I was looking for something similar to annotate a big change in business income. I'm not sure if there's a way to include a note or explanation in TurboTax (perhaps as details related to one of the line items?).
For your situation: the IRS website says not to include the fraudulent 1099 income on your return. It's not clear if they consider the technique of adding and subtracting a good one:
IRS on employment-related identity theft such as 1099s and W2s
IRS.gov Taxpayer Guide to Identity Theft
