{"paper_id":"8fbd842f-8b41-4847-8004-aa7f2a44830a","body_text":"Practice CMAJ\n686 CMAJ, April 5, 2011, 183(6) © 2011 Canadian Medical Association or its licensors\nA\n42-year-old woman presented to the\nemergency department with a four-day\nhistory of severe constipation, bilious\nvomiting and colicky abdominal pain. Her symp-\ntoms started with the onset of menses but dif-\nfered from the crampy dysmenorrhea for which\nshe had taken over-the-counter analgesics for\nmany years. She had no history of bloody or\nblack stool, or changes in her bowel function.\nApart from a 20 pack-year smoking history, her\nmedical, surgical and family histories were non-\ncontributory.\nOn examination, she was afebrile, and her\nabdomen was soft but distended, with hyperac-\ntive, high-pitched bowel sounds. There were no\nperitoneal signs. With deep palpation, we felt a\ntender, firm mass in the left lower quadrant. On\ndigital examination, her rectum was empty of\nstool and contained mucous that tested positive\nfor occult blood. A pelvic examination suggested\na retroverted, mobile uterus, with fullness in the\nleft adnexa and tender nodularities in the pouch\nof Douglas.\nLaboratory test results were within normal\nlimits except for a leukocyte count of 16 (normal\n3–10) × 10\n9/L. An abdominal radiograph showed\ndilated loops of bowel and multiple air–fluid lev-\nels, consistent with bowel obstruction. A com-\nputed tomography scan confirmed an obstruction\nin the distal portion of the large bowel secondary\nto a 7-cm rectosigmoid mass with mild ascites.\nOn transvaginal ultrasonography, the mass ap -\npeared to be 6 cm in diameter and in the left\nadnexal region, extending posterior to the uterus\nand in contact with the adjacent bowel. The right\novary appeared normal.\nWhat is the next most appropriate\ndiagnostic test or procedure?\na. Testing for the cancer antigen 125 (CA-125)\ntumour marker\nb. Magnetic resonance imaging (MRI)\nc. Colonoscopy\nd. Exploratory laparotomy\nGiven the findings of bowel obstruction and a\nrectosigmoid mass in our patient, we suspected\ncolorectal carcinoma. We proceeded with (c) a\ncolonoscopy, with the intent of obtaining a tissue\nsample for diagnosis. Surprisingly, no mucosal\nlesions were found. However, at the obstruction\nsite, the mucosa was edematous with an a cute\nangulation of the sigmoid colon, compatible \nwith extra luminal compression. These findings,\ntogether with the previous imaging results,\npointed to external compression of the bowel\nfrom an adnexal mass or an intramural gastro -\nintestinal lesion. As part of the recommended\nworkup for a pelvic or ovarian mass,\n1 we ordered\na CA-125 test; the results were not immediately\navailable.\nWe felt that MRI was the next most appropri-\nate noninvasive diagnostic test. The MRI images\nshowed a mass arising from within the bowel\nwall and extending to the subserosa (Figure 1).\nBoth ovaries appeared normal. \nOur next step was an urgent exploratory\nlaparotomy, which showed a nodular recto -\nsigmoid mass that was adherent to the rectovag  i -\n nal septum. We mobilized the lesion, resected \nthe diseased bowel and created a diverting\ncolostomy using the Hartmann procedure. A\nWhat is your call?\nBowel obstruction and pelvic mass\nAlly Murji MD, Mara L. Sobel MSc MD\nCompeting interests:None\ndeclared.\nThis article has been peer\nreviewed.\nCorrespondence to: \nDr. Mara L. Sobel,\nmara.sobel@utoronto.ca\nCMAJ 2011. DOI:10.1503\n/cmaj.091851\nFigure 1: Sagittal T2-weighted magnetic resonance\nimage showing a colonic mass (arrow) in a 42-\nyear-old woman with symptoms of large-bowel\nobstruction. \nwhat-sobel_Layout 1  16/03/11  10:57 AM  Page 686\n\nPractice\nCMAJ, April 5, 2011, 183(6) 687\nthorough examination of the pelvis did not find\nadditional areas of disease.