From the Guidelines
Follicles and cysts are distinct structures in the ovaries, with follicles being normal and essential for reproduction, and cysts being abnormal fluid-filled sacs that can cause symptoms and require medical intervention. The key difference between follicles and cysts lies in their definition, size, and clinical significance. According to the O-RADS US Risk Stratification and Management System 1, follicles are considered part of the physiologic category, consistent with normal ovarian physiology, whereas cysts are categorized as lesions that may or may not be consistent with normal physiology.
Some key points to consider when differentiating between follicles and cysts include:
- Size: Follicles typically measure 2-10mm in size during most of the menstrual cycle, with a dominant follicle growing to about 20-25mm before ovulation, whereas cysts are often larger than 25mm 1.
- Clinical significance: Follicles are essential for reproduction and naturally resolve after ovulation or regress if not selected for ovulation, whereas cysts may persist and require medical intervention 1.
- Types: Common ovarian cysts include functional cysts (follicular or corpus luteum cysts), which typically resolve on their own within 1-3 menstrual cycles, and pathological cysts like endometriomas or dermoid cysts, which may require surgical removal 1.
- Management: Most small, simple cysts can be monitored with ultrasound follow-up, while larger or symptomatic cysts might need treatment with hormonal contraceptives to prevent new cyst formation or surgical intervention if they cause significant symptoms or complications 1.
It's essential to note that the risk of malignancy in benign-appearing lesions on US is low, with a recent study by Gupta et al 1 demonstrating a risk of malignancy of < 1% in a cohort of 970 average-risk women. Additionally, unilocular cysts in the premenopausal population have a very low risk of malignancy, with a recent meta-analysis by Parazzini et al 1 demonstrating a risk of malignancy of 0.6% in 987 unilocular cysts removed surgically in premenopausal women.
In clinical practice, it is crucial to accurately diagnose and manage adnexal masses, taking into account the patient's symptoms, medical history, and ultrasound findings, to minimize the risk of complications and improve patient outcomes. This can be achieved by following the O-RADS US Risk Stratification and Management System 1 and the ACR Appropriateness Criteria 1, which provide guidance on the diagnosis and management of adnexal masses.
From the Research
Difference between Follicles and Cysts
- Follicles and cysts are two distinct entities in the human body, particularly in the context of ovarian health.
- Follicles are small, fluid-filled structures in the ovaries that contain eggs [ 2 ].
- Cysts, on the other hand, are abnormal, fluid-filled sacs that can develop in various parts of the body, including the ovaries [ 3 ].
Characteristics of Follicles
- Follicles are a normal part of ovarian function and play a crucial role in the menstrual cycle [ 4 ].
- They produce hormones, such as estrogen and progesterone, which regulate the menstrual cycle and support fertility [ 5 ].
- Follicles can be affected by various factors, including hormonal imbalances, age, and certain medical conditions [ 6 ].
Characteristics of Cysts
- Cysts can be benign or malignant and can cause a range of symptoms, including pain, bloating, and irregular menstrual bleeding [ 2 ].
- Ovarian cysts can be classified into different types, including functional cysts, dermoid cysts, and endometriomas [ 3 ].
- Cysts can be treated with various methods, including surgery, hormonal therapy, and watchful waiting [ 4 ].
Key Differences
- The main difference between follicles and cysts is their origin and purpose [ 2 ].
- Follicles are a normal part of ovarian function, while cysts are abnormal growths that can cause symptoms and complications [ 3 ].
- Follicles produce hormones, while cysts do not [ 5 ].
- Follicles are typically smaller and more fluid-filled than cysts [ 6 ].