Ovarian cysts are fluid-filled sacs or pockets within or on the surface of an ovary. They are common and typically benign (non-cancerous), often forming during the ovulation process when the ovary releases an egg. While most cysts are asymptomatic and resolve on their own without treatment, some may cause symptoms or require medical intervention.

Types of Ovarian Cysts. Ovarian cysts can be classified into several types, each with distinct characteristics and implications:

Functional Cysts:

1-Follicular Cysts: These are the most common type of functional cysts. They occur when the follicle grows larger than usual during the menstrual cycle but does not open to release the egg. Typically, these cysts resolve themselves within one to three months.

2-Corpus Luteum Cysts: After an egg is released, the empty follicle sac typically shrinks into a mass of cells called the corpus luteum, which produces hormones to prepare the next menstrual cycle. Sometimes, the sac doesn’t shrink but instead seals off and fluid builds up inside, forming a cyst. These can cause pain and bleeding but usually disappear on their own within a few weeks.

Pathological Cysts

1-Dermoid Cysts (Mature Cystic Teratomas): These are bizarre cysts, containing hair, skin, teeth, or even more complex organs. They can develop during a woman’s reproductive years and can grow quite large. Although they are not usually cancerous, they can cause ovarian torsion, leading to severe abdominal pain.

2-Endometriomas: Part of a condition known as endometriosis, these cysts form when endometrial tissue grows on the ovaries. This tissue can develop into a cyst, known as an “endometrioma,” or “chocolate cyst” due to its dark, chocolate-colored contents. These cysts can be painful, especially during menstruation and sexual intercourse.

3-Cystadenomas: These cysts arise from the outer surface of the ovary and can be filled with a watery or mucus-like fluid. They can grow very large and cause pain by pressing on nearby organs or causing ovarian torsion.

Neoplastic Cysts

1-Benign Neoplastic Cysts: These include cystadenomas, which can sometimes grow very large but are generally non-cancerous.

2-Borderline Tumors: These are considered low potential or borderline malignancy. They are more likely to recur than benign tumors but are less aggressive than invasive cancers.

3-Ovarian Cancer: The most serious type of cystic ovarian masses, malignant cysts require aggressive treatment, often including surgery and chemotherapy. They may have solid areas, irregular shapes, or evidence of spreading within the pelvis.

Ovarian cysts are most prevalent in premenopausal women but can occur in postmenopausal women as well. Functional cysts are especially common; however, the risk of developing pathologic cysts increases with age. The lifetime risk for a woman to develop an ovarian cyst is significant, with a vast majority experiencing at least one cyst during their reproductive years.

Normal Ovarian Physiology

The ovaries are a pair of reproductive glands in women that produce eggs (ova) and hormones, including estrogen and progesterone. Every month during a woman's reproductive years, the ovarian cycle occurs in phases: the follicular phase, ovulation, and the luteal phase. Ovulation is the process by which a mature egg is released from the ovarian follicle, which then transforms into the corpus luteum, secreting hormones to prepare the uterus for pregnancy.

Pathogenesis of Ovarian Cysts

Ovarian cysts form due to various reasons:

-Follicular cysts arise from the growth of a follicle that, for some reason, fails to rupture and release its egg, leading to the accumulation of fluid inside the follicle.

-Corpus luteum cysts develop when, after releasing the egg, the corpus luteum seals off prematurely, accumulating fluid.

-Pathological cysts, such as dermoid cysts and cystadenomas, result from abnormal cell growth, which may be unrelated to the menstrual cycle.

Distinction Between Functional and Pathological Cysts

Functional cysts are directly related to the menstrual cycle and usually harmless and transient. Pathological cysts, on the other hand, arise from abnormal cell growth and can sometimes lead to serious conditions, including ovarian cancer.

This foundational content sets the stage for understanding the complexities of ovarian cysts, focusing on their development, types, and implications for women's health. If this format meets your expectations, I can continue expanding on the subsequent sections, including clinical presentations, diagnostic approaches, and management strategies, following the detailed outline provided earlier.

