Cesarean scar endometriosis: Clinical presentation and imaging features with a focus on MRI

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1 Cesarean scar endometriosis: Clinical presentation and imaging features with a focus on MRI Poster No.: C-0505 Congress: ECR 2012 Type: Educational Exhibit Authors: A. S. Dumitrescu, T. Herold; Berlin/DE Keywords: Abdominal wall, MR, CT, Diagnostic procedure, Obstetrics, Abscess, Hemorrhage DOI: /ecr2012/C-0505 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. Page 1 of 33

2 Learning objectives Endometriosis is a common and important clinical problem of women, predominantly those in the reproductive age group. Endometriosis of the abdominal wall is less frequent and is mostly associated with cesarean section scars. It can pose diagnostic difficulties and should be in the differential diagnosis of abdominal wall lumps in females. The purpose of this exhibit is: 1. To review the clinical presentation and imaging findings of abdominal wall endometriosis with intramuscular as well as subcutaneous lesions following caesarian section; 2. To discuss diagnostic strategies with a focus on MRI imaging; 3. To briefly review this condition's incidence, pathology and treatment. Background Endometriosis was first described by Rokitansky in 1860 and is defined as the presence of endometrial glandular tissue outside of the uterus. Clinical presentation The most common symptoms are dysmenorrhea, dyspareunia, pelvic pain, and infertility, although only a minority of patients present with all the symptoms and many patients are asymptomatic. Localization Frequent localizations in the pelvis include the ovaries, uterine ligaments, serosal surfaces, cul-de-sac, fallopian tubes, rectosigmoid, and urinary bladder (Fig. 1 on page 3). [3] Extrapelvic endometriosis are bladder, kidney, bowel, omentum, lymph nodes, lungs, pleura, extremities, umbilicus, hernial sacs, and the abdominal wall. [4] Pathology Page 2 of 33

3 The foci of endometrial tissue are generally small (Fig. 2 on page 4). Typical histopathologic features are endometrial glands, endometrial stroma and hemosiderinladen macrophages (Fig. 3 on page 5). Ectopic endometrial glandular tissue is influenced by ovarian hormones and undergoes cyclic bleeding. Over time, the repeated hemorrhaging can produce extensive fibrosis surrounding the endometrial tissue, which can result in adhesions to neighboring structures, e.g. adnexal structures, peritoneum, bowel, depending on the localization. [12] Epidemiology The prevalence of endometriosis is difficult to determine accurately; however, it has been estimated to affect 5-10% of both symptomatic and asymptomatic women, the frequency being higher in women with infertility and pelvic pain. [1] Localization in the abdominal wall (Fig. 4 on page 6) is comparatively rare and most frequently follows obstetrical and gynecological surgeries. The actual incidence of abdominal wall endometriosis is unknown but one series reported that only 6% of these were unrelated to scars. [6] In another series the prevalence of surgically proven endometriosis in scars was 1.6%. [5] Therapy Treatment of endometriomas is most often surgical. Wide excision of abdominal wall lesions may sometimes require mesh placement. [21] Medical treatment involves use of progestogens, oral contraceptive pills, danazol, and gonadotrophin agonists. [22] It provides only partial relief in symptoms with no change in the lesion size and involves numerous side effects such as amenorrhea, weight gain, hirsutism, and acne. Surgically treated patients need to be followed up because of the chances of recurrence, which require re-excision. In cases of continual recurrence the possibility of malignancy needs to be ruled out. Images for this section: Page 3 of 33

