Rabu, 22 Juli 2009

Ovarian Cysts

An ovarian cyst is a fluid-filled sac in an ovary. They can be present from the neonatal period to postmenopause. Most ovarian cysts occur during infancy and adolescence, which are hormonally active periods of development. Most are functional in nature and resolve with minimal treatment. However, ovarian cysts can herald an underlying malignant process or, possibly, distract the emergency clinician from a more dangerous condition, such as ectopic pregnancy, ovarian torsion, or appendicitis. When cysts are large, persistent, or painful, surgery may be required, sometimes resulting in removal of the ovary. With the more frequent use of ultrasonography in recent years, their diagnosis has become more common.

Pathophysiology

From fetal life through a woman's reproductive life, ovarian follicles undergo varying rates of maturation and involution under the guidance of the hypopituitary axis.

Multiple follicles are recruited every month during the proliferative phase of the menstrual cycle. However, only one follicle reaches maturity and produces estrogen, releasing a mature oocyte at mid cycle. The follicular cyst transforms into a corpus luteum following ovulation and produces progesterone until the beginning of the next cycle. In the absence of fertilization of the oocyte, it continues to atrophy.

Follicular dysgenesis occurs with hypothalamic-pituitary dysfunction or because of native anatomic defects in the reproductive system. When follicular development into a corpus luteum is arrested, a luteal ovarian cyst can result.

Two functional ovarian cysts may develop: follicular cysts (ie, graafian follicular cysts) occur in the first 2 weeks of the cycle, and corpus luteal cysts occur in the later half of the cycle. The rupture of the follicular cyst can lead to sharp, severe, unilateral pain of mittelschmerz (occurring mid cycle), and it is experienced by approximately 25% of menstruating women. Similarly, failure of corpus luteum degeneration leads to a luteal cyst formation. These cysts may become inflamed or spontaneously hemorrhage, producing symptoms during the later half of the menstrual cycle.

Carcinomatous processes of the ovary, both primary and metastatic, frequently are complicated by cystic degeneration. The formation of inclusions of the ovary's germinal epithelium may lead to cystic development.

Endometriomas are cysts filled with blood from the ectopic endometrium.

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