A parasitic twin was found in a three-year-old Peruvian boy. Doctors in Peru plan to surgically remove the tissue from his stomach.

Dr. Carlos Astocondor of the medical team at Las Mercedes Hospital in northern Chiclayo described the rarity of a parasitic twin, known formally as Fetus in fetu. Astocondor said the condition occurs in about one of every 500,000 live births. It is when a child absorbs a twin's tissue while still in the womb, according to Yahoo! News.

Three-year-old Isbac Pacunda case is the fetal remains of eyes, bones and hair currently resting in his stomach. The partially-formed fetus weighs over one-and-a-half pounds and is nine inches long.

Dr Astocondor said the fetus' brain, heart, lungs and intestines never developed after it was absorbed by the other fetus (Isbac) inside the mother's womb.

The parasitic twin is considered parasitic because it lives off the host twin, feeding on Isbac's blood supply.

Isbac's surgery was scheduled to be performed Monday.

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