A 66-year-old Chinese man went to the hospital with abdominal swelling, only to find out his ailment was actually an ovarian cyst.
The elderly patient had been raised a male his whole life, his doctors reported in the June 2013 issue of the Hong Kong Medical Journal.
The full text of the study can be accessed online.
Doctors said the discovery was likely made so late because of the patient's exceptionally short stature -- about 4.5 feet tall -- and the fact he had a beard and what appeared to be a micropenis, a term for abnormally small male genitalia, according to the National Institutes of Health. No testes could be detected.
When pressed by doctors further, the man said his puberty and growth had stopped around age 10, and he had a history of urinary leakage since childhood. A CT-scan then revealed the cyst. Doctors then surgically removed the mass, and also removed their other discoveries: two ovaries, both fallopian tubes and a uterus which had atrophied.
They then disclosed the diagnosis to the patient, who had not known his family or medical history because he was an orphan born in Vietnam.
"The patient decided to continue perceiving himself as having a male gender with the possible need of testosterone replacement," wrote the report's authors, led by Dr. KF Lee, a physician in the department of medicine and geriatrics at Kwong Wah Hospital, Yaumatei, Kowloon, Hong Kong.
The unique case could be explained by two rare genetic disorders the doctors discovered, according to the study. The patient had a disorder called congenital adrenal hyperplasia due to 21-hydroxylase deficiency, or "CAH due to 21-OHD" for short.
The condition occurs in about one in 14,000 people, according to the rare disease website, Orphanet. It is caused by a genetic mutation in the CYP21A2 gene, which is responsible for production of hormones.
The Mayo Clinic adds CAH can cause problems with growth and development in children, including development of ambiguous genitalia. Other symptoms include very early puberty, infertility and excessive body hair in females.
The patient also appeared to have Turner's syndrome, a genetic disorder that affects about one in 3,000 females, according to the study's authors.
Almost all girls who have Turner's are short in stature, and have ovaries that don't work properly making most of them infertile, according to the NIH. It is caused by a loss of genetic materials from the female X sex chromosome. Turner's also puts females at risk for other health problems including high blood pressure, kidney problems, diabetes, cataracts, osteoporosis and thyroid conditions. There is no cure for the disease, but hormones can aid growth and sexual development.
The doctors wrote the Chinese patient's case was so rare, that only six other instances of both CAH and Turner's syndrome have been reported in medical literature to date. They subjects ranged in age from 1 to 28.
"The patient, by definition, is a woman who cannot get pregnant. But she also has CAH, which gave her the appearance of a man," Dr. Ellis Hon Kam-lun, a professor of pediatrics at Chinese University in Hong Kong, said to the South China Morning Post, which reported the case.
"It's an interesting and very rare case of having the two combinations. It probably won't be seen again in the near future," said Kam-lun, who was not involved in the study.
Wrote the researchers, "Were it not due to the huge ovarian cyst, his intriguing medical condition might never have been exposed."