EGYPTIAN doctors operating on a teenage boy in Cairo this week were astonished to find that what they thought to be a tumour was in fact a foetus.
Weighing more than four lbs (2 kg) and seven ins (18 cm) in length, the foetus had a head (but no brain), a mouth with four large teeth and a tongue, an abdomen, one arm and a hand with long fingernails.
Surgeons at Cairo's Demerdash hospital, where the operation was performed, say the foetus was the under-developed twin of Mr Hisham Ragab (16), a construction worker.
Mr Ragab came to the hospital earlier in the week complaining of a distended stomach and abdominal pain. An X-ray showed a sac pressing on his kidney.
Doctors say the bizarre phenomenon occurred at Mr Ragab's conception, when the fertilised ovum did not split as it usually does for twins. Instead, one part of it broke off and lodged itself inside the main ovum.
Although the body of the foetus stopped forming about four months later, medical examination of the teeth, which continued to grow for another two or three years, showed that it continued to live for 16 years by attaching itself to Ragab's liver and right kidney and feeding off blood and oxygen.
Medical sources in Cairo say that incomplete ovum division is rare but even more unusual is the maturity of the 16-year-old foetus. One doctor said there are problems with cell division in about one in 5,000 pregnancies, but the case of Mr Ragab was more like a one in 100 million
The incident has caused a sensation in Egypt, with lurid headlines referring to Mr Ragab as "the pregnant boy".
Dr Ahmed El-Fadaly, one of the surgeons who performed the operation, said yesterday that Mr Ragab was psychologically distressed by the press coverage but was completely normal physically.