{"paper_id":"a1a1530c-b569-4ac1-b926-5b358e20185d","body_text":"UCLA\nProceedings of UCLA Health\nTitle\nIntestinal Endometriosis: An Unusual Cause of a Rectal Mass\nPermalink\nhttps://escholarship.org/uc/item/7q19358n\nJournal\nProceedings of UCLA Health, 28(1)\nAuthors\nSkay, Anna\nMcEnerney, Laura\nPublication Date\n2024-10-24\neScholarship.org Powered by the California Digital Library\nUniversity of California\n\nProceedings of UCLA Health \n   -VOLUME 28 (2024)- \n   \nCLINICAL VIGNETTE  \n \n \nIntestinal Endometriosis: An Unusual Cause of a Rectal Mass \n \n \nAnna Skay, MD and Laura McEnerney, MD \nCase \n \nA 33-year-old woman with altered bowel habits for 5 months \npresented for a gastroenterology evaluation. She also reported \npain in her  lower back and sacrum. Other symptoms included  \nconstipation with less frequent loose stools with urgency and  \nsensation of incomplete emptying. She  stopped caffeine and \ntried a  “squatting potty” with no improvement in symptoms. \nThere was no rectal bleeding, but some intermittent abdominal \ncramping pain. without  specific aggravating factors. The pain \ndid not respond to over-the-counter medications. \n \nPast medical history included acne vulgaris. She was on topical \nbenzoyl peroxide -erythromycin and clindamycin swabs.  She \ndid not smoke, use drugs or drink significant amounts of alco-\nhol. She had no personal or family history of gastrointestinal \nmalignancies or other gastrointestinal disorders.  \n \nLaboratory evaluation included normal complete blood count , \ncomprehensive metabolic panel and TSH. Celiac panel was also \nnegative.  \n \nColonoscopy revealed a 15 mm nodular sessile lesion in the \ndistal rectum with active oozing (Figure 1). Multiple biopsies \nrevealed histology consistent with endometriosis (Figure 2).  \n \nMRI was performed  with endometriosis protocol, which \ninvolves intrarectal and intravaginal contrast. Findings included \nT1 hyperintense/T2 hypointense thickening along the left pelvic \nsidewall in the region of the left ureteral sacral ligament and 2.9 \ncm T2 hypointense/T1 isointense lesion with scattered internal \nareas of T1 hyperintensity within the upper rectum approxi -\nmately 7 cm from the anal verge with heterogeneous arterial \nenhancement. There were apparent adhesions of the adjacent \nmesorectal fascia and posterior vagina. \n \nDiscussion \n \nEndometriosis defined as endometrium tissue found outside the \nuterus. The organs involved are typically in the pelvic cavity. \nLess commonly, endometriosis can occur in the abdominal \ncavity or other distant sites. The prevalence of endometriosis is \nunknown with varying estimates published. Five  to 12% of  \npatients have  endometriosis lesions in the intestine.\n1 Ectopic \nendometrial tissue can also involve other organs including liver, \ngallbladder and pancreas.  Endometriosis lesion s in the bowel \ncan infiltrate the serosa, the sub -serosa and the muscular layer \nof the bowel wall. Endometriosis is found more commonly in  \n \n \nthe left colon than the right. L eft colon lesions can involve  the \nrectosigmoid junction or the middle to proximal sigmoid.  \nInfiltration in the right colon is reported  with involvement of \nthe cecum and terminal ileum.  The appendix can also be \ninvolved. Isolated small bowel involvement aside from the \nterminal ileum is rare.  When proximal rect al lesions are found \nthey are often part of a larger complex in the deep portion of the \nDouglas pouch and can infiltrate the posterior vaginal fornix \nand anterior rectal wall. 2 Intestinal endometriosis can cause \nvarious symptoms including diarrhea, constipation, bloating or \nrectal bleeding.\n2 Endometriosis located in the rectum can be \nassociated with cyclic dyschezia, or pain with defecation, and \ntenesmus.  In most women endometriosis is not obstructive.2  \n \nThere are three distinct histologic components to endometriotic \nbowel lesions including ectopic endometrial -like mucosa, \nsmooth muscle fibers and fibrous connective tissue.  Etiology \nof intestinal endometriosis is not completely understood,  with \nmenstrual reflux theory the most widely accepted hypothesis. If \nsome menstrual blood flows backward through the fallopian \ntubes into the abdominal cavity, endometrial tissue can enter the \nouter uterus. E ndometrial tissue can then infiltrate other areas \nwith peritoneal fluid flow and metaplasia. In the bowel the \nrectosigmoid site is the most common (65.7%).\n3 Peritoneal \nfluid can carry ectopic endometrial cells anywhere in the cavity, \nbut upright posture enables  fluid flow to deeper areas of the \npelvis.  \n \nEvidence suggest s women with endometriosis have altered  \nimmune cell function, with elevated T cell populations in endo-\nmetriosis tissue. There is increase in regulatory T cells (Tregs) \nthat express Forkhead Box P3 (Foxp3).  