Gynecologic Adenomyosis and Endometriosis: Key Imaging Findings, Mimics, and Complications

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1 Volume 38 Number 7 March 31, 2015 Gynecologic Adenomyosis and Endometriosis: Key Imaging Findings, Mimics, and Complications Saro. Manoukian, MD, Nicholas H. Shaheen, MD, and Daniel J. Kowal, MD After participating in this activity, the diagnostic radiologist should be better able to utilize ultrasound and MR imaging to help differentiate between gynecologic adenomyosis and endometriosis given their divergent management despite their significant overlap in symptoms. CME Category: Women s Imaging Subcategory: Genitourinary Modality: MRI Key words: Adenomyosis, Endometriosis, Ovarian Endo metrioma Adenomyosis and endometriosis are gynecologic processes with characteristic pathophysiologic, clinical, and imaging differences. Although adenomyosis refers to the presence of heterotopic endometrial glands and stroma within the myometrium, endometriosis involves the presence of endometrial glands and stroma outside of the uterus (Figure 1). Patients with either adenomyosis or endometriosis can have a similar clinical presentation. Imaging can be of great utility in differentiating between these 2 gynecologic pathologic processes, thereby guiding appropriate clinical management. Accurate diagnosis also is important because endometriosis has potentially more significant complications. Finally, differentiating an ovarian endometrioma from its mimics can obviate the need for more invasive procedures, such as laparoscopy or oophorectomy. Dr. Manoukian is Radiology Resident, Dr. Shaheen is Radiology Resident, and Dr. Kowal is CT Division Director, Department of Radiology, Saint Vincent Hospital, 123 Summer St, Worcester, MA 01608; sarma81@gmail.com. The authors and all staff in a position to control the content of this CME activity and their spouses/life partners (if any) have disclosed that they have no relationships with, or financial interests in, any commercial organizations pertaining to this educational activity. Adenomyosis of the Uterus Adenomyosis of the uterus represents heterotopic endometrial glands and stroma in the myometrium with adjacent smooth muscle hypertrophy. The pathogenesis of uterine adenomyosis involves endometrial migration via a basement membrane defect or through lymphatic or vascular channels. 1 Women age 40 to 50 years usually are affected. Although patients with uterine adenomyosis are usually asymptomatic, symptoms may include pelvic pain, menorrhagia, and dysmenorrhea. Risk factors for uterine adenomyosis include prior uterine trauma or surgery, multiparity, and hyperestrogenemia. Imaging is important because superficial uterine adenomyosis responds significantly better to endometrial ablation than does deep uterine adenomyosis. On ultrasound imaging, pseudowidening of the endometrium with a poorly defined endomyometrial junction often is seen in diffuse uterine adenomyosis because of heterotopic endometrium extending into the inner myometrium 2 (Figure 2). These heterotopic endometrial glands cause an appearance of subendometrial echogenic linear striations. 2 Also, the uterus is often globular and enlarged with heterogeneous myometrial echotexture. On MRI, diffuse uterine adenomyosis demonstrates thickening of the junctional zone of at least 12 mm. The junctional zone corresponds to the innermost layer of myometrium and is visualized as a distinct area of low signal on T2-weighted MR images, separating the high-signal endometrium from the intermediate-signal outer myometrium 3 (Figure 3). Although a junctional zone thickness greater than 12 mm is diagnostic of uterine adenomyosis (Figure 4), a junctional zone thickness of 8 mm or less effectively excludes adenomyosis as a diagnostic consideration. Lippincott Continuing Medical Education Institute, Inc., is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Lippincott Continuing Medical Education Institute, Inc., designates this enduring material for a maximum of 2 AMA PRA Category 1 Credits. Physicians should only claim credit commensurate with the extent of their participation in the activity. To earn CME credit, you must read the CME article and complete the quiz and evaluation on the enclosed answer form, answering at least seven of the 10 quiz questions correctly. This continuing medical education activity expires on March 30,

