Doctors suspected man had brain cancer. He actually had worms.

In Spain, a 60-year-old man sought medical help for persistent headaches that had begun two weeks earlier and worsened over time. Alongside his headache, he reported subtle behavioral changes. During a neurological assessment, doctors noted a slight delay in his movements but found no significant deficits. Blood tests showed normal results apart from an elevated IgE level, typically associated with allergic reactions, autoimmune diseases, and parasitic infections. A CT scan of the man's head revealed concerning multiple lesions throughout his brain, accompanied by swelling. Initially, the medical team suspected metastatic cancer, especially since the man had no known immunocompromising conditions and had not traveled abroad. To alleviate his headache, doctors prescribed an anti-inflammatory corticosteroid, which provided some relief. They then embarked on a comprehensive testing journey to locate any potential cancer, including a contrast-enhanced whole-body CT scan, a colonoscopy, and a hybrid PET/CT scan commonly used for cancer detection. Despite their thorough investigations, no malignancies were found. A subsequent brain MRI provided clearer insight into the lesions, revealing that they were not tumors but rather encapsulated tapeworm larvae. This unexpected discovery stunned the medical team, as tapeworms are not commonly found in Spain, and the patient claimed he had not traveled. However, the man's previous work in construction, which involved interactions with individuals from areas where pork tapeworms (Taenia solium) are endemic, may have been the source of his infection. His doctors speculated that he could have contracted the parasites through shared meals and bathrooms with coworkers, one of whom had a known tapeworm infection. This case highlights the importance of considering unusual infections in the differential diagnosis of neurological symptoms.