Clinical Presentation

Asymptomatic Cases. The patient doesn't feel any symptoms. Many ovarian cysts are discovered incidentally during routine pelvic examinations or imaging tests performed for other reasons. Asymptomatic cysts are usually monitored over time to see if they resolve on their own.

Symptomatic Cases. Symptoms may include:

-Pain: Often in the pelvis, which can be sharp or dull, constant or intermittent.

-Bloating or Swelling: Some women report feeling unusually bloated when they have an ovarian cyst.

-Menstrual Irregularities: Delayed, irregular, or unusually painful periods can occur.

-Urinary and Bowel Issues: Large cysts may press on the bladder or bowel, leading to frequent urination or constipation.

Emergency Symptoms

-Rupture: A ruptured cyst can cause severe pain and internal bleeding.

-Torsion: When a cyst becomes large enough, it can cause the ovary to move from its usual position, potentially twisting (torsion), which might cut off its blood supply and cause sudden, severe pain and vomiting.

The role of Ultrasound.

Ultrasound plays a pivotal role in the diagnosis, management, and follow-up of ovarian cysts. Its non-invasive nature, absence of radiation exposure, and detailed imaging capabilities make it an indispensable tool in gynecological practice. Below, I'll delve deeper into how ultrasound is utilized in the evaluation of ovarian cysts, focusing on its techniques, interpretations, and clinical applications.

Techniques of Ultrasound Examination

Transabdominal Ultrasound

In this approach, the ultrasound probe is placed on the abdomen to get a broad overview of the pelvic organs. This method is useful for viewing larger cysts or those that are positioned higher in the pelvis. It requires a full bladder, which serves as a window to better visualize pelvic structures.

Transvaginal Ultrasound

This technique involves inserting a probe into the vagina, which allows for closer proximity to the ovaries, providing higher resolution images. It is particularly effective for detecting smaller cysts and assessing their characteristics (e.g., wall thickness, presence of septa, and internal components). The transvaginal ultrasound is more detailed and is preferred for evaluating ovarian pathology.

Interpretation of Ultrasound Findings

Morphological Assessment

Ultrasound allows for the assessment of the cyst's shape, size, and structure. Characteristics such as:

a) Simple cysts: These appear as clear, fluid-filled sacs with a thin wall and no septations or solid components. Simple cysts are usually benign.

b) Complex cysts: These contain septations, thick walls, solid nodules, or a combination of fluid and solid materials. The complexity of a cyst may suggest a higher risk of malignancy.

Doppler Flow Studies

Using Doppler ultrasound, the blood flow within the cyst can be evaluated. Cysts with increased blood flow, especially in the solid components, may suggest malignancy due to the angiogenic activity often seen in cancerous growths.

IOTA Simple Rules

The International Ovarian Tumor Analysis (IOTA) group has developed simple rules based on ultrasound findings to classify ovarian tumors as benign or malignant. These rules include specific ultrasound features that, when present, can reliably suggest the nature of the cyst.

Clinical Applications of Ultrasound

Initial Diagnosis

Ultrasound is typically the first imaging test used when an ovarian cyst is suspected based on symptoms or during a routine pelvic exam. It helps confirm the presence of a cyst, document its size, and assess its nature (simple vs. complex).

Monitoring

For cysts that are not removed surgically, ultrasound is used to monitor their size and appearance over time. This monitoring helps in determining whether a cyst is growing, shrinking, or undergoing changes in its characteristics, which may necessitate further intervention.

Guiding Management Decisions

The findings from an ultrasound can help guide clinical decisions:

1-Simple cysts in premenopausal women often require no treatment, just follow-up scans to ensure they resolve on their own.

2-Complex cysts may require further evaluation with repeated imaging or surgery based on their appearance and the patient’s age and symptoms.

Surgical Planning

When surgery is indicated, preoperative ultrasound can help plan the procedure by mapping the location of the cyst and its relation to other pelvic organs. It can also help identify the best surgical approach (laparoscopic vs. open).

Postoperative Follow-up

After cyst removal, ultrasound may be used to check for residual cyst tissue, evaluate the healing of the ovarian tissue, and monitor for potential recurrence, especially in cases of endometriomas or neoplastic cysts.

November 2024