A Vietnamese boy left Halifax on Sunday for the United States to seek medical treatment for a disfiguring facial lesion that doctors in Canada declined to treat because they deemed the procedure too risky.

Son Pham, 10, will spend the next week at Children's Hospital Boston where doctors will assess and prepare him for treatment to shrink a growth on the left side of his face that's the size of a football.

Vietnamese boy Son Pham hopes that doctors in Boston can remove his facial lesion, which is caused by a buildup of blood vessels.
(CBC)

Surgeons will give Son a series of injections every six to eight weeks for at least a year to shrink the growth, a process called sclerotherapy, followed by surgery.

Doctors will meet Son, his supporter Olwyn Walter and a translator on Tuesday and they are expected to perform a tracheostomy that will help the boy breathe when his treatment begins.

Walter, who has been caring for Son since he arrived in Halifax in June, said the boy who was given up for adoption when he was three was in good spirits as he prepared for what will be many trips to the Massachusetts capital. It's expected he will return to Halifax in between treatments.

"We're all pretty excited," said Walter, vice-president of the Children's Bridge Foundation, shortly before she and Son boarded their Boston-bound flight. "We know that the journey ahead for the next year is not going to be an easy one, but it's finally getting started and we're very excited about that."

Son's departure marks a turning point in a story that was uncertain only a few months ago.

The boy was brought to Canada with the belief that Toronto's Hospital for Sick Children would be able to reduce, if not remove, the lesion.

But after months of reviewing Son's case, Toronto doctors said in November that they wouldn't proceed with an unspecified treatment because it posed risks and his condition isn't life-threatening.

Plastic surgeon Dr. John Mulliken has said he was mystified by the Toronto hospital's decision, and argued the growth could eventually block Son's airway and diminish his blood's ability to clot. Mulliken has said he was confident he could reduce the lesion by about 90 per cent.

The U.S. doctors are offering their services for free. Boston's Ray Tye Medical Aid Foundation has donated $150,000 U.S. for Son's medical costs, while Walter's group has paid $200,000.

She said they'll need to raise another $75,000 to cover other costs, including accommodations, medicine and Son's trip back to Vietnam.

With files from the Canadian Press