A fibroid, or uterine leiomyoma, is a type of non-cancerous growth that commonly develops inside the womb, or uterus. Fibroid degeneration takes place when the fibroid has been increasing in size over a number of years, and its blood supply is no longer adequate to support the center of the tumor. Degeneration, involving cell death, occurs inside the fibroid, and calcification, where calcium is deposited in the fibroid tissue, may be seen on an ultrasound scan. The process of fibroid degeneration may sometimes cause pain in the pelvic region.
Uterine fibroids are extremely common, being the most frequently occurring non-cancerous, or benign, growths found in women before the menopause. Fortunately, most fibroids do not cause any symptoms, and treatment is only required in up to a fifth of all cases. Typically, fibroids grow within the wall of the uterus, with a minority developing on the outside of the uterus or growing in the space inside it. There may be one or many fibroids, and sizes can range from being too small to see to several inches (centimeters) in diameter.
Usually, this type of degeneration is more likely to occur in larger tumors, and although fibroids normally increase in size at a slow rate, their development can be affected by hormone levels. Estrogen stimulates growth, and a deficiency of estrogen, such as after menopause, causes fibroids to shrink. When a fibroid suddenly grows too big and its blood supply is outstripped, the resulting fibroid degeneration can cause quite severe pain, localized to a particular area of the pelvis. The pain may resolve without anything other than painkillers, usually in less than a month. Sometimes degeneration is more gradual, in which case the pain is milder but carries on for longer.
Fibroid treatment varies according to the symptoms, the size and position of any growths, and whether a woman hopes to have children in the future. Where there is a large fibroid undergoing degeneration and causing ongoing pain, the treatment may be a hysterectomy to fully remove the tumor. Sometimes a procedure called a myomectomy can be used, where any fibroids are excised but the uterus is saved, or an endometrial resection may be carried out, in which the lining of the womb is removed together with the fibroid. Methods which spare the uterus have the disadvantage that fibroids may recur.
Some methods used to shrink fibroids mimic the natural process of fibroid degeneration either by targeting the blood supply to the tumors or by destroying the central cells directly. One treatment involves injecting tiny plastic beads into the arteries that lead to the fibroids, effectively blocking the blood supply. In another technique, laser or ultrasound energy is focused on the cells in the center of a fibroid, causing them to die off.