An aggressive form of cancer was discovered shortly after ESPN reporter Edward Aschoff died on Christmas Eve, his fiancee revealed Wednesday, clearing up part of the mystery of why a seemingly healthy young man died on his 34th birthday.

Aschoff’s death initially was attributed to hemophagocytic lymphohistiocytosis (HLH) and multifocal pneumonia, but Katy Berteau tweeted Wednesday that the results of a lung biopsy, delivered after his death, showed that he was terminally ill.

“Unbeknownst to us, Edward had stage 4, non-Hodgkin’s lymphoma in his lungs,” she wrote in what she said would be the last message from Aschoff’s Twitter account. “This is an aggressive type of cancer that is usually undetectable until it is very advanced.”

Aschoff, a Los Angeles-based reporter who covered college sports, was being treated for pneumonia and HLH, a rare disease that attacks the immune system and can be caused by cancer, when he died in what ESPN says was a Los Angeles area hospital.

“Both pneumonia and non-Hodgkin lymphoma can trigger HLH in the body and that is seemingly what happened with Edward,” Berteau wrote. “All of this combined is what led to his very rapid decline those last few days, and ultimately his passing.”

He and Berteau had headed for an emergency room on Dec. 1 with what he tweeted was a virus that had “morphed into this monster” and he was admitted to the hospital a week later. He began antibiotics the next day and tweeted on Dec. 6: “Anyone ever had multifocal (bilateral) pneumonia in their early 30s as some who never gets sick and has a very good immune system? Asking for two friends … my lungs.”

When antibiotics did not work, he underwent further tests and doctors began treating him for HLH. He continued to deteriorate and died three days after being moved into an intensive care unit. Aschoff, a respected college sports reporter, and Carley McCord, who was killed in a plane crash on the day of the national semifinal games, were memorialized in the press box at the national championship game Monday night.

Berteau chose to share the information about what killed him for simple reasons. “I hope this information helps people in dealing with this tragedy. It has helped me knowing that his passing was inevitable, and I’m at least grateful he didn’t have to go through the painful treatment and drawn out process of battling the disease,” she wrote, adding: “He wouldn’t have wanted to go out like that. His [butt] was too vain.

“I also wanted to provide this update because he would have wanted everyone to know that something way bigger than pneumonia took him down.”

On Dec. 26, she wrote “to share the brightness that he showed, even up until the last day he was awake. He kept the doctors and nurses constantly laughing, and always made a point to thank them and tell them what a great job they were doing.” Even in the ICU, she wrote, he was talking with a friend about wrapping her Christmas presents. “He loved people with his entire being,” she added.

A memorial and celebration of his life is scheduled for Saturday in Oxford, Miss., where he grew up. He attended the University of Florida, where he studied journalism and played bass drum for the school’s marching band. Upon graduating in 2008, he covered Gators football, basketball and baseball for the Gainesville Sun and joined ESPN in 2011 to blog about the Southeastern Conference. He rose quickly through the ranks and relocated from Atlanta to Los Angeles in 2017 to take on a national role that included more television appearances, while also working as a TV and radio sideline reporter during football broadcasts.

“Ed was one of the smartest, brightest reporters I’ve ever had the pleasure of working with,” ESPN executive editor Lauren Reynolds said in a statement at his death. “Watching him grow from our co-SEC reporter with Chris Low to a multiplatform national reporter was a treat. For as good of a reporter Ed was, he was an even better person. He always put people first — those whose stories he told, and those who had the honor of working alongside him."

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