2 Figure 1. Adenomyosis represents heterotopic endometrial glands and stroma in the myometrium. Endometriosis represents functional ectopic endometrial glands and stroma outside of the uterine cavity, commonly manifesting as an endometrioma. Figure 2. Transvaginal ultrasound of the uterus demonstrates endometrial pseudowidening (white arrow) with a poorly defi ned endomyometrial junction (dashed arrow). Heterogeneity of the myometrium also is present. Additional MR findings include poorly defined junctional zone margins, intrazonal T2-hyperintense punctate foci representing cystic dilatation of heterotopic glands 3 Figure 3. Sagittal, T2-weighted MR image of the uterus demonstrates its normal zonal anatomy. The outer myometrium (1) is intermediate signal intensity. The inner myometrium (2) (also known as the junctional zone) is hypointense and normally <12 mm in thickness. The endometrium (3) is normally hyperintense. (see Figure 4), and T1-hyperintense punctuate foci indicating hemorrhage, all of which are findings that add specificity to the diagnosis. ecause of its superior sensitivity and specificity compared with ultrasound, MRI is the imaging modality of choice for the diagnosis of uterine adenomyosis. 2 The definitive treatment for diffuse uterine adenomyosis is hysterectomy, particularly in women with debilitating symptoms. Endometrial ablation can be performed for more superficial disease, which is best evaluated on MRI. 2 Mimics of Focal Adenomyosis. A myometrial contraction could mimic focal adenomyosis, but myometrial contractions are transient and change in appearance over time. 2 Although typically diffuse, uterine adenomyosis also can occur focally and even appear mass-like as an adenomyoma. Uterine leiomyomas (fibroids) are well-defined, rounded lesions with mass effect on the endometrium, unlike focal uterine adenomyosis, which is poorly defined, elliptical, and without mass effect. Although both uterine fibroids and adenomyosis are hypointense on T2-weighted MR images, focal uterine adenomyosis contains punctate hyperintense foci, signifying dilated cystic endometrial glands. 2 Differentiating the two conditions is clinically relevant because of divergent management: uterine conservation with myomectomy for leiomyomas versus hysterectomy for uterine adenomyosis. The continuing education activity in Contemporary Diagnostic Radiology is intended for radiologists. Contemporary Diagnostic Radiology (ISSN ) is published bi-weekly by Lippincott Williams & Wilkins, Inc., Hunters Green Parkway, Hagerstown, MD Customer Service: Phone (800) ; Fax (301) ; customerservice@lww.com. Visit our website at LWW.com. Publisher, Randi Davis. Copyright 2015 Wolters Kluwer Health, Inc. All rights reserved. Priority Postage paid at Hagerstown, MD, and at additional mailing offices. POSTMASTER: Send address changes to Contemporary Diagnostic Radiology, Subscription Dept., Lippincott Williams & Wilkins, P.O. ox 1600, Hunters Green Parkway, Hagerstown, MD PAID SUSCRIERS: Current issue and archives (from 1999) are available FREE online at Subscription rates: Individual: US $ with CME, $ with no CME; international $ with CME, $ with no CME. Institutional: US $ , international $ In-training: US resident $ with no CME, international $ GST Registration Number: Send bulk pricing requests to Publisher. Single copies: $ COPYING: Contents of Contemporary Diagnostic Radiology are protected by copyright. Reproduction, photocopying, and storage or transmission by magnetic or electronic means are strictly prohibited. Violation of copyright will result in legal action, including civil and/or criminal penalties. Permission to reproduce in any way must be secured in writing; go to the journal website ( select the article, and click Request Permissions under Article Tools, or customercare@copyright.com. Reprints: For commercial reprints and all quantities of 500 or more, reprintsolutions@wolterskluwer.com. For quantities of 500 or under, reprints@lww.com, call , or fax EDITOR: Robert E. Campbell, MD, Clinical Professor of Radiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania FOUNDING EDITOR: William J. Tuddenham, MD EDITORIAL OARD: Teresita L. Angtuaco, MD ruce L. McClennan, MD George S. isset III, MD Johnny U. V. Monu, MS, Msc William G. radley Jr., MD, PhD Pablo R. Ros, MD, MPH, PhD Liem T. ui-mansfield, MD William M. Thompson, MD Valerie P. Jackson, MD Opinions expressed do not necessarily reflect the views of the Publisher, Editor, or Editorial oard. A mention of products or services does not constitute endorsement. All comments are for general guidance only; professional counsel should be sought for specific situations. Indexed by io-science Information Services.

