**1. Introduction**

436 Endometriosis - Basic Concepts and Current Research Trends

Wieser, F., Fabjani, G., Tempfer, C., Schneeberger, C., Sator, M., Huber, J. & Wenzi R. (2003).

Zong, LL., Li, Y.L. & Ha, X.Q. (2003). Determination of HGF concentration in serum and

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Analysis of an interleukin-6 gene promoter polymorphism in women with endometriosis by pyrosequencing, *J Soc Gynecol Investig,* Vol. 10, No. 1, (January

peritoneal fluid in women with endometriosis, *Di Yi Jun Yi Da Xue Xue Bao,* Vol. 23,

Endometriosis is the presence of endometrial glands as well as stroma at the locations outside uterus. It affects up to 10% of women. Grossly there are three forms of the disease, namely a) superficial endometrial implants, b) ovarian endometriomas or endometriotic cysts, and c) deep infiltrating endometriosis. All the three forms depict varied manifestation of a single disease and require a careful pre operative work up to know the extent and distribution of the disease precisely as it is critical to frame the plan of management.

The superficial implants are typically 2-3 mm in size rooted in the serosal tissue of the peritoneum. They initially appear as red highly vascular lesions. Later, repeated haemorrhage and inflammation triggers fibrosis and haemosiderin deposition in them causing raised powder burn lesions. It is hard to find such lesions by USG or MRI. Traditional method of diagnostic endoscopy still remains the golden standard of reference to diagnose and stage this form of disease.

Endometriomas of the ovary or chocolate cysts of the ovary contain degraded blood products. The dark and gelatinous material in them is surrounded by fibrous wall of variable thickness. Endomeriotic cysts are often bilateral and multiple. Both the USG and MRI play key role in its evaluation.

The deep infiltrating endometriosis (DIE) is defined as the implant penetrating into the retroperitoneal space or the wall of the pelvic organs to the depth of at least 5mm. (Knoninckx et al). They usually appear as solid nodules. These types of lesions permeate deep into the surrounding fibromuscular tissues and induce smooth muscle proliferation and fibrous reaction effecting development of solid nodules. In case of visceral involvement, they can infiltrate into the muscle layer from the serosal layer. The resulting smooth muscle proliferation can lead to stricture formation and later obstruction.

#### **2. Natural history of the disease**

The natural history of the symptomatic disease is uncertain. The lesions may either continue to be same or may evolve further or may regress. Its malignant transformation is uncommon

Imaging Tools for Endometriosis: Role of Ultrasound, MRI

level echoes (figure 1).

and Other Imaging Modalities in Diagnosis and Planning Intervention 439

accepted by most of the patients. TVS has superior image quality and resolution as compared to TAS. Thus it has high sensitivity (92%) and specificity (99%) in detecting endometriomas. The typical ultrasound findings include a cystic mass with diffuse, low-

Fig. 1. Grey-scale Transvaginal ultrasound of an endometrioma(M). Note the characteristic

Depending on the age of the haemorrhage, the contents of the cyst, may vary in appearance. At times, an endometrioma may resemble a cystic-solid or entirely solid mass. Punctate echogenicities in the wall of endometriomas are less commonly seen but add specificity to the diagnosis. Endometriomas can be multilocular with internal thin or thick septations and thick irregular walls. Mild vascularity may be identified on color Doppler (figure 2). Color Doppler US shows no blood flow in the fine septations, whereas blood flow can often be detected in thick septations because of revascularization of chronic haematoma. Internal

diffuse, low-level echoes of the endometrioma giving a solid appearance

moving echos within endometrioma may reveal color signal.

and its exact incidence is not known. This is diagnosed only if there is no evidence of metastasis from any primary sites and the surrounding tissue has presence of benign as well as the malignant endometrial tissue.
