A unique medical case has been reported in which researchers have discovered cancer cells in a dwarf tapeworm residing in a human immunodeficiency virus (HIV) patient. The cells that might have been caused by the patient's weakened immune system developed into cancer-like tumors that looked nearly the same as the human tumors in the man's body.
This case was published in the New England Journal of Medicine. It was created by the Centers for Disease Control and Prevention (CDC).
The name of the tapeworm was ymenolepis nana. It rarely causes tumors in humans, although CDC researchers explained that if low-immune system patients are diagnosed with tumors they should get treatment, which might prevent a cancer diagnosis.
CDC researchers learned about the HIV patient in 2013. When the 41-year-old man checked into a Columbia hospital his symptoms included weight loss, fever, and problems breathing, according to NPR. Biopsies on the man's tumors showed they grew quickly like cancer cells, but lab tests showed that the cells were 10 times smaller than human cells.
At first CDC was baffled by the cells, and its theory was that it was a kind of slime mold, according to The Verge. After years of tests they found tapeworm DNA in the cancer-like cells.
However, doctors were unable to give the patient a treatment early enough to destroy the tapeworm. The patient died three days after they discovered the tiny parasite.
A tapeworm can infect people by two ways. They include eating food containing the worm's eggs, or consuming insects that are worm hosts.
Peter Olson is a tapeworm expert working at the Natural History Museum in London. He explained the worms usually stay in the stomach, and most hosts do not know they are there.