Actor Sam Neill died suddenly and unexpectedly at 78, his family announced Monday. He had spent four years battling angioimmunoblastic T-cell lymphoma, a rare and aggressive form of blood cancer. No cause of death was given. His family said he was believed to be cancer-free at the time of his death in Sydney, Australia.
Neill was best known for his role in the 1993 film Jurassic Park. He was diagnosed with the rare lymphoma in 2022, according to a report by Healthline. In his memoir, Did I Ever Tell You This?, Neill wrote that doctors had initially diagnosed swollen glands in his neck as undetected COVID. A PET scan eventually revealed the true diagnosis.
He underwent four rounds of chemotherapy. In late 2023, he announced on Instagram that his cancer had been in remission for eight months. He also received CAR-T cell therapy, a type of immunotherapy treatment that genetically changes the body's immune cells so they can fight cancer. As recently as April 2026, Neill said publicly that he was cancer-free, though he noted he still required infusions every two weeks.
Angioimmunoblastic T-cell lymphoma, known as AITL, is an aggressive form of peripheral T-cell lymphoma. It accounts for 20 to 30 percent of all peripheral T-cell lymphoma cases. The median age for diagnosis is 65. The cancer affects white blood cells known as T-cells and can spread to the lungs, liver, or bone marrow.
Symptoms include fatigue, high fever, night sweats, and skin rash. Those symptoms can resemble autoimmune diseases, which contributes to delayed diagnosis. Diagnosis requires a biopsy of tumor tissue, and additional exams such as blood tests, CT scans, bone marrow biopsies, and PET scans may also be used.
AITL affects immune-regulating cells, meaning it can cause immune system malfunction in addition to tumor growth. The exact cause is not known, but the disease can be driven by genetic mutations in stem cells as well as secondary mutations in genes that regulate how DNA is used. Many AITL cases involve the Epstein-Barr virus, which can infect non-cancerous cells surrounding the affected T-cells.
Swaminathan Iyer, a professor of lymphoma-myeloma at the UT MD Anderson Cancer Center in Texas, described the disease as particularly difficult to catch. "AITL can go undiagnosed for some time," Iyer told Healthline. "In many cases, the disease presents with non-specific symptoms such as skin rash, diarrhea, weight lo" — the quote in the source material ends there. He also said that "Angioimmunoblastic T‑cell lymphoma (AITL) can be a challenging disease to diagnose and treat."
Neill's case drew attention to AITL in part because of how public his treatment journey was. He documented his diagnosis, chemotherapy, remission, and ongoing maintenance treatment across interviews and social media. His death, coming after what appeared to be a successful course of treatment, reflects how unpredictable the disease can be even after remission is achieved.