3 A Figure 4. T2-weighted MR image demonstrates a poorly defined, widened junctional zone (box) containing hyperintense punctate foci (arrow), representing cystic dilatation of heterotopic endometrial glands in diffuse uterine adenomyosis. Endometriosis Endometriosis represents functional ectopic endometrial glands and stroma outside of the uterine cavity. Endometriosis is in some ways similar to uterine adenomyosis, which was formerly referred to as endometriosis interna. 1 The most accepted theory of the pathogenesis of endometriosis is that it results from metastatic implantation of endometrial tissue into the peritoneal cavity from retrograde menstruation. 4 Endometriosis is seen predominantly in women of childbearing age, with an overall prevalence of 10%. In addition, 5% of cases are seen in postmenopausal women. 5 The most common presenting symptoms are pelvic pain and infertility. Risk factors include age and prolonged exposure to menstruation, such as early menarche, nulliparity, short menstrual cycles, and prolonged menstrual flow. 4 Endometriosis can present in three forms: ovarian endometriomas, endometrial implants, and deep pelvic endometriosis with adhesions. Endometriomas are chronic cysts that occur within the ovary from repeated cyclic hemorrhage. These ovarian endometrial cysts are referred to as chocolate cysts because they contain thick, dark, degenerated blood products. 4 On ultrasound, endometriomas contain homogeneously diffuse low-level echoes (Figure 5), a finding observed in 95% of Figure 5. Endometrioma. Transvaginal ultrasound of an adnexal lesion with homogeneously low-level internal echoes, consistent with endometrioma. Figure 6. Endometrioma. A: T1-weighted, fat-suppressed MR image demonstrates a homogeneously hyperintense adnexal lesion (arrow), consistent with an endometrioma. This lesion is classically described as light bulb bright. : T2-weighted MR image demonstrates corresponding hypointensity (dashed arrow) because of the high concentration of iron, protein, and viscosity. This fi nding is classically referred to as T2-shading. endometriomas. 4 Less commonly, endometriomas may demonstrate echogenic wall nodularity and have thin or thick septations. 6 Ultrasound is highly sensitive and specific in the evaluation of endometriomas. However, ultrasound is extremely poor in evaluating the other forms of endometriosis (i.e., endometrial implants and deep pelvic endometriosis with adhesions), 6 which are thought to be the principal causes of pelvic pain and infertility in affected patients. The most common and specific MR appearance of endometriomas is the presence of lesions that are homogeneously T1-hyperintense (referred to as light bulb bright ) and T2- hypointense (referred to as T2 shading ) 5 (Figures 6A and 6). T2 shading occurs because of the high concentration of iron and protein and increased viscosity and protein crosslinking within the lesion. 6 Less commonly, endometriomas can appear T2-hyperintense because of differences in concentration of blood products. A definitive diagnosis of an endometrioma is made if there is a T1-hyperintense lesion with T2 shading or if multiple T1-hyperintense cysts are visualized, regardless of their signal intensity on T2-weighted images. 6 MRI is the most specific modality for diagnosis of endometriosis, with a sensitivity of 90% and a specificity of 98%. 6 A T1-weighted, fat-suppressed sequence further improves sensitivity, as fat suppression narrows the dynamic signal range and increases lesion conspicuity, allowing detection of endometriomas and endometrial implants as small as 5 mm (Figure 7). 6 3

