SPAIN — A 60-year-old man in Spain was diagnosed with neurocysticercosis after doctors initially suspected metastatic cancer. The man presented to doctors with a headache that had persisted for two weeks and was worsening.

He reported subtle changes in his behavior. A neurological exam revealed a mild delay in his movements. A computed tomography (CT) scan of the man's head showed multiple lesions distributed throughout his brain accompanied by swelling. His blood work indicated elevated IgE levels. Doctors prescribed an anti-inflammatory corticosteroid for his headache, which provided relief.

Doctors initially suspected metastatic cancer as the cause of the brain lesions. They performed a whole-body, contrast-enhanced CT scan, a colonoscopy, and a hybrid positron emission tomography/CT scan to search for malignancies. Tests did not reveal any cancer. The man was not immunocompromised.

Doctors performed a magnetic resonance imaging (MRI) scan of the man's brain, which revealed that the lesions were encapsulated tapeworm larvae rather than tumors. The MRI scan showed the heads, called scolexes, of the tapeworms. Testing after the MRI revealed the man's immune system had produced antibodies against Taenia solium. The doctors diagnosed the man with neurocysticercosis.

When Taenia solium cysticerci enter a person's central nervous system, the condition is called neurocysticercosis. Taenia solium can infect humans by ingesting cysts in undercooked meat or by ingesting eggs through fecal contamination. Doctors prescribed the man two anti-parasitic drugs, and he recovered from the infection.

Tapeworms are not endemic to Spain, and the man had never traveled internationally. Doctors speculated that the man's infection resulted from cryptic transmission. He had worked in construction until he retired 10 years prior to the diagnosis, often alongside people who had migrated from regions where pork tapeworms are endemic. Doctors suggested the infection could have resulted from sharing meals and bathrooms with coworkers, one of whom reportedly had a tapeworm infection.

Doctors reported the case in the journal Emerging Infectious Diseases. "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 doctors stated.