While under the knife the man was having fat moved from his torso down towards his genitalia.
However, M the 30-year-old died following a leakage of the material injected into his penis.
The Swedish operation was revealed by the Journal of Forensic Sciences.
Although unnamed, the dead man was revealed to have died when fat moved into his lungs.
The fat, intended for his penis, caused an embolism.
The terrifying incident resulted in a ruptured blood vessel and a cardiac arrest.
Tragically the man died two hours later, unlike the more than 8,000 men who undergo successful similar operations.
‘This is the first described case where a seemingly simple and safe procedure of penis enlargement by autologous fat transfer caused sudden death in a healthy young man,’ the study said.
The operations were attacked by some doctors who say they are best avoided.
‘It’s a completely useless procedure that never works and disfigures men, and could kill you,’ urologist Tobias Kohler of the Mayo Clinic in Rochester, Minnesota told Buzzfeed News.