NEW YORK • Doctors had broken the disheartening news to Ms Rachel Palma, explaining that the lesion on her brain was suspected to be a tumour, and her scans suggested that it was cancerous.
Ms Palma, 42, a newlywed entering a new chapter in her life, said she was in shock, unwilling to believe it was true.
Last September, surgeons at Mount Sinai Hospital in New York City opened Ms Palma's cranium and steeled themselves for a malignant brain tumour, said the chief neurosurgery resident at the hospital's Icahn School of Medicine.
But instead, Dr Jonathan Rasouli said, they saw an encapsulated mass resembling a quail egg.
"We were all saying, 'What is this?'" Dr Rasouli recalled on Thursday in a phone interview with The Washington Post.
The surgeons removed it from Ms Palma's brain and placed it under a microscope. Then they sliced into it - and found a baby tapeworm.
Ms Palma said: "Of course I was grossed out. But of course, I was also relieved. It meant that no further treatment was necessary."
She said she had long been struggling with insomnia and, when she could sleep, nightmares. She had also experienced hallucinations, imagining that things were happening when they were not.
By January last year, her symptoms had worsened. Ms Palma said she started having trouble holding things, such as her coffee mug, which she inadvertently dropped. She had trouble texting people, so she resorted to calling them. She started experiencing confusion - locking herself out of the house and staring at her computer screen, unable to make sense of the words.
After appointments with the doctors and trips to the emergency room, she went to see specialists at Mount Sinai Hospital who identified a lesion on her left frontal lobe, near a speech centre.
She was later diagnosed with neurocysticercosis, a parasitic infection in the brain caused by the tapeworm Taenia solium.
Dr Bobbi Pritt, director of the Clinical Parasitology Laboratory at Mayo Clinic, said Taenia solium is not common in the United States but the parasite can present in two different forms.
The most common form, she said, is the adult tapeworm, which is ingested from undercooked pork and lives in the gut.
The less common way to get the parasite is when people who have the adult form shed microscopic eggs in their stool and, if they do not properly wash their hands, pass on the tapeworm to others.
If the person who has the adult tapeworm gets the eggs on his or her hands and then prepares another person's food, that other person can unknowingly eat the eggs.
The eggs then travel to the small intestine, hatch into larvae, penetrate the bowel wall and get into the bloodstream, where they can migrate throughout the entire body, including the brain.