A man died after developing tumours from cancer cells carried by a tapeworm in his body, according to a report published in the New England Journal of Medicine.
The man (41) went to a hospital in Medellín, Columbia, in 2013 with fever, coughing, fatigue and weight loss. Doctors found he had a tapeworm, Hymenolepis nana (H.nana), as well as several growths throughout his lungs, liver and other organs.
The man, who was diagnosed with HIV in 2006, had developed cancer-like tumours. His doctors were puzzled because the cells in the growths were “small in size and suggested nonhuman origin”.
This posed a “diagnostic conundrum”, as the cells had some “overt features” of cancer, but were 10 times smaller than cancer cells normally seen in humans.
It was known he had a tapeworm, but there were no identifying signs of normal tapeworm tissue in the masses, according to the report.
Through molecular testing, they eventually found H.nana DNA in the tumours.
The man had reportedly not been taking his HIV medication and the case study suggests that due to the deficiency in his immune system, the tapeworm cancer cells were able to grow within the parasite. The cells then mutated and invaded the human tissue.
The diagnosis was made while the man was still alive, but he died 72 hours later, having already begun palliative care.
It was a "crazy" case that "caused many sleepless nights," said Dr Atis Muehlenbachs, the lead pathologist in the case.
“It should have been obvious this was cancer or an infection and not being able to tell between the two for months is unusual,” Dr Muehlenbachs told the BBC.
H.nana is the most common human type of tape worm and up to 75 million people are estimated to be carriers for the parasite.
The report says that the transformation of tapeworm cancer cells could be mistaken for human cancer in countries where HIV and H.nana are widespread.
The latest case should prompt a “deeper exploration of the relationships between infection and cancer”, the paper says.