\nWhat is your diagnosis?\na. Gastrointestinal stromal tumour\nb. Gastrointestinal lymphoma\nc. Sigmoid phlegmon (inflammatory mass)\nd. Deeply infiltrating gastrointestinal endo -\nmetrio  sis\nDiscussion\nAfter reviewing the pathology findings (Figure\n2), we diagnosed (d) deeply infiltrating gastroin-\ntestinal endo metriosis. Foci of endometriosis\nwere also identified in mesenteric lymph nodes\n(Figure 3).\nEndometriosis is characterized by the pres-\nence of functional endometrial glands and\nstroma outside of the uterus. This common con-\ndition affects up to 10% of women of reproduc-\ntive age, most often involving the ovaries and\nutero sacral ligaments. Gastrointestinal involve-\nment occurs in up to 34% of women with pelvic\nendometriosis.\n2 The diagnosis of gastrointestinal\nendometriosis may be difficult to establish be -\ncause its symptoms are relatively nonspecific.\nPatients may present with abdominal pain, bloat-\ning, tenesmus, dyschezia (painful bowel move-\nments), rectal bleeding, diarrhea, constipation or\nobstruction.\n3 The differential diagnosis is often\nbroad; the main considerations include appen-\ndicitis, diverticulitis, inflammatory bowel dis-\nease, irritable bowel syndrome and malignant\ndisease. The incidence of endometriosis causing\nbowel obstruction is unknown, although com-\nplete obstruction occurs in less than 1% of pa -\ntients with gastrointestinal endometriosis.\n4\nThe symptoms associated with gastrointesti-\nnal endo metriosis vary according to the depth\nand site of involvement. Disease of the small\nintestine usually manifests as abdominal pain,\nbloating and obstruction, whereas patients with\ncolonic endometriosis are more likely to present\nwith altered bowel habits (decreased stool cali-\nbre, diarrhea, constipation, hematochezia) and an\nabdominal mass. 5 Early in the disease process,\nsymptoms may be associated with menses, with\ncyclical episodes present in 40% of patients with\ngastro intestinal involvement.6 Often, however,\nsymptoms become continuous as the lesions\ninfiltrate the bowel wall and lead to localized\nfibrosis, smooth muscle hypertrophy and luminal\nstenosis.\nAdding to the challenge of diagnosing gas-\ntrointestinal endometriosis is the often false-\nnegative result of endoscopic biopsies. The biop-\nsies tend to be superficial and miss the foci of\nendometriosis that are located in the deeper\nbowel layers. When deeply infiltrating gastroin-\ntestinal endometriosis is suspected clinically,\ntrans vaginal ultrasonography and MRI may\nprove valuable in reaching the diagnosis. With a\nsensitivity of 91% and a specificity of 97%,\ntransvaginal ultrasonography is the first-line\nimaging modality for such patients.\n7,8 Likewise,\nMRI detects invasive intestinal endometriosis\nFigure 2: Specimen from colon resection. Endo metriotic glands (arrows), stroma\nand accompanying hemorrhage (H) caused marked thickening of the bowel wall\nand luminal narrowing (hematoxalin–eosin stain, original magnification × 20).\nFigure 3: Mesenteric lymph node from colon resection showing foci of endo -\nmetriosis (arrows) and hemorrhage (H) (hematoxalin– eosin stain, original mag-\nnification × 20).\nwhat-sobel_Layout 1  16/03/11  10:57 AM  Page 687\n\nPractice\n688 CMAJ, April 5, 2011, 183(6)\nwith a sensitivity of 88% and a specificity of\n93%, and it may be useful when the results of\nultrasonography are equivocal. 9 Although CA-\n125 levels may be elevated in endometriosis, the\ntest is primarily used as a tumour marker, with a\nsensitivity of 80% for advanced ovarian cancer.\nHowever, it has poor specificity and may be ele-\nvated in several benign and malignant conditions,\nincluding endometriosis and colon cancer.