Practical histopathology بسم الله الرحمن الرحيم Practical histopathology Lab 11 (Uterine Fibroids)

Cereus membrane Mucosal layer

Overview A uterine fibroid is a common type of benign (non-cancerous) monoclonal tumors arising from the smooth muscle cells of the myometrium. Uterine fibroids occur in up to one third of all women and are actually the leading reason for hysterectomy (removal of the uterus). Uterine fibroids, myomas, or leiomyomata contain a large amount of extracellular matrix ECM (collagen, proteoglycan, fibronectin) and are surrounded by a thin pseudocapsule of areolar tissue and compressed muscle fibers. Myometrium= the smooth muscle tissue of the uterus. إستئصال الرحمhysterectomy

Uterine fibroids may grow as a single tumor or clusters. They often increase in size and frequency with age, but may also revert in size after menopause. While not all women with fibroids experience symptoms, these may include excessive menstrual bleeding, pelvic pain and difficulty getting pregnant. They are hormonally responsive, and estrogens appear to promote their growth. Local estrogen concentrations have been shown to be higher in myomas than in the surrounding myometrium, possibly because of a higher concentration of aromatase.

Cont.. Clinically uterine fibroids may initially be detected as small nodules identified only by imaging studies; they can potentially progress through a spectrum of growth from grape size to large masses that can be palpated through the abdominal wall. Clinical convention holds that symptoms and need for treatment are in large part related to: A combination of type of fibroid. position within the uterus. fibroid size.

Types of uterus fibroids Fibroids are most often grouped as one of four types: sub mucous (beneath the mucosa, or uterine lining) The least common of the various types. These fibroids develop just under the lining of the uterine cavity. Large submucosal fibroid tumors may increase the size of the uterus cavity, and can block the fallopian tubes which can cause complications with fertility.

2. subserous (beneath the serosa): Subserosal fibroids typically develop on the outer uterine wall. This type of fibroid tumor can continue to grow outward increasing in size. The growth of a subserosal fibroid tumor will put additional pressure on the surrounding organs.

3. Pedunculated Fibroids: This occur when a fibroid tumor grows on a stalk, resulting in pedunculated submucosal or subserosal fibroids. These fibroids can grow into the uterus and also can grow on the outside of the uterine wall.

4. Intramural Fibroids: Intramural fibroid tumors typically develop within the uterine wall and expand from there. These uterine fibroids are the most common. When an intramural fibroid tumor expands, it tends to make the uterus feel larger than normal, which can sometimes be mistaken for pregnancy or weight gain.

What Causes Fibroids? 1- Hormones Estrogen and progesterone are the hormones produced by the ovaries. They cause the uterine lining to regenerate during each menstrual cycle and may stimulate the growth of fibroids. 2- Family History :Fibroids may run in the family. 3- Pregnancy Pregnancy increases the production of estrogen and progesterone in your body. Fibroids may develop and grow rapidly while women are pregnant.

Biologic Effects of Estrogen and Progesterone on Fibroid Tissue.

In peripheral tissues (skin and adipose tissue) and the ovaries, aromatase catalyzes the formation of estrogen, which reaches uterine fibroid tissue through the circulation. In addition, aromatase in fibroid tissue converts androstenedione of adrenal or ovarian origin to estrogen locally. The biologically potent estrogen, estradiol, induces the production of PR by means of ERα. PR is essential for the response of fibroid tissue to progesterone secreted by the ovaries.

Progesterone and PR are indispensible to tumor growth, increasing cell proliferation and survival and enhancing extracellular-matrix formation. In the absence of progesterone and PR, estrogen and ERα are not sufficient for fibroid growth. Immunohistochemical staining in fibroid tissue (insets, brown) indicates nuclear localization of ERα or PR in smooth-muscle cells.

Symptoms Change in menstruation (Longer, more frequent, or heavy menstrual periods, Menstrual pain (cramps),Vaginal bleeding at times other than menstruation and Anemia (from blood loss). Pain in the abdomen or lower back. Enlarged uterus abdomen. Miscarriages. Infertility . Fibroids also may cause no symptoms at all.

Treatment (Myomectomy) A common alternative to hysterectomy for fibroids is myomectomy, the surgical removal of fibroid tumors and a procedure considered standard of care for removing fibroids and preserving the uterus. It therefore may be recommended for women who wish to become pregnant.

Myomectomy is most often performed through a large abdominal incision. After removing each fibroid, the surgeon repairs the uterus to minimize potential bleeding, infection and scarring. Proper repair is critical to reducing the risk of uterine rupture during a future pregnancy.