PB, Young RH. Endometriosis of \nthe intestinal tract: a study of 44 cases of a disease that \nmay cause diverse challenges in clinical and pathological \nevaluation. Am J Surg Pathol 2001;25:445-54.\n2. Collins DC. A study of 50,000 specimens of the human \nvermiform appendix. Surg Gynecol Obstet 1955;101:437-\n45.\n3. Berker B, Lashay N, Davarpanah R, Marziali M, Nezhat CH, \nNezhat C. Laparoscopic appendectomy in patients with \nendometriosis. J Minim Invasive Gynecol 2005;12:206-9.\n4. Apostolidis S, Michalopoulos A, Papavramidis TS, \nPapadopoulos VN, Paramythiotis D, Harlaftis N. Inguinal \nendometriosis: three cases and literature review. South \nMed J 2009;102:206-7.\n5. Uncu H, Taner D. Appendiceal endometriosis: two case \nreports. Arch Gynecol Obstet 2008;278:273-5.\nFIG 1.  Thickening of the walls of the appendix (orange arrow)\nFIG 2.  Endometrial stroma (black arrow), endometrial gland (red arrow), and blood \n(blue arrow)","source_license":"CC0","license_restricted":false}