**5.5 Endometriosis of the vagina**

Endometriosis of the vagina includes lesions infiltrating the anterior rectovaginal pouch, posterior vaginal fornix and retroperitoneal area between the anterior rectovaginal pouch and posterior vaginal fornix.

Patients tipycally refer dyspareunia.

MRI represents the ideal complement to physical examination and TVUS in order to predict lesion extension upward and posteriorly. Sometimes, the use of a water enema is used to predict the extension of the lesion toward the rectum.

In patients with vaginal endometriosis axial and sagittal T2-weighted Turbo Spin Echo images usually show hypointense nodules. Anterior attraction of the rectum toward the torus uteri and asymmetric thickening of the rectal wall are associated to rectal wall infiltration. Determining the depth of infiltration of the rectal wall allows the gynaecologist to discuss the surgical approach (nodulectomy vs bowel resection) with the colorectal surgeon. The use of the endorectal coil optimizes the finding of MRI [22].

T1-weighted images with fat suppression could demonstrate T1 isointensity of the nodule and some small hyperintense foci, suspected for micro-haemorragies (**Fig. 8 A**).

Most patients with vaginal involvement also demonstrate obliteration of the retrouterine excavation (**Fig. 8 B, C**); in such cases the extension of the pelvic focus may lead to ureteral infiltration and ureterohydronephrosis.

Fig. 8. T1-weighted image with fat suppression demonstrates isointensity of the nodule and some small hyperintense foci, suspected for micro-haemorragies (A). Axial (B) and sagittal (C) T2-weighted image show obliteration of retrouterine escavation by an hypointense nodule, with anterior attraction of the rectum toward the torus uteri and asymmetric thickening of the rectal wall.

#### **5.6 Endometriosis of the bowel**

Rectosigmoid endometriosis represents 70% of cases of intestinal endometriosis.

Clinical symptoms of patients with endometriosis of the recto-sigmoid colon are manifested as crampy pain, flatulence, painful tenesmus, constipation, diarrhoea and bowel obstruction.

Pelvic Endometriosis: A MR Pictorial Review 457

intensity is low on T1-weighted images and variable on T2-weighted images. Contrast enhancement of a mural nodule at fat-suppressed T1-weighted sequences is the most important finding for a diagnosis of malignant shift. The "shading" sign within the cystic mass is rarely observed on T2-weighted images because of the diluition of the hemorrhagic fluid caused by tumor secretions. Accordingly, disappearance of the "shading" sign within

MRI is progressively becoming a widely employed technique in the diagnosis and preoperative staging of endometriosis. It should be performed in selected patients according to the results of TVUS and the severity of symptoms. This imaging method has the advantage to cover the entire pelvis thus, helping the surgeon to achieve a complete

[1] Missmer SA & Cramer DW. The epidemiology of endometriosis. Obstetrics and

[3] Chapron C, Fauconnier A, Vieira M, Barakat H, Dousset B, Pansini V, Vacher-Lavenu

[4] Revised American fertility Society classification of endometriosis: 1985. Fertil Steril 1985;

[5] Tuttlies F. et al. ENZIAN-Score, eine Klassifikation der tief infiltrierenden Endometriose:

[6] Clement PB. Diseases of the peritoneum. In: Kurman RJ, ed. Blaustein's pathology of the female genital tract. 4th ed New York, NY: Springer-Verlag, 1994; 660-680. [7] Okaro E, Valentin L. The role of ultrasound in the management of women with acute and

[8] Mais V, Guerriero S, Ajossa S, Angiolucci M, Paoletti AM, Melis GB. The efficiency of

[9] Guerriero S, Mais V, Ajossa S, Paoletti AM, Angiolucci M, Melis GB. Transvaginal

[10] Bazot M., Malzy P., Cortez A., Roseau G., Amouyal P., Darai E. Accuracy of

MC, Dubuisson J.B.. Anatomical Distribution of deeply infiltrating endometriosis : surgical implications and proposition for a classification. Hum Reprod 2003; 18:157-

chronic pelvic pain. Best Practice and Research Clinical Obstetrics and

transvaginal ultrasonography in the diagnosis of endometrioma. Fertil and Steril

ultrasonography combined with CA-125 plasma levels in the diagnosis of

transvaginale sonosgraphy and rectal endoscopic sonography in the diagnosis of deep infiltrating endometriosis. Ultrasound Obstet Gynecol 2007; 30:994-1001. [11] Chapron C, Vieira M., Chopin N, Balleyguier C, Barakat H, Dumontier I, Roseau G,

Fauconnier A, Foulot H, Dousset B. Accuracy of rectal endoscopic ultrasonography and magnetic resonance imaging in the diagnosis of rectal involvement for patients presenting with deeply infiltrating endometriosis. Ultrasound Obstet Gynecol 2004;

the mass on T2-weighted images is a diagnostic clue to its malignancy [26].

