Does an ultrasound clearly differentiate between ovarian cyst and ovarian cancer. Does ovary/period pain after eating sound like large cyst.?

Ultrasound. An ultrasound may show whether the ovary is fluid filled or solid, or simple or complex. Ovarian cancer is usually complex and solid, but not always. A repeat ultrasound is often recommended. A CA 125 blood test may help differentiate the two... Refer to: http://www.mayoclinic.org/diseases-conditions/ovarian-cancer/expert-answers/ca-125/faq-20058528.
Not always. . A cyst can have a very benign appearance or a very malignant appearance. US findings combined with clinical scenario can help determine if a mass can be watched or needs surgery now. For a suspicious mass the only way to be sure is to remove the mass and have it checked by a pathologist. Hope this helps. .