Kyste ovarien 1 englOVARIAN CYST (1): DEFINITION AND CAUSES

Dr. Claude Allouche, Gynecologist

Ahuza Clinic, Raanana
📞 058 726 02 64

What is an ovarian cyst?

An ovarian cyst is a fluid-filled swelling located on one or both ovaries. These organs, at the end of the fallopian tubes, play a crucial role in reproduction. While ovarian cysts are usually benign, their presence is abnormal and they can be classified into two types:

  • Functional, which regress spontaneously in 90% of cases.
  • Organic, which do not regress spontaneously.

Prevalence: 5 to 7% of women will develop an ovarian cyst during their lifetime. Even young girls (10–16 years old) may develop functional or, more rarely, organic cysts.

Functional ovarian cysts

These are the most common (90% of cases) and result from hormonal imbalances. Their size can fluctuate during the menstrual cycle, but they usually disappear within a few weeks.

Types of functional cysts:

  1. Follicular ovarian cyst: arises from the abnormal development of a follicle containing an ovum.
  2. Luteal ovarian cyst: caused by an increase in the size of the corpus luteum (a temporary gland that secretes hormones after ovulation).

Contributing factors:

  • Ovulation-stimulating treatments (infertility).
  • Recent insertion of a levonorgestrel-releasing intrauterine device (IUD).
  • Tamoxifen treatment (commonly prescribed after breast cancer).

Overview of the menstrual cycle

The menstrual cycle consists of two phases, separated by ovulation:

  • Follicular phase (preparation for ovulation): stimulates follicular maturation via FSH and thickens the uterine lining.
  • Ovulation: triggered by a surge in LH, releasing the ovum.
  • Luteal phase (post-ovulation): the corpus luteum produces progesterone to prepare the uterus for pregnancy.

If fertilization does not occur, the cycle restarts with menstruation. The average cycle length is 28 days (ranging from 23 to 35 days).

Organic ovarian cysts

Unlike functional cysts, organic cysts do not regress spontaneously, and their size remains stable throughout the menstrual cycle. Their cause is currently unknown.

Four types of organic cysts:

  1. Serous cysts: the most common, containing fluid and thin walls.
  2. Mucinous cysts: multi-chambered, filled with thick or paste-like fluid.
  3. Dermoid cysts: containing fat, calcified deposits, and sometimes other bodily tissues.
  4. Endometriotic cysts: linked to endometriosis, filled with fluid and blood.

Potential complications:

  • Increased risks for cysts over 5 cm (ovarian torsion, hemorrhage).
  • Mandatory analysis to rule out malignancy.

Ovarian cyst vs. PCOS

The polycystic ovary syndrome (PCOS) is a distinct condition caused by hormonal imbalances. It is characterized by:

  • Irregular or absent periods (amenorrhea).
  • Excess androgens (hirsutism, acne, hair loss).
  • Infertility due to a high number of underdeveloped follicles.

👉 Want to learn more about PCOS? Check out our dedicated publication.

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Source: ameli.fr