Tumour with hair, fat, bone, nails and eyes

He thinks the mass in Mengru's body was a highly developed tumour or dermoid cyst.

A dermoid cyst is a growth that contains developmentally mature skin complete with hair follicles and sweat glands, sometimes clumps of hair, and often pockets of sebum, blood, fat, bone, nails, teeth, eyes, cartilage and thyroid tissue.

But he added that it was difficult for him to confirm Mengru's case without at least a picture of the mass that doctors removed from her abdomen.

Dr Lee Keen Whye, an obstetrician and gynaecologist at Gleneagles Medical Centre, said that he had previously removed dermoid cysts which had hair, fat, bones and muscles in them.

"But they are arranged in an irregular manner. It's like an unfertilised egg that has undergone change out of order," he said.

Once, he had even removed a dermoid cyst with a skull in it.

More common than foetus-in-fetu, a dermoid cyst can appear on anyone regardless of race, sex, or age.

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This article was first published in The New Paper.