Would Pet Insurance be a waste of money in this situation?

So we just took our 4 year old cat into the vet for a suspected ear infection, which she does have, but the vet also would like to check for polyps at her next visit. (She had so much fluid in her ear that they were unable to see much) If she does end up with the diagnosis of polyps eventually requiring surgical removal, would insurance cover this or deny it as a preexisting condition? I will probably be getting her insurance regardless after that visit but was just wondering if anyone has had a similar experience.