Let me try this again one ovary larger than other ovary only shows simple folllicular cyst on ultrasound nothing abnormal can cancer present a just an enlargrment with nothing abormal on ultrasound?

It can: Although generally cancers show up as complex cysts, often containing irregular material in the cysts on ultrasound. Biopsy is the best way to determine if it is cancer.

Not likely: Ovaries are very active organs with monthly changes, enlarging and shrinking. Cysts come and go. Usually pelvic ultrasound is repeated after 4-6 weeks. A tumor may persist. Cancer may continue to grow. In medically literature, a size greater than 5 cm may prompt surgical intervention. Again, there are no way to rule out cancer until the ovary is removed.