A woman died after a routine biopsy pierced a swollen blood vessel in a lump in her windpipe, an inquest has heard.
Marian O'Reilly, 76, of Fordstown, Navan, Co Meath died within three hours of the biopsy despite medics' best efforts to save her on 2 February 2015.
Dublin Coroner's Court heard of only one other similar case documented worldwide in medical literature.
Ms O'Reilly, who had surgery at age 12 in 1951 to remove half of her left lung, had been suffering frequent respiratory infections, the court heard.
She underwent a biopsy without any event in 2012 but because the infections became more frequent towards the end of 2014, Ms O'Reilly was referred to the Bons Secours Hospital in Dublin for a bronchoscopy, a procedure used to examine the inside of the lungs.
Doctors noted that a polyp in Ms O’Reilly’s windpipe had grown and a biopsy was taken to check if it was malignant.
However, during the procedure, the polyp began to bleed uncontrollably after a blood vessel was opened leading to the woman's death two and a half hours later.
"I have done 30,000 of these [biopsies] and never seen this before," Professor Conor Burke, a respiratory consultant at the Bons Secours Hospital, said.
"The location of that type of blood vessel was unusual and it bled profusely," said Coroner Dr Myra Cullinane.
"It's clear this is an exceptionally rare occurrence, with only one other similar case recorded in world literature," said Dr Cullinane.
Returning a verdict of medical misadventure, the coroner extended her sympathies to Ms O’Reilly’s family.