Yamini Karanam, a PHD student at Indiana University, sought medical help last September after she started having trouble reading and talking.
At one point Karanam, from Hyderabad, could barely eat and pain ran from her head throughout her body.
Karanam was diagnosed with pineal tumour after doctors spotted what they thought was a cyst on Karanam's pineal gland, a tiny pea-like structure in the centre of the brain, 'The Washington Post' reported.
Shahinian made a tiny incision in the back of Karanam's head, then strung an endoscope into her skull and through a natural channel in her brain to the site of the suspected tumour.
However, Shahinian was shocked to discover that the tumour was actually a teratoma: a clump of bone, hair and teeth.
Some doctors believe teratomas are twins that never quite develop and are instead absorbed into the surviving baby's body.
Shahinian successfully removed the teratoma and now expects Karanam to make a full recovery.