4 Fig. 1: Most common sites of endometriosis. Page 4 of 33

5 Fig. 2: Typical presentation of endometriosis foci at laparoscopy. Page 5 of 33

6 Fig. 3: Microphotograph of an endometrioma (H&E stain). Page 6 of 33

7 Fig. 4: Gross specimen of abdominal wall endometriosis. Page 7 of 33

8 Imaging findings OR Procedure details Imaging considerations Endometriosis, in patients with scars, is more common in the abdominal skin and subcutaneous tissue compared to muscle and fascia. Endometriosis involving only the rectus muscle and sheath is very rare. [7] In this unusual localization, clinical as well as initial imaging findings are likely to be misinterpreted by physicians and radiologists (e.g., as abscesses or malignant tumors). Along with the comparative rarity of the disease this leads to frequent overlooking of the correct diagnosis. [8,9,10] Usually, the initial imaging examination for suspected endometriosis is pelvic ultrasound. Magnetic resonance imaging (MRI) provides superior anatomic detail and better defines abnormalities found using ultrasonography. The multiplanar capability, high sensitivity for detection of blood products, and ability to identify sites of disease hidden by dense adhesions have made MRI the noninvasive imaging technique of choice for more accurate disease detection and staging. [13,14] It has been shown that MRI has high accuracy in assessing the extension of the disease and assisting surgical treatment planning. [15] Most endometriomas have a relatively homogeneous high signal intensity on native T1weighted images. On T2-weighted scans, endometriomas often exhibit a phenomenon known as T2-shading, i.e. T2 shortening often associated with a dependent layering on T2-weighted scans reflecting the chronic accumulation of blood degradation products resulting from repeated hemorrhaging over months and years. [16,17] Fat suppression narrows the dynamic signal range, thereby accentuating differences in tissue signal. Thus, lesion conspicuity is improved. Furthermore, differentiation between hemorrhagic and fat components is also facilitated. This has been shown to improve the sensitivity of MR imaging in the detection of small lesions and to increase its specificity, since fat-containing lesions such as dermoids are eliminated from the differential diagnosis. [18, 19, 20] Contrast-enhanced sequences are useful for detection of very small endometrial implants associated with inflammatory reaction, as well as assessing for malignant change. [23] Sample case Page 8 of 33

9 A 33 years old female Caucasian patient was referred to our department for imaging of a painful, subcutaneous nodular lesion in the left lower quadrant of the anterior abdominal wall situated at the site of the cesarean section she had undergone 2 years before. Clinical examination at admission revealed a palpable, hard nodule, sensitive to pressure. The patient reported having noticed this some 18 months before, the nodule becoming progressively painful over time. Initial imaging involved ultrasound examination at admission as well as contrastenhanced CT of the abdomen and pelvis in our department. The CT scans revealed two adjacent solid nodular lesions, each some 2 cm in size, one in the left rectus abdominis muscle (Fig. 5 on page 18) and another in the corresponding subcutaneous fat (Fig. 6 on page 18), along with signs of a localized inflammatory reaction in the surrounding fat tissue (Fig. 7 on page 19). Fig. 5-7: Contrast-enhanced CT scans of the abdominal wall lesions Page 9 of 33

10 Fig. 5: CT: Intramuscular lesion. References: A. S. Dumitrescu; Berlin, GERMANY Page 10 of 33

11 Fig. 6: CT: Subcutaneous lesion. References: A. S. Dumitrescu; Berlin, GERMANY Page 11 of 33

12 Fig. 7: CT: Sagittal reconstruction. References: A. S. Dumitrescu; Berlin, GERMANY The unambiguously solid density of the lesion and the absence of discernible gas inclusions virtually ruled out an abscess of the abdominal wall. Rather, the findings were interpreted as pointing primarily towards a chronic inflammatory, i.e. granulomatous lesion of as yet unclear aetiology, with a soft tissue tumor as a possible differential diagnosis, possibly associated with a secondary hematoma of the abdominal wall. Page 12 of 33

13 Subsequently the patient was referred to MRI for further, more differentiated imaging. Here, renewed questioning of the patient revealed that pain and swelling associated with the lesion showed a certain periodicity and peaked at the time of menstruation. MRI scanning protocol: 1.5T MR scanner (Siemens Avanto) T1w TSE (axial and sagittal) T2w TSE (axial) TIRM (sagittal) T1w TSE with fat-sat (axial) intravenous injection of 17 ml Gadolinium-based contrast agent (Prohance) T1w TSE with fat-sat (axial and sagittal) The examination confirmed the presence of two neighboring foci in the left rectus abdominis muscle as well as subcutaneous, with limited inflammation of the surrounding fat tissue. On the T1-weighted scans the lesions showed slight hyperintensity, both native and fat saturated: Fig. 8-10: T1-weighted imaging of the abdominal wall foci. Page 13 of 33

14 Fig. 8: T1w TSE: Sagittal plane with both foci visible. References: A. S. Dumitrescu; Berlin, GERMANY Fig. 10: T1w fat-sat: subcutaneous lesion. References: A. S. Dumitrescu; Berlin, GERMANY a) without fat-sat; b) with fat-sat. The T2-weighted scans showed low lesion signal, a phenomenon known as T2 shading [24]: Page 14 of 33

