A parasitic infection can sometimes produce symptoms that resemble a brain tumour. A 60 year old man in Spain sought medical attention after about two weeks of persistent headaches along with mild changes in behaviour. Initial brain imaging showed several lesions throughout the brain, which raised concern for possible metastatic cancer. However, further investigations including scans of the rest of the body, and additional tests did not reveal any primary tumour. Because the cause remained unclear, doctors carried out a high resolution MRI scan. This revealed multiple fluid filled cysts in the brain containing larvae of Taenia solium, the pork tapeworm. The condition is known as neurocysticercosis. It occurs when a person accidentally ingests tapeworm eggs, usually through food or water contaminated with human faecal matter. This is different from eating pork containing adult tapeworms. After ingestion, the eggs hatch, the larvae enter the bloodstream, and in rare cases they reach the brain where they form cysts. The MRI findings showed these cysts clearly enough for doctors to identify the larvae within them. Once the true cause was discovered, an invasive brain biopsy was avoided. The man was treated with antiparasitic medication and made a full recovery without complications. What made the case unusual was that he had never travelled outside Spain, where this infection is rare. Doctors believe exposure may have occurred years earlier through indirect contact with someone from an area where the parasite is more common. “Autochthonous Neurocysticercosis Brain Lesions Mimicking Metastatic Disease, Spain” Emerging Infectious Diseases