Powerball winner Gloria C. Mackenzie, 84, left, leaves the lottery office escorted by her son, Scott Mackenzie, after claiming a single lump-sum payment of about $370.9 million before taxes on Wednesday, June 5, 2013, in Tallahassee, Fla.

A pending lawsuit in Florida is a good example of why jackpot winners need to choose wisely when deciding who manages their windfall.

The suit, filed on behalf of Gloria Mackenzie, age 90, alleges that her son and his financial advisor mismanaged her winnings after she won the Powerball jackpot in 2013.

Her after-tax haul was about $278 million. The suit claims that Mackenzie has suffered damages in excess of $10 million.

"The money was earning between .02% and .08%," said Greg Anderson, Mackenzie's attorney. "Then Gloria was charged $2 million in fees."

Court documents say the son, Scott, had control over her money, which she had split with him because he helped her buy the winning ticket. At the time, with an advertised haul of $590.5 million, the jackpot was the largest in Powerball history.

The son turned management of his mother's share over to a financial advisor who hosted a local radio show that Scott listened to, according to the suit. That advisor is identified as Harry "Hank" Madden, a certified financial planner and owner of Madden Advisory Services in Jacksonville, Florida. Madden did not return a call seeking comment.