Doctors speculated the clot stayed intact due to a higher-than-usual concentration of a particular protein component of blood plasma, caused by the man's infection, which could have made the blood in his airways unusually rubbery.
It came from a 36-year-old man with end-stage heart failure who spat out the medical anomaly in one piece during a coughing fit in hospital.
The unidentified patient was receiving treatment in the Intensive Care Unit at the University of California San Francisco Medical Center, according to a November 29 article in the New England Journal of Medicine. "So with all these patients, you have to give them anticoagulants to make the blood thinner and prevent clots from forming".
A man has died after coughing up part of his lung, according to a report in the New England Journal of Medicine.
Wieselthaler called the occurrence "very, very, very rare".More news: Diamondbacks Trade All-Star First Baseman Paul Goldschmidt to Cardinals
"We were astonished", Wieselthaler said.
Though it resembles a coral, root system, or some other kind of growth, the above photo actually depicts a blood clot over 15cm wide in the near-perfect form of the right bronchial tree of a human lung, the Atlantic reported on Thursday.
After his extreme cough, doctors performed a bronchoscopy and intubated the man immediately, and discovered some blood in the basilar branches of his lung.
After being supplied oxygen via a tube, the man's coughing ceased two days later, leading to the removal of the tube.
In 2005, a heavily pregnant woman coughed up a similar but smaller bronchial tree clot.
One week after extubation, he died from complications of heart failure (volume overload and poor cardiac output) despite placement of the ventricular assist device.