\n10\nColonic masses with obstruction\nA clinical presentation of an abdominal mass\nand bowel obstruction in the context of worsen-\ning gastrointestinal symptoms and equivocal\ndiagnostic tests frequently raises the sus picion of\ngastrointestinal cancer. Negative findings on\ncolonoscopy do not necessarily rule out malig-\nnant disease, because primary extraluminal neo-\nplasms and neoplastic changes arising from\nendometriosis (endometrioid adenocarcinoma\nand clear-cell adenocarcinoma) frequently\ninvolve only the outermost layers of the colon.\nThe differential diagnosis of intramural gastroin-\ntestinal lesions causing large bowel obstruction\nis shown in Table 1.\n8,11,12 Although primary col-\norectal lymphoma may also present as an extra-\nluminal mass, mucosal involvement often can be\nseen with colonoscopy.11\nThe presence of a colonic mass with intact\nmucosa can also indicate sigmoid phlegmon, the\nmost common complication of diverticular dis-\nease.11 Patients with acute diverticulitis tend to\npresent with pain in the left lower quadrant of\nthe abdomen, altered bowel habits, low-grade\nfever and mild leukocytosis. On pelvirectal\nexamination, a tender mass may be palpable.\nComputed tomography is the diagnostic test of\nchoice for acute diverticulitis. 11 In our patient,\nphlegmon was unlikely because of the absence\nof both colonic diverticula and signs of inflam-\nmation of the bowel wall on imaging.\nManagement\nEndometriosis can be managed both medically\nand surgically. In its clinical practice guidelines\non the treatment of endo metriosis, the Society of\nObstetricians and Gynaecologists of Canada rec-\nommends combined estrogen–progestin hor-\nmonal contraceptives or progestin alone as first-\nline medical therapy. Gonadotropin-releasing\nhormone agonists and the levo norgestrel-\nreleasing intrauterine device should be consid-\nered second-line therapeutic options. Non -\nsteroidal anti- inflammatory drugs and opioids\nmay provide effective analgesia while awaiting\nsymptom resolution from hormonal therapy.\nSurgery is generally reserved for refractory\nsymp toms, severe invasive disease, infertility,\npelvic mass or diagnostic uncertainty.\n13\nManagement of gastrointestinal endometrio-\nsis depends on the extent of disease. The Ameri-\ncan Congress of Obstetricians and Gynecologists\nTable 1: Differential diagnosis of intramural gastrointestinal lesions causing obstruction of the large \nbowel \nCondition Characteristics \nDeeply infiltrating endometriosis  • Patients present with dysmenorrhea, chronic pelvic pain, deep \ndyspareunia and dyschezia \n• Symptoms are initially cyclical but may become continuous as \nthe disease progresses \n• Diagnosis can be aided by transvaginal ultrasonography and \nMRI\n8\n \nDiverticulitis with sigmoid \nphlegmon \n• This condition is a complication of acute diverticulitis \n• Patients present with pain in the left lower quadrant, altered \nbowel habits and low-grade fever \n• In the acute phase, CT is often diagnostic, showing an inflamed \nsoft-tissue mass\n11\n \nGastrointestinal mesenchymal \nneoplasm*  \n• Patients with this rare type of neoplasm present with nonspecific \ngastrointestinal symptoms (bloating, early satiety), bleeding, \npain and symptoms of bowel obstruction \n• CT is the imaging modality of choice, showing a smoothly \ncontoured mass\n11\n \nColorectal lymphoma • Patients present with pain, weight loss and symptoms of an \nabdominal mass \n• Colonoscopy is often diagnostic, showing diffuse mucosal \nnodularity, induration, ulceration and a mass\n11\n \nNote: CT = computed tomography, MRI = magnetic resonance imaging. \n*Includes gastrointestinal stromal tumour, leiomyoma, leiomyosarcoma, lipoma, liposarcoma and schwannoma. \nwhat-sobel_Layout 1  16/03/11  10:57 AM  Page 688\n\nPractice\nCMAJ, April 5, 2011, 183(6) 689\nrecommend suppression of ovarian function with\na gonadotropin-releasing hormone agonist as\nfirst-line medical treatment of extrapelvic endo -\nmetriosis. For patients presenting with bowel\nobstruction or those with severely advanced\nintestinal disease, surgical resection is the treat-\nment of choice. 