An ovarian cyst is any collection of fluid, surrounded by a very thin wall, within an ovary. Any ovarian follicle that is larger than about two centimetres is termed an ovarian cyst. Such cysts range in size from as small as a pea to larger than an orange. Ovarian cysts occur in women of all ages including neonatal period and infancy. They are most prevalent during infancy, adolescence and during the childbearing years. With ultrasonography ovarian cysts can be demonstrated in nearly all premenopausal and approximately 18% postmenopausal women.
Polycystic ovarian cancer is a heterogeneous disorder of uncertain Cause. There is strong evidence that it is a genetic disease. Such evidence includes the familial clustering of cases, greater concordance in monozygotic compared with dizygotic twins and heritability of endocrine and metabolic features of PCOS.