cyst of the ovary, follicular

cyst of the ovary, follicular A fluid-filled sac in the ovary. A follicular cyst is the most common type of ovarian cyst. It results from the overgrowth of a follicle, the fluid-filled cyst that contains an egg, that does not rupture to release the egg. Normally ovarian cysts resolve with no intervention over the course of days to months. See also cyst, ovarian.