Cysts are collections of fluid surrounded by a thin membrane, as opposed to lumps or nodules which are solid.
Ovaries produce cysts as part of their normal functioning. That happens during the process of ovulation. The egg matures inside a cyst that typically grows up to 3 or 4 cm in diameter. This cyst, also known as a follicle then breaks, releasing the fluid and the egg.
Because of the cystic nature of the ovaries, ovarian tumours tend to be cystic.
Ovarian cyst is a very broad term that describes several different entities including normal physiological follicles, benign tumours and malignant or cancerous ones.
Most ovarian cysts are asymptomatic and are picked up when an ultrasound is done for some other reason. When present, symptoms are not very specific and include: dull ache or a sensation of heaviness and pressure in the pelvis and/or abdomen, abdominal bloating and irregular periods.
Other symptoms relate to complications such as ovarian torsion or cyst rupture. These are acute events usually accompanied by severe, sudden onset pain.