Based on your use of the words "investment" and "sold" it seems like this should be reported using the "Stocks, Mutual Funds, Bonds, Other" interview and telling TurboTax that you did not receive a 1099-B. You'd then provide your basis - the $50K - in that interview, resulting in the short term gain.
I don't understand why the transaction was reported on a 1099-MISC if this was really an "investment."
