On her blog she described having "problems with reading comprehension, listening comprehension. If a couple of people were talking in a room, I wouldn't understand what was happening".
She was frustrated as doctors could not establish what was wrong.
"The neurologist would say the neurosurgeon is not being practical in your case. And the neurosurgeon would say the neurologist is not being optimistic in your case," she said. "And I'm like, could someone be educated about this?
"Months and weeks slipped through my fingers. There weren't any diagnostic procedures left to run. Consultations followed procedures but nobody said anything useful."
Her friends raised US$32,000 ($42,300) which helped pay for surgery by Dr Hrayr Shahinian at the Skull Base Institute in Los Angeles, who performed radical keyhole surgery using fibre optic technology.
That allowed him to discover that she had a "teratoma" - a rare unborn twin - insider her. Shahinian said he had removed up to 8000 brain tumours and it was only the second teratoma he had seen.
Karanam told NBC she believed it was an "evil twin sister who's been torturing me for the past 26 years".
Teratomas have baffled scientists for almost a century. Some have speculated they are basically twins that never quite develop and are absorbed into the surviving baby's body. Newborns occasionally have large teratomas attached like a conjoined twin. Sometimes adults realise they have one.
In 2009, a British man "gave birth" to an "undeveloped identical twin" when a small lump pushed its way out of his abdomen. Earlier this year Hong Kong doctors discovered two partially developed fetuses inside a newborn's abdomen.
