A 66-year-old man who visited a doctor complaining of a swollen stomach was told he was actually a woman.
The patient, who was raised as a male, was sent to hospital where the abdominal mass was found to be a benign ovarian cyst, the Hong Kong Medical Journal revealed.
He was diagnosed with Turner’s syndrome, making him by definition a woman, but he has chosen to continue living as a man and may receive male hormone treatment.
The syndrome usually occurs when sex chromosomes fail to separate during the formation of an egg or sperm, Medical Daily explains.
This results in a missing or incomplete X chromosome, of which women are supposed to have two.
It affects girls and women and results in characteristics including fertility and short stature. The UK-based Turner Syndrome Support Society lists further physical features as including “a web neck, broad chest and widely spaced nipples, low hairline and increased carrying angle of the elbows.”
The Vietnam-born man, who is an orphan, is 4ft 5, has no testicles and a micropenis. Although he has a beard, he informed his doctors he had suffered a history of urinary leakage and stopped growing after reaching puberty at the age of 10.
"The patient, by definition, is a woman who cannot get pregnant. But she also has congenital adrenal hyperplasia (CAH), which gave her the appearance of a man," Chinese University paediatrics professor Ellis Hon Kam-lun told the South China Morning Press.
"It's an interesting and very rare case of having the two combinations. It probably won't be seen again in the near future.
The NHS reveals life expectancy among patients with Turner syndrome is slightly reduced, but that it is usually possible to lead a relatively normal and healthy life.
It adds the syndrome affects about one in every 2,000 baby girls.