7 Although there is no evidence\nsupporting the use of preoperative medical sup-\npressive therapy, a postoperative course of hor-\nmonal therapy (three months or longer) is often\nprescribed for patients with residual disease or\npersistent pain, or to extend the pain-free interval\nafter surgery.\n7 We prescribed a gonadotropin-\nreleasing hormone agonist for our patient. At the\nlast follow-up visit, she was awaiting the rever-\nsal of her colostomy.\nReferences\n1. Le T, Giede C, Salem S, et al. Initial evaluation and referral\nguidelines for the management of pelvic/ovarian masses. \nJ Obstet Gynaecol Can2009;31:668-73.\n2. Kratzer GL, Salvati EP. Collective review of endometriosis of\nthe colon. Am J Surg 1955;90:866-9.\n3. De Ceglie A, Bilardi C, Blanchi S, et al. Acute small bowel\nobstruction caused by endometriosis: a case report and review of\nthe literature. World J Gastroenterol2008;14:3430-4.\n4. de Bree E, Schoretsanitis G, Melissas J, et al. Acute intestinal\nobstruction caused by endometriosis mimicking sigmoid carci-\nnoma. Acta Gastroenterol Belg1998; 61: 376-8.\n5. Yantiss RK, Clement PB, Young RH. Endometriosis of the\nintestinal tract: a study of 44 cases of a disease that may cause\ndiverse challenges in clinical and pathologic evaluation. Am J\nSurg Pathol 2001;25:445-54.\n6. Jubanyik KJ, Comite F. Extrapelvic endometriosis. Obstet\nGynecol Clin North Am1997;24:411-40.\n7. Practice bulletin no. 114: management of endometriosis. Obstet\nGynecol 2010;116: 223-36.\n8. Piketty M, Choplin N, Dousset B, et al. Preoperative work-up\nfor patients with deeply infiltrating endometriosis: transvaginal\nultrasonography must definitely be the first-line imaging exami-\nnation. Hum Reprod 2009;24:602-7.\n9. Bazot M, Bornier C, Dubernard G, et al. Accuracy of magnetic\nresonance imaging and rectal endoscopic sonography for the\nprediction of location of deep pelvic endometriosis. Hum\nReprod 2007;22:1457-63.\n10. Clarke-Pearson DL. Screening for ovarian cancer. N Engl J Med\n2009; 361:170-7.\n11. Corman ML, editor. Colon and rectal surgery. 5th ed. Philadel-\nphia (PA): Lippincott Williams & Wilkins; 2005. \n12. Yantiss RK, Clement PB, Young RH. Neoplastic and pre-neo-\nplastic changes in gastrointestinal endometriosis: a study of 17\ncases. Am J Surg Pathol2000;24:513-24.\n13. Leyland NA, Casper R, Laberge P, et al. Society of Obstetri-\ncians and Gynaecologists of Canada clinical practice guideline.\nEndometriosis: diagnosis and management. J Obstet Gynaecol\nCan 2010;7(2 Suppl):S1-S32.\nAffiliations: From the Department of Obstetrics and Gyne-\ncology, University of Toronto, Toronto, Ont.\nContributors: Both authors contributed substantially to\nwriting the manuscript and revising it for important intellec-\ntual content and approved the final version submitted for\npublication.\nAcknowledgements: The authors thank Dr. Maja Barnard\nfor help with the histological images and Dr. Caroline Chan\nand Mr. Ashish Papneja for help with the clinical images,\ndetails of the case and the initial literature review. The\nauthors also thank these people, and Dr. Paul Shuen, the clin-\nical physician who supervised the case, for their help in\nreviewing the manuscript.\nResources\n• Society of Obstetricians and Gynaecologists of\nCanada: Clinical practice guidelines on the\ndiagnosis and management of endometriosis\n(www.sogc.org/guidelines /documents\n/gui244CPG1007E .pdf)\n• Practice bulletin no. 114: management of\nendometriosis. 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