4 Figure 8. Axial CT scan demonstrates thoracic endometrial seeding with pleural thickening (calipers), round atelectasis (circle) secondary to chronic pleural irritation, and a pleural effusion found to be a hemothorax. A are part of the differential diagnosis, but there are useful imaging characteristics that can help differentiate these mimics from endometriomas. Hemorrhagic cysts are usually solitary, unilocular, evolve into more complex-appearing cysts over time, and resolve within 6 weeks, unlike endometriomas that persist.7 On ultrasound, hemorrhagic cysts typically demonstrate a reticular pattern of echogenic Figure 7. Multiple endometriomas. A: T1-weighted MR image shows a right adnexal hyperintense lesion (dashed arrow), consistent with an endometrioma. : T1-weighted, fat-suppressed MR image reveals a punctate left adnexal hyperintense lesion (solid arrow), also an endometrioma that could not be visualized on the sequence without fat suppression. There are numerous potential sites of implantation in endometriosis. The gastrointestinal (GI) tract is the most common site, occurring in 12% to 37% of cases, most commonly the rectosigmoid colon. Serosal, and less commonly, transmural implantation may occur, with patients experiencing bloating, cramping, and pain during defecation.7 The urinary tract is the next most common site of involvement in up to 20% of cases, typically involving the urinary bladder, followed by the ureters. Patients may present with urinary urgency, dysuria, and gross hematuria.7 Up to 30% of women with endometriosis have fallopian tube involvement at laparoscopy, with hematosalpinx likely occurring secondary to adhesions. Hematosalpinx appears as a T1-hyperintense tubular adnexal structure and may be an isolated finding in a patient with endometriosis. The thorax is a rare site of involvement but is the most frequent form of extra-abdominal endometriosis. The thoracic endometriosis syndrome manifests as catamenial pneumothorax, hemothorax, and lung nodules (Figure 8). Women with thoracic endometriosis can present with pleuritic chest pain, pleural effusions, or cyclic hemoptysis.7 The treatment for endometriosis is medical when symptoms include pelvic pain or dyspareunia, usually with antiinflammatory agents or hormonal therapy. In the case of infertility, treatment is surgical, which involves the removal of endometriomas or lysis of adhesions in a patient with deep pelvic endometriosis.7 Mimics of Endometriosis. Hemorrhagic cysts, mature cystic teratomas, and ovarian mucinous epithelial neoplasms 4 A C Figure 9. Hemorrhagic ovarian cysts. Transvaginal ultrasound (A) of an adnexal lesion with low-level echoes and thin, reticular, echogenic strands representing clot and fibrin within a hemorrhagic cyst. On MRI, hemorrhagic ovarian cysts are usually solitary T2-hyperintense () and T1-hyperintense (C) lesions (arrows).

