I would not be concerned, but, I would go to the gyn and have it checked....probably nothing. There is a great forum for Ovarian Cysts. There are many fabulous women over there that can probably offer more guidence and support regarding cysts. This forum is mainly about Ovarian Cancer.
It couldn't hurt to see a gynecologist about this. Did you complete menopause? Any cyst that develops post-menopause should be investigated.