The malignant tissue had been discovered as the president took a routine medical check-up. The tumour was detected at an early stage and has been successfully removed, the president's office said.
"Following thorough consultations with Slovenian doctors, the president took their advice that the best course of treatment in the given circumstances would be robotic surgery, which enables the fastest recovery.
"The president followed the doctors' advice that the operation be conducted in Innsbruck, which has extensive experience with this type of surgery," the statement said.
It added that the president paid for the costs of the operation himself.