5 A Figure 10. Mature cystic teratoma. A: Ultrasound of a large cystic adnexal lesion demonstrates low-level internal echoes with the appearance of an endometrioma. : On an axial CT scan, this lesion demonstrates fat and calcium density (dashed arrow) within a Rokitansky nodule characteristic of a mature cystic teratoma. Figure 11. orderline mucinous epithelial ovarian tumor. Transvaginal ultrasound of an adnexal lesion demonstrates low-level echoes, resembling an endometrioma. However, this lesion is larger than a typical endometrioma and is a pathology-proven borderline mucinous epithelial ovarian tumor, which could be characterized more defi nitively on MRI. Figure 12. Endometrioid carcinoma. Axial CT scan of a large bilobed right adnexal mass. This was a pathology-proven endometrioid carcinoma, the most common malignancy to arise from endometriosis. In addition, there is synchronous endometrial hyperplasia, a fi nding that occurs in 30% of patients with endometrioid carcinoma. fibrin strands (Figure 9A), as opposed to the homogeneous low-level echoes of endometriomas. 7 On MRI, hemorrhagic cysts are usually both T1- and T2-hyperintense (Figures 9 and 9C). Moreover, hemorrhagic cysts are clotforming rather than viscous and contain little iron (i.e., no T2 shading ). 7 Mature cystic teratomas (dermoid cysts), particularly those with high sebum content, may mimic endometriosis on ultrasound and appear as cystic masses with low-level internal echoes similar to an endometrioma (Figure 10A). If not detected on ultrasound, the fat and calcium-containing Figure 13. Clear cell carcinoma of the ovary. Ultrasound of a cystic adnexal lesion with papillary projections (arrow) demonstrates intranodular Doppler flow, raising suspicion for malignant transformation. This lesion was a pathology-proven clear cell carcinoma, the second most common malignancy to arise from endometriosis. Figure 14. Scar endometriosis. Axial CT scan of a biopsyproven subcutaneous endometrial implant (dashed arrow) along a transverse incision site secondary to iatrogenic spread from a cesarean delivery. Rokitansky nodule pathognomic for a dermoid cyst typically is visible on CT (Figure 10) and especially MRI. On MRI, T1 fat-suppressed imaging differentiates dermoid cysts from endometriomas with high specificity. 7 orderline mucinous epithelial ovarian tumors may demonstrate low-level echoes on ultrasound because of loculated mucin and, therefore, may resemble endometriomas (Figure 11). However, these tumors are typically much larger than endometriomas. On MRI, these lesions may be multilocular, have enhancing solid components, or have a stained glass appearance because of variations in mucin concentration within loculi. 6 Complications of Endometriosis. Malignant transformation is rare in endometriosis, occurring less than 1% of the time. The most common malignancies arising from endometriosis are endometrioid carcinoma (Figure 12) followed by clear cell carcinoma 6 (Figure 13). The most reliable imaging finding in evaluating for malignant transformation of an endometrioma is the presence of an MRI contrast-enhancing or Doppler-positive mural nodule (see Figure 13). 4 On MRI, enhancing mural nodules are sensitive (97%) but not specific (56%) for malignant transformation. 5 Other, less reliable imaging features suggesting malignant transformation include loss of T2 shading and interval increase in size. 5 Scar endometriosis represents iatrogenic spread of endometrial tissue related to surgery, a complication seen in 1% of all patients who have had a cesarean delivery. Patients can present with a palpable mass or cyclical pain weeks to years after surgery. 6 On ultrasound, a solid hypoechoic mass is seen with internal vascularity on Doppler imaging. On CT, a soft tissue density is encountered in the subcutaneous tissues of the abdominal wall in the expected region of a Pfannenstiel incision 6 (Figure 14). Tissue sampling typically is required to confirm the diagnosis. Conclusion Uterine adenomyosis and endometriosis are gynecologic processes with often overlapping clinical symptoms. This CME activity emphasizes the key imaging differences between these two entities and differentiates them from their mimics, thereby guiding appropriate therapy. 5

