Doctors have advised 74-year-old Koirala to undergo a thorough check-up after they detected patches on his lungs during a medical examination at a hospital here.
A CT-scan found a scar on the Prime Minister's lungs, according to his personal doctor Kabir Nath Yogi.
Koirala, suffering from lung infection for some time, is also under medication for Bronchitis.
He visits New York every year for a follow-up after he had a surgery for tongue cancer nearly five years ago.
