A Colombian man reportedly died after parasitic worms were found growing inside of his vital organs. But the worms weren't exactly to blame for his death - apparently, the worms were cancerous.

Unilad reports:

"The case - which was detailed in the New England Journal of Medicine - originally baffled doctors as this was the first known report of a person having cancer cells developed from a parasitic organism."

As it turns out, the 41-year-old man had HIV, which weakened his immune system. Because of this, the worm-cancer was able to grow for years inside the man's body.

Doctors in Colombia were left unsure of what the man suffered from back in 2013. This prompted the UK's Natural History Museum and the United States Centers of Disease Control and Prevention to team up in an effort to diagnose the unheard of cancer.

Talking to BBC News, Dr. Atis Muehlenbachs - who worked on the case - said:

"This has been the most unusual case, it caused many sleepless nights. [...] It should have been obvious this was cancer or an infection and not being able to tell between the two for months is unusual."

Upon initial screening, the tumors seemed normal looking and even of average size in both his lungs and liver. But after thorough investigation, doctors found "that the infected cells were a tenth of the size of normal human cells."

Molecular testing was also done, where they found the tumors to have high levels of tapeworm DNA.

Unfortunately, the man was not able to get proper treatment for the disease by the time the doctors finally figured out what the baffling cancer was. The man passed away just three days after the worm DNA was found.

The United States Centers of Disease Control and Prevention said that the cancer-worm is a rare disease. They also added that the infection could be avoided by cooking raw vegetables and proper hand washing.