A 60-year-old man in Spain couldn’t shake his headache. It had been getting worse for two weeks, and he’d noticed subtle shifts in his behavior. His blood work showed elevated IgE — a marker for immune responses tied to allergies, autoimmune conditions, and parasitic infections.
The CT scan showed multiple lesions scattered throughout his brain, surrounded by swelling. His doctors, ruling out other causes, suspected metastatic cancer. He hadn’t traveled internationally, wasn’t immunocompromised, and had no obvious risk factors.
They were wrong. It was neurocysticercosis — a parasitic infection caused by Taenia solium, the pork tapeworm.
Here’s how it works. The tapeworm can infect humans two ways: by eating undercooked pork containing larvae, or by ingesting eggs through fecal contamination. Those eggs hatch, burrow into the bloodstream, and embed in tissues — including the brain. Once there, they form cysticerci, the lesions that his doctors mistook for tumors.
The man’s MRI triggered antibody testing that confirmed the infection. Doctors prescribed two anti-parasitic drugs, and he recovered fully.
The case report, published in Emerging Infectious Diseases, drives home a point: doctors shouldn’t rule out parasitic infections just because a patient hasn’t traveled abroad, even in regions where cancer is statistically far more likely. Catching it sooner would have spared him unnecessary and invasive cancer procedures.
