Dave Coulier has been diagnosed with stage 3 non-Hodgkin lymphoma and is undergoing treatment to battle the “very aggressive” form of cancer, according to multiple media reports.

Coulier, 65, co-star of the ABC-TV sitcom “Full House” and a resident of St. Clair Shores, said he was diagnosed in October after an upper respiratory infection which caused major swelling in his lymph nodes, People magazine reported Wednesday.

According to People magazine, as Coulier’s swelling increased rapidly, with one area growing to the size of a golf ball, he said his doctor advised PET and CT scans as well as a biopsy, which ultimately gave him news that changed his life. .

“(My doctors) said, ‘Hey, we wish we had better news, but you have non-Hodgkin lymphoma, B-cell lymphoma,” Coulier told NBC’s Today show Wednesday morning.

“The first thing I said to them was, ‘Wait a minute — cancer?’(I was) feeling like I got punched in the stomach because it never happens to you. You always hear about it happening to someone else.”

Coulier has been diagnosed with B-cell lymphoma, a type of cancer that develops in B-lymphocytes, according to the American Cancer Society. B-cell lymphomas account for the vast majority of non-Hodgkin lymphomas. Every year, more than 80,000 Americans are diagnosed with non-Hodgkin lymphoma.

He grew up in St. Clair Shores where he played on youth hockey leagues and graduated from Notre Dame High School in Harper Woods in 1977 before he began a career in standup comedy. He soon transitioned to doing voice-overs for dozens of shows and cartoons and landed various TV roles, including “Full House” and its sequel “Fuller House.”

After learning of his diagnosis, Coulier teamed up with his wife, Melissa Bring, and with some of his close friends in the medical field to work out a strategy to fight the disease “head-on.”

“We all kind of put our heads together and said, ‘OK, where are we going?’ And they had a very specific plan for how they were going to treat this,” he told People, noting that a bright spot in his diagnosis was when his bone marrow test came back negative. “At that point, my chances of curable went from something low to 90% range. And so that was a great day.”

Early on into his diagnosis, Coulier immediately started chemotherapy. He shaved his head as a “preemptive strike,” and he opens up about his experience further on his podcast Full House Rewind with Marla Sokoloff.

Coulier lost his mother and a sister to breast cancer as well as a niece. All were young women when they died.

“I saw what those women in my family went through, and I thought to myself, ‘If I can be just 1/10th of a percent as strong as they were, then I’m going to be just fine,” he told the magazine.

Amid his treatments, he says that he’s been leaning on his sister Karen — and leaning into their shared humor — to keep his spirits up.

“My sister was a registered nurse, and so she’s seen this from different optics than I have,” he said. “She’s been so supportive and she’s funny. So we’re making jokes about this. One of my jokes is in four short weeks I’ve gone from a Virgo to a Cancer. I’m a huge hockey fan. So when they said ‘You’ve got NHL,’ I thought, ‘I finally made it to the NHL.’”

He said after receiving the news, he found himself “remarkably calm with whatever the outcome was going to be. I don’t know how to explain it, but there was an inner calm about all of it, and I think that that’s part of what I’ve seen with the women in my family go through. They really instilled that in me and inspired me in a way because they were magnificent going through what they went through, and I just thought, ‘I’m OK with this too.’”

On an unrelated note, Coulier is about to become a grandfather. His son, Luc, is expecting his first child.