Usual and unusual endometriosis locations. an MRI based approach Poster No.: C-1950 Congress: ECR 2014 Type: Educational Exhibit Authors: E. E. Martin, M. I. BOLAÑO VEGA, D. L. PINEDA, S. JARUFFE, E. P. MENDOZA MORENO, R. F. Román; Buenos Aires/AR Keywords: Localisation, MR, Pelvis, Genital / Reproductive system female, Cysts DOI: 10.1594/ecr2014/C-1950 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 15
Learning objectives To describe the MR imaging features in usual and unusual sites of presentation in a group of cases with biopsy proven endometriosis Page 2 of 15
Background Endometriosis is classically defined as the presence of endometrial glands and stroma outside the uterine cavity and myometrium. It is an estrogen-dependent disease that affects 5-20% of women of reproductive age that result in suggestive symptoms and appearances. Its etiology is multifactorial, several theories exist however, the most widely accepted is the metastatic theory, which holds that endometrial cells and stroma implant in ectopic locations within the pelvis, most likely secondary to retrograde menstruation The ovary is the most common site of presentation of this disease followed in frequency by pelvic peritoneal implants, however other locations outside the peritoneal cavity has been described. Peritoneal lesions may be superficial or deep, depending on the degree of peritoneal invasion and anatomically may compromise any of the compartments of the pelvis (anterior, middle and posterior). The extraperitoneal implants can occur in the pelvis or even have been reported in more distant sites such as the chest cavity. Page 3 of 15
Findings and procedure details MRI is the technique of choice for more accurate disease detection and staging because its multiplanar capability, high sensitivity for detection of blood products, and ability to identify sites of disease hidden by dense adhesions The imaging characteristics largely depend on the topography of the lesions. For practical purposes, endometriosis is classified into three categories: ovarían endometriosis, deep pelvic endometriosis and deep extra-peritoneal endometriosis. Ovarian endometriosis, called endometriomas usually manifest as cystic lesions with thick walls and hematic content, often are multiple and bilateral. The classic endometrioma shows shading, defined as a range of low-signal intensities on T2weighted images and a corresponding high signal on T1-weighted images. (Figure 1) Loss of signal in the T2-weighted sequences is caused by high concentrations of intracystic methemoglobin, other protein or iron products. Some lesions shows heterogeneous signal due to blood products in various stages of degradation arising from multiple episodes of bleeding. (Figure 2). Deep pelvic endometriosis corresponding to subperitoneal invasion by endometriotic focus exceeding5 mm in depth. Pelvic Implants can be classified according to involved compartment in: anterior, middle or posterior (Figure 3). Endometriosis in anterior compartment include endometrial implants within vesicouterine pouch, vesicovaginal septum, bladder (Figure 4) and ureter (Figure 5). Endometriotic lesions of the urinary tract are associated with lesions in other pelvic locations in up to 50%-75% of cases. Endometriosis in middle compartment includes involvement of the uterus, ovaries, fallopian tubes, and uterine ligaments with ovarian endometriomas as most common..although it can also be observed as fibrotic implants. Uterine ligaments may also be affected and usually manifest as thickening or nodules. (Figure 6) The posterior compartment is bounded by the rectal fascia. The lesions at this level involve the rectovaginal pouch, retrocervical area-torus uterinus, uterosacral ligaments, posterior vaginal fornix, rectovaginal septum, and rectum. Deep nodular endometriosis is typically found in the rectovaginal septum, usually appear as ill-defined hypointense tissue thickening on T2-weighted images. Page 4 of 15
Bowel endometriotic implants are estimated to occur in 12-37% of patients with endometriosis, most often affects the rectosigmoid (Figure 7), but also can affect appendix, cecum, and distal ileum ( Figure 8 ). In MRI it is visualized as T2-weighted hypointense retractile nodules adhering to bowel wall. Abdominal wall is the most common site of presentation of extraperitoneal endometriosis, being easily identified on T1 fat suppression sequences as hyperintense foci in the abdominal wall (Figure 9). Sometimes could be identified in extra pelvic sites as thoracic or abdominal cavity. Page 5 of 15
Images for this section: Fig. 1: Figure 1. Ovarian endometriosis. 35 y.o female with history of infertility. Cystic adnexial left mass (#) with heterogeneous signal showing blood products ( hyperintensity in T1w and hypointense in T2 and T2 - FATSAT. Page 6 of 15
Fig. 2: Figure 2. Blood products in ovarian endometriosis. 27-year-old woman with chronic pelvic pain. Sagittal T2-w, sagittal fat-suppressed T2-w and T1w coronal and axial depicting and heterogeneous mass with blood products# in left adnexus (#). Page 7 of 15
Fig. 3: Figure 3. Classic division of pelvic and peritoneal compartiments useful for staging of deep endometriosis. Fig. 4: Figure 4. Anterior compartiment in deep pelvic endometriosis. An irregular mass protruding into bladder through posterior wall best appreciated in T2 w images (# in A, B and D). Bladder mass shows intralesional blood products (#). Page 8 of 15
Fig. 5: Figure 5. Endometriosis causing uronephrosis. Figure 5. 32-year-old woman with chronic pelvic pain and right hydronephrosis. A. Irrregular and spiculated thickening and stranding of the perivesical fat on the right uretero vesical junction (# in A, B and C). (D) Three-dimensional contrast-enhanced fat-suppressed excretory phase depicts an obstructive pattern of hydronephrosis. Page 9 of 15
Fig. 6: Figure 6. Middle compartiment endometriosis. 36 y.o female with chronic pelvic pain. MRI showing tiny foci of blood products in left parametrium ( # A, B, C and D) and ipsilateral teres ligament (#). Page 10 of 15
Fig. 7: Figure 7. Posterior compartiment endometriosis. 29 y.o. female with dyspareunia, dysmenorrhea and catamenial rectal bleeding. A focal implant in rectal - sigmoid junction ( # in A and B ) involving anterior wall, mesorrectal fascia and peritoneal reflection. An ovoid focal structure in right ovarium showing heterogeneous high signal in T2 and T1 consistent with and hemorragic cyst Page 11 of 15
Fig. 8: Figure 8. Bowel endometriosic implants. 39 y.o female with massive uterus enlargemente and difusse adenomiosis (#). In posterior uterine wall and serosa there are some T2w hyperintense foci infiltrating mesorrectal fascia with sigmoid anterior wall involvement ( # in A, B and C).An hemorragic cyst / endometrioma is shown in left adnexa ( # in D, E and F ). Dilated bowel loops in ileo-cecal area are shown with a focal enhancing structure provocating extrinsic compresión ( # ) Page 12 of 15
Fig. 9: Figure 9. Abdominal wall endometriosis. 34 y.o. female with cyclic left lower quadrant pain and history of cesarean delivery. T2-weighted MR image of the pelvis shows a pseudonodular area with mild increase of signal intensity (arrow) in the anterior rectus sheath. T1-weighted and T1-weighted fat-suppressed shows heterogeneous signal intensity mass with high-signal-intensity punctate foci and contrast enhancement. Page 13 of 15
Conclusion Endometriosis is a common gynecological disorder that shows a wide anatomic distribution. The presence of endometriosis in unusual sites may represent a diagnostic challenge, requiring the radiologist to be familiar with the main features according to location. Page 14 of 15
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