Tregs promote per -\nsistence of endometriotic tissue. Macrophages have aberrant \nbehavior in endometriosis with increased secretion of certain \ncytokines including IL -6, IL -10, IL -12 and TGF β1. Various \nmacrophage phenotypes in endometriosis tissue promote \nfibrosis, proliferation and migration. NK cells in the peritoneal \nfluid of women with endometriosis have diminished activity, \nwhich allows immune escape of free endometrial cells \ntransferring into peritoneal fluid.\n3   \n \nIntestinal endometriosis symptoms can be nonspecific leading \nto diagnostic difficulties.  Intestinal endometriosis can be noted \non imaging including transvaginal ultrasound, rectal endo-\nscopic sonography (EUS), helicoidal computed tomography \n(CT) scan and magnetic resonance imaging (MRI). 1 MRI for \n\n  \n \nintestinal endometriosis should follow a  specific protocol. For \nrectosigmoid endometriosis, MRI has sensitivity of 63 to 98% \nand specificity of 89 to 100%. MR enterography can be \nconsidered for lesions proximal to the rectosigmoid. MRI \nprotocol for intestinal endometriosis recommends a partially \nfilled bladder, supine position, abdominal strapping, use of anti-\nperistaltic agent (such as glucagon), rectal opacification with \ncontrast as well as vaginal opacification with contrast.\n1  \n \nTreatment of intestinal endometriosis according to the  2022 \nEuropean Society for Human Reproduction and Embryology \nguidelines includes hormone therapy and surgery . Both can be \neffective to reduce pain. Hormonal therapy includes combined \nhormonal contraceptives, gonadotropin -releasing hormone \nantagonists or gonadotropin-releasing hormone agonists.3 Two \nthirds of patient s with rectosigmoid endometriosis can be suc -\ncessfully managed with hormonal therapy. Intermittent imaging \nshould be performed to monitor for lesion progression.2  \n \nSurgical approaches with best reported  outcomes involve \ncomplete laparoscopic eradication of endometriotic tissue. A \nmultidisciplinary team is recommended to make individual \ndecisions based on symptoms, risks, recurrence rates, surgeon’s \nexpertise and potential complications.2 Surgical approaches for \nrectal endometriosis include superficial resection (shaving), \ndiscoid resection and segmental resection. Superficial resection \nor “shaving” can be considered if there is no involvement of the \nbowel beyond the muscularis propria.  Superficial resection is a \nmore commonly used technique with lower complication risk \nbut is limited to infiltration up to 5mm in depth.  Discoid \nresection is full thickness resection restricted to the anterior \nrectal wall. It can be considered if there is involvement of the \nbowel beyond the muscularis propria with individual lesions \nless than 3cm and infiltration less than 50% of the lumen.  \nSegmental resection is recommended if there are multiple \nnodules, lesions larger than 3 cm or infiltration more than 50% \nof the bowel lumen.\n4 \n \nConclusion \n \nIntestinal endometriosis is the  uncommon involvement of the \ngastrointestinal tract by endometriosis. Most lesions affect the \nrectosigmoid. MRI with endometriosis protocol has high \nsensitivity and specificity. Treatment options include hormonal \ntherapy and surgical interventions. Multidi sciplinary approach \nto treatment is recommended.  \n \n \n \n \n \n \n \n \n \n \n \n \nFigures \n \n \n \n \n \nFigure 1.  Rectal mass seen from 11 o’clock to 4 o’clock \npositions.  \n \nA.    \nB.   \n \nFigure 2. Histology of rectal mass showing endometrial glands. \nA. Hematoxylin and eosin stain. B. Immunohistochemistry \nstains for endometrial glands and stroma right panel.  \n \n \n \n \n \n \n \n \n\n\n  \n \nREFERENCES \n \n1. Bazot M, Kermarrec E, Bendifallah S, Daraï E. MRI of \nintestinal endometriosis. Best Pract Res Clin Obstet \nGynaecol. 2021 Mar;71:51- 63. doi:  10.1016/ \nj.bpobgyn.2020.05.013. Epub 2020 Jun 14. PMID: \n32653334. \n2. Vercellini P, Sergenti G, Buggio L, Frattaruolo MP, \nDridi D, Berlanda N . Advances in the medical \nmanagement of bowel endometriosis. Best Pract Res Clin \nObstet Gynaecol . 2021 Mar;71:78 -99. doi: \n10.1016/j.bpobgyn.2020.06.004. Epub 2020 Jun 24. \nPMID: 32680785. \n3. Yin W, Li X, Liu P, Li Y, Liu J, Yu S, Tai S . Digestive \nsystem deep infiltrating endometriosis: What do we know. \nJ Cell Mol Med . 2023 Dec;27(23):3649-3661. doi: \n10.1111/jcmm.17921. Epub 2023 Aug 25. PMID: \n37632165; PMCID: PMC10718155. \n4. Popoutchi P, Marques Junior OW, Averbach P, \nCardoso Filho CAM, Averbach M . Surgical techniques \nfor the treatment of rectal endometriosis: a systematic \nreview of randomized controlled trials and observational \nstudies. Arq Gastroenterol. 2021 Oct -Dec;58(4):548-559. \ndoi: 10.1590/S0004 -2803.202100000-97. PMID: \n34909864.","source_license":"CC0","license_restricted":false}