Adenomyosis is a medical condition in which the endometrial tissue (inner mucous membrane lining of the uterus) invades the adjacent muscle layer, myometrium; as evidenced by presence of either endometrial glandular tissue or stromal tissue or both in the myometrial layer. This condition is commonly found in women between 35 and 50 years of age. The most common presenting symptoms of adenomyosis include increased amount of blood loss during menstruation. Sometimes excessive pain during menstruation is the most bothersome symptoms rather than blood loss.
The exact underlying cause of adenomyosis is yet to be identified however there are various theories which postulate the origin of adenomyosis. Estrogen is the single most important factor for growth and spread of adenomyosis as with menstruation gradually the symptoms of adenomyosis are relieved.  Treatment options depend upon the stage and extent of spread of the disease. In cases with mild to moderate symptoms certain hormone medicines, NSAIDs gives satisfactory results, however with severe degree of symptoms surgical removal of the uterus known as hysterectomy is essential.

Endometriosis is another gynecological condition in which the endometrium is present outside the uterus namely the ovaries, the fallopian tubes, etc. In many women both adenomyosis and endometriosis may co-exist
Symptoms
In many patients of adenomyosis there may not be any presenting symptom (silent) however adenomyosis may present with number of symptoms like heavy and prolonged blood loss during menstruation, excruciating pain in the lower abdominal (pelvic) area with worsening of the pain with progression of age, painful intercourse, spotting between two menstrual bleeding, passage of blood clot, etc. Usually the uterus becomes about two to three times enlarged in comparison to normal uterus. Thus uterus which is normally a pelvic organ gradually becomes a lower abdominal organ leading to bulging and pain in that area.

As such adenomyosis do not lead to any long term complications, however prolonged blood loss may lead to chronic anemia and the excruciating pain and the excessive blood loss may lead to confinement, work day loss, poor school or office performances along with depression, frustration, irritability, etc.
Causes
The exact underlying cause of adenomyosis is not known however there are different hypothesis regarding the origin of adenomyosis. These are
1. Invasion of the endometrial cells in the muscle layer (myometrium) like following surgeries requiring incision on the uterine wall like Caesarean section
2. Developmental: according to this theory when the uterus is first formed in a female fetus some endometrial tissue gets trapped in the myometrial cell line leading to adenomyosis in later life.
3. Inflammation in the uterine wall: as per this theory inflammatory changes in the lining of the uterus immediately following child birth leading to break in the normal lining of the uterus may result into adenomyosis.
4. Stem cell theory: recently it is been suggested that stem cells from the bone marrow may invade the uterine muscle lining, may later differentiate into endometrial cells and ultimately lead to adenomyosis.
Estrogen, one of the important circulating hormones in the female body eventually plays an important role in the growth of adenomyosis.
Risk factors
Common risk factors include history of uterine surgery like fibroid removal (myomectomy) or caesarean section and middle age. Usually women in their 40’s are most commonly affected in comparison to younger women as these women are exposed to high level of estrogen for prolonged period.
Treatment
Treatment of adenomyosis depends upon stage and the severity of symptoms. Commonly used drugs are NSAIDs and hormonal agents like estrogen of progesterone containing pills etc.
Surgical removal of the uterus (hysterectomy) is the ultimate cure required in patients suffering from a severe degree of pain and morbidity.