Welcome to OCF. When I first came here looking for information five years ago, my husband's dentist had identified a leukoplakia on his tongue, and an initial biopsy by an oral surgeon had resulted in a diagnosis of moderate dysplasia (though the pathologist's report also warned of a possible "skip effect," meaning that cancer cells could be in areas that were not taken for biopsy -- my guess is that he saw something suspicious, but not definitive).

Here's how OCF's founder, Brian Hill, responded to my initial post asking what that meant and whether I should be concerned about a four- to six-week wait between the initial biopsy and the removal of the whole white patch by a local ENT (the boldface is mine):
[quote=Brian Hill]This is not a rush situation. Leukoplakia is a PRE-cancerous condition that does not always move completely into malignancy. Dysplasia are those cells which are no longer normal, but they are not really malignant yet ... an in-between state, so to speak. Dysplasias also do not always go completely over to the dark side, but they are a step in that direction ... and having them removed, or watched very regularly, is prudent. Dysplastic leukoplakias can often return after surgical removal, many times done with a laser, sometimes via a blade excision. Keep an eye on things even after the removal from now until forever.[/quote]
About a month after the oral surgeon's biopsy, the ENT removed the whole patch under general anesthesia (the oral surgeon just took a little bit for the initial biopsy), and the pathology report showed squamous cell carcinoma in situ, with a tiny bit superficially invasive -- in other words, it did turn to the dark side, but it was caught at the earliest stage possible. Once cancer was found, my husband was seen by a specialist at a top cancer center, and no further treatment was needed. He did get frequent checks the first year; the spacing between appointments stretched out over time, and he now gets checked at the cancer center once a year -- plus his dentist does a VELscope examination at each cleaning.

You are very fortunate to have a proactive dentist who evidently does a thorough oral exam and recognized something that needed a closer look. Take a deep breath, remember that a majority of leukoplakias are NOT malignant, and come here with any questions you may have.

(And Sandy's suggestion to check with your general practitioner is a good thought. Perhaps your GP could make a referral directly to an ENT -- ideally one with experience in oral cancer, rather than one who simply takes out tonsils, puts in ear tubes, and such.)