Gynecology Clinics of North America 2003 ; 30 : 1-19 [2] Olive DL, Schwartz LB. Endometriosis. N Engl J Med 1993; 328:1759–1769

**6. Conclusions** 

**7. References** 

161.

43: 351-352.

1993, 60:776-780.

24:175-179.

resection and prevent post-surgical recurrence.

Zentralbl Gynacol 2005; 127: 275-282.

Gynaecology 2004, Vol 18 No 1 1 pp 105-123.

endometrioma. Fertil and Steril 1996, 65:293-298.

Among patients with rectosigmoid endometriosis also dyspareunia is another common symptom. Endometriosis less frequently affects appendix, cecum and distal ileum.

The implants are usually serosal but they can erode through the subserosal layers and cause a fibromuscular hyperplasia of the muscularis propria. Due to the normal appearance of the mucosa in most patients with bowel endometriosis, diagnosis by colonoscopy is often false negative. The appearance of gastrointestinal implants on double-contrast barium enema images is characterized in most cases by a puckering or a crenulated appearance of the affected wall; when the lesion causes a circumferential narrowing of the rectosigmoid colon the differential diagnosis with a primary colon carcinoma is difficult.

Fig. 9. Diagnostic criteria of bowel invasion at MRI are: colorectal wall thickening with traction of the rectum toward the torus uteri (A, B, C).

At MRI, bowel lesions show a signal intensity similar to fibromuscular tissue (hypointense), with occasional hyperintense foci of T1- and T2- weighted images. An asymmetric thickening of the lower surface of the sigmoid wall or a colorectal wall thickening with attraction of the rectum toward the torus uteri is a common sign (**Fig. 9**).

According to Roy C *et al* [23]*,* the use of the contrast media helps in reaching the diagnosis of an invasion inside the muscular layer of the intestinal wall. In such cases a thin bright layer on T2-weighted images together with post-contrast enhancement on fat-suppressed T1 weighted images and obliteration of fatty tissue plane between the nodule and the intestinal wall, represents the diagnostic clue of muscular layers involvement. Combined pelvicphased array and endovaginal coils improve the diagnostic power in the detection of intestinal wall invasion, when compared to phased array alone.

### **5.7 Malignant transformation**

A limited number of endometriosis patients (<5%) will develop ovarian cancer.

Women with endometriosis-associated cancer are typically pre-menopausal, have high incidence of endometrioid and clear cell histologies, and have early stage disease [24].

The association between endometriosis and intra-peritoneal cancer still remains unclear. Probably, women with endometriosis are more susceptible to malignant transformation because of a deficit in their immune system that enables the endometriosis to flourish. Also estrogen may play a role, so endometriosis should be closely monitored in women in the reproductive age [25].

The typical morphologic appearance of an endometriosis-associated carcinoma is that of a unilateral large cystic mass containing hemorrhagic fluid and mural nodules. Signal intensity is low on T1-weighted images and variable on T2-weighted images. Contrast enhancement of a mural nodule at fat-suppressed T1-weighted sequences is the most important finding for a diagnosis of malignant shift. The "shading" sign within the cystic mass is rarely observed on T2-weighted images because of the diluition of the hemorrhagic fluid caused by tumor secretions. Accordingly, disappearance of the "shading" sign within the mass on T2-weighted images is a diagnostic clue to its malignancy [26].

#### **6. Conclusions**

456 Endometriosis - Basic Concepts and Current Research Trends

Among patients with rectosigmoid endometriosis also dyspareunia is another common

The implants are usually serosal but they can erode through the subserosal layers and cause a fibromuscular hyperplasia of the muscularis propria. Due to the normal appearance of the mucosa in most patients with bowel endometriosis, diagnosis by colonoscopy is often false negative. The appearance of gastrointestinal implants on double-contrast barium enema images is characterized in most cases by a puckering or a crenulated appearance of the affected wall; when the lesion causes a circumferential narrowing of the rectosigmoid colon

**A B C**

symptom. Endometriosis less frequently affects appendix, cecum and distal ileum.

