What is endometriosis?

Endometriosis is a common condition affecting women. It is a chronic, painful, and often progressive disease in women. The causes of <stong>endometriosis</stong> are unknown.It has widel variability in symptoms and severity, so diagnosis is at times difficult.

Endometrial Implants

Endometriosis occurs when cells from the mucus membrane lining the uterus (endometrium) form implants that attach, grow, and function outside the uterus, generally in the pelvic region.



Endometrial implants consist of both following cell types:

• Gland cells. These cells secrete hormones and other fluids and are normally located in the uterine lining.
  
• Stroma cells. These are the framework cells that build supportive tissue.

Endometrial cells contain receptors that bind to estrogen and progesterone, which promote uterine growth and thickening. During endometriosis these cells become implanted in organs and structures outside the uterus, where these hormonal activities continue to occur, causing bleeding and scarring.
Endometrial implants vary widely in size, shape, and color. Over the years, they may diminish in size or disappear or they may grow.

• Early implants are usually very small and look like clear pimples.
  
• If they continue to grow they may form flat injured areas (lesions), small nodules, or cysts called endometriomas, which can range from sizes smaller than a pea to larger than a grapefruit.
  
• Implants also vary in color; they may be colorless, red, or very dark brown. These so-called chocolate cysts are endometriomas filled with thick, old, dark brown blood that usually appear on the ovaries.

Location of Implants

Implants can form in many areas, most commonly in the following:

• The peritoneum. This is the smooth surface lining that covers the entire wall of the abdomen and folds over inner organs in the pelvic area.
  
• On or next to the ovaries.

Less commonly they occur in other areas:

• The cul-de-sac, an area between the uterus and rectum.
  
• The connective tissue that supports the uterus (called the uterosacral ligaments).
  
• The vagina.
  
• Fallopian tube.
  
• In the urinary tract (in about 20% of cases, usually without causing symptoms).
  
• In the gastrointestinal tract (in between 12% and 37% of patients).

Very rarely, they have been reported in areas far from the pelvis, including the lungs and even the arms and thighs.



Process of Endometriosis

The process of endometriosis Iis similar to menstruation (periods) at certain stages:

• Each month, the endometrial implants respond to the monthly cycle just as they would in the uterus: they fill with blood, thicken, break down and bleed.
  
• Products of the endometrial process cannot be shed through the vagina as menstrual blood and debris does. Instead, the implants develop into collections of blood that form cysts, spots, or patches.
  
• Lesions may grow or reseed as the cycle continues.

The lesions are not cancerous, but they can develop to the point that they cause obstruction or adhesions (web-like scar tissue) that attach to nearby organs, causing pain, inflammation, and sometimes infertility.