6 References 1. Tamai K, Togashi K, Ito T, et al. MR imaging findings of adenomyosis: correlation with histopathologic features and diagnostic pitfalls. Radiographics. 2005;25: Reinhold C, Tafazoli F, Mehio A, et al. Uterine adenomyosis: endovaginal US and MR imaging features with histopathologic correlation. Radiographics. 1999;19:S147-S Novellas S, Chassang M, Delotte J, et al. MRI characteristics of the uterine junctional zone: from normal to the diagnosis of adenomyosis. AJR Am J Roentgenol. 2011;196: ennett GL, Slywotzky CM, Cantera M, et al. Unusual manifestations and complications of endometriosis spectrum of imaging findings: pictorial review. AJR Am J Roentgenol. 2010;194:WS34-WS McDermott S, Oei TN, Iyer VR, et al. MR imaging of malignancies arising in endometriomas and extraovarian endometriosis. Radiographics. 2012;32: Woodward PJ, Sohaey R, Mezzetti TP Jr. Endometriosis: radiologicpathologic correlation. Radiographics. 2001;21: Chamie LP, lasbalg R, Pereira RM, et al. Findings of pelvic endometriosis at transvaginal US, MR imaging, and laparoscopy. Radiographics. 2011;31:E CME QUIZ: VOLUME 38, NUMER 7 To earn CME credit, you must read the CME article and complete the quiz and evaluation on the enclosed answer form, answering at least seven of the 10 quiz questions correctly. Select the best answer and use a blue or black pen to completely fill in the corresponding box on the enclosed answer form. Please indicate any name and address changes directly on the answer form. If your name and address do not appear on the answer form, please print that information in the blank space at the top left of the page. Make a photocopy of the completed answer form for your own files and mail the original answer form in the enclosed postage-paid business reply envelope. Only two entries will be considered for credit. Your answer form must be received by Lippincott CME Institute, Inc., by March 30, At the end of each quarter, all CME participants will receive individual issue certificates for their CME participation in that quarter. These individual certificates will include your name, the publication title, the volume number, the issue number, the article title, your participation date, the AMA credit awarded, and any subcategory credit earned (if applicable). For more information, call (800) All CME credit earned via Contemporary Diagnostic Radiology will apply toward continuous certification requirements. AR continuous certification requires 75 CME credits every 3 years, at least 25 of which must be self-assessment CME (SA-CME) credits. All SAM credits earned via Contemporary Diagnostic Radiology are now equivalent to SA-CME credits ( Online quiz instructions: To take the quiz online, log on to your account at and click on the CME tab at the top of the page. Then click on Access the CME activity for this newsletter, which will take you to the log-in page for Enter your username and password. Follow the instructions on the site. You may print your official certificate immediately. Please note: Lippincott CME Institute will not mail certificates to online participants. Online quizzes expire on the due date Which one of the following MR imaging findings is most suspicious for malignant transformation of an endometrioma? A. Calcifications. Increase in size C. Loss of T2 shading D. Enhancing mural nodule E. Faint peripheral enhancement 2. A 42-year-old woman experiences debilitating symptoms caused by diffuse uterine adenomyosis. The treatment for this patient should be A. radiation therapy. hysterectomy C. focal excision D. chemotherapy E. analgesics 3. Which one of the following is the most common site of urinary tract involvement in a patient with endometriosis? A. Kidneys. Proximal ureters C. Distal ureters D. Urethra E. Urinary bladder 4. Which one of the following uterine junctional zone measurements (thickness) on MRI is diagnostic of uterine adenomyosis? A. 4 mm. 6 mm C. 8 mm D. 10 mm E. 12 mm 5. Which one of the following is a chronic, nonresolving ovarian cyst that occurs from repeated cyclic hemorrhage? A. Endometrial implant. Endometrioma C. Deep pelvic endometriosis D. Hemorrhagic cyst E. Dermoid cyst 6. Which one of the following is the most common site of GI involvement in endometriosis? A. Rectosigmoid colon. Cecum C. Terminal ileum D. Appendix E. Duodenum 7. Which one of the following MR sequences is most sensitive at detecting tiny endometrial implants? A. T1-weighted. T1-weighted, opposed-phase C. T1-weighted, fat-suppressed D. T2-weighted E. Diffusion-weighted 8. Ultrasound examination of a 45-year-old woman reveals an adnexal mass with homogeneously low-level echoes. The differential diagnosis of the adnexal mass could include all of the following lesions, except A. endometrioma. mature cystic teratoma C. borderline mucinous ovarian tumor D. clear cell carcinoma E. hemorrhagic cyst 9. The term light bulb bright refers to an endometrioma seen on which one of the following MR sequences? A. T1-weighted. T2-weighted C. Short-tau inversion recovery D. Proton density E. Diffusion-weighted 10. Which one of the following conditions refers to heterotopic endometrial glands and stroma within the myometrium? A. Leiomyoma. Adenomyosis C. Endometrioma D. Endometriosis E. Hemorrhagic cyst