Fig. 9. Diagnostic criteria of bowel invasion at MRI are: colorectal wall thickening with

attraction of the rectum toward the torus uteri is a common sign (**Fig. 9**).

A limited number of endometriosis patients (<5%) will develop ovarian cancer.

intestinal wall invasion, when compared to phased array alone.

**5.7 Malignant transformation** 

reproductive age [25].

At MRI, bowel lesions show a signal intensity similar to fibromuscular tissue (hypointense), with occasional hyperintense foci of T1- and T2- weighted images. An asymmetric thickening of the lower surface of the sigmoid wall or a colorectal wall thickening with

According to Roy C *et al* [23]*,* the use of the contrast media helps in reaching the diagnosis of an invasion inside the muscular layer of the intestinal wall. In such cases a thin bright layer on T2-weighted images together with post-contrast enhancement on fat-suppressed T1 weighted images and obliteration of fatty tissue plane between the nodule and the intestinal wall, represents the diagnostic clue of muscular layers involvement. Combined pelvicphased array and endovaginal coils improve the diagnostic power in the detection of

Women with endometriosis-associated cancer are typically pre-menopausal, have high incidence of endometrioid and clear cell histologies, and have early stage disease [24].

The association between endometriosis and intra-peritoneal cancer still remains unclear. Probably, women with endometriosis are more susceptible to malignant transformation because of a deficit in their immune system that enables the endometriosis to flourish. Also estrogen may play a role, so endometriosis should be closely monitored in women in the

The typical morphologic appearance of an endometriosis-associated carcinoma is that of a unilateral large cystic mass containing hemorrhagic fluid and mural nodules. Signal

the differential diagnosis with a primary colon carcinoma is difficult.

traction of the rectum toward the torus uteri (A, B, C).

MRI is progressively becoming a widely employed technique in the diagnosis and preoperative staging of endometriosis. It should be performed in selected patients according to the results of TVUS and the severity of symptoms. This imaging method has the advantage to cover the entire pelvis thus, helping the surgeon to achieve a complete resection and prevent post-surgical recurrence.

#### **7. References**


**26** 

*Hong Kong* 

**Pathophysiological Changes in** 

Tao Zhang, Gene Chi Wai Man and Chi Chiu Wang

 *Prince of Wales Hospital, Shatin, New Territories,* 

*Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong,* 

Endometriosis is a common but complex gynecological disorder of unknown pathogenesis. It is characterized by ectopic growth of endometrial tissues. Based on Sampson's classical implantation theory, retrograde menstruation, immune escape, adhesion, angiogenesis and growth of endometrial cells are essential milestones in the pathogenesis of endometriosis. The cellular communications of immune, endothelial and endometriotic cells during endometriosis development are mediated via cytokines and chemokines. Many specific cytokines in peritoneal fluid of patients with endometriosis are aberrant from normal women. However, it's not clear at which stage of endometriosis these aberrant cytokines begin to change and owing to the limitation with human study the functions of these cytokines were only investigated in vitro. On the other hand, the onset of angiogenesis is initiated by oxidative stress due to cellular and tissue hypoxia, which is mainly coordinated by the hypoxiainducible factors (HIFs). HIFs stimulate VEGF transcription and activation in endometriosis lesions in acquiring new blood vessels for survival and growth. Monitoring inflammatory response, oxidative stress and angiogenesis in the endometriosis lesions is of vital importance in understanding the pathophysiological changes during early development of endometriosis. In our studies, we investigated for the first time the dynamic changes of oxygen reactive species and angiogenesis in the endometriosis implants by in vivo imaging techniques and characterized regulation of cytokines, hypoxia and angiogenesis factors within the first 24 hour of experimental endometriosis in mice. We identified significant oxidative stress and hypoxia responses in the endometriosis implants in early phase only, but specific estrogen-dependent cytokine activations and angiogenesis signaling in late phase. In this chapter, we will describe the non-invasive in vivo imaging method as a valuable tool for monitoring oxidative stress and angiogenesis in endometriosis and to understand its role in the early development and growth of endometriosis. We will also demonstrate oxidative stress preceded hypoxia and cytokine activation and angiogenesis signaling in the pathogenesis of early endometriosis.

Endometriosis is one of most common gynecological disorder, but poorly understood condition. As early as in 1860, von Rokitansky (Rokitansky, 1860) is the first one to describe

**1. Introduction** 

**2. Development of endometriosis 2.1 Sampson's implantation theory** 

**Early Endometriosis** 