15 Fig. 12: T2w TSE: subcutaneous lesion. Fig. 11: T2w TSE: intramuscular lesion. References: A. S. Dumitrescu; Berlin, References: A. S. Dumitrescu; Berlin, GERMANY GERMANY Fig : T2-weighted imaging of the endometriomas. Furthermore, in all performed scans but especially in the inversion recovery scans (TIRM) the lesion showed small signal-free dots characteristic of small hemosiderin inclusions. Page 15 of 33

16 Fig. 13: TIRM: intramuscular lesion. References: A. S. Dumitrescu; Berlin, GERMANY Fig : TIRM scans. Fig. 14: TIRM: subcutaneous lesion. References: A. S. Dumitrescu; Berlin, GERMANY After contrast injection the lesions showed marked enhancement: Page 16 of 33

17 Fig. 15: Post-contrast T1: subcutaneous focus. References: A. S. Dumitrescu; Berlin, GERMANY Fig : Post-contrast T1w scans. Fig. 16: Post-contrast T1: intramuscular lesion. References: A. S. Dumitrescu; Berlin, GERMANY The MRI appearance of the lesions ruled out an abscess and confirmed the similarity of the intramuscular and subcutaneous foci. It further suggested subacute and chronic micro-hemorrhaging within the lesions, possibly consistent with hypervascularized tumors such as melanoma or soft tissue sarcoma but also with ectopic endometrial tissue islands, i.e. endometriosis. Page 17 of 33

18 At this stage correlation with anamnestic data (especially the fluctuation of symptoms with the menstrual cycle) proved crucial, ultimately tipping the balance of evidence in favor of endometriosis. This diagnosis was confirmed by subsequent biopsy and surgical therapy was succesfully performed. Images for this section: Fig. 5: CT: Intramuscular lesion. Page 18 of 33

19 Fig. 6: CT: Subcutaneous lesion. Page 19 of 33

20 Fig. 7: CT: Sagittal reconstruction. Page 20 of 33

21 Fig. 8: T1w TSE: Sagittal plane with both foci visible. Page 21 of 33

22 Fig. 9: T1w fat-sat: intramuscular lesion. Page 22 of 33

23 Fig. 10: T1w fat-sat: subcutaneous lesion. Page 23 of 33

24 Fig. 11: T2w TSE: intramuscular lesion. Page 24 of 33

25 Fig. 12: T2w TSE: subcutaneous lesion. Page 25 of 33

26 Fig. 13: TIRM: intramuscular lesion. Page 26 of 33

27 Fig. 14: TIRM: subcutaneous lesion. Page 27 of 33

28 Fig. 15: Post-contrast T1: subcutaneous focus. Page 28 of 33

29 Fig. 16: Post-contrast T1: intramuscular lesion. Page 29 of 33

30 Fig. 17: Post-contrast sagittal scan of both foci. Page 30 of 33

31 Conclusion Endometriosis is a common and important clinical problem of women, predominantly those in the reproductive age group. The condition is associated with islands of ectopic endometrial tissue. Localization in the abdominal wall as presented above is rare and mostly associated with a cesarean section. Such lesions can mimic tumors of the soft tissue or hematomas of other origin. It is important to keep this rare differential diagnosis in mind and to inquire about any association of the clinical symptoms with the menstrual cycle, since the presence of cyclic pain in a cesarean associated incisional mass is almost pathognomonic for the condition. The noninvasive imaging method of choice is contrast-enhanced MRI. Biopsy is necessary to confirm the diagnosis. Upon confirmation the lesions must be surgically removed, lest they lead to significant reduction in quality of life and fertility. Here, MRI imaging is also important in surgical treatment planning, especially in finding additional lesions that need to be treated. Personal Information A.S. Dumitrescu, T. Herold Institut für Röntgendiagnostik HELIOS Klinikum Berlin-Buch Schwanebecker Chaussee Berlin, Germany You can the corresponding author at: andrei.dumitrescu@fu-berlin.de References 1. Olive, D.L., Schwartz, L.B. Endometriosis. N Engl J Med : Khetan N, Torkington J, Watkin A, Jamison MH, Humphreys WV. Endometriosis: presentation to general surgeons. Ann R Coll Surg Engl 1999; 81: Page 31 of 33

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