The boy was admitted to a nursing home here with severe stomach pain and it was initially suspected that a tumour was causing it, Dr Sirshendu Giri, who treated the boy, said today.
However, after conducting tests like ultrasonography and CT scan, it was found that a dead embryo was inside the boy's abdomen.
He was operated upon last night and the foetus with hands, legs, nails and partially formed head was removed, Giri said.
The boy, hailing from Kharikabandh village under Binpur police station, is alright now but still under observation, he said.
This medical abnormality called "foetus in foetu" (baby within a baby) is rare as it occurred once in every five to six lakh people, the doctor added.