You would think the 4th floor of Children's Memorial Hospital, the brain tumor center, would be a most depressing place, where lives are shattered and dreams put to rest. Especially during the holidays, having a seriously or terminally ill child is about as intense a heartache as they come.

Yet in the hands of Dr. Stewart Goldman and his team, it's a surprisingly upbeat place much of the time, where life lessons are learned and tragedies take on new meaning. And that's not just because of Goldman's corny jokes, extensive Christmas tie collection, and "Feliz Navidad" vocals as he walks the hallways.

"This isn't about dying," Goldman says. "It's about living."

Goldman's focus is on crafting an active, fulfilling life for the family and child, no matter if that life is a few months, a few years or decades.

Many families--including those who have lost their children to brain tumors--say Goldman and the team of doctors and nurses ease their pain with a rare combination of humor, sensitivity and scientific genius.

"He gave me my son back for a few months, the most glorious gift anyone could give us," said Debi Tibbles, whose son, Oliver, 7, died of a brain tumor in March 2004. "They're truly angels."

As a pediatric oncologist and key member of the Falk Brain Tumor Center at Children's, Goldman has one of the toughest, most emotionally draining jobs at the hospital.

Pediatric brain tumors remain the most stubborn of childhood diseases. They are the second leading cause of cancer-related death in children, behind leukemia, and make up 21 percent of childhood tumors.

There have been some encouraging medical advances. Survival rates of brain tumors in children have increased slightly in the last few decades--with more than half the children surviving longer than five years.

But the toxicity from aggressive drug treatments or radiation may leave the survivors with profound problems down the road. Survivors are at great risk for secondary tumors, abnormal growth, and learning and behavioral problems.

It's the challenge of making progress in these uphill battles--plus the lessons learned from parents and patients--that has Goldman hooked.

"We see the best in people coming out," he says.

For those new to the oncology floor at Children's Memorial, it's not hard to pick out Stew Goldman, 46. You hear him even before you see him because he bursts into song as he walks the halls and shouts out patients' names, calling them by the nicknames he has chosen. If he's not singing, he's likely telling one of his jokes.

His approach generates attention not only from patients, but also from colleagues, who see Goldman as the glue that binds the various elements of treatment--surgery, chemo, radiation, research and social work.

"He changes the energy in this place," said Mary Fiorito, who runs a parent support group. "He just recognizes that you need to energize the kid, however you can do it, to fight."

A die-hard White Sox fan, Goldman loves teasing patients who are Cubs fans about his team's World Series victory. Patient Tom Ford, 17, got him back by displaying the Cubs' Web site on the patient room computer just before Goldman arrived.

Yet the fun is sprinkled with serious talk. "I'm going to joke with you, but that doesn't mean we don't take this seriously," he tells one patient, a 7-year-old girl just diagnosed with a brain tumor. He also tells the girl, just beginning her yearlong chemo treatments, to keep going to sleepovers and birthday parties.

"This is about being a normal kid who happens to have a brain tumor," Goldman says to her worried parents. Although Goldman is perpetually upbeat, his work has serious side effects.

As a member of a national group of oncologists involved in clinical trials of experimental drugs, Goldman is on the cutting edge of new treatment efforts, constantly searching for something new that might work. Sometimes the drugs he prescribes to patients who have resisted traditional therapies fail, and children die from the drug's toxicity even before the tumor kills them.

He keeps a drawer filled with letters and homemade gifts from patients, many who died years ago.

He never cries in front of families when he's sharing bad news--he doesn't want them to feel they have to comfort him--but the tears fall at other times, like the middle of sappy movies.

Goldman, who lives in Oak Park with his wife, Dee, and three young children, wants to make sure his work doesn't take a toll on his family. So he squeezes in time to coach baseball and soccer teams, goof around and attend school events. But the pager is always beeping.

"It's both uplifting and draining," Goldman says after a particularly long day. "I frequently say I don't want to do this forever. I just don't think I can keep it up forever. It does take something out of you."

Even on the downcast days, Goldman works exhaustively to give families what he sees as the most important gift--hope.

Take Alex Rodriguez, 5, adorable and happy in his red sweater and Santa hat during a recent visit.

As his parents file into a conference room, Alex stays behind in the waiting area with relatives.

Mom grabs a tissue box, dad puts an arm around her, and Goldman gently pulls up images of Alex's brain tumor on a computer screen. The first set is from August, before Alex started a trial chemotherapy drug.

The next are black-and-white pictures of the tumor today. The mass looks like a golf ball--and it's brighter, larger. Alex's tumor is growing.

"Life has taken some unusual turns," Goldman says quietly. "From the back of the brain forward, you can see the tumor mass."

Alex's parents, Sandy and Phil Rodriguez of Schererville, Ind., first learned of their son's tumor when he was 2 1/2. Alex was vomiting. His parents took him to the local emergency room, thinking he was suffering from the flu.

Instead, an MRI revealed he had an aggressive brain tumor. The family has been on a painful path since then, with two surgeries and traditional chemotherapy. But the tumor still can't be contained.

Goldman says the family may want to consider a third surgery, but there are risks.

"I don't think we can get this completely out without causing him significant neurological impacts," Goldman says.

The parents know this means their son, who has escaped major learning and developmental problems until now, likely faces a different future.

Yet even while he's sharing this, Goldman is discussing new drugs and offering reason to hope. "We have multiple options," he says.

The Rodriguezes leave the meeting feeling comfortable that Goldman and the medical team will do everything possible for their child.

Goldman "just cares for these kids like they're his own," Sandy Rodriguez said later. Holding back tears coming from the conference room, she walks into the patient room to greet her son, still in his Santa hat. Her face fills with worry, but Alex doesn't pick up on that. Instead, his face lights up as Goldman walks in.

"I'm hungry!" the child says.

"Well, how about a lizard sandwich?" Goldman asks.

Alex's little body shakes with laughter.