Thorbjorn Johansson, 64, had sought medical attention for foot injury in March 2009, but his medical samples were mixed up with those of another patient, TheLocal.se reported Thursday.
Karolinska University Hospital in Stockholm admitted the error in 2011, saying the misdiagnosis had caused "serious injury or illness."
When Johansson was told in 2009 he had lung cancer, he said "it was awful information to receive."
A former international building trades consultant, Johansson said he has been unable to work and has permanent nerve damage.
"I get out of breath just walking up the stairs or a slope," he said.
Johansson and his attorney are preparing a lawsuit against the hospital.