A US man developed an "uncontrollable Irish accent" after being diagnosed with prostate cancer, despite having never visited Ireland, researchers say.
The North Carolina man, who was in his 50s, was presumably afflicted with foreign accent syndrome (FAS), the British Medical Journal reports.
The rare syndrome gave the man, who had no immediate family from Ireland, a "brogue" that remained until his death.
Several similar cases have been recorded globally in recent years.
The case was jointly studied and reported by Duke University in North Carolina and the Carolina Urologic Research Center in South Carolina.
"To our knowledge, this is the first case of FAS described in a patient with prostate cancer and the third described in a patient with malignancy," said the report's authors.
Much of the man's identifying characteristics, including his name and nationality, were not included in the report.
It says he lived in England in his 20s and had friends and distant family members from Ireland. But they add he had never previously spoken with the foreign accent.
"His accent was uncontrollable, present in all settings and gradually became persistent," the researchers say in their report, adding that it first began 20 months into his treatment.
Even as his condition worsened, the accent remained until his death months later.
"He had no neurological examination abnormalities, psychiatric history or MRI of the brain abnormalities at symptom onset," the report said.
"Despite chemotherapy, his neuroendocrine prostate cancer progressed resulting in multifocal brain metastases and a likely paraneoplastic ascending paralysis leading to his death."
The researchers suspect the voice change was caused by a condition called paraneoplastic neurological disorder (PND).
PND happens when cancer patients' immune systems attack parts of their brain, as well as muscles, nerves and spinal cord.
Other people who have suffered FAS have described to the BBC the unsettling feeling of hearing a "stranger in the house" whenever they speak.
In 2006, UK woman Linda Walker suffered a stroke and discovered that her Geordie accent had been replaced by a Jamaican-sounding voice.
One of the first reported cases was in 1941 when a young Norwegian woman developed a German accent after being hit by bomb shrapnel during a Second World War air raid.
She was shunned by locals who thought she was a Nazi spy.
