India batsman Yuvraj Singh is suffering from cancer, Indian news channel NDTV reported, quoting media reports.
The report stated that he is currently undergoing chemotherapy in the USA. His chemotherapy treatment started in February and will go on till March. He left for the US on January 26.
His tumour was detected in October but it was said to non-malignant.
However, the report added that it has now been diagnosed as malignant. It is currently unknown when Yuvraj will be able to return to cricket.
Yuvraj Singh's physiotherapist Jatin Chaudhary said the cancer is at a dangerous place in the body but is curable, according to Britain's Press Association.
"It is a rare tumour and is cancerous but it has been detected in stage one itself," Chaudhary said.
"Doctors had to decide whether to continue medication or go for chemotherapy but since parts of the tumour are just above the artery of his heart, there was a danger that while running it could burst. But it is 100% curable.
"The doctors decided that he would have to undergo chemotherapy and he travelled to the US on January 26. At the end of March, he would undergo a CT scan and should recover by then. After that it is just some rehabilitation in April before he is fit to be back on the field in May," he added.
Chaudhary said since the 30-year-old has been taking ayurvedic treatment, he will not need extensive chemotherapy sessions.
"After ayurvedic treatment only three cycles of chemotherapy are required. Initially when the cancer was diagnosed after a biopsy in October end, doctors feared that the treatment would be six cycles of chemotherapy," Chaudhary said.
"Thankfully no surgery is required, he is already a lot better than what he was and can't wait to be back on the cricket field."
Chaudhary also said the delay in treatment was due to a wrong diagnosis by a hospital last year.
"His first biopsy report was stolen from his car and the second from a hospital I don't want to name did not give the correct diagnosis. It was a Russian doctor who detected the cancer and after consultations with doctors in US, it was decided that Yuvraj would undergo chemotherapy," he said.
"Once he is done with chemo in March, his rehabilitation would be complete by April end and he would be perfectly fit to play in May," he added.
Yuvraj battled a golf-ball sized non-malignant lung tumour which first affected him during India's triumphant World Cup campaign last year.
Yuvraj, 29, who was declared the man of the tournament after the World Cup win at home in April, had opted out of the next one-day series against the West Indies for health reasons.
"During the World Cup, Yuvraj found himself constantly troubled by bouts of coughing and vomiting," his mother Shabnam Singh had said in a statement at the time.
She said Yuvraj initially ignored the problem, assuming it was due to stress and did not want anything to distract him.
"When the problem persisted after the World Cup, we decided to seek medical advice... scans then showed us that Yuvraj was dealing with something really serious. A golf-ball size lump (was) found over his left lung," she said.
Yuvraj wrote on his Twitter page at the time that he was "overwhelmed" by the support he had received. "I am absolutely fine, just need to get match fitness and training. Will be back soon," he said.
Yuvraj, who made his international debut in 2000, has played 37 Tests, 274 one-day internationals and 23 Twenty20 matches for India.
He was part of India's champion team at the inaugural World Twenty20 in South Africa in 2007, where he smashed England fast bowler Stuart Broad for six sixes in one over.
The explosive hitter has been the lynchpin of India's middle-order in limited-overs cricket, although he has not met with the same success at the Test match level.
During the World Cup campaign this year, Yuvraj scored 362 runs and grabbed 15 wickets in nine matches to carry off the man of the tournament award.
At the Test level, Yuvraj has scored 1,775 runs at an average of 34.80 with three centuries and 10 fifties.