A Colombian man received some shocking news about the cause of the lung cancer he was battling.
The fast-growing tumors in the man’s lungs were not actually made up of human cells but instead caused by a tapeworm living inside of him.
"We were amazed when we found this new type of disease — tapeworms growing inside a person, essentially getting cancer, that spreads to the person, causing tumors," Atis Muehlenbachs, a staff pathologist at the Centers for Disease Control and Prevention’s Infectious Diseases Pathology Branch (IDPB), told LiveScience.
The 41-year-old Colombian man, whose name was not publicly disclosed, died 72 hours after doctors determined the cancerous tumors were caused by H. nana, the most common tapeworm in humans that infects up to 75 million people worldwide at any given time.
The man went to the doctor after suffering from fits of coughing, fever and weight loss.
He was diagnosed with HIV more than 10 years earlier, but was not taking his medications, and doctors say that this worsened his immune system – thus aiding the parasite cancer in his body.
While a CT scan revealed that the man had tumors in his lung and lymph nodes, biopsies of the tumor showed bizarre, unrecognizable cells, prompting Colombian medical professionals to call the CDC for help.
And that’s how the tapeworm was discovered.
"In the initial months, we wondered if this was a weird human cancer or some unusual, bizarre emerging protozoa-amoeba-like infection," Muehlenbachs told the Washington Post. "Discovering these cells had tapeworm DNA was a big surprise — a really big surprise."
Researchers at the CDC, who published their findings earlier this week in the New England Journal of Medicine, said that the Colombian man likely ingested some microscopic tapeworm egg in food contaminated by mouse droppings, insects or human feces.
The discovery that the tapeworm caused the cancer raises a number of unsettling questions for the medical community: Do drugs that treat tapeworm infections treat cancer cells from tapeworms? Where did the mutant cells originate? Can other organisms that live inside or on people that could transmit cancer cells?
"We didn’t believe that cells from a human parasite could become malignant and then invade human tissue. … It's just very unusual that the parasite’s cells became cancerous inside a human and then invaded into human tissue," said Bobbi Pritt, director of clinical parasitology at the Mayo Clinic.
Pritt added that that the fact that tapeworms are also vulnerable to cancer makes some sense because "every living animal is made up of cells that divide and could become cancerous."