In a major step forward for medicine that offers promise for other patients, the Long Island, N.Y., girl was her own organ donor
Doctors removed a life-threatening, baseball-sized tumor from deep inside the girl's abdomen after removing her stomach, pancreas, spleen, liver and small and large intestines.
The organs were chilled during the grueling 23-hour operation so they could be reimplanted after the surgery.
Other doctors had told the McNamaras that the tumor was inoperable and to prepare for the worst.
Heather's mother, Tina McNamara, said today on "Good Morning America" that the family went from doctor to doctor looking for answers.
"We weren't giving up," she said. "We couldn't imagine turning around and saying we're out of options."
Dr. Tomokai Kato, who performed a similar surgery on a Florida woman last year, led the team of seven surgeons through Heather's surgery. She is believed to be the first child to undergo this type of surgery.
Heather left New York-Presbyterian Hospital in New York City Tuesday after her recovery from surgery Feb. 6.
Doctors restored the small and large intestines and the liver, but Heather's pancreas, spleen and stomach were too damaged by the tumor to be restored.
Doctors created a pouch from intestinal tissue that will help her digest food, but she will face dietary restrictions like those in patients recovering from gastric bypass surgery.
With the loss of her spleen and pancreas, Heather will be more vulnerable to certain infections and have type 1 diabetes.
Nevertheless, Heather's doctors remain optimistic about her ability to adjust to these physiological changes.
Kato said on "Good Morning America" that he is amazed by Heather's recovery, saying that she "looks almost perfect."
The operation was a huge challenge that took a lot of planning, said Kato. He said he was very frank with the McNamaras about the possible risks and benefits of the surgery.
But after the successful surgery, Heather has a new lease on life gives other patients with otherwise inoperable tumors a chance for recovery.
"I just want to say whoever is out there and has a medical problem, a child with a medical problem...," McNamara said during a Tuesday press conference.
Heather completed the sentence for her mom: "There is hope."