A medical case in Spain took an unexpected turn when doctors discovered that what looked like advanced brain cancer in a 60-year-old man was actually caused by parasitic tapeworm larvae.

The unnamed patient from Castellón initially sought medical help after experiencing progressive headaches and subtle behavioral changes for about two weeks.

Initial CT scans revealed multiple abnormal lesions that appeared consistent with tumors spread from another part of the body, prompting physicians to suspect metastatic brain cancer.

However, a series of follow-up exams including a whole-body scan and colonoscopy failed to locate any cancerous growths elsewhere.

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The inconclusive results raised new questions about the patient’s condition, according to the case report published in the CDC journal Emerging Infectious Diseases.

A more detailed MRI provided the breakthrough. Doctors detected several fluid-filled cysts, and within some of them, a visible tapeworm head was identified.

Blood tests confirmed the presence of neurocysticercosis, a rare parasitic infection caused by the pork tapeworm Taenia solium.

The discovery overturned the initial cancer diagnosis and led physicians to begin treatment with the antiparasitic drugs albendazole and praziquantel, as well as corticosteroids to reduce brain inflammation. The patient responded well and made a full recovery without complications, the report stated.

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Researchers wrote that the man had no history of travel to regions where the disease is common, making the case unusual.

The infection may have occurred years earlier if he accidentally ingested microscopic tapeworm eggs, possibly during construction work alongside colleagues from areas where the parasite is endemic.

Neurocysticercosis occurs when people ingest the parasite’s eggs through food or water contaminated with fecal matter. The larvae may then enter the bloodstream and form cysts in the brain and other tissues.

While eating undercooked infected pork can cause an intestinal infection, ingesting eggs often leads to the severe neurological form seen in this patient.

As a single case, the authors emphasized that their report cannot confirm the presence of local transmission in Spain, but it highlights the possibility. They noted that data from the United States show fewer than two percent of reported neurocysticercosis cases are domestically acquired.

A prior review found just 18 locally acquired cases across Western Europe between 1990 and 2011. The report therefore adds to limited evidence suggesting the parasite can occasionally surface in non-endemic regions.

In some patients, neurocysticercosis can cause serious neurological complications including seizures, cognitive decline, or stroke.

The researchers said that recognizing the infection early could avoid unnecessary cancer-related procedures and allow for faster, targeted therapy.

“Our case emphasizes that the absence of travel history should not preclude NCC from the differential diagnosis of multiple ring-enhancing brain lesions, even in regions where metastatic cancer is statistically much more likely,” the authors concluded.