Normally such type of ovarian cysts go of their own in 8 to 12 weeks but if it doesnt go or if it is causing symptoms like excessive bleeding or intense pain,then it best to get it removed surgically.
More than 95% of ovarian cyst are benign but in rare cease it can be cancerous also and hese chances are increased in post menopausal women.
Before removal a blood test
for ovarian cancer
called as CA125 ( Tumor marker
) is also done,to see whether it is cancerous or not,although it can give false positive result also.
Consult a Gynecologist and get yourself examined and treated properly.